|
1. |
Proceedings of the Chemical Society. September 1964 |
|
Proceedings of the Chemical Society ,
Volume 1,
Issue September,
1964,
Page 273-312
Preview
|
PDF (4204KB)
|
|
摘要:
PROCEEDINGS OF THE CHEMICAL SOCIETY SEPTEMBER 1964 CHANGES IN THE SOCIETY’S PUBLICATIONS Two important developments in the Society’s publications scheduled to become effective at the beginning of next year are now announced. CHEMISTRY IN BRITAIN (A new joint publication of the Chemical Society and the Royal Institute of Chemistry) FORsome months discussions have been taking place between the Society and the Institute on the possibility of producing a joint monthly publication to replace the existing Proceedings of ihe Chemical Society and the Journal of the Royal Institute of Chemistry. The Councils of the Society and of the Institute are happy to an- nounce that complete agreement has now been reached and the new journal to be called Chemistry in Britain will commence publication in January 1965.It will be sent free to members of each society. Those who are members of both societies may claim a rebate of 10s. 6d. in lieu of a second copy of Chemistry in Britain and arrangements for this to be done will be notified. The price to non-members will be E5 per annum. Chemistry in Britain will not contain the “Communications” which at present appear in Proceedings (see separate announcement) but it will nevertheless be appreciably larger than either of the existing publications and will be much more than a mere amalgam of the two. A wide range of articles on scientific professional and industrial matters is planned as well as news and announcements personal items book reviews obituary notices letters to the editor and a comprehensive diary of forthcoming meetings.This development is regarded as an important landmark in collaboration between two of the major bodies serving the interests of chemists in Britain. It will provide a better service for members of either body and is likely to result in very substantial economies. Although the func- tions of the two societies are different (and com- plementary) they do between them include in their membership virtually every qualified chem- ist in this country. There are approximately 21,000 members of the Institute and 15,000 of the Society and surprisingly (and deplorably) only about 3,500 of these are common members of both bodies. Each society is growing at the rate of about 1,OOO members a year.A circulation in excess of 35,000is aimed at in the first year and it is confidently expected that Chemistry in Britain will live up to its name and come to be recognised as the voice of chemistry in this country. 273 PROCEEDINGS CHEMICAL COMMUNICATIONS FORthe past seven years the Society has pub- lished urgent preliminary accounts of scientific research in its Proceedings. This practice has proved highly acceptable to authors and readers but the ever-increasing flow of material has caused extreme pressure on the limited space available in Proceedings. The Council has there- fore decided that as from January 1965 pre- liminary communications shall form a separate publication of the Society.The new Journal Chemical Communications is intended to be a forum for preliminary accounts of work that is likely to prove of general appeal or of urgent specialist interest. The policy of the Society remains that not all research work warrants duplicate publication but the Council recognises that there is a demand for preliminary publication of some types of information. The first issue of Chemical Communications will be issued in mid-January and the publication will appear thereafter twice-monthly. Although Communications will be subjected to refereeing it is hoped to achieve more rapid publication than is possible in Proceedings. All Fellows will receive the first six issues of Chemical Communications without extra pay-ment.Thereafter it will be available at the annual rate of El. Non-Fellows may subscribe at the rate of E5 per annum. SIMONSEN LECTURE* Molecular Rearrangements of Terpenes By GUY OURISSON (INSTITUT DE CHIME,STRASBOURG) RFJARRANGEMENTS~ form an integral part of terpene chemistry and sometimes take a truly spectacular course. It is often in the terpene series that these re- arrangements are best known and most easily studied and structural elucidation of the terpenes or discussion of their reactivity must very frequently take into account more or less complex rearrange- ments. In this Lecture I shall review some of the most common of these rearrangements and I shall illustrate them by examples taken from our recent work.As we proceed I shall have to discuss in some detail the mechanisms involved. It is most appropriate that I must devote a great part of my time to a sesquiterpene longifolene (1). It (1) is just over forty years that this substance was dis- covered in Pinus ZongifoZia,2 by the man whose memory this Lecture commemorates. This has given me even more pleasure to be our Society’s Simonsen Lecturer as I had personally been in touch some ten years ago with the late Sir John about longifolene. Wagner-Meerwein Rearrangements.-Owing to the pathways of their biosynthesis terpenes incor- porate in their structure quaternary carbon atoms and potential carbcnium ions (i.e. hydroxyl groups or double bonds). This combination gives an excep- tional importance to Wagner-Meexwein rearrange ments in acidic conditions I Starting material + -CR-C+-I J.II End products t -C+-CR-The group R is often a methyl group but sometimes a ring carbon atom. In polyterpenes methyl groups are often easily displaced from one ring junction to the next. In the simplest examples only one methyl group migrates. This is the case in the Westphalen rearrangement of the cholestanetriol diacetate (2) to the Westphalen diol (3)3 and for the formation of the lactone (5) from the dihydroabietic acid (4)? In these two re- * Delivered before the Society at the Imperial College of Science and Technology London S.W.7 on February 13th 1964; at The University Oxford on February 14th; at The University Liverpool on February 17th; and at The University Glasgow on February 19th.1 de Mayo Ed. “Molecular Rearrangements,” Interscience Publ. Inc. New York 1963. Simonsen J. 1920 117 570; 1923 123 2642; Bradfield Francis and Simonsen J. 1934 188. 8 Cf. Fieser and Fieser “Steroids,” Reinhold Publ. Corp. New York 1959 p. 325. Barton Chem. and Ind. 1948,638; Subluskey and Sanderson J. Amer. Chem. SOC.,1954,76 3512; Velluz Muller Petit and Mathieu Bull. SOC.chim. France 1954 401. SEPTEMBER 1964 ACO HO OAC (2) 8 (4) actions interactions present in the starting material are decreased in the end product. This applies to the much more complex rearrangements exemplified by the friedelene (6) -oleanene (7)‘j and by the a-amyrin (8) -(+)-a-amyradiene (9)s“back-bone” rearrangements.In these cases methyl groups and hydrogen atoms are all moved to the next carbon atom. The configuration of these compounds is such that all the rearranged groups are axial and trans to one another so that a fully concerted reaction can be-and has been explicitly-postulated leading by a one-step mechanism to the end product. As a matter of fact this postulate of a synchronous multi- stage rearrangement had been used to derive the configuration of friedelene at the various centres in- vol~ed.~ This is no longer tenable even though the stereochemical conclusion is still true several inter- 275 mediates have been isolated in particular in the re action of friedelene’ and with the hydrocarbon (10) derived from adiantoxide.* ___+ 1 c- It is therefore probable that these reactions pro- ceed from one carbonium ion to the next and to the corresponding olefin then start again until they reach the carboniurn ion of lowest energy the “sink” carbonium ion (cf.7). II I1 I Ill -C+-CMe-CH-CMe + -CMe-C+-CH-CMe-11 I Ill I Ill -CMe-CH-Cf-CMe-+-CMe-C=C-CMe-I IqL I I -CMe-CH-CMe-CL + etc. It is usually easy to discern that the structures of the starting material and of the end product differ by the elimination of at least one unfavourable strain factor. For example in the transformation (lla) of the friedelanyl cation to the oleananyl cation (1 1 b) two axial Me-Me interactions are intro- duced and two are removed but the very unfavour- able strain in the D/E region is removed without compensation.This appears to be the deciding factor. In the case of a-amyrin it may be the re- moval of the strain in the cis-decalin D/E ring junction; in that of adiantoxide the removal of the trans-perhydroindane D/E ring junction. This energy factor is probably best described as a “thermodynamic conformational driving force.” It so happens that it Corey and Ursprung J. Amer. Chem. Suc. 1956 78 5041 ;Dutler Jeger and Ruzicka Helv. Chim. Acta 1955 38 1268; Brownlie Spring Stevenson and Strachan J. 1956 2419. ’Allan Fayez Spring and Stevenson J. 1956 457. Courtney Gascoigne and Szumer J. 1958 881. Berti Bottari and Marsili Tetrahedron Letters 1964 1. is apparently accompanied in all these cases by a kinetic conformational driving force easing the successive steps of the rearrangements.During each of these steps the strain decreases in the transition state as the methyl group bends away from its initial towards its new position of bonding (cf. 12). This lowers the activation energy for each individual step in the migration. Me $Me (rz) Whatever the true nature of the intermediates and transition states involved these must approach in geometry the corresponding cyclopropyl derivatives ; they must also approach them in electronic character (as a “protonated cyclopropane”) as some cases are known where the migrating methyl group is so to speak frozen mid-way into a cyclopropyl grouping (cf. 13).9 H@ PROCEEDINGS Strains we have shown are therefore facilitating kinetically the rearrangements as well as driving them to completion.This is made particularly efficient when the strains involved and lost are large the molecule is then acting like a spring unwinding itself. We have recently encountered two such examples. The epoxide (14) of calarene is rearranged to the eudesmenediol monoformate (15) in less than five seconds by cold formic acid. In a few minutes this is converted into the eudesmadienol (16) and etc. then slowly into the formate (17).1° Despite its extreme ease the rearrangement can certainly not be fully concerted the C-0 bond opened is cis to the migrating methyl group as was demonstrated by the determination of the absolute configuration of the intermediate aIcohoI (16) by Horeau’s method.ll Analogous reactions have been observed with aristolene epoxide (18) which gives the same fast series of events.12 Ring Contra~tions.-We~~ and others14 have recently studied rather intensively the details of the contraction of ring A of triterpene alcohols and we shall not discuss this important reaction at all here.Ring EnZargements.-Ring enlargements by Wagner-Meerwein rearrangement have played an important role in the correlation of the various series of triterpenes. Thus lupeol(19) could be con- verted into derivatives of the oleanane series.lb -OH 83 Beaton Easton Macarthur Spring and Stevenson J. 1955 3992. lo Streith Pesnelle and Ourisson Bull. SUC.chim.France 1963 518. l1 Horeau Tetrahedron Letters 1961 506; 1962 965. l2 Pesnelle unpublished work. l3 Biellmann and Ourisson Bull. SOC.chim. France 1962 331. l4 Moriarty and Wallis J. Org. Chem. 1959,24,1274,1987; Shoppee and Johnston J. 1%1,3261; Bancroft Haddad, and Summers J. 1961 3295. Ames Halsall and Jones J. 1951 450. SEPTEMBER 1964 During this process two strain factors are removed the trans-perhydroindane D/E ring junction and the peri-interaction of the isopropenyl side-chain with C-12. At least in the first steps migration of the double bond into the ring system would increase ROH 2Cw (23) CH..*OR (2 2) this peri-interaction so that there is no useful escape from the strains other than ring enlargement.Other cases are it is true more difficult to under- stand. Thus while the bicyclic alcohols (20) and (21) are easily enlarged (by solvolysis of their toluene- p-sulphonates16) this is not true of their tricyclic homologues of the longifolene series. Solvolysis of the toluene-p-sulphonates of longifolol (22) and of isolongifolol(23) gives only the elimination product 10ngifolene.l~ The Wagner Rearrangement sensu stricto.-This is the historic case of the conversion of pinene (24) into successively bornyl chloride (25) camphene (26) and isobornyl chloride (27) and finally by epi- merisation into bornyl chloride.l* Tertiary chlorides (“pinene hydrochloride” and “camphene hydro- chloride”) are intermediates. The most remarkable characteristics of this series of rearrangements which is depicted in the second set of formulae in a way initially proposed by Dr.D. Rogers is its stereospecificity which in itself must be very informa- tive about the nature of the ions involved. Two extreme views are at present under considera- tion in an effort to correlate this stereospecificity with the kinetic data obtained in the study of this reaction sequence the intermediacy of %on-classical ion~” (which tends to be now the classical view) and that of classical carbonium ions. Recent discussion^^^ illustrate the present state of indecision as to which description to choose. One extreme view recently put forward,20 is that the camphene-isobornyl chloride reaction involves a fast equilibrium between classical ions (28).The stereospecificity would then be due to the “wind- shield-wiper effect” of the moving bridge sweeping approaching ions away from the endo-face of the bicyclic system. However this can certainly nut be simultaneously the explanation for the reaction of pinene converted into bomyl chloride through what would be the same classical bornyl ion or else we must have in this rigid system two conformations for the bornyl ion to ensure that it “remembers” l6 Berson and Reynolds-Warnhoff J. Amer. Chem. SOC.,1964 86 595; Berson and Willner ibid. p. 609 and references cited therein. l7 Lhome unpublished work. l8 Meerwein and van Emster Ber. 1920 53 1815; 1922 55 2500. Beltrame Bunton Dunlop and Whittaker J. 1964 658 and references cited therein.2o Brown in “The Transition State,” Chem. SOC. Special Publ. 1963 p. 140. 278 PROCEEDINGS where it comes from. We prefer at least provi- sionally to think that the reaction of camphene proceeds through some kind of bridged ion (29) + (2 9) (27) responsible at least for the stereochemical outcome if not for all of the kinetic features of the reaction. The reaction of pinene to give bornyl chloride might of course proceed through the classical car- bonium ion (30); in that case there would be no stereochemical difficulty as the bornyl cation (31) could give the end product simply by attack on its less shielded endo-side. This very brief discussion would be much too simple if we did not mention that the origin of the ions involved (by solvolysis by nitrous deamination etc.) can have a direct influence on their fate.Solva- tion of the ions is certainly of great importance and we have not taken it into account. (33) Wagner-Meer wein Rearrangements in the Longi-folene Series.-Longifolene as an analogue of camphene undergoes a similar rearrangement under the influence of hydrogen halides,2l but no tertiary halides can be isolated and the product is a longi- bornyl halide (32) not the expected longi-isobornyl halide. This was demonstrated ten years ago by Moffett and Rogers.22 We had interpreted this re- action as implying intermediacy of plain carbonium ions (33) and (35). Attack on the non-classical ion (34) would have been impeded here by the nearly perfect shield provided by the large bridge.An alter- native explanation by De~ar~~ postulated interven- tion of two non-classical ions (36) successively (written originally as n-cornplexe~).~~ The reverse sequence can also be brought about.21 In this case the rate of solvolysis is a hundred times greater than that of bornyl chloride but still a 21 Naffa and Ourisson Bull. Soc. chim. France; 1954 1416; Ourisson and Ourisson ibid. p. 1415. Moffett and Rogers Chem. and Ind. 1953 916. 23 Dewar Bull. Soc. chini. France 1954 1420. SEPTEMBER 1964 thousand times smaller than for isobornyl chloride. We had explained the acceleration by the relief of strain brought about by the increase in distances between non-bonded atoms in the carbonium ion (35) the steric acceleration due to this factor can be evaluated quantitatively (albeit with approximations of unknown magnitude) and fits the kinetic data very Dewar’s alternative proposal23 of the intermediacy of non-classical ions (as m-complexes) cannot lead to Quantitative estimates but we can offer no basis for ihoice between the two explanations.Another type of Wagner-Meenvein rearrange-ment of longifolene has very recently been elucidated by the Poona school of Sukh D~v.~~ It is the forma- B (I $6 67) tion with strong acids of isolongifolene (32) whose structure has been proved. The proposed mechanism formulated here for the sake of brevity as proceeding through classical ions is remarkable in particular in that it places a carbonium ion at a bridgehead-a rather flexible one to be true.This complicated series of rearrangements is made even more complex because the first ion implied can racemise by the 1,Zshift of the large bridge a pro-cess similar to one of the mechanisms of racemisa-tion of camphene. This results in partial racemisation of the isolongifolene isolated; the racemisation is more or less complete depending upon the reaction conditions. The “~-longifolene” described earlier by Zeiss and Araka~a~~ is isolongifolene largely race- mised. (38) (34 (3 9) In the same series we find also an analogue of the pinene-bornyl chloride rearrangement. Longipinene (38) the “longi-”homologue of pinene gives with hydrogen chloride longibornyl chloride.25 However in the same conditions another sesquiterpene homo- logue of pinene copaene (39 gave a mixture of di-hydrochlorides including compound (40) but no “copabornyl chloride.”26 This reaction is of course analogous of b-cleavage of pinene to dipentene di- hydrochloride;27 the factors leading to the suppres- sion of the otherwise predominant rearrangement are not evident.Rearrangements Accompanying Oxidation.-We shall now discuss some rearrangements of a different nature concentrating our attention again on the longifolene series. When longifolene is oxidised 24 Prahlad Ranganathan Nayak Santhanakrishnan and Dev Tetrahedron Letters 1964,417 ;cf. Zeiss and Arakawa, J. Amer. Chem. Soc. 1954 76 1653.25 Erdtman and Westfelt Actu Chem. Scand. 1963 17 2351. 26 Kapadia Nagasampagi Naik and Dev Tetrahedron Letters 1963 1933. 27 Tilden Ber. 1879 12 1131. PROCEEDINGS quite abnormal reactions occur terminal oxidation to acids:* cleavage by peracids,28 epoxidationZ9 and formation of lactones30 with ozone and ring en- largement with almost all oxidising reagents.= This complex of abnormal reactions has been clarified recently by Sukh Dev and his collabora- tor~.~~ We have been able to provide independent confirmatory evidence on two of the key ~teps.,~~~~ The sequence of reactions explaining all the facts is shown in scheme (41) where the substances marked+ (4 1) have been isolated and characterised. The key step for cleavage (to the CI4-ketone and -alcohols) is a Bayer-Villiger oxidation.The key step for the ring enlargement is an a-aldol- a-ketol rearrangement formally equivalent to a Wagner-Meerwein re-arrangement 0-H 0-H I I -c-c /’ -c-+C / tf I \o I\ R R 0-.1 OH 0-H ‘I I II -c-c-o--c+-c-o-I I R R It is most probable that similar paths are followed in the other oxidations of bridged terpenes with a >C=CH group when abnormal products are found. (2 6) (4 2) (4 3) (4 (4 5) One interesting reaction of this type of some importance for its role in the early establishment of a wrong structure for this m0noterpene,3~ is the oxida- tion of camphene (26) by permanganate to cam- phenic acid (42) a product normally expected from the oxidative cleavage of endocamphene (43); it appears most probable now that this reaction follows the course outlined above through the a-aldol- a-ketol rearrangement.In regard to this reaction of camphene I would like to revive an old and forgotten observation. Carbocamphenylonone(44) the a-diketone derived from endocamphene can be subjected to a benzilic acid rearrangement by treatment with bases giving camphenilic acid (45).% However the inverse ring enlargement can in this case also be carried out by heating the lead salt of camphenylic acid.37 This is an example of a retro-benzilic acid rearrangement for which I know of no other case. Another type of oxidation much used in structural work is dehydrogenation,38 which can often lead to unwelcome rearrangements.In tricyclic sesquiter- penes such as longifolene it has been of little diagnostic value. In fact whereas the bicyclic deriva- tive longifolic acid (46) gives with selenium the ex- pected dimethylazulene (47),39 rearrangements ac- company its dehydrogenation with palladised char- coal. The complex mixture of indanes obtained already ten years ago has now been in great part For instance camphene and a-fenchene give on attempted ozonolysis largely the acids formed by terminal oxidation and lactones.33 Cyclovetivene with perbenzoic acid gives infer alia the cleavage ketone-34 (T q:qH 28 Naffa and Ourisson Bull. SOC. chim. France 1954 115. 2g Munavalli and Ourisson Bull. SOC. chim. France in the press.30 Ghatgey and Bhattacharyga Perfumery Essent. Oil Record 1956 47 122. 31 Nayak and Dev Tetrahedron 1963 19 2269. 32 Lhomme unpublished work. 33 Treibs and Schmidt Ber. 1928 61 459. 34 Chiurdoglu and Tullen Bull. SOC.chim. belges 1957 66,169. 36 Wagner J. Russ. Phys. Chem. SOC. 1896 28 64; Ber. 1897 29 124. 36 Hirsjarvi Suomen Kemi. 1957 B 30 64 and references cited therein. 37 Hintikka Ber. 1914 47 512. Plattner in “Neuere Methoden der organischen Chemie,” Vol. I Verlag Chemie Berlin 1943. 3g Kubota and Ogura Chem. and Znd. 1958,951. SEPTEMBER 1964 identified;40 it is fortunate that the nature of these products (48-50) was not established before that of the starting material as this might have led easily to wrong deductions ! (49) Transannular Rearrangements.-Transannular re-actions are known for many terpenes notably sesquiterpenes.We shall restrict our discussion to a new series of transannular reactions initiated by free radicals that we have encountered in the chemistry of longifolene. The reaction studied was the Kharasch addition of tetrahalogenomethanes which is either light- or peroxide-induced. With camphene this reaction gives the normal product the very reactive tertiary halide (51).41 However longifolene gave with carbon tetrachloride21-or better with bromotrichloromethane adducts whose relative inertness to bases pointed from the start to a re-arranged structure. We had tentatively indicated that they appeared to be longibornyl derivatives (52) and (51) CCI, (24 cc 5 ccl3 28I the result of a free-radical Wagner-Meenvein re-arrangement.21 This appeared to be confirmed by their conversion by strong bases into longifolene- w-carboxylic acid (53).We have shown that they are not the postulated longibornyl derivatives but pro- ducts of free-radical transannular hydrogen transfer (54). The first evidence against the longibornyl struc- ture came from an attempted correlation with longi- bornyl bromide. The trichloromethyl group was re- duced indirectly by the sequence indicated in the Figure to a hydrogen atom to give an isomer (55) of longibornyl bromide. The nuclear magnetic resonance spectrum of the bromide (55) revealed a I 1 I 4 -C-CH5 CCI3 4 -C- CH-CC12 -C-CZC- CI I I/ I =9 cps I t I -C-COqH I I I I C-C--C-C H3 -C-CH,jOTs -C-CHiOH If I I J6 c.ps split signal for one of the methyl groups which must therefore be secondarv.This led to a revision of the structure eventually shown to be that indicated.42 The hydrogen atom transferred across the ring in fact hardly changes place in the eight-membered ring delineated in (56). All that really takes place is the shift of one electron. The corresponding shift of two electrons in reverse happens in the solvolysis of the bromide (53 which leads quantitatively to longi- f01ene.~~ 40 Munavalli unpublished work. 41 Dupont Dulou and Clement Bull. SOC.chim.France 1950 1056. 42 Helmlinger unpublished work. ~~ ~ A further very revealing reaction is the solvolysis of the intermediate methyl ester (57).There the incipient positive charge would be destabilised being a to a methoxy carbonyl group. An alternative re- arrangement then takes place the ring contraction to a new tricyclic system (58) very similar to that of copaene mustakone,26 and helrnintho~poral.4~ Many other reactions of the adducts (54) can only be understood on the basis of this structure. I hope this short review will have illustrated the wealth of interesting reactions provided by the re- arrangements of terpenes and also the wealth of PROCEEDINGS questions that are still open even in their most fundamental aspects. -.pt-cy C 94pg-QH:q: (-1 b7) (58) I wish also to use this opportunity to emphasise that in the case of many natural products and in particular of longifolene the determination of the RO*H2c structure is only one of the steps of the study of the p47 chemistry of these compounds which may be of course of particular interest as a “brain teaser”.(55) (56) However even if the structure is solved by X-ray crystallography and if the total synthesis has been accomplished there is every reason to believe that c-.-‘-\.-much of interest will accrue from a deeper study of o-. I a ,’ the reactions of the complex products provided so I t,,! abundantly by Nature. I take great pleasure in thanking my associates in the study of longifolene Dr. S. M. Munavalli and MM. D. Helmlinger and J. Lhomme as well as my collaborators in the other fields mentioned in the text.The friendship of Dr. Sukh Dev with whom a permanent contact has been maintained for nearly ;--y& ten years is also appreciated. The text of this -.-.-.-. Lecture has largely benefited from criticisms and .,a helpful discussions with Dr. H. Felkin and Dr. J. M. (56) Mellor. 43 Mayo Spencer and White Canad.J. Chem. 1963 41 2996. SEPTEMBER 1964 283 COMMUNICATIONS a-Elimination from 9-Bromofluorenes By D. BETHELL and A. F. COCKERILL* TREATMENT 9-bromofluorene with bases (e.g. of benzyltrimethylammonium hydroxide potassium t-butoxide) in t-butyl alcohol solution yields 9,9'-bi- fluoreny1idene.l It has previously been shown that the mechanism of the reaction involves rapid pre- equilibrium formation of 9-bromofluorenyl car-banion which displaces bromide ion from a second molecule of 9-bromofluorene in the rate-determining step subsequent /3-elimination of hydrogen bromide from the intermediate dimeric halide being very fast.The evidence for this mechanism was as follows (i) exchange of the 9-hydrogen in 9-bromofluorene under the influence of bases is much more rapid than bifluorenylidene formation; (ii) bifluorenylidene formation is kinetically of the second order in 9-bromofluorene;(iii) observed second-order velocity constants are proportional to the basicity of the reaction medium as measured by the indicator p-nitroaniline. Observation (ii) was taken to exclude the alternative mechanism involving slow carbene formation from the carbanion.2 We now report that substituents in the fluorene nucleus can modify the mechanism of the reaction their ability to do so being in part dependent upon the nature of the reaction medium.Some of our results obtained by the previously describedl spectro- photometric procedure are given in the Table. In t-butyl alcohol containing benzyltrimethyl- ammonium hydroxide and water in varying amounts Velocity constants for the disappearance of substituted 9-bromofluorenesin t-butyl alcohol at 30" Base PhCH,.NMe,OH-+ KOBut Subst. Order k* Order k* - 2 4-4x 1o2 2 2.2 x lo1 3-Me 2 9*4xlo1 - - 2-Me0 2 1.3 x 103 2 8.1 x lo1 3-Br 2 8.4~104 2 1.1 xi04 2-c1 2 1-8x 105 1 0-76 2-Br 2 4.6~105 1 1.1 4-CN 2 5-3x lo8 1 51 2-NO2 2 1.7 x 109 1 79 * Values in 1.mole.-' min.-l or min.-l as appropriate interpolated or extrapolated from measurements over a range of medium basicities refer to media for which [ArNH-]/[ArNH,] = 0.89 p-nitroaniline being used as indicator. all compounds so far investigated are converted quantitatively into the corresponding dimeric olefin according to a second-order kinetic law. With potas- sium t-butoxide as base however compounds con- taining powerful electron-withdrawing substituents follow first-order kinetics in 9-bromofluorene observed velocity constants still paralleling the basicity of the reaction medium. Since it is unlikely that these substituents would make removal of the 9-hydrogen rate-determining a conclusion which we have verified by studies on 2,9-dibromo-9-deutero- fluorene we regard the first-order kinetic behaviour as indicating rate-determining formation of carbene by loss of bromide ion from the 9-bromofluorenyl carbanion.2 Subsequent reaction of the carbene probably with another carbanion,2b to form the dimeric olefin would be expected to be rapid.Attempts to trap the carbene by means of olefins have so far been unsuccessful. 9-Bromo-2-methoxyfluorene and 3,9-dibromo-fluorene react with potassium or sodium t-butoxide according to second-order kinetics. At constant base concentration addition of dimethyl sulphoxide or tetramethylene sulphone to the mixture increases the basicity of the medium3 and causes the observed second-order rate constants to increase at first.At higher concentrations of additive the kinetic form becomes complex further additions leading to kinetics of first order in 9-bromofluorene. For the 2-methoxy-compound with 0-01 6hl-potassium t-but- oxide different concentrations of dimethyl sul-phoxide and tetramethylene sulphone (ca. 1.2~ and O-~M, respectively) are necessary to bring about this change in kinetic form but significantly the change occurs in media having similar abilities to remove a proton from nitroaniline indicators. The basicity of the medium cannot be the only factor determining the change however since increasing the basicity by increasing the concentration of potassium t-butoxide in t-butyl alcohol without additives causes no devia- tion from the second-order behaviour.Dimethyl sulphoxide and tetramethylene sulphone promote base-induced cleavage of carbon-hydrogen bonds and we therefore conclude that the first-order kinetic behaviour observed in the presence of these additives indicates again rate-determining carbene formation. (Received August 5th 1964.) * The Robert Robinson Laboratories University of Liverpool. Bethell J. 1963 666. a Cf. (a) Hanna Iskander and Riad J.,1961 217; (6)Swain and Thornton J. Amer. Chem. SOC.,1961 83,4033. Cram Rickborn and Knox J. Amer. Chew. SOC.,1960 82 6412; Cram Kingsbury and Rickborn ibid. 1961, 83 3688; Stewart O'Donnell Cram and Rickborn Tetrahedron 1962,18,917. PROCEEDINGS A Novel Silicoboron Halide SiBCl By A.G. MASSEY and D. S. URCH* DURING the preparation of diboron tetrachloride by tetrachloride and boron trichloride present as im- the action of a mercury discharge on boron tri- purity. The source of silicon was probably the quartz chloride vapourl we obtained a very small sample of discharge cell since it was considerably etched where a colourless thermally stable liquid which was the discharge had impinged on its surface; other shown by mass-spectral studies to be dichloro(tri- silicon compounds which were identified in traces in chlorosilyl)boron Cl,BSiCl, mixed with boron the diboron tetrachloride were hexachlorodisiloxane trichloride and silicon tetrachloride. hexachlorodisilane and octachlorotrisilane. Dichloro(trichlorosily1)boron was identified by the We think that dichloro(trichlorosily1)boron arises characteristic pattern of mass peaks (21 3-222) from the combination of boron trichloride and silicon caused by the various isotopes of boron silicon and tetrachloride in the discharge and if this is correct chlorine and by its cracking pattern which gave the the method may be generally applicable to the ions BSiC14+ BSiC13+ BSiC12+ BSiCl+ BSi+ Si+ preparation of many mixed-element halides.A rather and B+; the intensities of the peaks due to SiCl3+ similar preparation of germylsilane H3GeSiH3 in SiCl,+ SiClf BC12+ and BCl+ were also much which a silent electric discharge was used has been stronger than expected for the amounts of silicon described (Received,June 17th 1964.) *Chemistry Department Queen Mary College London E.l.Urry Wartik Moore and Schlesinger J. Arner. Chern. Soc. 1954 76 5293; Holliday Massey and Taylor un- published work. Spanier and MacDiarmid Inorg. Chern. 1963 2 215. Activation of Molecular Hydrogen by Complexes of Rhadium(m) By R. D. GILLARD P. B. STOCKWELL, J. A. OSBORN and G. WILKINSON* WErecently found1 that many syntheses involving A similar homogeneous catalysis is observed in the the nucleophilic replacement of halide ions co-aquation of rhodium trichloride. The solution of ordinated to rhodium(m) by nitrogenous ligands rhodium trichloride in water does not contain mono- were enormously catalysed by reducing agents meric species only; a strong absorption band at capable of forming hydride ion such as hypophos- 380 mp is presumably due to polymeric species.This phorous acid. One such reaction is red solution (Amax. 506 mp) when treated with 1,2,6-[Rhpy,Cl,] +py = trons-[Rh pyaCI,]CI (1) molecular hydrogen at pressures up to 1 atm. and room temperature rapidly becomes yellow (Amax. (where py = pyridine). On the basis of a kinetic 447 and 350 mp). Again no net hydrogen uptake study of this reaction with ethanol as catalyst it was occurs and no isosbestic point was observed during suggested2 that the mechanism involved a reduced the reaction. The electronic spectrum of the product state such as rhodium(1). agrees with that recorded3 (Amax. 450 349 mp) for We now find that reaction (1) is catalysed very the trans-[Rh(H20)4C12]+ cation.We suggest a effectively by molecular hydrogen at room tempera- hydridic mechanism involving heterolysis of hydro- ture and atmospheric pressure or less. No net gen by the rhodium trichloride the resultant hydride hydrogen uptake is observed. This constitutes a very ion replacing chloride nucleophilically with subse- simple preparation of trans-[Rh py4C1,]C1 which quent displacement of hydride by water. Similar may also be made simply by treating an aqueous results were obtained when methanol was the solvent pyridine solution of rhodium trichloride with mole- the process catalysed here being the replacement of cular hydrogen. We suggest that the catalysis of chloride by methanol. reaction (1) occurs as follows The suggestion that an intermediate hydride is PY PY PY responsible for the catalyses is supported by the observations that ethanolic solutions of rhodium tri- chloride or 1,2,6-trichlorotripyridinerhodium(m) containing hex-1-ene take up molecular hydrogen at H++ H-H room temperature and pressures up to 1 atm.the *Department of Chemistry Imperial College London. Gillard. Osborn. and Wilkinson J.. in the Dress. Rund Basolo &d Pearson Znorg. *Chem.,i964,3 658. Wolsey Reynolds and Kleinberg Znorg. Chem. 1963 2 463. SEPTEMBER 1964 olefin being converted into n-hexane. This is not a simple reaction; as observed recently at 65” hex- 1 -ene is catalytically isomerised by ethanolic rhodium trichloride. We now find that this isomerisa- tion follows the same pattern at 20” trans-hex-2-ene being the major product and it appears that the hydrogen uptake is mainly due to this isomer.This initial isomerisation accounts for the induction period observed for the hydrogenation. The homo- Harrod and Chalk J. Ameu. Chem. Soc. 1964 86 1776 Harrod and Halpern. Canad.J. Chem. 1959 37 1933. geneous nature of such hydrogenations is demon- strated by the sudden change in the rates of reaction if any metallic rhodium begins to be formed. Homo-geneous hydrogenation catalysed by rhodium(m) complexes has previously been observed5 only for the ferric-ferrous reduction in aqueous solution at 80” where the catalytic intermediate [HRhCl,]3- was suggested. (Received,July 27th 1964.) Complex Fluor oxenat es(vr)* By R. D. PEACOCK, H.SELIG and I. SHEFT~ XENONHEXAFLUORIDE is distinguished from other hexafluorides by its ability to attack readily dry borosilicate glass and quartz,l and this suggested to us that it might act as an ionising solvent like bromine trifluoride or iodine pentafluoride. Though because of electrode attack we have been so far unable to measure the conductance of xenon hexa- fluoride or of solutions with xenon hexafluoride as solvent we have been able to prepare complexes between xenon hexafluoride and the alkali fluorides. Casium fluoride is somewhat soluble in liquid xenon hexafluoride and readily combines with it to form casium heptafluoroxenate(w) CsXeF ,. The yellow salt is stable up to 50° but when further heated it loses xenon hexafluoride yielding the colourless dicaesium octafluoroxenate(vI) Cs,XeF, which is stable up to 400”.Casium heptafluoro- xenate(v1) gives a well-defined Debye X-ray powder pattern and has pseudotetragonal symmetry; the true unit cell has not yet been elucidated. Rubidium fluoride is scarcely soluble in xenon hexafluoride but combines with it in a similar way to give the colourless heptafluoroxenate(vI) RbXeF, stable only below 20° and the colourless octafluoro- xenate(vI) Rb,XeF, stable up to 400”. Potassium fluoride and sodium fluoride also absorb xenon hexa- fluoride but composition studies of the products although incomplete suggest that only the dimetal octafluoroxenates(v1) are stable at room temperature. The sodium salt decomposes below 100” and has been used to purify xenon hexafluoride.2 Lithium fluoride apparently does not combine with xenon hexafluoride but barium fluoride shows some evidence of reaction.All the fluoroxenates as expected are hydrolysed in the atmosphere to products that retain oxidising power and hence still contain xenon. The infrared spectra of the heptafluoroxenates differ from those of the octafluoroxenates and also from that of xenon hexafluoride itself but certain of the octafluoro- xenates notably that of sodium show a strong absorption peak at 1200 cm.? which is absent from the spectra of others indicating different crystal symmetries. The fluoroxenates(vI) which would be “bases” in the xenon hexafluoride as solvent in the same way as the recently prepared xenon hexafluoride com- plexes with arsenic pentafluoride and boron tri- fluoride3 would be “acids,” raise interesting struc- tural and chemical problems.Their solubility in the solvent is much less than that of the alkali fluoride “bases” in bromine trifluoride and in selenium tetra- fluoride; in particular the existence of two sets of compounds recalls the behaviour of complexes between alkali fluorides and uranium hexafluoride? and between alkali fluorides and other transition- metal hexafl~orides.~ It is hoped that these points and the anomalous colour of casium heptafluoro- xenate(v1) will yield to further experimentation. Incidentally rubidium and caesium octafluoroxenate are the most stable solid xenon compounds yet known.(Received,July 6th 1964.) * Based on work performed under the auspices of the U.S. Atomic Energy Commission. 7 Argonne National Laboratory Argonne Ill. U.S.A; Permanent address of R.D.P. Department of Chemistry, University of Birmingham England. Chernick Claassen Malm and Plurien “Noble-Gas Compounds,” ed. Hyman University of Chicago Press Chicago 1963 p. 106. Sheft Spittler and Martin Science 1964 145 701. Selig Science 1964 144 537. Malm and Selig Abstract of paper presented at her. Chem. SOC. Meeting Atlantic City September 9th 1962 p. 40N. Hargreaves and Peacock J. 1958 4390. PROCEEDINGS 1,2-Tetrakisdichlorobrylethane By C. CHAMBERS and S. M. WALKER* A. K. HOLLIDAY DIBORON TETRACHLORIDE and acetylene are reported1 to undergo only 1:l addition to form the liquid Cl,B*CH:CH.BCl (I).We have found that in presence of an excess of the tetrachloride further addition occurs; a second peak appears in the proton magnetic resonance spectrum to the high-field side of the single peak due to compound (I) which cor- respondingly decreases in intensity. The ultimate reaction ratio was 2B,C1,:C2H and the only pro- duct appeared as colourless moisture-sensitive crystals m.p. 29-30'. Molecular-weight determina- tion (vapour density) gave M = 349 and analysis confirmed the 2 1 formula; the formation of glyoxal after degradation by hydrogen peroxide and the single high-field peak in the nuclear magnetic resonance spectrum are consistent with the formula (Cl2B),CHCH(BC1,) ,(11).Unlike compound (I) the gem-boron compound (11) was stable up to 200°,did not react with bromine yielded no hydrocarbon when heated with propionic acid and reacted with trimethylamine only with difficulty. The chlorine atoms were however readily replaced by NMe or OH groups and the hydroxy- compound [(HO),B],CHCH[B(OH),] decom-posed quantitatively on being heated thus B,(OH),C2HZ + CZH + 2B,O + 2H,O Although several gem-boron compounds have been reported, their properties have not been described; those of compound (11) suggest behaviour intermediate between simple ? B-C -* -compounds and the carboranes3 where the -CH-CH- unit participates in an unreactive cage of boron atoms. (Received JuZy 3rd 1964.) * Donnan Chemistry Laboratories The University of Liverpool.Ceron Finch Frey Kerrigan Parsons Urry and Schlesinger J. Amer. Chern. SOC.,1959 81 6368. Brown and Zweifel J. Amer. Chem. SOC. 1961,83,3834; Matteson and Shdo ibid.,1963,85,2684; Zakharkin and K.ovredov Izvest. Acad. Nauk S.S.S.R. Ser. Khirn. 1964 2 393. R. Adams Inorg. Chern. 1963 2,1087 and following papers. The Formation of Negative Ions by Field Ionisation By A. J. B. ROBERTSON and P. WILLIAMS* KINGand ZACHARIAS~ looked without success for the formation of H-ions when a beam of hydrogen atoms impinged on a wire which was emitting elec- trons under the influence of a high electric field (field emission). We have observed the formation of negative ions on using a cold field-emitting tungsten wire as ion source in a mass spectrometer.The wire about cm. in diameter was placed parallel to an adjacent plane electrode containing a slit through which the ions passed. A voltage between the wire and the electrode of several thousand volts gave a macroscopic field at the wire surface of the order of lo6vlcm. This field is intensified sufficiently to cause field emission by roughness in the wire surface.2 The electron current from the wire always greatly ex- ceeded the ion current when the high field was applied and gases were ionised at pressures of about 1 x mm. Hg. Iodine and chlorine gave I-and C1- ions. C1-was the most abundant ion formed from carbon tetrachloride which also gave ions at mle = 47 59 and 70 (f5%) probably due to CC1 C,Cl- and CI2- respectively.Acetylene gave mainly the ion C2H- which was also present in the back- ground mass spectrum from the hydrocarbon tap grease as were CH- and C-ions. The ions appeared to be formed at the surface since pre-treatment of the surface greatly affected the efficiency of ionisation (ratio of ion current to elec- tron current). Ionisation by electron collision in the gas phase can occur by resonance capture and ion- pair formation. The conditions in the ion source where the electrons are continuously accelerated are such that the first process is far less important than the second. Ion-pair formation occurs at electron energies above -10 ev with a maximum cross- section at energies of 50-100 ev. Thus the ions would be formed at a potential some tens of volts different from that of the surface and would give rise to a broad peak in the mass spectrum with a maximum displaced from that due to ions formed on the surface.I-ions formed in the high field and also formed by thermal ionisation at the wire surface without the high field were compared and the Aeld- ion peak was neither displaced nor broadened. Cal- culations indicate that gas-phase ionisation is rela- tively unimportant in agreement with the deductions from the experiments. We suggest that negative ions are formed by a field-ionisation process in which electrons penetrate the potential barrier at the metal surface by quantum- * Department of Chemistry King's College Strand London W.C.2.J. G. King and J. R. Zacharias Adv. Electronics and Electron Phys. 1956,8,61. a A. J. B. Robertson B. W. Viney and M. Warrington Brit. J. Appl. Phys. 1963 14 278. SEPTEMBER 1964 287 mechanical tunnelling. The process seems to be the dissociation or it may undergo a field-induced dis- reverse of that which occurs when positive ions are sociation in somewhat the same way as a positive formed by field ionisation. The molecular negative ion.' ion may be formed in an excited state leading to (Received August 5th 1964.) H. D. Beckey 2.Nuturforsch. 1962 17a 1103. Reaction of c@-Unsaturated Acid Chlorides with Enamines By P. W. HICKMOTT* REACTION of acryloyl chloride with alcohols in thepre- sence of pyridine has been shown1 to give mainly the adduct R0,CCH2CH2.+NC5H5 Cl- obtained from the intermediate complex CH2=CHCO-+NC5H5Cl-.This reaction could be a stepwise process involving a keten intermediate (C5H,N+CH2CH=C =OCI-),l or a synchronous process in which the pyridine is transferred to the /%position as the alcohol approaches the carbonyl group (cf. A). Since enamines have been shown to react with acid chlorides,2 electrophilic olefins,2 and ketens? it was of interest to see how they would react with @-unsaturated acid chlorides. None of the Stork acylation products (I) have as yet been isolated. Reaction of acryloyl chloride with 4-cyclohex-1'-enylmorpholine in benzene and acid hydrolysis of the precipitated product (B) gave 13-2-oxocyclohexylpropionicacid (I1 ; R = H).That this was not the isomeric acid (111; R = H),formed by cleavage4 of the ketone (I) was shown by prepara- tion of an authentic sample of the former acid by hydrolysis of 2-2'-cyanoethylcyclohexanone2 (infra-red spectra identical and no depression of mixed m.p.). Decomposition of the precipitate (B) with cold water gave an oil which was separated by chromatography on silica gel into two main com- ponents one has not yet been identified; analyses of the other were correct for the vinyl ketone (I; R = H) but this and the isomeric structure (IV; R = H) were ruled out by spectroscopic data [vmax. 1725 1700 cm.-l in CHCI, r 7.0-8.4 (complex band) absence of OCH and CH2=CHC0 resonance at 6.4 and 34-50 r respectively]. The infrared spec- trum of the enol-lactone (V; R = H),prepared from the keto-acid (11; R = H),5also showed significant differences (vmax.1755 cni.-l in CHC13. This pro- duct is therefore tentatively assigned the bicyclic diketone structure (VI; R = H). In similar conditions cinnamoyl chloride and 4-cyclohex- 1 '-enylmorpholine gave /?-2-oxocyclo-* Royal College of Advanced Technology Salford. hexyl-p-phenylpropionic acid (11; R = Ph) m.p. 130-132" (lit. 126-128") an oil which is tenta- tively assigned the structure (VI; R = Ph) in accord with analyses and spectral data and compound (VII; R = Ph) which was isolated in three crystalline forms; of these forms one gave an immediate violet colour with alcoholic ferric chloride in alcohol whereas the other two did not a result which to- gether with the infrared spectra indicates that the &st is essentially the pure enol form while the others are polymorphic forms of essentially pure /3-diketone.OHC-CMe,*CO*CHiCHiCAkjCHO (VI II) Acryloyl chloride and 1-isobut-1 '-enylpiperidine has so far yielded the dialdehyde (VIII) character-ised by a crystalline bis-2,4-dinitrophenyl hydrazone derivative and spectral data. The author thanks Mr. P. Hampson of Imperial Chemical Industries Limited Dyestuffs Division for determination and interpretation of n.m.r. spectra and Miss M. Redshaw of this Department for infra- red determinations. (Received July 3rd 1964.) Hickmott. J.. 1964 883. * Stork Brizzolara Landesman Smuszkovicz and Terrell J.Amer. Chem. SOC.,1963 85,207. Hasek and Martin J. Org. Chem. 1961 26,4775; 1963,28 1468; Berchtold Harvey and Wilson ibid. 1961 26 4776; Opitz Kleeman and Zimmermann Angew. Chem. 1962,74 32. Hauser Swamer and Ringler J. Amer. Chem. Soc. 1948,70,4023; Hunig and Lendle Chem. Ber. 1960,93 909. Mannich and Koch Chem. Ber. 1942,75 803. Cordier and Meszaros Compt. vend. 1962 255 1125. PROCEEDINGS The Spectrum of Phenyl By G. PORTER and B. WARD* WE have observed at high resolution in the vapour phase electronic absorption spectra which we attribute to the phenyl radical and to its derivatives. The radicals were formed by flash photolysis with 4000 J energy per flash of aromatic vapours in the presence of 0-5 atm. pressure of argon and they were observed by means of a 21-ft.grating spectrograph and path lengths of 8-10 m. Lifetimes under these conditions were less than 100 microsec. The phenyl radical was observed after flash photolysis of benzene chlorobenzene bromo-benzene and iodobenzene. Analyses of the ultimate products carried out by Dr. Tsang in this laboratory have established that the principal product detectable by vapour-phase chromatography is in each case biphenyl. The spectrum of phenyl consists of a system of sharp double-headed bands in the region 4300-5300 A. The principal features of the spec- trum are readily interpreted in terms of two vibra- tion frequencies 571 and 896 cm.-l which probably correspond to the es+ and a, frequencies of the B, state of benzene1 with frequencies 521 and 923 cm.-l respectively.The origin of the system is at 18,908 cm.-l. The spectra of halogenated derivatives have also been observed as shown in the Table. It is noteworthy that the ortho- meta- and para- disubstituted isomers yield characteristically different monosubstituted phenyl radicals having no bands in common showing that isomerisation by hydrogen- atom migration does not occur in phenyl and its derivatives not even in the hot radical which must be present immediately after photodissociation. The appearance of phenyl absorption in the visible region is interesting but not surprising in view of the numerous electron configurations which are possible. The ground state may have configurations n6n or n5n2.The former could give rise to a n -n transition (and also a n --f n* transition analogous to that of benzene which is of much higher energy than the observed spectrum) the latter to an n --f 7~ or a n 4n transition.The red shift on halogen sub- stitution is the opposite of that in the rather ana- logous n -n* spectra of halogenated pyridines. The magnitude of this shift the relative effect of ortho- meta- and para-substitution and the fact that fluorine produces a greater shift than do the heavier halogens are all in accordance with the assignment of our spectrum to a n 3 n transition and a n6n configuration of the ground state of phenyl radicals. (Received,July 29th 1964.) * Department of Chemistry The University Sheffield 10.Sponer Nordheim Sklar and Teller J. Chern.Phys. 1939 7 207. Photochemical Formation of Cyclopentadienyls from Benzene Derivatives By G. PORTER and B. WARD* A NEW type of reaction has been observed in the photolysis of anilines phenols thiophenols nitro- benzenes and their halogenated derivatives in which a carbon atom is eliminated from the ring along with the nitrogen- oxygen- or sulphur-containing side- group to form cyclopentadienyl or halogenated cyclo- pentadienyls. This reaction occurs in addition to the formation of phenoxyl and anilino-radicals previously reported1 and is in marked contrast to the behaviour of benzene and halogenated benzenes which form phenyls2 and of alkylbenzenes which form benzyl- type radica1s.l * Department of Chemistry The University Sheffield 10.Porter and Wright Trans. Faraday SOC.,1955 51 395. Porter and Ward preceding Communication. All the molecules mentioned above give on flash photolysis in the vapour phase well-resolved transient band spectra in the region 3000-3900 A. The evidence for the assignment of these spectra to cyclopentadienyl radicals and their halogenated derivatives is as follows (i) A common spectrum with strongest band at 3343 A attributed to cyclo- pentadienyl is observed from aniline phenol nitro- benzene thiophenol anisole and phenetole. (ii) A spectrum attributed to fluorocyclopentadienyl with strongest band at 3250 A is observed from p-fluoro- nitrobenzene. (iii) A common spectrum attributed SEPTEMBER 1964 289 to chlorocyclopentadienyl with strongest band at 3424 A is observed from m-and p-chlorophenol m-and p-chloroaniline o-and p-chloronitrobenzene and o-chloroanisole.(iv) A common spectrum attributed to bromocyclopentadienyl with strongest band at 3550 .$ is observed from 0-and p-bromo- phenol o- in- and p-bromoniirobenzene and p-bromoaniline. The spectrum derived from the unhalogenated compounds mentioned in (i) above is also obtained much more strongly from cyclopentadiene. Product analysis after flash photolysis of phenol shows carbon monoxide and hydrogen in approximately equimolar amounts and further products not yet identified but no biphenylene and only a trace of bi p heny 1. The fact that all three halogenated isomers give identical spectra shows either that rapid isomerisa- tion occurs or that all positions of substitution are equivalent.Since the spectra consist of many sharp bands which appear in the same intensity ratio from Thrush Nature 1955 178 155. the different isomers we believe that the latter inter- pretation is the more probable and this leads almost unequivocably to the assignment of our spectra to cyclopentadienyl and its derivatives. The two strongest bands of our spectrum from cyclopenta- diene are identical with two bands reported by Thrush3 to be obtained on flash photolysis of this compound and our observations support his assign- ment of these bands. Although certainly unexpected the ring fission of phenols anilines thiophenols and nitrobenzenes is energetically feasible.Heats of formation of cyclo- pentadienyl and its derivatives are of course not yet known but there is little doubt that the energy of formation of carbon monoxide carbon mono-sulphide or hydrocyanic acid is more than adequate to compensate for the energy required to break the aromatic ring. We are indebted to Dr. S. M. Tsarrg for carrying out the product analysis of phenol. (Received,July 29th 1%4.) A New Synthesis of Keto-sugars By G. J. F. CHITTENDEN and R. D. GUTHRIE* WE report a synthesis of keto-sugars in good yield not involving direct oxidation. Reaction of methyl 4,6 -0-benzylidene -3 -deoxy -3 -phenylazo -a -D-glucosidel (I) with sodium methoxide in methanol gave the corresponding phenylhydrazone (1II)t (86 %) characterised as the 2-acetate.This rearrange- ment is typical of that of simple phenylazoalkanes.2 Reaction of the phenylhydrazone (111) with benzal- dehyde in dilute acetic acid gave methyl 4,6-0- benzylidene- a-~-ribo-3-hexuloside (IV) (50%) m.p. 184-186" v(C0) 1745 cm.-l A,,,. 260 mp (in EtOH; E 220) characterised both as its p-nitro- phenylhydrazone and as its 2-p-nitrobenzoate. Mild acid hydrolysis of the 3-keto-sugar (IV) yielded a R1 R2 R3 R4 R1 R2 X (I) H OH N,Ph H (Ill) H OH N-NHPh (11) OH H H N,Ph (IV) H OH 0 (V) OH H N-NHPh (VI) OH H 0 product that had the paper-chromatographic charac- teristics reported3 for methyl-a-~-ribo-3-hexuloside. Reaction of methyl 2,3-anhydro-4,6-0-benzyli-dene- a-D-mannoside with phenylhydrazine in meth- anol under a reducing atmosphere followed by oxidation with mercuric oxide gave methyl 4,6-0- benzylidene -3 -deoxy -3 -phenylazo -a -D -altroside (I) (56 %) characterised as its 2-p-nitro- benzoate and by reduction to the corresponding (known) 3-aminoaltroside.Treatment of this com- pound with methanolic sodium methoxide gave the corresponding phenylhydrazine (V) (78 %) charac-terised as its 2-acetate which with benzaldehyde in dilute acetic acid yielded methyl 4,6-O-benzylidene- a-D-arabino 3-hexuloside (VI) (43 %) m.p. 190-192" v(C0) 1740 cm.-l A,,,. 257 mp (in EtOH; E 317) again characterised as its p-nitrophenyl- hydrazone and its 2-p-nitrobenzoate. With two routes now available to phenylazo-sugars (via sugar "dialdehydes" and via epoxides) this new synthesis of keto-sugars promises to be of general applicability.(Received July Sth 1964.) * The Chemical Laboratory University of Sussex Brighton. t All new compounds reported are crystalline and had satisfactory analyses. R. D. Guthrie and L. F. Johnson J. 1961,4166. A. J. Bellamy and R. D. Guthrie unpublished work. 0. Theander Acta Chem. Scand. 1957 11 1557. 290 PROCEEDINGS ~~ ~~~~~~ ~ Pauling’s Electronegativities for Me Ph CN CF, and OH Groups from Bond Dissociation Energies By Ewcos CONSTANTINIDES* VALUES XR for electronegativities of groups R on Pauling’s scale are obtainable from bond dissocia- tion energies. The formula used for this purpose is of the same form as that used by Paulingl for calcula- tion of electronegativities of elements (based on the postulate of the geometric mean) XR = XH f 0183(D(R-H) -[D(R-R)*D(H-H)]*I$ The present calculation makes use of the polarity of group-hydrogen bonds; the nature of these is less diversified by the variety of interactions likely to operate in bonds involving atoms electronically less simple than hydrogen.Electronegativities assigned to groups by this method (see Table) have magnitudes representative of the chemical and physical behaviour of the groups. GroupR Me Ph CN CF3 OH XR 1.57 1.74 2.75 2.86 3-24 The value assigned to the methyl group indicates a polarity CH3+H- in methane and a dipole moment pcH= -0.3 D.This agrees with Coulson’s calcula- tions2 (max. pcH=0-4D) and with the spectroscopic value pcH=0.33 D (Hiller and Straley3). The cyanide group a “pseudohalogen” is placed between iodine and bromine. The electronegativity of the isocyanide group however is likely to be higher. The value for the electronegativity of the hydroxyl group leads to the polarity Cl+OH- in hypochlorous acid. The application of Markownikoffs rule to the electro- philic addition of hypochlorous acid to olefins draws on this assumption. The trifluoromethyl group is shown to be more electronegative than the methyl group although D(CF3-H) and D(CH,-H) are approximately equal. The relative contributions of covalent and ionic energies to the bond dissociation energies are however unequal.(Received July 3r 1964.) * 24 Conway Street London W.l. 1 L. Pauling “The Nature of the Chemical Bond,” Cornell Univ. Press New York,3rd edn. 1960 p. 91. 2 C. A. Coulson Trans. Faraday SOC.,1942 38 433. R. E. Hiller jun. and J. W. Straley J. MoZ. Spectroscopy 1960 5 24. See Discussion on the Paper by M. Szwarc “The Transition State,” Special Publication No. 16 The Chemical Society London 1962 p. 109. The Relative Acceptor Powers of Silicon and Germanium Tetrahalides Toward Pyridine and Isoquinoline By J. M. MILLERand M. ONYSZCHUK* UNTEnow the relative acceptor powers of silicon and germanium tetrahalides namely GeX > Six4 and F > C1 > Br > I have1 with one exception2 been inferred from positive or negative formation of their co-ordination compounds.We have now measured with a precision calorimeter? the heats of reaction at 25 O of silicon and germanium tetrahalides with pyridine (py,as the neat liquid) and isoquinoline (is as a 1% solution in hexane) which form in- soluble 1:2 adducts. Infrared measurements in the casium bromide range indicate that all of these com- plexes except those of pyridine with SiCl and SiBr, are trans-octahedrall~* Values of heats of formation -AHin kcal./mole at 25” corrected to the following conditions are shown in the Table. In all cases except that of silicon tetrahalide- pyridine complexes heats of formation decreased in Mx4(1) + Py(1) MX4(1) + iq(so1n.) SiF4,2py 29.01 &O-82 SiC14,2py 51.67 h0.67 SiBr4,2py 46.05 f0.68 SiF4,2iq 27.80A0.69 SiC1,,2iq 17-36f0.30 SiBr4,2iq 12.79 h0.43 --f MX,,2PY(S) -j MX4,2h(S) GeF4,2py 48.35 i0-83 GeC1,,2py 41-44 &0.86 GeBr4,2py 33.79 f0.41 GeF4,2iq 35.70i 1.33 GeC1,,2iq 22.29 If0.13 GeBr4,2iq 18.01 h0.45 the order F > C1> Br.This suggests that the order of acceptor power is SiF > SiCl > SiBr toward isoquinoline and GeF > GeCl > GeBr toward pyridine and isoquinoline assuming that lattice energies are similar in a series of related complexes having the same structure. This assumption does not hold for silicon tetrahalide-pyridine complexes * Inorganic Chemistry Laboratory McGill University Montreal 2 Canada. Beattie Quart. Rev. 1963 17 382. Fergusson Grant Hickford and Wilkins J.1959 99. Greenwood and Perkins J. Inorg. Nuclear Chem. 1957 4 291. 4 Hickie and Onyszchuk unpublished observations. SEPTEMBER 1964 because of structural differences in the series. Since SiC1,,2py and SiBr4,2py are cis-octahedral they un- doubtedly have higher dipole moments and therefore higher lattice energies than trans-SiF4,2py. Heats of formation of silicon tetrahalide-pyridine complexes therefore do not permit a true evaluation of relative acceptor properties. In the absence of structural differences it is evident that heats of formation of 291 germanium tetrahalide adducts are greater than those of the corresponding silicon complexes. This con- firms that germanium tetrahalides are stronger electron-pair acceptors than their silicon analogues.Explanations for the observed acceptor sequences will be discussed in subsequent detailed reports of this work. (Received,June 23rd 1964.) Hydrogen Exchange at the meso-Positions of Porphyrins and Reduced Porphyrins By R. BONNETT and G. F. STEPHENSON* WE have obtained some kinetic results on hydrogen exchange at meso-positions of octaethylporphyrin (I) and its 7,8-dihydro- (11) and 5,6,7,8-tetrahydro-derivatives (111) by following the diminution in trifluoroacetic [2H]acid of the nuclear magnetic resonance (n.m.r.) signals due to these protons. The spectra of the compounds at zero time (see T values in the Table) show a marked decrease in ring current at each reduction step (cf.italicised values). meso 5 6 7 8 (1) -0.98(~) -(10 0.0.5(~) -5.4(m) 1.20(s) (W 1-02(s) 6- 16(m) 2*27(s) 2*93(d) Although the deuteration of the y-and &positions of chlorins has been 0bservedl9~ (e.g. of rhodo-chlorinl in CH3C02D at go") no exchange of the meso-hydrogen of porphyrins has been detected under these conditions. It has now been shown that under more vigorous conditions (CF3C02D at 100") deuteration of the methine bridges of the por- phyrin (I) does occur although the exchange is slow and the experiment (exchange of H for D; exchange of D for H; isolation of porphyrin and identification) takes about two months to complete satisfactorily. No exchange is detectable in this solvent at room temperature. However on a preparative scale meso-deuteration of the porphyrin (I) can be effected over- night in 90% D2S04-D20at 20".Clearly the meso-positions of an octa-alkylporphyrin are susceptible to electrophilic attack under certain conditions. In the chlorin the exchange of the y-and &protons (1.20 T) was as expected much faster than that of the a-and /?-protons (0.05 T),and at room tempera- ture only the former reaction was detected. At loo" however exchange of a-and /3-protons was much faster than exchange in the porphyrin system. The tetrahydro-compound (111) showed a wide range of meso-reactivity. At room temperature the signal due to the y-proton (2.93 T) disappeared quickly while that due to the /3-and 8-protons (2.27 T)decreased at about one-fifteenth of that rate :the signal due to the a-proton was essentially unaltered at room temperature.Unfortunately this experiment could Ar Satd. Ar Satd. CH2CH3 CH2.CH3 CHZ.CH3 CH,.CH -8- 13(t) -not be carried out at 100" owing to decomposition of the substrate. (1 1 (a) 7,8CHEt-CHEt @I) 5.6:7,8CHEt-CHEt "&X Et It is concluded that the rates of proton exchange at the mesu-positions increase in the following order (I) 4 (1I)aP < (1I)yG < (III)/38 < (111)~. These reactivities follow reasonably well the pattern of charge densities derived from modified Huckel calculations.3 (Received July loth 1964.) * Chemistry Department Queen Mary College London E.l. R. B. Woodward and V. SkariC J. Amer. Chern.Soc. 1961 83,4676. J. J. Katz R. C. Dougherty F. C. Pennington H. H. Strain and G. L. Closs J. Amer. Chem. Soc. 1963 85 4049. M. Gouterman G. H. Wagniere and L. C. Snyder J. Mol. Spectroscopy,1963 11 108. PROCEEDINGS The Structure of Simarolide the Bitter Principle of Simarouba amara By JUDITH POLONSKY *t WE have previously1 reported the isolation from the bark of Simarouba amara (Simaroubaceae) of a new bitter constituent simarolide (C,H,O), that con- tained a five-membered lactone-ring one acetoxy- group one hydroxyl group and at least one keto- group. Additional work in conjunction with the following Communication establishes the complete structure as (I; R = H R’ = Ac). The molecular formula C ,H,,Og was deduced from the molecular weight determined by X-ray crystallography2 of simarolide and confirmed by mass spectrometry of several of its derivatives.The nuclear magnetic resonance (n.m.r.) spectrum of simarolide (in CDC1,) reveals one secondary and three tertiary methyl groups a doublet centred at T 9.1 (J = 6 c.P.s.) and singlets at 7 9.09 9.0 and 8.84. The acetyl singlet appears at r 8.08. Further this spectrum shows a doublet (1 proton) at r 6.38 which must be assigned to the secondary hydroxyl proton coupled with the proton attached to the same carbon atom. With 0.1 N-alkali under controlled conditions simarolide (I; R = H R’ = Ac) gives besides recovered simarolide deacetyl simarolide (I; R = R’ = H) and two acidic compounds namely simarenic acid1 (11; R = H R’ = Ac) and deacetyl- simarenic acid (11; R = R’ = H) Amax.220 mp. As we have previously indicated simarenic acid (C2&@g) arises by hydrolysis of the y-lactone group and loss of one mole of water.l The presence of the side chain in simarenic acid as in (11) is shown by the following facts (a) the n.m.r. spectra (in deuterioacetone) of simarenic acid (11; R = H R = Ac) and of its deacetyl derivative (11; R = R’ = H) show two broad singlets at r 3.80 and 3-52 due to the :C=CH group the presence of which was confirmed by formation of formaldehyde on ozonolysis of simarenic acid. (b)Catalytic hydrogena- tion of the acids (11) (R = H R’ = Ac and R = R’ = H) affords the respective 20,21 -dihydro-deriva- tives which do not show significant ultraviolet absorption but the n.m.r.spectra of whose methyl esters reveal clearly an additional secondary methyl group. (c) Treatment of simarolide and simarenic acid (and of their deacetyl derivatives) with con- centrated phosphoric acid gives formaldehyde but the latter is not formed on treatment of the dihydro- compounds (11; 20,21-dihydro R = H R’ = H or Ac). This reaction may be considered as elimination of a primary alcohol by a reverse aldol reaction preceded by hydration in the case of the acidic compounds (11). Since simarolide contains only a secondary hydroxyl group the primary hydroxyl group must be involved in the y-lactone group and situated in the 19-position with respect to a carbonyl group.(d) Finally the mass spectrum of the methyl ester of dihydrosimarenic and of deacetyl dihydro- simarenic acid have base peaks at n7ie 129 arisingfrom the cleavage of the 13,17-bond as proved by the presence of a peak at m/e 143 in the mass spectrum of the corresponding ethyl ester of dihydrosimarenic acid. OH The hydroxyl group present in simarolide is part of an a-ketol group which is sterically crowded by the 1 1-acetoxy-group. Thus comparative titration with periodic acid shows that in contrast to simarolide and simarenic acid only the deacetyl compounds (I and 11; R = R’ = H) readily con- sume one mole of the reagent. Similarly simarolide is recovered almost quantitatively after treatment with bismuth trioxide, but oxidation of deacetyl- simarolide leads rapidly to the diosphenol (I; 2,3-unsaturated; R = R’ =H) (positive FeCl test) (Amax.278 mp). Acetylation of this diosphenol yields the diacetate (I; 2,3-unsaturated; R = R’ = Ac) (Amax. 237 mp,log E 3.78) whose n.m.r. spectrum * C.N.R.S. Institut de Chimie des Substances Naturelles Gif-sur-Yvette (S. et O.) France. t With the technical assistance of Mrs. Z. BaskCvitch. Polonsky Bull. Soc. chim. France 1959 1546. These measurements were kindly carried out by Professor W. N. Lipscomb (U.S.A.) in 1959. Rigby J. 1951 793. SEPTEMBER 1964 (in CDCl,) shows a doublet (1H) at 7 4.0 (J = 2.5 c.P.s.) due to the vinyl proton at C-3 and a notable down-field shift of the bands of the secondary and of one of the tertiary methyl groups.The structure of simarolide as (I; R = H R' = Ac) and of its absolute stereochemistry has been determined by X-ray analysis2 (following communi- cation) ofthe m-iodobenzoate (I;R = m-I.CGH4*C0, R' = Ac) and of the 4-iodo-3-nitrobenzoate by the Glasgow group whom we thank for their co-opera- tion. Simarolide is thus an acetate of a CZ5compound and its occurrence in the Simaroubaceous plant may be of biogenetic significance since the other bitter sub- stances of this plant family q~assin,~ glau-~haparrin,~ carubin whose structures are closely related to that of simarolide could be formed by cleavage of the 13,17-bond. The presence of an oxygenated group at position 13 in the CI9 bitter principles sama- 293 ~-derine7 and cedron~line,~?~ may be relevant in this ~ontext.~ The absolute configuration of simarolide suggests that its biogentic precursor may be a tetra- cyclic triterpene of the tirucallol (IV) or possibly of the butyrospermol (d7-euphol) type from which a carbon atom in ring A (at c-4) and four mrbon atoms at the end of the side chain have been removed and carbon atoms 20-23 converted into a y-lactone ring.The biogenesis might then follow the path pro- posed for limonin,' involving a 1,2-methyl migration and the formation of a 16,17-s-lactone- Opening of this lactone ring and recyclisation to a 7-hydroxyl €TOUP would lead to the basic skeleton of ~imarolide.~ We thank Prof. E. Lederer for his interest Mr. A. Gaudemer for assistance in the interpretation of the n.m.r.spectra and the National Institute of Allergy and Infectious Diseases (U.S. Public Health Service) for a grant. (Received June 12th 1964.) Valenta Gray Om Papadopoulos and Podesva Tetrahedron Letters 1962 1433 and earlier papers cited there. Geissman and Ellestad Tetrahedron Letters 1962 1083; Davidson Hollands and P. De Mayo ibid. p. 1089; I.U.P. A.C. Symposium Kyoto April 1964. Polonsky Fouquey and Gaudemer Bull. SOC. chim. France 1963 169; 1964 1827; and earlier papers cited there; see also X-ray analysis by Kartha Haas Schaffer and Kaistha Nature 1964 389. Polonsky Zylber and Wijesekera Bull. SOC.chim. France 1962,1715; Polonsky and Zylber I.U.P.A.C. Symposium Kyoto April 1964. Arigoni Barton Corey Jeger et al.Experientia 1960 16 41 ; Barton Pradhan Sternhell and Templeton J. 1961 255. 9 Bredenberg (Chem. and Ind. 1964 73) suggested that the simaroubaceae Czocompounds could arise biogenetically by hydrolysis of limonin-like compounds. The Constitution and Absolute Stereochemistry of Simarolide the Bitter Principle of Simarouba amara By W. A. C. BROWN and G. A. SIM* WE have investigated the crystal structures of the m-iodobenzoate and the 4-iodo-3-nitrobenzoate of simarolide? the bitter principle of Simarociba amara. Our results define the molecular structure of simaro- lide as (I; R = H). The absolute configuration shown was deduced by Bijvoet Peerdeman and van Bommel's anomalous-dispersion method.2 Throughout the X-ray analysis the chemical information concerning simarolide was very limited; it was known to have the composition (C&@) where probably n = 9 and to contain a five-membered lactone ring and a hydroxyl an acetoxy and at least one keto-group.ly3 The m-iodobenzoate crystallises in the monoclinic system space group P2, with cell dimensions a = 13.81 b = 6-57 c = 20.16 A 18 = 94" 27'.With two molecules of C34H390101 in the unit cell d (calc.) = 1.34 g.cm.-, whereas determination of the density yielded d (meas.) = 1.50 g.~m.-~. From equi-inclination Weissenberg photographs 1258 inde- pendent structure amplitudes were evaluated. The co-ordinates of the iodine atom were obtained initially from a Patterson synthesis and successive three-dimensional electron-density distributions were evaluated in order to locate the remaining atoms.The situation was complicated by the pseudo-symmetry inherent in the monoclinic space group but eventually we were able to propose the partial structure (11; R = m-IC6H4CO). At this stage the value of R was 27%. The remaining features of the molecule were indistinct and it was by no means clear to us whether the discrepancy between the experimental and the calculated density was to be accounted for by solvation of the crystals or by revision of the molecular formula. Consideration of the density indicated that if the molecular formula of simarolide was (C&O)g each molecule of the iodo- benzoate ester must be associated with two mole- cules of acetone the solvent from which the crystals were grown.* Chemistry Department The University Glasgow W.2. Polonsky Bull. Soc. chim.France 1959 1546. Bijvoet Peerdeman and van Bommel Nature 1951 169 271. Polonsky personal communication. 294 The infrared spectra of simarolide and its deriva- tives demonstrated unambiguously the presence of a y-lactone system whereas the partial structure (11) indicated the presence of a &lactone. Moreover the acetoxy-group in simarolide had been suspected3 of being immediately adjacent to a keto-group as deacetylsimarolide in contrast to simarolide is readily attacked by periodic acid. Since there was no chemical evidence about the type of ring system present in simarolide it seemed possible albeit rather unlikely that the structure we had deduced was in- correct because of wrong choices of alternative atomic sites in the earlier pseudo-symmetric electron- density distributions (cf.the X-ray analysis of bromo- dihydroisophotosantonic lactone4). In the circum- stances we concluded that the most direct and satis- factory route to the true structure was a comparison between the various electron-density distributions we had calculated for the rn-iodobenzoate and an electron-density distribution for a second derivative of simarolide. The 4-iodo-3-nitrobenzoate formed reasonable crystals from acetone and a crystal-structure analysis was undertaken. The unit cell is orthorhombic space group P2,2,2 with dimensions a =20.73 b = 26.72 c = 6-53A.The experimental value for the density is 1.53 g.~m.-~ while with four molecules of C34H3@12NI in the cell the calculated density is 1 -43 g.~m.-~. From equi-inclination Weissenberg photographs 1808 independent structure amplitudes were derived. The iodine atom occupies a general position in the unit cell and the first three-dimen- sional electron-density distribution did not display pseudo-symmetry. Atoms corresponding to the structure (11; R = 4-iodo-3-nitrobenzoyl) were well resolved apart from those of the nitro-group. The second electron-density distribution defined (I ;R = H) as the structure of simarolide. The discrepancy between the experimental and the calculated densities was clearly due to solvation of the PROCEEDINGS crystals.The region occupied by the acetone mole- cule in the unit cell of the 4-iodo-3-nitrobenzoate was apparent in the electron-density distributions but the individual atoms were not resolved in the diffuse electron density suggesting positional disorder of the solvent. The presence of acetone in the crystals was confirmed by mass spectrometry. On the basis of the iodine carbon nitrogen and oxygen atoms but with omission of the solvent molecule the value of R for the 4-iodo-3-nitro- benzoate derivative is 21% at the present stage. Further refinement of the m-iodobenzoate is also continuing; for this derivative with the solvent molecules omitted from the structure-factor calcula- tions the value of R is now 24 %. The structural relation of simarolide to the bitter principles of the quassin5 group and the triterpenoids of the limonin6 group provides strong evidence for the proposed biogenesis' of the quassin group from euphol-derived triterpenoids and indicates that the absolute stereochemistry of quassin is probably as shown in (111).h We are indebted to Professor J. Monteath Robertson F.R.S. for his advice and interest and to Mme. J. Polonsky for supplies of the simarolide derivatives. (Received,June 12th 1964.) Asher and Sim Proc. Chem. SOC.,1962 11 1. Valenta Gray Orr Papadopoulos and Podesva Tetrahedron 1962 18 1433. Arnott Davie Robertson Sim and Watson J. 1961,4183; Experientia 1960 16 49; Barton Pradhan Sternhell and Templeton J. 1961 255. Bredenberg Chem. and Znd.1964 73 ;Polonsky preceding communication. Spin-Spin Coupling with the Hydroxyl-protons of Alcohols By J. MALCOLM BRUCEand P. KNOWLES* SPIN-SPIN coupling between the hydroxyl-and since these solvents contain traces of acids which a-protons of alcohols is readily detected for solu- catalyse exchange of the hydroxyl-protons. tions in dimethyl sulphoxide1p2 or acetone,l but it has It has now been found that the expected splitting been stated1s2 that coupling is rarely observed when patterns are readily observed at 60 Mc./sec. and 40" carbon tetrachloride or deuterochloroform is used for solutions of methanol ethanol and propan-2-01 * Department of Chemistry University of Manchester. D. E. McGreer and M. M. Mocek J. Chem. Educ. 1963,40,358 and references therein.a 0. L. Chapman and R. W. King J. Amer. Chem. Soc. 1964 86 1256. SEPTEMBER 1964 in carbon tetrachloride deuteriochloroform chloro- form or benzene and at 80” for 13% solutions of methanol in carbon tetrachloride or benzene pro- vided that the solvent and solute are distilled from anhydrous sodium carbonate that the chloroform is not unduly exposed to light and that borosilicate glassware is used. Precautions to exclude air or traces of moisture are unnecessary. Purified3 carbon tetrachloride and some samples of commercial deuteriochloroform are sufficiently free from acid to allow the observation of hydroxyl- proton spin-coupling effects even for methanol and care should therefore be taken in interpreting the solution spectra of hydroxylic substances of un-known structure.(Received June 24th 1964.) A. Weissberger (ed.) “Technique of Organic Chemistry,” Interscience Publ. Tnc. New York 1955 Vol. VII p. 41 3. Rate and Product Isotope Effects in Proton-transfer Reactions By V. GOLD and M. A. KESSICK* INreactions with a rate-limiting proton transfer from an acid catalyst to a substrate kinetic isotope effects can be measured by two alternative methods. Either rate comparisons of the reaction in light and heavy water as solvent are made or the isotopic composi- tion of product is compared with that of a reaction medium containing more than one hydrogen isotope. In the reaction between vinylmercuric iodide and sulphuric acid (25~), the two effects have recently been measured yielding values of 2.2 f0.2 for the direct-rate comparison (at 25”) and 7.4 for the pro- duct comparison (at 55”).lIt has been suggested that the difference between these two values is probably due to a “secondary solvent isotope effect,”2 arising from the different isotopic composition of the solvent in the two experiments.We have observed a similar difference between the two isotope effects in the hydration of isobutene in dilute aqueous acid.3 Whereas the ratio n(1 -rn)/rn(l -n) (n being the atom fraction of deuterium in the solvent and rn the mole fraction of t-[2Hl]butyl alcohol in the isolated product) has a value of 3.9 f 0.5 the reaction velocity in ordinary water is only 1.45 times faster than that in deuterium oxide.The value of the rate comparison is confirmed by a series of measurements in isotopically mixed media which conform to the Gross-Butler att tern.^ The product ratio is con- sistent5 with the results for analogous experiments with triti~m.~ We believe that in first order the difference between the t~o isotope effects can be understood in terms of established theory without the postula- tion of new effects. The explanation has general applicability to all reactions of this type. In a solution of a strong acid in an isotopically mixed solvent the isotopic abundance in the hydrogen ions differs from that of the solvent,6 and the iso- topically mixed hydrogen ions H,DO+ and HD20+ coexisting in solution will transfer protons and deuterons with rate constants that are related to those for H30+ and D30+.’If secondary medium effects are entirely ignored this theory [see equation (14) of ref.71 predicts the product isotope effect as related to the rate constants (kE,kD)for proton and deuteron transfer in H20 and D20,respectively by the equation n(1 -m)/m(l -n) = Z-(1+2a)kH/kD. In this expression I is the exchange constant per lyon (I = L-l/g,where L is the fractionation parameter of the Gross-Butler theory4) and a the Bronsted exponent of the proton-transfer reaction. For a reaction with specific hydrogen-ion catalysis a = 1 and in this case the factor E-(1+2a)distinguishing rate and product isotope effects has a numerical value about 3 at 25” and ca.7% lower at 55”.8t The cor- responding ratio obtained by Kreevoy and Kretch- merl (with a small correction to relate both results to the same temperature 55”) is 3.6 -l= 0-3. These results therefore bear out the theoretical predictions and point to the comparative unimportance of the “secondary solvent isotope effect.” (Received JuZy 23rd 1964.) 7 * Although the foregoing discussion has been couched in terms of the formula Chemistry Department King’s College Strand London W.C.2. H30+(since there is now substantial evidence6** in its favour for the discussion of this type of problem) the numerical result of the calculation is independent of the formula assumed for the hydrogen ion. M. M. Kreevoy and R. A. Kretchmer J. Arner. Chem. SOC.,1964 86 2435.C. A. Bunton and V. J. Shiner Jr. J. Arner. Chern. SOC.,1961 83 3214. V. Gold and M. A. Kessick T.A.E.A. Symposium on Isotope Mass Effects in Chemistry and Biology Vienna 1963; Pure Appl. Chem. 1964 8,421. E. L. Purlee J. Amer. Chem. Soc. 1959 81 263. This result supersedes a contrary statement in ref. 3. See also E. L. Purlee and R. W. Taft Jr. J. Amer. Chem. SOC.,1956 78 5807. C. G. Swain E. C. Stivers J. F. Reuwer and L. J. Schaad J. Amer. Chem. SOC.,1958,80 5885. V. Gold Proc. Chem. Soc. 1963 141 and references quoted therein; A. J. Kresge and A. L. Allred J. Amer. Chem. Soc. 1963 85 1541. V. Gold Trans. Faraday SOC.,1960 56 255. K. Heinzinger and R. E. Weston J. Phys. Chem. in the press. PROCEEDINGS A New Synthesis of Benzyne By C.D. CAMPBELL and C. W. REES* BENZYNE is generated rapidly and almost quantita- tively under very mild conditions by the oxidation of 1 -aminobenzotriazole (I) with lead tetra-acetate presumably by fragmentation of the nitrene (11). + 2N (1) NH2 (n) :N Addition during minutes of -aminobenzotri-azole in dry benzene to a stirred suspension of lead tetra-acetate (2 mol.) and 2,3,4,5tetraphenylcyclo-pentadienone (tetracyclone) (2 mol.) in benzene * King's College Strand London W.C.2. under nitrogen gave tetraphenylnaphthalene m.p. 204-206" identical with an authentic specimen in 95 % yield; unused tetracyclone was recovered quantitatively. Similarly 1-amino-5-methylbenzotri-azole gave 6-methyl-l,2,3,4-tetraphenylnaphthalene m.p.222" in 98-5:/ yield. Lead tetra-acetate could be replaced by nickel peroxide (B.D.H.) and the corresponding benzyne adducts from anthracene and furan could be ob- tained similarly. 1-Aminobenzotriazole is readily prepared by a modification of Trave and Bianchetti's method,1 from o-nitraniline* (Received July 1Oth 1964.) G. Bianchetti and R. Trave Atti Accad. naz. Lincei Rend. Classe Sci.5s. mat. nat. 1960 28 652. Absolute Rate Constants for Reaction of Atomic Selenium with Olefins By A. B. CALLEAR and W. J. R. TYERMAN" ATOMIC selenium and carbon monoselenide (CSe) are produced by isothermal flash photolysis of carbon diselenide (CSe,) vapour. Initially the atoms are electronically hot but they are rapidly deactivated by nitrogen$ in the presence of an inert gas the atomic selenium persists for -lop4sec.its spectrum being replaced by that of diselenium (Se,) in absorp- tion. If olefins are added to the gas mixtures the rate of decay of the atomic selenium is increased no di- selenium is formed and strong new band systems appear in the far-ultraviolet spectrum. The same spectra were observed in experiments with carbon oxyselenide (COSe) and these can be assigned to cyclic selenides because the spectrum which resulted from flashing carbon diselenide with trans-but-2-ene was not obtained from the cis-isomer. The spectrum of ethylene selenide has intense bands at 2259 and 2208 A which may be observed up to 100 sec. after the flash; from the kinetics of their formation a rate constant of 7 x ethylene and a second compound containing a double bond.In the Table results are compared with oxygen2 and sulphur atom3 rates. Relative reactivities of Group VI atoms towards olefins and derivatives (298" & ~OK). Ethylene Propene But-1-ene cis-But-2-ene trans-But-2-ene Isobutene Buta-l,3-diene Acetylene A cryloni trile Vinyl chloride O2 1 5.8 5.8 23.8 25-3 25.0 34.3 ---s3 Se 1 1 3.6 2.6 & 0.2 3.6 7.1 f0-6 -24 f1-5 -56 f3.0 -44.7 f3.0 -98.3 f4.0 I <o-1 -3.5 & 0-5 -1.3 & 0.1 ~m.~ A striking feature of the Table is that despite the change from the first to the third Period of the ele- sec-l was derived for addition of atomic selenium to ethylene at 300"~.A large excess of nitrogen pre- vented any significant temperature rise and also equilibrated the distribution between the selenium (43P) states. Relative rate constants for reaction of atomic selenium have been determined by measuring the intensities of the olefin selenide spectra produced after photolysis of carbon diselenide in a mixture of ments atomic selenium still exhibits the electrophilic character which CvetanoviC recognised4 for the re- actions of atomic oxygen; substitution of electron- donating groups for hydrogen increases the reactivity of the olefins. Clearly the same factors determine the reactivity for each of the atomic species. Increase of electron density in the double bond may decrease the change in internal energy for formation of an inter- * Department of Physical Chemistry University of Cambridge.A. B. Callear and W. J. R. Tyerman Nature 1964 202 1326. R. J. CvetanoviC Ah. Photochem. 1963 1 115. 0. P. Strauss and H. E. Gunning Adv. Photochem. 1963 1 248. R. J. CvetanoviC Canad.J. Chem. 1960 38 1678. SEPTEMBER 1964 mediate biradical and this will tend to reduce the activation energy. CvetanoviC discusses correlations with various other addition rates to olefins and gives "free-energy" plots to support the electrophilic nature of the reactions. Whilst perfluorobut-Zene is reported3 to be inert towards reaction with sulphur atoms acrylonitrile and vinyl chloride react more rapidly than ethylene with selenium atoms.This indicates that the reactivity of the double bond does not depend solely on the electron-donating power of substituent groups. (Received,July 27th 1964.) Substitution and Elimination Reactions in the Catalytic Hydrogenation of Organic Halides By D. A. DENTON and P. L. SIMPSON" F. J. MCQUILLIN ABSORBED organometallic derivatives are consideredl to be intermediates in catalytic hydrogenolysis of organic halides. We have examined some instances in which the products of hydrogenolysis apparently arise by alternative modes of reaction of such an intermediate. a-Bromo-lactones of the type (I) were found to give on hydrogenation a substantial yield of the cyclohexanedicarboxylic acid (111) in addition to the debromo-lactone (11).The lactonic product (11) was stable to hydrogenolysis and the acid (111) must therefore arise during displacement of the halogen. We inferred that the products (11) and (111) represent respectively the outcome of substitution and elimination reactions of a common intermediate viz. \-/O.COR Br' -C;-Cq O*COR BrPd' ' 9 ,O-COR -c-c-)CH-CH< H' ' The elimination step (ii) could be substantiated; bromo-lactones derived from dihydro-$-santonin2 (IV) and oleanolic acid on hydrogenation re-formed the parent olefin in quantitative yield. These examples were chosen since the olefinic bonds are resistant to hydrogenation. 0 0 The results of hydrogenolysis of the bromo-lactone (I) and related substances are closely similar to the chemical reduction of the series of mercury cyclo- hexyls (V; R = C02H CH2.0H OMe O-CH,Ph) which on reduction with hydrazine gave the cyclo- hexene (YII) and cyclohexane derivative (VI) in comparable am~unt.~ Significantly the bromo-lactone (VIII) is cata- lytically debrominated without fission of the lactone ring and the mercury derivative (IX) similarly gave no bicycloheptene on chemical red~ction.~ Bicyclo-heptene is a strained olefin.6 We suggest that in hydrogenolysis the ease of formation of the olefinic intermediate may determine the relative proportions of reaction by the alternative paths (i) and (ii).0-Br' CO,H ClHg" Hydrogenation was carried out at room tempera- ture and pressure in alcohol containing potassium acetate equivalent to the halide as buffer and palladised charcoal as catalyst.(Received July 17th 1964.) * Organic Chemistry Department School of Chemistry The University Newcastle upon Tyne 1. Cf. J. S. Campbell and C. Kemball Trans.Faraday SOC.,1963 59 2583. W. G. Dauben and P. D. Hance J. Amer. Chem. SOC.,1955 77,2451; W. Cocker and S. Hornsby J. 1947 1157. A. Winterstein and G. Stein Z. physiol. Chem. 1952 211 56. Cf. K. Alder G. Stein R. F. V. Buddenbrock W. Eckardt W. Frercks and S. Schneider Annalen 1934 514 1. H. B. Henbest and B. Nicholls J. 1959 227. Cf. R. B. Turner W. R. Meador and R. E. Winkler J. Amer. Chem. SOC.,1957 79,4116. PROCEEDINGS Photolysis of 1-(1,2-Diphenylcyclopropyl)-3-diazopropan-2-one By SATORU and NICHOLAS MASAMUNE T.CASTELLUCCI* RECENTLY we reported that a photochemically pared it from (I) with copper. The formation of generated a-keto-carbene adds to a double b0nd.l We have now observed unusual photo-induced re- arrangements of 1-(1,2-diphenylcyclopropenyl)-3-diazopropan-Zone which are in marked contrast to our earlier finding.The recent communication on the silver oxide-catalysed rearrangement of 1-(1,2,3-tri-phenylcyclopropenyl)-3 -diazopropan -2 -one2 has prompted us to report our results in preliminary form. Application of the Amdt-Eistert reaction to 1,2-diphenylcyclopropenecarboxylic acid afforded an acid m.p. 120° which was converted into the corresponding diazomethyl ketone (I) through the acid chloride.Irradiation of a methanolic solution of (I) and silicic acid chromatography gave a neutral compound (11) C,,H,,O, m.p. 73-5-75". The presence of the CH,.CO,Me group was indicated (vmaX. 1733 cm.-l a singlet at T = 6.42 and by incorporation of two deuterium atoms with base). The ultraviolet spectrum is practically superimpos- able with that of 1,3-diphenylcyclobutene,and the n.m.r. spectrum is in agreement with the structure shown in (11). Using the LAOCOON programme for the least-square fitting of the ~pectrum,~ we obtained the following coupling constants J5,6 = -14.55 J3,5 = -0.25 J3,6 = 0.68 J3,4 = 9.63 J4,5 = 4.63 and J4,6 = 1-33 c./sec. The calculated spectrum agreed with that observed. Since 5,6-diphenyltricyclo [2,1,1 ,05v6]hexan-2-one (111) could be a possible intermediate we have pre- 3,4-diphenylphenol on thermolysis at 160-1 75O confirms that structure (111) is correct.H ".in';: HL$-H6 R @) CO OCH, CHN Photolysis of (111) under the conditions described above provided 2,4-diphenylphenol (IV) quantita- tively.* The formation of phenol (IV) from (111) and the absence of (IV) in the photolysate of (I)eliminates (11) as a possible intermediate in the formation of (11) from (I). The photochemically generated carbene must possess a different energy state from that produced with copper. It is interesting to note that Small reported a silver oxide-catalysed rearrangement of her diazoketone, very similar to that reported herein. (Received June 15th 1964.) * Mellon Institute Pittsburgh Pa.U.S.A. Present address (S.M.) Department of Chemistry University of Alberta, Edmonton Alberta Canada. Masamune J. Amer. Chem. SOC.,1964,86 735. Small J. Amer. Chem. SOC.,1964 86 2092. Bothner-By and Castellano in preparation; we are grateful to Dr. Castellano for performing these calculations. Surprisingly 4,5-diphenyltricyclo [l ,I ,I ,04v5]pentane survived similar photolytic conditions. The Mode of Ionisation of Aromatic Amines and the Choice of Indicators for the Determination of Acidity Functions in Alkaline Media By M. R. CRAMPTON and V. GOLD* THE choice of indicators for the determination of the H function in acid media was based by Hammett and Deyrup on the cryoscopic behaviour of organic bases in sulphuric acid.l This criterion allows a distinction between primary and secondary bases (or protona- tion versus hydroxide loss) and acidity functions2 Ho and Jo.A similar test for the mode of ionisation of organic indicators in alkaline media and a clear distinction between H-and J-functions has not so far been available. We now report that n.m.r. measurements on nitro-substituted aromatic amines in basic media establish such a criterion. The spectra differ for species formed by proton loss and those formed by base addition. The results here quoted refer to dimethyl sulphoxide as solvent in presence of methanolic sodium methoxide a solvent system of * King's College Strand London W.C.2. Hammett and Deyrup J. Amer. Chem.Soc. 1932 54 2721;1933 55 1900. Paul and Long Chem. Revs. 1957 57 1. SEPTEMBER 1964 current interest.3c The particular substrates have in the past been used as indicators in basic media? Acidic indicators which lose a proton on ionisation (exemplified by 2,4-dinitroaniline and 2,4-dinitrodi- phenylamine) are recognisable by the gradual shift of the aromatic proton resonances to higher field as methanolic sodium methoxide is added to the solu- tion in dimethyl sulphoxide. There is no change in the pattern of the spectrum but the broad resonance of the amine protons shifts and becomes sharper through exchange with hydroxylic protons. Addition of a methoxide group to the indicator molecule manifests itself in a more profound change of the aromatic region of the spectrum.This be- haviour is given by NN-dimethylpicramide and the spectrum completely confirms the previously sug- gested* formula (I) for this complex. The aromatic protons are now nonequivalent and show a spin- coupled structure with J -1-5 c./sec. Their chemical shifts (-6-17 and -8.46 p.p.m. from tetramethyl- silane as internal reference -i0.03 p.p.m.) are com- parable to shifts of -6.14 and -8.42 p.p.m. for the analogous 1- and 3,5-protons respectively in the complex (11) formed from 1,3,5-trinitrobenzene and sodium meth~xide.~ The spectrum of picramide in dimethyl sulphoxide containing some methanolic sodium methoxide shares some of the features of both types of be-haviour but the predominant reaction is that of methoxide addition.This confirms the previous con- clusion from more indirect evidence that there is both proton loss and methoxide addition with this indicator.* The occurrence of methoxide addition is most clearly demonstrated by the resonance of methoxyl protons (not due to methanol) which is observed when the solid compound prepared from picramide and sodium methoxide is dried and then dissolved in dimethyl sulphoxide. NO2 (1) For the four amines under discussion further addi- tion of sodium methoxide to the ionised solutions has a large effect only in the case of NN-dimethyl- picramide. The two aromatic absorptions now merge in a single line of double intensity shifted only slightly further upfield from the resonance of the 3-proton in (I).The occurrence of this further interaction agrees with previous conclusions! The new evidence indi- cates that a 1 :2 complex is formed by addition of two methoxyl groups in equivalent positions (33). It is clear from the above findings which indicators may be used in the quantitative study of these particular alkaline media. (Received August 12th 1964.) See e.g. (a) Schaal J. Chim. Phys. 1955 52 784; (b) Stewart and ODonnell J. Amer. Chem. SOC.,1962 84 493; (c) Stewart O’Donnell Cram and Rickborn Tetrahedron 1962 18 917. * Gold and Rochester J. 1964 1697. Crampton and Gold J. in press. Conformational Isomers of [14]Annulene By Y. GAONI and F. SONDHEIMER” THEnuclear magnetic resonance (n.m.r.) spectrum of [14]annulene (I)ls2 has been shown3 to consist of two sharp singlets at 7 4.42 and 3.93 in a ratio of ca.6 1. It has now been found that this phenomenon is due to the existence of two conformational isomers isomer A being responsible for the higher-field band and isomer B for the lower-field band. Thin-layer chromatography (t.1.c.) of [14lannulene on Kieselgel G produced one spot. On the other hand when Kieselgel G coated with silver nitrate* was employed. two unequal neighbouring spots were formed the more plentiful isomer A being the slower- moving. On rapid extraction with ether and im- mediate rechromatography both spots were barely changed. However equilibration of the two con- formers was fairly rapid as rechromatography of an ether solution of either spot after storage for 30 min.at room temperature produced both spots as had the original solution. The two conformers have appreciably different * The Daniel Sieff Research Institute Weizmann Institute of Science Rehovoth Israel. Present addiess of F.S. University Chemical Laboratory Lensfield Road Cambridge. F. Sondheimer and Y. Gaoni J. Amer. Chem. SOC.,1960,82,5765. J. Bregman Nature 1962 194 679. L. M. Jackman F. Sondheimer Y. Amiel D. A. Ben-Efraim Y. Gaoni R. Wolovsky and A. A. Bothner-By f. Amer. Chem. SOC.,1962,84,4307; F. Sondheimer,Pure Appl. Chem. 1963,7 363. See C. B. Barrett M. S. J. Dallas and F. B. Padley Chem. and Ind. 1962 1050; L. J. Morris ibid. p. 1238; R. Wolovsky and F. Sondheimer unpublished results.ultraviolet (u.v.) spectra; e.g. isomer A shows Amax. 317 (main) and 378 mp in pentane while isomer B exhibits a considerably less intense maximum at 317 mp and only a shoulder in the 380 mp region. The equilibration could be followed by the U.V. spectra which became identical after each pentane solution had been kept for ca. 30 min. The composition of the equilibrium mixture is temperature-dependent as shown by n.m.r. spectro- scopy for CDCI solutions. The ratio of the two bands was 5.6:1 at 30" 5-3:1 at 40" 4.9:1 at 60° and 4.6 1 at 80". Crystalline [14]annulene1 consists of isomer A for immediate examination of fresh solutions gave essentially only the r 4.42 peak (only very small r 3-93 peak) and exhibited t.1.c. and U.V.character-istics typical of this isomer. The equilibrium mixture (n.m.r. t.l.c. u.v.) was again found after 30 minutes' storage. A likely explanation for the isomerism is that one PROCEEDINGS conformer possesses the structure (I) having H1 and H2 above H3 and H4 (= Ia) and the other has H1 and H3 above H2and H4(= lb). The energy barrier accounting for the existence of the isomers is pro- vided by the overcrowding of the internal hydrogen atoms. The room-temperature X-ray study of the crystalline substance (I) indicates that the molecules are centrosymmetric unless the molecular packing is disordered.2 Isomer A is therefore presumably represented by (Ia) and isomer B by (Ib). (Received July 28th 1964.) The Oxidation of Triphenylphosphine with Hydrogen Peroxide F.FAIRBROTHER, By D. B. COPLEY J. R. MILLER,and A. THOMPSON* DURING the last few years much interest has been taken in the reactions of triphenylphosphine oxide1P2 and triphenylarsine oxides3 with transition-metal ions. One method used for the preparation of these 0xides~9~ consists in the oxidation of triphenylarsine or triphenylphosphine with a mixture of 100-vol. hydrogen peroxide and acetone at 25-30" followed by removal of the solvents under vacuum at room temperature. The unexpected appearance of molecular chlorine as one of the products of the reactions of triphenyl-phosphine oxide prepared by this method with niobium and tantalum pentachlorides led us to an examination of the method of preparation of the tri- phenylphosphine oxide.We now report that this method does not lead directly to the formation of triphenylphosphine oxide but to the hydrogen per- oxide adduct (Ph3PO),,H202. The phosphine (20 g.) was dissolved in acetone (40 g.) at 25-30' and 100-vol. hydrogen peroxide (15 c.c.) added; the Sol- vents were removed under reduced pressure and the residue dried at mm. at room temperature. The adduct is a white solid soluble in chloroform methanol and acetone with the following properties * Department of Chemistry University of Manchester Manchester 13. Goodgame and Cotton J. 1961 3735. Isslieb and Mitscherling Z. anorg. Chem. 1960 304 73. Goodgame and Cotton J. Amer. Chem. SOC.,1960,82 5774. Horner Tyree and Venezky Inorg. Chem.1962,1 844. Shriner and Wolf Org. Synth. 1950 30 97. SEPTEMBER 1964 the values in parentheses being the corresponding values reported for Ph,PO by m.p. 131" (158-159'); Y (P=O) 1180 cm.-l (1195 cm.-l) [Found C 73-9; H 5.45. (Ph,PO),,H202 requires C 73.2;H 5.4%]. The stoicheiometry was con- firmed by estimation of the hydrogen peroxide directly by titration with acid potassium permangan- ate and also by heating in a vacuum at 160"; hydrogen peroxide was then evolved and a weight loss corresponding to one molecule of hydrogen peroxide to two of the phosphine oxide observed. The product obtained from heating in vacuo was identified as triphenylphosphine oxide m.p. 158- 159"; v (P=O) 1195 cm.-l [Found C 77.5; H 5.35. Ph,PO requires C 77.6;H 5~4x1.When this was recrystallised from a mixture of 1Wvol. peroxide and methanol followed by removal of the solvents under vacuum it again yielded the peroxide adduct identified as before by m.p. spectroscopy and analysis. The i.r. spectra of the adduct in Nujol and in Bannister and Cotton J. 1960 1878. Cotton Barnes and Bannister J. 1960 2199. * Hadzi J. 1962 5128. 301 hexachlorobutadiene mulls are very similar to those of pure triphenylphosphine oxide but possess a strong broad absorption at 3200 cm.-l which is readily assigned to an 0-H stretching frequency. The complete absence of any absorption in the 1600-1700 cm.-l region indicates that this adduct is not a hydrate. Moreover the absence of any shift in the frequency of the strong band at 1180 cm.-l on deuteration (Le.using D202)confirms the assign- ment of this frequency to a P=O vibration and not to an 0-H deformation. The slight decrease (15 cm.-l) in this P=O frequency and the position of the 0-H stretching frequency lead to the con- clusion that the substance is a simple adduct of Ph,PO and H202 in which two molecules of tri-phenylphosphine oxide are held together by hydrogen bonding by a bridging hydrogen peroxide molecule other hydrogen bonded adducts of tri- phenylphosphine oxide have previously been re-ported.8 (Received July 28th 1964.) LETTER TO THE EDITOR Taxane By R. LYTHGOE and S. UYEO* K. NAKANISHI INDEPENDENT studies carried out in three laboratories on certain constituents of Taxus species have arrived at identical conclusions regarding their frame~ork.l-~ These constituents belong to a new type of diter- penoid and since undoubtedly other compounds having the same skeleton exist in the plant we sug- gest the name "Taxane" for the nucleus (A) together with the following numbering system the latter based on that appropriate4 to the I.U.P.A.C.name (4,8,12,15,15 -pentamethyltricyclo[9,3,1,03~8]penta-decane). For the sake of convenience however the following trivial names will be retained Taxicin-I1 (B; R = R" = H R' = OH) Taxicin-II1 (B; R = R' = R" = H) and Taxinine2s3 (B; R = Ac R' = H R" = COCH :CH-Ph) (i.e. O-cinnamoyltaxicin-I1 tri-acetate). * (B.L.) School of Chemistry The University Leeds 2; (K.N.) The Department of Chemistry Tohoku University Sendai;(S.U.) The Faculty of Pharmaceutical Sciences Kyoto University Kyoto.Langley Lythgoe Scales Scrowston Trippett and Wray J. 1962 2972; Eyre Harrison Scrowson and Lythgoe Proc. Chem. Soc. 1963 271. Kurono Nakadaira Onuma Sasaki and Nakanishi Tetrahedron Letters 1963 21 53 ;Nakanishi Kurono and Bhacca ibid.,p. 2161. Uyeo Ueda Yamamoto Hazama and Maki J. Pharm. Soc. Japan 1962,82 1081 ;Ueda Uyeo Yamamoto and Maki Tetrahedron Letters 1963 2167. We thank Dr. K. Hirayama Research Laboratory Fuji Photo Film Co. Ltd. Odawara Japan for the nomenclature and numbering. PROCEEDINGS NEWS AND ANNOUNCEMENTS Research Fund.-The Research Fund of the Chemical Society provides grants for the assistance of research in all branches of Chemistry.Applications for grants will be considered in December 1964 and should be submitted on the appropriate form not later than November 16th 1964. The total amount available for distribution is approximately El ,100 and applications from Fellows will receive prior consideration. Forms of application together with the regulations governing the award of grants may be obtained from the General Secretary. The Corday-Morgan Medal and Prize.-This Award consisting of a Silver Medal and a monetary Prize of 500 guineas is made annually to the chemist of either sex and of British Nationality who in the judgement of the Council of the Chemical Society has published during the year in question and in the immediately preceding five years the most meritorious contribution to experimental chemistry and who has not at the date of publica- tion attained the age of thirty-six years.If in the opinion of the Council two or more candidates are of equal merit a medal may be awarded to each and the prize divided equally among them. Copies of the rules governing the Award may be obtained from the General Secretary of the Society. Applications or recommendations in respect of the Award for the year 1963 must be received not later than December 31st 1964 and applications for the Award for 1964 are due before the end of 1965. Recent Developments in Free Radical Chemistry.- There will be a discussion Meeting on this subject in the Rooms of the Society Burlington House on Thursday November 19th at 6 p.m.The following short introductory papers will be given Professor D. H. Hey “Recent developments in free-radical addition reactions” Professor R. N. Haszeldine “Polar effects in free- radical addition reactions” Professor R. H. Thomson “Nitroxide radicals” which will be followed by a general discussion. Election of New Fellows.-43 Candidates were elected to the Fellowship in August 1964. Deaths.-We regret to announce the deaths of the following Mr. T. L. Elliott (1.7.64) a Fellow for more than 50 years; Mr. K. Gardner (17.8.64) who was Chief Analytical Chemist at Fisons Pest Control Limited. The Perkin Centenary Trust.-The Perkin Centen- ary Scholarships for 1964 have been awarded to Mr.D. Harris of Heaton Moor Cheshire tenable at the Royal College of Advanced Technology Salford; to Mr. T. A. Moran of Illingworth Yorkshire tenable at the Bradford Institute of Technology; and to Mr. J.A. Scott of Burneside Westmorland tenable at the Royal College of Advanced Technology Salford. Symposia etc.-An advanced lecture course on Chemisorption and Catalysis will be held at the Manchester College of Science and Technology from January 7-8th 1965. Full details and applica- tion forms are available from The Registrar The Manchester College of Science and Technology Sackville Street Manchester 1. A One Day Conference on “Cryogenics in Rela- tion to Vacuum,” organised in collaboration with the Joint British Committee for Vacuum Science and Technology will be held in London on February 26th 1965.Further enquiries should be addressed to The Administration Assistant The Institute of Physics and the Physical Society 47 Belgrave Square London S.W.l. A Symposium in Medicinal Chemistry on The Interaction of Drugs with Receptors will be held in London on April 5-8th 1965. Further enquiries should be addressed to Dr. Alma B. Simmonds School of Pharmacy Chelsea College of Science and Technology Manresa Road London S.W.3. A Symposium on Thermal Analysis will be held at the Northern Polytechnic on April 13-14th 1965. Further enquiries should be addressed to Dr. B. R. Currell Northern Polytechnic Holloway Road London N.7. Seventh Biennial Conference on Carbon spon- sored by The American Carbon Committee will be held in Cleveland Ohio U.S.A.on June 21st-25th 1965. Further enquiries should be addressed to W. W. Lozier (Programme Chairman) or J. C. Bowman (Local Arrangements Chairman) Union Carbide Corporation Carbon Products Division P.O. Box 61 16 Cleveland Ohio-44101. Personal.-Dr. A. Akisanya has been appointed Associate Professor of Chemistry in the newly established Faculty of Science in the University of Lagos. Mr. F. S. AnseZZ has been appointed Vice-principal of the Northumberland County Technical College Ashington. Professor G. M Badger of the University of Adelaide has been appointed to the Executive of the Australian Commonwealth Scientific and Industrial Research Organisation.Mr. J. Barritt has been elected President of the Society of Dyers and Colourists. Dr. K. W. BenfZeyhas been elected to the Fellow- ship of the Royal Society of Edinburgh and has been appointed an Honorary Lecturer in Chemistry in the University of Hull. SEPTEMBER 1964 Mr. S. G. Brooker has been elected President of the New Zealand Institute of Chemistry. Dr. P. Bruck formerly Imperial Chemical Industries Research Fellow at the University of Hull has been appointed Senior Research Chemist at the Bell & Howell Centre Pasadena California. Mr. H. Buchwald formerly of the Occupational Hygiene Service Slough has been appointed Chemist to the Division of Industrial Health Services for the Alberta Provincial Government Canada.Dr. A. G. Catchpole has been appointed Vice- Principal of Kingston College of Technology. Dr. R. G. CaveZl formerly of the University of Cambridge has been appointed Assistant Professor of Chemistry at the University of Alberta Edmonton Canada. Dr. 1M. R. Churchill,formerly of Sheffield Univer- sity has been appointed to an Instructorship in Chemistry at Harvard University Massachusetts U.S.A. Sir James Cook and Dr. G. E. Watts have accepted invitations to serve as Members of the Council for National Academic Awards. Dr. A. S. Curry has been appointed Director of the Home Office Forensic Science Laboratory (East Midland Area) Nottingham. Dr. J. C. Dacre of the University of Otago has been elected Chairman of the Otago Branch of the New Zealand Institute of Chemistry.Mr. G. C. Davidson has been appointed Chief Chemist of the Westburn Sugar Refineries Limited Greenock. Dr. A. G. Davies has been appointed Reader in Chemistry at University College London. Dr. G. G. Dearing formerly of Grimsby College of Further Education has been appointed Head of the Science Department at Christ’s College Liverpool (University of Liverpool Institute of Education). Dr. H. C. Dunn is attending the Third United Nations Conference in Geneva on the Peaceful Uses of Atomic Energy as a member of the Official U.K. Party under the leadership of Sir William Penney. Dr. E. Dux has been appointed Marketing Director of the Adhesives Division of Corn Products (Sales) Limited.Dr. P. S. Fitt formerly of the Institut de Biologie Physico-Chimique Service de Biochimie Paris has been appointed Assistant Professor of Biochemistry at the University of Ottawa Canada. Dr. J. L. Garnett has been awarded an American Chemical Society Petroleum Research Field grant for research within the University of New South Wales. Dr. L. A. Goodson formerly of Shell Chemical Company Carrington is to take up a post with the Chemical Abstracts Service Colombus Ohio U.S.A. Dr. M. Green has been awarded the degree of D.Sc. at the University of Durham primarily for investigations in the physical chemistry of semi- conductor surfaces. In anticipation of the granting of university status upon Battersea College of Technology the title of Professor has been conferred upon Dr.V. S. Grifiths Head of the Department of Spectroscopy and Chemical Physics and Dr. J. E. Salmon Head of the Department of Chemistry. Dr. G. Hetherington has been appointed Research Manager of Thermal Syndicate Limited. Dr. A. N. Hughes formerly of the University of Southampton has been appointed to a lectureship in Organic Chemistry in the University of Medical Sciences Bangkok Thailand. Dr. K. E. Jabalpurwala formerly Research Associate at Boston University Massachusetts U.S.A. has now joined Zinc Oxide Company of Canada Limited Montreal Canada as Chief Chemist. Dr. D. G. Jones has been appointed Research and Development Director and a Member of the Board and Dr. A. A. L. Challis has been appointed a Joint Research Manager at the Heavy Organic Chemicals Division of Imperial Chemical Industries Limited.Dr. W. Idris Jones has been appointed a Member of the new Water Resources Board. Mr. N. Kirby formerly Government Chemist of Kenya has taken up an appointment in the Research Department of John Mackintosh & Sons Ltd. Norwich. Dr. F. M. Lea Director of the Building Research Station has been awarded the third Walter C. Voss Award presented by the American Society for Testing and Materials. Sir Patrick Linstead has been appointed to a science consultative group by the B.B.C. to help it in the production of programmes; the group will meet twice a year to discuss science programmes with B.B.C. representatives.Professor S. E. Livingstone of the University of New South Wales has been awarded a Royal Society and Nuffield Foundation Commonwealth Scholar- ship which will enable him to spend nine months at University College London working with Professor R. S. Nyholm on the chemistry of metal complex compounds. Dr. K. Merck has recently resigned as Chairman of Elektrochemische Werke Munchen A.G. (a member of the Laporte Industries Group) and has been unanimously elected Honorary President. Dr. E. A. Moelwyn-Hughes and Dr. A. Yofe have been appointed Praelectors and Fellows of Darwin College the newly formed Postgraduate College at Cambridge. Mr. L. Munday formerly of Birkenhead Technical College has been appointed Head of the Department of Chemistry and Biology at the Napier Technical College Edinburgh.Dr. F. H. McDowall has been appointed Director of the Dairy Research Institute Palmerston North New Zealand. Dr. F. J. McQuillin has been appointed to a Readership in Organic Chemistry at the University of Newcastle-upon-Tyne. Dr. D. Nas@uri of the University of Calcutta and at present a Visiting Scientist in the University of Notre Dame Indiana has been awarded the degree of D.Sc. by the University of Calcutta for his research in synthetic organic chemistry. Mr. A. T. Neuflhas been appointed Head of the Chemistry Department of Raines Foundation Grammar School London E.1. Dr. E. J. Newman has been appointed Head of the Analytical Laboratories at Hopkin and Williams Limited.Dr. R. F. Packham Head of the Chemistry Division of the Water Research Association has been granted a years leave of absence to take up a Research Fellowship at Harvard University. Dr. T. J. Painter is working at the Norwegian Institute for Seaweed Research N.T.H. Trondheim from September 1964 to March 1965. Dr. G. B. Petersen of D.S.I.R. Palmerston North New Zealand has been awarded a Carnegie Travel Grant to visit Research Institutions in the United States. Dr. R. J. Porter formerly at the Winthrop Laboratories has been appointed Senior Research Associate in the Department of Chemical Engineer- ing University of Newcastle-upon-Tyne. Mr. H. V.Potter Director and Former Chairman of Bakelite Limited has retired after 50 years in the plastics industry.Dr. R. A. Reed has been appointed to the Board of Whiffen& Sons Limited Fisons' industrial chemical subsidiary. Dr. E. L. Richards of the Massey Agricultural College Palmerston North New Zealand has been elected Chairman of the Waikato Branch of the New Zealand Institute of Chemistry. Dr Ann E. Robinson formerly of the Chelsea PROCEEDINGS College of Science and Technology has been appointed Biochemist in the Department of Forensic Medicine at the London Hospital Medical College. Dr. A. Robson has been appointed Professor of Fibre Science at the Department of Textile Industries University of Leeds. Dr. J. Russell has been posted to the Patents Section of the Defence Research Staff at the British Embassy in Washington U.S.A.Mr. G. G. Shone formerly of D.S.I.R. has been appointed Lecturer in Chemistry at the North Staffordshire College of Technology. Professor S. N. Slater has been appointed for a term of office to the newly-created position of Assistant Vice-Chancellor of the Victoria University of Wellington. Dr. J. A. S. Smith has been appointed to a Reader- ship in Molecular Sciences at the University of Warwick from June lst 1965. Dr. J. K. Smith formerly of the Mid-Essex Technical College Chelmsford has been appointed Senior Lecturer in Inorganic Chemistry at the College of Technology Birkenhead Cheshire. Dr. E. G. Soper who has retired from the position of Vice-Chancellor of the University of Otago New Zealand has been appointed a Professor Emeritus.Dr. F. S. Spring has been appointed to the Board of Barium Chemicals Limited. Mr. D. Swallow has been appointed Works Cost Control Manager at Lankro Chemicals Limited Eccles,M anc hes ter . Mr. S. W. Tan?is now at the Institut fur Organische Chemie University of Basel. Dr. J. Taylor has been re-elected Honorary Treasurer of the Institute of Physics and the Physical Society. Dr. D. H. Thow formerly of Johnson Matthey and Company Limited is now Research and Development Manager of Mine Safety Appliances Company Limited Catalyst Division Glasgow. Dr. A. H. Woodhead is now at the Sugar Milling Research Institute University of Natal Durban. Professor F. G. Young Sir William Dunn Professor of Biochemistry at Cambridge has been appointed the first Master of Darwin College the newly formed postgraduate college at Cambridge.CHEMICAL SOCIETY STAFF APPOINTMENTS Mr. W. D. Broomhead Publications Sales Officer has retired on grounds of health after 38 years of service with the Society. He has been succeeded by Mr. A. Turpin formerly Administrative Officer who has been a member of the Society's staff since 1930. Mr. D. 3'. Renwick has joined the staff as Administrative Officer on August 24th. SEPTEMBER 1964 305 PROGRAMME OF MEETINGS* OCTOBER 1964 TO JANUARY 1965 London Thursday October 15th 1964 at 6 p.m. Tilden Lecture “Experiments with Orientated Molecules,” by Dr. A. D. Buckingham M.A. To be given in the Lecture Theatre School of Pharmacy 29-39 Brunswick Square W.C.1. Thursday October 29th at 2 p.m. Symposium on “The Chemical Significance of the Mossbauer Effect.” To be held at Queen Mary College Mile End Road E.l. (Details will be circulated to Fellows.) Thursday November 19th at 6 p.m. Discussion Meeting on Free Radicals. To be held in the Rooms of the Society Burlington House W.l. Thursday December 17th at 6 p.m. Pedler Lecture “The Widening Outlook in Aromatic Chemistry,” by Professor W. Baker M.A. D.Sc. F.R.S. To be given in the Chemistry Lecture Theatre King’s College Strand W.C.2. Thursday January 14th 1965 at 6 p.m. Faraday Lecture “Some Aspects of the Kinetics and Analyses of Very Fast Chemical Reactions,” by Professor R. G. W. Norrish Sc.D.F.R.S. To be given in the Lecture Theatre The Royal Institution 21 Albemarle Street W.l. Aberdeen Thursday November 12th 1964 at 8 p.m. Lecture “The Chemistry of Oxidative Phosphoryla- tion,” by Dr. V. M. Clark M.A. Joint Meeting with the University Chemical Society to be held in the Chemistry Department The University. Tuesday November 24th at 8 p.m. Lecture “The Substituent Effects of Positive Poles in Aromatic Nitration,” by Dr. J. H. Ridd. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Biochemistry Lecture Theatre Marischal College. Aberystwyth (Joint Meetings with the University College of Wales Chemical Society to be held in the Edward Davies Chemical Laboratory.) Thursday October 15th 1964 at 5 p.m.Lecture “The Design and Development of Atomic Reactors,” by Dr. J. R. Wakefield. Thursday October 29th at 5 p.m. Lecture “Xanthophanic and Glaucophanic Acid,” by Professor L. Crombie D.Sc. F.R.I.C. Thursday November 12th at 5 p.m. Lecture “Topographical Studies of Crystal Sur- faces,” by Dr. J. M. Thomas. Thursday December loth at 5 p.m. Lecture “Addition Accompanying Substitution in Some Aromatic Systems,” by Professor P. B.D. de la Mare Ph.D. D.Sc. Thursday January 21st 1965 at 5 p.m. Lecture “Tetraterpenes,” by Professor B. C. L. Weedon D.Sc. A.R.C.S. Birmingham (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University.) Friday October 23rd 1964 at 4.30 p.m.Lecture “Free Radicals Containing Nitrogen,” by Professor A. F. Trotman-Dickenson Ph.D. Friday November 2&h at 4.30 p.m. Lecture “Ways of Promoting Chemical Reactivity,” by Dr. G. Baddeley. Friday December 4th at 4.30 p.m. Lecture “Synthetic Sex Hormones,” by Professor A. J. Birch D.Phil. F.R.S. Friday January 15th 1965. Lecture to be given by Dr. N. Bartlett. Brighton (Joint Meetings with the University Chemical Society to be held in the Chemical Laboratory The University of Sussex.) Monday October 12th 1964 at 5.30 p.m. Lecture “Polyacetylenes from Mushrooms and Daisies,” by Professor Sir Ewart Jones D.Sc. F.R.S. Monday October 26th at 5.15 p.m. Lecture “Metal to Metal Bonds in Inorganic Com- pounds,” by Professor R.S. Nyholm D.Sc. F.R.S. Monday November 9th at 5.15 p.m. Lecture “Optical Rotatory Dispersion,’’ by Profes- sor W. Klyne M.A. Ph.D. Monday November 23rd at 5.15 p.m. Lecture “Fluoroalicyclic Compounds,” by Professor J. C. Tatlow Ph.D. F.R.I.C. Monday January 11 th 1965 at 5.15 p.m. Lecture to be given by Dr. C. A. Vernon. Monday January 25th at 5.15 p.m. Lecture “Bonds and Orbitals,” by Professor H. C. Longuet-Higgins M.A. D.Phil. F.R.S. Bristol (Joint Meetings with the Society of Chemical Industry and the Royal Institute of Chemistry to be held in the Department of Chemistry The Univer- sity unless otherwise stated.) * Off-prints of this programme can be obtained from the General Secretary The Chemical Society Burlington House London W.l.Thursday October 8th 1964 at 6 p.m. Informal Dinner and Lecture “Applications of Heat and Mass Transfer in Metallurgical Practice,” by Dr. S. E. Woods M.A. Wednesday October 14t h. Lecture “The Assessment of Toxicity Hazards from the use of Plastics Raw Materials,” by Dr. L. Goldberg F.R.I.C. Also joint with the Plastics Insti- tute to be held in the Technical College Gloucester. Thursday October 15th at 6.30 p.m. Lecture “Chemicals from Oil,” by Mr. W. G. Firth M.A. B.Sc. To be given at Street Somerset. Thursday October 22nd at 5.30 p.m. Lecture “Xanthophanic and Glaucophanic Acids,” by Professor L. Crombie D.Sc. F.R.I.C. Also joint with the Student Chemical Society. Thursday October 29th at 7.30 p.m.Ladies’ Evening “Materials and Fashions in Ladies’ Footwear.” To be held at the College of Advanced Technology Ashley Down Bristol. Thursday November 19th at 5.30 p.m. Lecture “Some Effects of Molecular Orientation in Gases and Liquids,” by Dr. A. D. Buckingham M.A. Also joint with the Student Chemical Society. Thursday November 26th at 7.30 p.m. Social Evening to be held at Cheltenham. Thursday December 3rd at 6.30 p.m. Lecture “Aerosols-The Development of Pres-surised Packaging,” by Mr. P. Dyson B.A. B.Sc. Thursday January 21st 1965 at 5.30 p.m. Lecture “Organometallic Co-ordination Chemistry of the Group I1 Elements,” by Professor G. E. Coates D.Sc. F.R.T.C. Also joint with the Student Chemical Society.Friday January 22nd at 5.30 p.m. Lecture to be given by Dr. N. Bartlett. Thursday January 28th at 6.30 p.m. Short Papers. Cambridge (Joint Meetings with the University Chemical Society to be held in the University Chemical Laboratory Lensfield Road.) Friday October 23rd 1964 at 8.30 p.m. Lecture “Symmetry Structure and Spectroscopy,” by Professor A. D. Walsh M.A. Ph.D. Friday November 6th at 8.30 p.m. Lecture “The Stabilisation of Low-valent States of Transition Metals by Tertiary Phosphines,” by Professor J. Chatt Sc.D. F.R.S. Friday November 20th at 8.30 p.m. Lecture “Some Recent Studies on the Biosynthesis of Alkaloids,” by Professor D. H. R. Barton D.Sc. F.R.S. PROCEEDINGS Cardiff Monday November 16th 1964 at 5 p.m.Lecture “Some Applications of Electron Spin Resonance Spectroscopy in Elucidating Reaction Mechanisms,” by Dr. R. 0. C. Norman B.A. To be given in the Department of Chemistry University College Cathays Park Cardiff. Dublin (Meetings to be held in the Department of Chemistry Trinity College.) Friday November 27th 1964 at 7.45 p.m. Lecture “Dissociation of Energies Ionisation Potentials and Electron Affinities of Molecules and Radicals,” by Professor W. C. Price F.R.S. Joint Meeting with the Werner Society. Wednesday January 13th 1965 at 5.30 p.m. Tilden Lecture “Syntheses in the Cardiac-active Steroid Field,” by Professor F. Sondheimer Ph.D. A.R.C.S. Durham (Joint Meetings with the University Chemical Society to be held in the Science Laboratories South Road.) Monday October 12th 1964 at 5 p.m.Lecture “Explosives,” by Dr. B. D. Shaw. Monday November 9th at 5 p.m. Lecture “Multiple Bonds in Inorganic Chemistry,” by Dr. M. F. Lappert F.R.I.C. Monday November 23rd at 5 p.m. Official Meeting and Lecture “Chemical Methods of Attaining High Temperatures,” by Professor P. Gray M.A. Ph.D. Monday November 30th at 5 p.m. Lecture to be given by Dr. M. C. Whiting M.A. Wednesday December 2nd at 5.15 p.m. Lecture “Applications of Nuclear Magnetic Reson- ance Spectroscopy,” by Dr. J. E. Page F.R.I.C. Edinburgh Tuesday November loth 1964 at 4.30 p.m. Lecture “Stepwise Equilibria,” by Dr. F. J. C. Rossotti M.A. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University.Thursday November 12th at 7.30 p.m. Lecture “Modern Aspects of Structure Determina- tion,” by Professor W. D. Ollis Ph.D. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College. Thursday December loth at 7.30 p.m. Lecture “Collagen and its Soluble Derivatives,” by SEPTEMBER 1964 307 Professor A. G. Ward M.A. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College. Tuesday January 19th 1965 at 4.30 p.m. Lecture “Ionic Polymerisation,” by Professor C. E. H. Bawn O.B.E. F.R.S. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University.Thursday January 21st at 7.30 p.m. Lecture “Organic Semiconductors,” by Professor D. D. Eley O.B.E. F.R.S. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College. Exeter (Meetings to be held in the Washington Singer Laboratories Prince of Wales Road.) Friday November 13th 1964 at 5.15 p.m. Lecture “Some Aspects of Electrophilic Aromatic Substitutions,” by Professor C. Eaborn Ph.D. D.Sc. Friday December 4th at 5.15 p.m. Lecture “Organic Semiconductors,” by Professor D. D. Eley O.B.E. F.R.S. Glasgow Thursday October 22nd 1964 at 4 p.m. Lecture “The Chemistry of the Vitamin B, Co-enzyme,” by Professor A.W. Johnson Sc.D. Ph.D. Joint Meeting with the Andersonian Chemical Society and the Alchemist’s Club to be held in the Chemistry Department The University of Strath- Clyde. Thursday November 19th at 4 p.m. Lecture “Atomic and Molecular Events at the Surfaces of Metals,” by Professor F. C. Tompkins Ph.D. F.R.S. Joint Meeting with the Alchemist’s Club to be held in the Chemistry Department The University. Thursday January 21st 1965 at 4 p.m. Lecture “AlkyI and Aryl Derivative of Transition Metals,” by Professor J. Chatt M.A. Sc.D. F.R.S. Joint Meeting with The Andersonian Chemical Society to be held in the Chemistry Department the University of Strathclyde. Hull (Joint Meetings with the University Students Chemical Society to be held at the Lecture Theatre The University unless otherwise stated.) Thursday October 22nd 1964 at 7.30 p.m.Lecture “Applications of Reaction Kinetics to Analytical Problems,” by Professor H. M. N. H. Irving M.A. D.Sc. Joint Meeting with the Royal Institute of Chemistry to be held in the Chemistry Department The University. Thursday November 12th at 4 p.m. Lecture “Chemical Methods of Attaining High Temperatures,” by Professor P. Gray M.A. Ph.D. Thursday November 26th at 4 p.m. Lecture “Some Aspects of the Chemistry of Titan- ium and Neighbouring Elements,” by Dr. G. W. A. Fowles. Leicester Monday October 26th 1964 at 5 p.m. Tilden Lecture “Experiments with Orientated Mole- cules,” by Dr. A. D. Buckingham M.A.To be given at the Department of Chemistry The University. Thursday November 12th at 5 p.m. Lecture “Spectroscopic Aspects of Optical Rotary Power,” by Professor S. F. Mason M.A. D.Phi1. Joint Meeting with the Chemical Society of Leicester College of Technology to be given at the College of Technology. Liverpool (Joint Meetings with the Society of Chemical Industry the Royal Institute of Chemistry and the University Chemical Society to be held in the Donnan Laboratories The Chemistry Department The University.) Thursday October 29th 1964 at 5 p.m. Lecture “Some Aspects of Electrophilic Aromatic Substitution,” by Professor C. Eaborn Ph.D. D.Sc. Thursday November 26th at 5 p.m. Lecture “The Role of Organometallic Compounds in the Development of Co-ordination Chemistry,” by Professor F.G. A. Stone M.A. Sc.D. Manchester (Meetings to be held in Theatre R/H 10 Renold Building Manchester College of Science and Technology unless otherwise stated.) Thursday October lst 1964 at 9.30 a.m. Symposium on “The Problems of Food Additives”. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Renold Building (RC/9) Manchester College of Science and Technology. Thursday October 22nd at 6.30 p.m. Lecture “Stereochemistry of Squalene Biosyn- thesis,” by Dr. G. J. Popjak F.R.S. Thursday November 12th at 6.30 p.m. Lecture “The Corrin Ring System,” by Professor A. W. Johnson M.A. Ph.D. A.R.C.S. Thursday December 10th at 6.30 p.m.Lecture “Recent Developments in Radiation Chem- istry,” by Professor J. J. Weiss D.Eng. Ph.D. Thursday January 21st 1965 at 6.30 p.m. Lecture “Some Recent Developments in the Chemistry of Higher Co-ordination Numbers,” by Professor R. S. Nyholm D.Sc. F.R.S. Newcastle-upon-Tyne (Meetings to be held in the Chemistry Department The University.) Tuesday January 19th 1965 at 6.30 p.m. Lecture “Some Aspects of Public Analysis,” by Mr. J. Markland B.Sc. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry. Tuesday January 26th at 5.15 p.m. Lecture to be given by Dr. N. Bartlett. Northern Ireland (Joint Meetings with the Royal Institute of Chem- istry the Society of Chemical Industry and the Andrews Club to be held in the Department of Chemistry David Keir Building Queen’s University Belfast.) Tuesday November 3rd 1964 at 7.45 p.m.Lecture “The Nature of Reactive Intermediates in Cationic Polymerisation,” by Professor D. C. Pepper M.A. Ph.D. Thursday January 14th 1965 at 7.45 p.m. Tilden Lecture “Syntheses in the Cardiac-active Steroid Field,” by Professor F. Sondheimer Ph.D. A.R.C.S. North Wales (Joint Meetings with the University College of North Wales Chemical Society to be held in the Chemistry Department University College Bangor unless otherwise stated.) Wednesday October 21st 1964 at 7.30 p.m. Lecture “How Poppies make Opium,” by Professor A. R. Battersby Ph.D. Joint Meeting with the Royal Institute of Chemistry to be held in the Chemistry Department Denbighshire Technical College Wrex- ham.Thursday October 22nd at 5.30 p.m. Lecture to be given by Dr. F. J. C. Rossotti M.A. Thursday November 19th at 5.30 p.m. Lecture “Some Problems in Carbohydrate Chem- istry,” by Professor E. J. Bourne D.Sc. F.R.I.C. PROCEEDINGS Norwich (Meetings to be held in Lecture Room 2 The University of East Anglia Wilberforce Road unless otherwise stated.) Thursday October 29th 1964 at 5.30 p.m. Lecture “Recent Developments in the Chemistry of Diazonium Salts,” by Professor J. M. Tedder M.A. Ph.D. D.Sc. Thursday November 26th at 5.30 p.m. Tilden Lecture ‘‘Experiments with Orientated Mole- cules,” by Dr. A. D. Buckingham M.A. Thursday December 3rd at 7.45 p.m. Lecture “Metal to Metal Bonds in Inorganic Com- pounds,” by Professor R.s. Nyholm D.Sc. F.R.S. Joint Meeting with the Royal Institute of Chemistry to be held at the Great White Horse Hotel Ipswich. Thursday January 28th 1965 at 7.30 p.m. Lecture “Infrared Spectroscopy and Molecular Dynamics,” by Professor N. Sheppard M.A. Ph.D. Joint Meeting with the Royal Institute of Chemistry to be held at the Norwich City College Ipswich Road Norwich. Nottingham (Joint Meetings with the University Chemical Society to be held in the Large Lecture Theatre the Department of Chemistry The University.) Tuesday October 13th 1964 at 5 p.m. Lecture “Colour Photography,” Dr. L. A. Williams F.R.I.C. Tuesday October 27th at 5 p.m. Lecture to be given by Dr.E. A. V. Ebsworth B.A. Tuesday November loth at 5 p.m. Lecture “Some Aspects of Polyacetylene Chem- istry,” by Professor Sir Ewart Jones D.Sc. F.R.S. Tuesday November 24th at 5 p.m. Lecture “Symmetry Structure and Spectroscopy,” by Professor A. D. Walsh M.A. Ph.D. Tuesday January 12th 1965 at 5 p.m. Lecture “Behind the Scenes with the Public Analyst,” by Mr. E. R. W. Fogden B.Sc. Tuesday January 26th at 5 p.m. Lecture to be given by Dr. T. M. Sugden F.R.S. Oxford (Joint Meetings with the Alembic Club to be held in the Inorganic Chemistry Laboratory.) Monday October 19th 1964 at 8.30 p.m. Lecture “Stereochemistry of Substitution in Transi- tion-metal Complexes,” by Dr. M. L. Tobe. Monday November 2nd at 8.30 p.m. Lecture “Experiments with Orientated Molecules.” by Dr.A. D. Buckingham M.A. SEPTEMBER 1964 Monday November 16th at 8.30 p.m. Lecture “Gastrin a Peptide Hormone,” by Pro- fessor G. w. Kenner Ph.D. Sc.D. Monday January 25th 1965 at 8.30 p.m. Lecture “Total Synthesis of Sex Hormones and Analogues,” by Professor A. J. Birch D.Phil. F.R.S. Reading (Joint Meetings with the Royal Institute of Chem-istry and the University Chemical Society to be held in the Large Chemistry Lecture Theatre The University.) Tuesday October 20th 1964 at 5.30 p.m. Lecture “Metal-metal Bonds,” by Professor R. S. Nyholm D.Sc. F.R.S. Tuesday November 17th at 5.30 p.m. Tilden Lecture “Experiments with Orientated Mole- cules,” by Dr. A. D. Buckingham M.A.Sheffield (Joint Meetings with the Royal Institute of Chemistry and the University Chemical Society to be held in the Department of Chemistry The University.) Thursday October 15th 1964 at 4.30 p.m. Lecture “Optical Rotatory Power,” by Professor S. F. Mason M.A. D.Phi1. Thursday December loth at 4.30 p.m. Lecture “Unimolecular Isomerisation Reactions of Some Cyclopropanes,” by Dr. H. M. Frey. Swansea (Joint Meetings with the Student Chemical Society to be held in the Chemistry Lecture Theatre University College.) Monday October 26th 1964 at 4.30 p.m. Lecture “Myths and Legends in Analytical Chem- istry,” by Professor R. Belcher Ph.D. D.Sc. Monday November Znd at 4.30 p.m. Lecture “Some Aspects of the Chemistry of Bacterial Cell Walls,” by Professor J.Baddiley Ph.D. D.Sc. F.R.S. Monday November 9th at 4.30 p.m. Lecture “The Role of Organometallic Compounds in the Development of Co-ordinate Chemistry,” by Professor F. G. A. Stone M.A. Ph.D. Monday November 30th at 5 p.m. Lecture “The Hydrogen Bond,” by Dr. L. J. Bellamy. Also joint with the Royal Institute of Chemistry. Southampton (Meetings to be held in the Lecture Theatre the Chemistry Department The University unless otherwise stated.) Friday October 9th 1964 at 5 p.m. Lecture “Some Recent Advances in Biosynthesis,” by Professor D. H. R. Barton D.Sc. F.R.S. Friday October 16th at 7 p.m. Lecture “The Chemist in the Electroplating In- dustry,” by Mr. A. E. Wyszynski. To be given in Lecture Room H9 College of Technology Ports-mouth.Friday October 23rd at 5 p.m. Lecture “Liquid Nitrogen Oxides as Reaction Media,” by Professor C. C. Addison D.Sc. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry. Friday November 6th at 7 p.m. Lecture “The Compounds of the Inert Gases,” by Dr. R. D. Peacock. To be given in Lecture Room H9 College of Technology Portsmouth. Friday December 4th at 5 p.m. Lecture “A Chemist at Sea,” by Dr. L. H. N. Cooper F.R.I.C. Friday January 15th 1965 at 5 p.m. Lecture “Shock Waves in Chemistry,” by Professor J. N. Bradley Ph.D. A.R.I.C. Joint Meeting with the Royal Institute of Chemistry. Tees-side (Joint Meetings with the Royal Institute of Chem- istry and the Society of Chemical Industry to be held at the Constantine College of Technology Middlesbrough unless otherwise stated.) Thursday October Sth 1964 at 8 p.m.Lecture “Nucleic Acid Structure 1953-1 964,” by Dr. S. Arnott. To be given at the Vane Arms Hotel Stock t on-on-Tees . Friday October 16th at 7 p.m. Lecture “Safety in Laboratories,” by Dr. A. A. L. Challis F.R.I.C. Tuesday October ZOth at 8 p.m. Lecture “Ore Minerals and Evaporites in North- East England,” by Professor K. C. Dunham D.Sc. F.R.S. Tuesday October 27th at 8 p.m. Lecture “The Mossbauer Effect an Exciting New Technique in Structural Chemistry,” by Professor N. N. Greenwood Ph.D. Sc.D. To be given in the Vane Arms Hotel Stockton-on-Tees. Thursday November 19th at 8 p.m. Lecture “Some New Synthetic Reactions,” by Professor A.J. Birch D.Phil. F.R.S. Wednesday January 20th 1965 at 8 p.m. Symposium on Heterocyclic Systems with Quater-nary Bridgehead Nitrogen Atoms. Wednesday January 27th at 7.45 p.m. Scientific Film Show to be held at the Synthonia Theatre Balasis Lane Billingham. PROCEEDINGS OBITUARY NOTICES ROBERT BRUCE DUFF 1917-1963 ROBERT DUFF who died suddenly in Aberdeen BRUCE on July 29th 1963 at the age of 46 had worked since 1949 at the Macaulay Institute for Soil Research where he made important contributions to our knowledge of the carbohydrates of soil and the chemical activities of soil micro-organisms. Duff was born on August 31st 1917 and from Boroughmuir Secondary School entered the Univer- sity of Edinburgh in 1936 to read chemistry.He had a brilliant undergraduate career winning the Class Medal in his third year and graduating with First-class Honours in 1940. He held the Vans Dunlop Scholarship in Chemistry for two years and after graduating was awarded a Carnegie Research Scholarship. His research at Edinburgh was interrupted by the growing demands of the war effort in September 1941 he went to a Ministry of Supply Research Unit in Swansea and three months later to I.C.I. (Explo- sives Group) at Ardeer where he remained until October 1945. He then returned to Edinburgh and his Carnegie Research Scholarship and completed his work for the Ph.D. degree in December 1946. After nine months as a research fellow in the Department of Physiology of the Medical School of Birmingham University he returned to Edinburgh this time as an I.C.I.Fellow. All his published work comes either from his periods in Edinburgh or his fourteen years at the Macaulay Institute. At Edinburgh Dr. E. G. V. Percival had been prompted by the occurrence of sulphated polysac- charides in certain marine algae to begin a study of the sulphuric esters of galactose. Duff joined in this work and was able to show that monosubstituted sulphuric esters of several methyl hexosides yielded on alkaline hydrolysis the corresponding 3,6-an- hydrohexosides. The biochemical interest of this observation lay in the fact that 3,6-anhydrogalactose residues were known also to be present in seaweed polysaccharides.By the use of a sulphate prepared from 1,2 -0 -isopropylidene -3 -methyl -gluco-furanose in which substitution prevents the forma- tion of a 3,6-anhydro-derivative he and Percival obtained presumptive evidence that an ethylene oxide structure in position 5,6 could also be formed methanolysis of the product and subsequent acid hydrolysis yielded 3,6-dimethylglucose. The reac-tions of the sulphates were thus analogous to those of the p-toluenesulphonates. The properties of the monosaccharide sulphates and their relation to the anhydro-sugars obtainable from sulphated polysaccharides have been a con- tinuing source of interest for chemists and biochem- ists and the procedure for the preparation of the hexose-6-sulphates described by Duff and Percival in 194 1 has since been employed on many occasions.At the Macaulay Institute Duff joined the Depart- ment of Soil Organic Matter. Investigations of the organic fractions of soils begun at the foundation of the Institute in 1930 had received a new impetus with the development of partition chromatography in the 1940’s. Duff concentrated his attention on that fraction of the soil polysaccharide which is extracted by hot water and which is considered to have an important effect upon the maintenance of good crumb structure. He showed that this fraction con- tained in addition to the commoner hexoses and pentoses rhamnose fucose and some other sugars which he concluded must be partly methylated. This he confirmed in 1961 by the isolation of 2-0-methyl- rhamnose and 4-O-methylgalactose ; the latter had not previously been found in nature.The discovery of 6-deoxyhexoses and methylated sugars in soil led to speculations about their origin and hence about the origin of the polysaccharides in which they occurred. Duff expressed the opinion in 1952 that they must be of microbial origin. He had already established close collaboration with Dr. D. M. Webley and this continued when the latter became Head of a separate Department of Micro-biology. Together they examined the carbohydrates produced by a variety of micro-organisms most of them isolated from soil. They discovered for example that Bacillus megaterium produced con- siderable quantities of 6-O-acetylglucose a substance which had never been found in nature nor syn-thesised before.They also observed the excretion of sugars of the pentose cycle (sedoheptulose ribulose etc.) by Nocardia upaca growing on glucose. The source of the methylated sugars however still eluded them and the search continued. At the time of his death Duff was making a survey of the sugars in polysaccharides produced by bacteria isolated by Webley from the root region of grasses. The soil nocardias had attracted Dr. Webley’s attention because they can live on hydrocarbons as sole carbon source. With Duff he began a series of experiments along the lines of the classical work of Knoop on @-oxidation in animals. These were later extended to include the oxidation of various substi- tuted w-phenoxy-n-alkyl-carboxylicacids having SEPTEMBER 1964 herbicidal action.The results demonstrated that #3-oxidation occurred and in some cases the corre- sponding p-hydroxy-acid was isolated as an inter- mediate. The effects of various substituents of the benzene ring on the rate of oxidation were also examined. A quite different aspect of soil biochemistry was revealed by a study of organisms capable of solu- biking phosphate and silicate minerals. Previous workers had implicated several acids in this process but none is as effective as 2-ketogluconic acid which Webley and Duff found to be the agent by which their most active “phosphate-dissolvers” exerted their action. In collaboration with Dr.R. 0. Scott they described in 1963 the action of one of these bacteria on a wide range of insoluble natural and artificial minerals. The use of paper chromatography in a search for unusual sugars in a variety of plants had led Duff in the course of the last two years to the discovery that the branched-chain pentose apiose is a minor con- stituent of very many higher plants. The intense reaction of its aglycone with a reagent used for detecting sugars had also led to the isolation of a new crystalline glycoside from Plantago species; this has subsequently been shown to be related to catalposide the characteristic glycoside of the catalpa tree. 31 1 The study of humic substances presents formidable problems to organic chemists but few seem to have been attracted by it.It was fortunate that someone of Duff’s calibre should have been brought into the work at the Macaulay Institute. The wide range of problems which he found there presented a challenge which could be met adequately only by a chemist well equipped in all branches of his subject. In disposition Duff was independent to a degree that led him to isolate himself scientifically and socially from all but a few ofhis colleagues. Never- theless once he had established an understanding with someone he collaborated very effectively often becoming the driving force in the partnership. Though usually loth to discuss his research with others he always looked forward to his talks with his former professor E. L. Hirst who visited the Institute regularly as a member of the governing Council.He met his obligations to a wider audience by contributing papers to Biochemical Society meet- ings and by participating in the publication of 13 full papers in chemical biochemical and agricultural journals. He leaves a widow herself a graduate and Ph.D. in chemistry of the University of Edinburgh and one daughter. J. S. D. BACON. W. E. S. TURNER 1881-1963 EMERITUSPROFESSORWILLIAMERNEST STEPHEN industries of supplies of materials usually obtained TURNER who died on October 27th 1963 at his son’s house in Derbyshire will long be remembered as the father figure of Glass Technology. Born on September 23rd 1881 into a very humble home in Wednesbury Staffs. he won a scholarship to King Edward VI School Birmingham and thence again in 1898 to Mason College now the University of Birmingham where he graduated B.Sc.(London) with Honours in Chemistry in 1902 proceeding to M.Sc. (Birmingham) in 1904. In that year W. P. Wynne F.R.S. had been appointed to the Chair of Chemistry at University College (about to become the University of) Sheffield and he chose Turner as the new junior member of his department. For the next ten years Turner remained a lecturer in Chemistry in due course undertaking full responsibility for all teaching of physical chemistry publishing some 20 papers in the Journal mostly on molecular association together with a well-known monograph on that subject and graduating D.Sc. (London) in 19 1 1.In 1914 however came the turning point in his career. The outbreak of war had deprived many from the Continent and at the same time had brought demands for goods they had never made before. There was need of scientific advice and the Univer- sity authorities accepted Turner’s suggestion that an Advisory Committee should be formed to help those engaged in industry in the locality who were con- fronted by such difficulties. Of this Committee Turner was the Secretary and the leading spirit. During the eighteen months of its existence the Committee dealt with very numerous and very varied enquiries but it was soon noticed that a remarkable number of them came from firms making glass. The West Riding of Yorkshire is one of the main centres of the glass industry and from the enquiries he received and from visits to a large number of glass firms in the area Turner became convinced that there was urgent need for systematic scientific instruc- tion and research into Glass Manufacture.In 1915 at his suggestion backed strongly by his chief W. P. Wynne the University established a new department for this purpose with Turner as its Head. From then onwards although while the War lasted he continued to teach in the Department of Chemistry Turner’s great talents and immense energies were directed almost entirely to the develop- ment of Glass Technology as an applied science and to the service of the industry he had adopted. In 1920 he was appointed the first Professor of Glass Tech- nology.The contacts he had made with local manu- facturers soon widened until he and his department were known throughout the industry and he enlisted as members of his staff a succession of young men who afterwards held high positions in it. Beginning in cramped quarters in the main university buildings the Department moved in 1921 to a disused glass works in Darnall some three miles away where it remained for 18 years and where a great bulk of work recorded in some 350 published papers and innumerable reports on specific investiga- tions firmly established its reputation not only with the British industry but internationally. From the beginning Turner emphasised the importance of the closest relations with industry.Before the establishment of regular undergraduate courses the earliest teaching took the form of extra-mural classes in glass-making centres; he and members of the Department did much visiting of glass works and frequently conducted investigations there. At that time many firms worked by rule of thumb and there was much unnecessary secrecy; Turner set himself to broaden communications and as a result of his initiative the Society of Glass Tech- nology-like the Department a pioneer in this field- was founded at the end of 1916 and its Journal designed with Transactions and Abstracts very much on the lines of the Journal of the Chemical Society of those times first appeared in the following year. With the exception of two periods as President Turner was Secretary of the Society from the beginning until 1946 and he edited the Journal until 1951.The formation of the Society did much to encourage friendly interchange of information and it soon acquired an international membership while in the 1930’s a regular international body the Inter- national Commission on Glass was also formed of which Turner was President for 20 years. Through these institutions and his worldwide travels Turner became known not merely as a name but as a person wherever glass is made or studied. A high point in his career came in the late 1930’s. It had long been desired to bring the Department from its isolated position back into the University area. The main problem was finance. In 1935 a suit- able site became available but the University was already appealing for funds for other urgent needs.Turner undertook to get the money needed solely from the Glass Industry and in a remarkably short time he obtained the f40,OOO required and the Department moved into its present delightful premises during 1938-39. He had been elected F.R.S. in 1938 and his friends in the Society of Glass Technology gave him his portrait by Edward J. Halliday which now hangs in the Lecture Theatre. Turner retired from his Chair at the end of 1945 and was made Emeritus Professor. Retirement did not however mean much slackening in activity. For a while he continued to edit the Society’s publica- tions and from 1947 to 1962 practised as a con- sultant travelling even more extensively than before.He continued to publish largely on the history of glass-making up to his death. He was awarded the O.B.E. in 1918 the Honorary degree of Doctor of Technical Science in 1954 and was an honorary member of many foreign scientific bodies. No-one who met Turner whether student colleague client or member of one of his societies is ever likely to forget him. The tall almost emaciated frame the deep voice and in later years the splendid beard gave him all the appearance of the prophet that he was. Utterly devoted to his chosen field of work he combined an indomitable will with enormous industry and a remarkable power to charm. His work will be remembered throughout the glass industry when all who knew him in person will have gone.A. W. CHAPMAN.
ISSN:0369-8718
DOI:10.1039/PS9640000273
出版商:RSC
年代:1964
数据来源: RSC
|
|