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Proceedings of the Chemical Society. March 1962 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue March,
1962,
Page 97-132
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摘要:
PROCEEDINGS OF THE CHEMICAL SOCIETY MARCH 1962 TILDEN LECTURE* Recent Studies on Many-membered Riirgs By R. A. RAPHAEL ALTHOUGH many macrocyclic compounds were terms of the necessary distortion of the carbon- known before 1947 it is probably true to say that this carbon bond angles from the normal tetrahedral date marks the beginning of widespread systematic valuet (Baeyer strain). The excess energy or cyclo-studies of this structural group. In that year Prelog and Stoll reported details of their independent development of the acybin synthesis which for the 12 -first time made available for precise examination G-adequate quantities of macrocyclic carbocyc1es.l It -g 10-was very quickly recognised that there was no smooth -U 8: regular interdependence of properties and ring size.3 A seemingly anomalous discontinuity was found for * 6-a wide range of physical and chemical properties of r-Y 4-derivatives of the eight- to eleven-membered ring 0-C systems (the so-called medium-size rings) with a * 2-u)- turning-point at the ten-membered ring.2 Thuscyclo-u) decanone is particularly inert to many ketonic re-8 0-agents (e.g.,cyanohydrin formation) while cyclodecyl s-toluene-p-sulphonate shows a particularly high re- -2 activity in solv~lysis.~~~ One further aspect of this phenomenon is shown in Fig. 1 which illustrates the excess enthaipy of the cycloalkanes over that of an infinite polymethylene chain.* It is seen that an energy excess in the medium-sized ringsreaches a maximum FIG.1 at cyclononane and cyclodecane.The existence of (Reproduced,with permission from Dunitz and Prelog, such thermochemical strains in cyclopropane and Angew. Chem. 1960,-876.) cyclobutane has long ago received an explanation in * Delivered before The Society at Imperial College London on October 13th 1960; at Tees-side on February 3rd, 1961 ;and at University College,Dublin on April 26th 1961. t This normal value is usually taken as that derived from a regular tetrahedron i.e. 109.5". However it is pertinent to.note6 that the actua! GC-C angle deteeed for straight-chain alkanes and their derivatives is rather larger than this a typical value being 112.0" for hexatnacontane. Prelog Centenary Lecture,J. 1950,420. Prelog in "Perspectives in Organic Chemistry," InterscienCe PUM.Inc. New York 1956 p. 96. Brown Centenary Lecture J. 1956 1248. 'Dunitz and Prelog Angew. Chem. I960,72,896. Bryan and Dunitz. Helv. Chh. Acta 1960,43,3. 97 pentane derives mainly from unfavourable partial conformations (Pitzer strain) involving high bond- opposition forces.* Both of these effects are minimal for the rigid chair conformation of cyclohexane. The strain in the medium-sized rings was initially atri- buted to a combination of Pitzer strain and a third factor intramolecular overcrowding arising from van der Waal's compressions across the ring (trans- annular strain). Several attempts have been made to calculate those medium-size conformation of mini- mumenergy which involve the optimum compromise between the above effects.' Recently a more direct method has been applied to this question and the fruitful X-ray investigations of Dunitz and his colleagues have revealed some unexpected points.A LJ FIG. 2. Conformation of trans-l,6-diaminocyclo- decane dihydrochloride. (Reproduced with permission from Dunitz and Prelog Angew. Chem. 1960,72,898.) FIG.3. Idealised representation of cyclodecane. (Reproduced with permission from Dunitz and Prelog Angew. Chem. 1960,72,900.) The result of the structure analysis of the triclinic modification of the dihydrochloride of trans-l,6-PROCEEDINGS diaminocyclodecaneais reproduced in Fig. 2. This shows clearly that there are two groups of hydrogen atoms three above the ring and three below,which are subjected to a high degree of steric compression and thus direct confirmation is provided of the reality of transannular strain.Most surprisingly however the structure shows practically no Pitzer strain this favourable arrangement being accommodated by de formation of the C-G-c angles round the ring to an expanded average value of 1 17". The representation in Fig. 3 is a very close approximation to the shape of the ten-membered ring revealed in this way. A similar analysis of cyclononylamine hydro bromides derived a much less regular shape for the nine- membered ring (Fig. 4); here again however a similar transannular compression of hydrogen atoms is revealed and the Gc-c angles again possess an expanded value averaging 117".Unlike those in the ten-membered ring the partial conformations round the nine-membered ring are not all favourably staggered and thus Pitzer strain does make some con- tribution to the high energy content of the latter. A t A FIG.4. Conformation of cyclononylamine hydro-bromide. (Reproduced with permission from Dunitz and Prelog Angew. Chem. 1960,72,898.) A further intriguing point was the discovery that the unit cell of cyclononylamine hydrobromide con- tains two different conformations of the molecule which show closely similar shapes for the nine membered ring itself but differ in the position of attachment of the amine function (A and B in Fig. 4). Structure analysis of the solid cyclododecane itselfg * These are at a maximum in a planar model for cyclopentane but are lessened at the expense ofangIe deformation in multiplanar conformations for this ring.s Pitzer and Donath J.Amer. Chem. SOC.,1959 81 3213; Brutcher Roberts,Barr,and Pearson ibid. p. 4915; McCullogh et at. ibid. p. 5880; Low Tetrahedron Letters 1960 No. 1 3. Allinger,J. Amer. Chem. SOC.,1959,81,5727; Pauncz and Ginsberg Tetrahedron 1960,9,40. * Dunitz et al. Helv. Chim. Ada 1960,43 760; 1961,44,2027 2033; Proc. Chem. Soc. 1961,463. Dunitz and Shearer Helv. Chim. Acta 1960,43 18. MARCH1962 FIG.5. Probable confornzation of cyclododecane. (Reproduced with permission from Dunitz and Prelog, Angew. Chem. 1960,72,897.) indicates a conformation in which all strain factors are minimised (Fig. 5) involving no Pitzer strain greatly reduced transannular strain and smaller C-C-C angles (average value 112”);the drop in the heat content curve (Fig.1) for this hydrocarbon is therefore nicely rationalised. a +sp-cIinat a -syn-clinol a -sy” -c~rnat a dt-perlplanar b -syn-clinal b -syn-clinal b anh-periplanar b mtc-periplonor The immediate molecular environment of a ring methylene group may be defined by its relationship to its two flanking pairs of methylene group^.^ Examples of such five carbon conformations are shown in (I) to (IV). (They may be described in terms of the torsion angles across the bonds a and b by the recently introduced nomenclaturelo.) Con- formation (I) occurs six times in the chair form of cyclohexane and conformation (IV) is the familiar zig-zag arrangement of the paraffins.In the medium- sized rings conformations (11) and (III) play an important part and the above conformations for the nine- ten- and twelve-membered rings may be delineated as shown in Fig. 6. FIG.6. The results of this X-ray work immediately pose the question whether the solid-state conformations thus derived can be used as a basis for the inter- pretation of the properties of such systems in solu- tion. This of course is a major extrapolation but there are a number of pointers suggesting that the above conformations are favoured in a wide variety of circumstances. Thus it has already been mentioned that the two conformations of cyclononylamine hydrobromide existing in the crystal possess a closelq similar shape for the nine-membered ring.Again X-ray analysis of the monoclinic form of trans-1,6-diaminocyclodecane dihydrochlorides has revealed the same shape for the ten-membered ring as that already found in the triclinic form (Fig. 2) although the two crystalline modifications represent two dis- tinct conformations of the molecule differing in the manner of the attachment of the amino-groups. Similar examination of the cis-l,6-diamine dihydro- chloride has again disclosed the same geometry for the ten-membered carbocycle.* More convincingly the infrared spectra of cyclodecane and cyclododecane indicate that each of the hydrocarbons possesses the same conformation in both the solid and the liquid state.ll Even more striking are the indications from solution infrared spectroscopy in the region arising from the symmetrical “scissoring” deformation of the methylene grouping.12 In the case of cyclohexane made up of identical methylene environments of type (I) only one sharp band is observable at 1450 cm.-l.The conformation for cyclodecane as shown in Fig. 6 is seen to possess three different methylene environments and this is mirrored by the appearance of three bands in the above region at 1483 1454 (shoulder) and 1445 cm.-l. Similarly the cyclododecane conformation shown is made up of only two methylene environments and the infrared spectrum of this hydrocarbon shows only two com- parable bands at 1470 and 1447 cm.-l. The corres- ponding ketones exhibit analogous behaviour and this multiple-absorption phenomenon was found to persist even in the gas phase for the one compound so studied cyclo-octanone.12 This and other evidence,13 points strongly to the probability of a unique conformation the so-called skewed crown for cyclo-octane and its simple derivatives.Although much more corroborative evidence is needed it thus seems at least feasible as a first approximation that the above conformations for the medium-sized rings might be used for the conforma- tional analysis of their chemistry (with the reserva- tion that these delicately balanced conformations might be very sensitive to substituent effects). For instance in the ten-membered ring as shown in Fig. 3 a relief of transannular strain would result from one of the ring members’ adopting a trigonal rather than lo Klyne and Prelog Experientia 1960 16 521.I1 Billeter and Giinthard Helv. Chim. Acta 1948 41 338. l2 Chiurdoglu Doehaerd and Tursch Chem. and Znd. 1959 1453; Bull. SOC.chim. France 1960 1322. laAllinger and Shih-En Hu J. Amer. Chem. SOC.,1961,83 1664. tetrahedral arrangement. This provides at least a partial explanation of the high rate of solvolysis of cyclodecyl toluene-p-sulphonate and the non-reaction of cyclodecanone with hydrogen cyanide. Thiscyclodecane conformation also provides a satis- fying rationale4 for the wide variety of stereospecific transannular reactions14 occurring in this series by means of a 1,s- or 1,Ghydride shift. Thus in one of the earliest examples hydroxylation of cis-cyclo- decene with performic acid was found to produce only one of the two possible cyclodecane-1,6-diols (probably the cis) while trans-cyclodecene gave the other stereoisomeric 1,6diol in an equally clear-cut manner;15 bromination proceeds in a similar fashion.16 (It is noteworthy that such transannular reactions do not occur in the more spacious cyclo- dodecane system the cyclododecenes give mainly the expected 1,2-di0ls.~') A selection of further examples of transannular reactions in this ring system is given below.The reality of a 1,6-hydride shift in the first example has been demonstrated by deuterium-labellingof the starting diol as shown to give a product with total retention of the deuterium.H& OH PROCEEDINGS SolvoIysls c10 (35 OCO*C6HiN02-p H -22c Even quite mundane physical properties may be used in comparing ring shapes as may be shown by the examples in Table 1 from the extensive work of Huisgen and his Even a cursory inspection TABLE 1. Lactone B.p./ p Hydrolysis rate const. ring size 1Omm. (D) 104k2 at 0" (1. sec.-l mole-l) 4 51 3.8 -5 80 4.09 1480 6 98 4-22 55,000 7 106 4.45 2550 8 82 3-70 3530 9 73 2-25 116 10 87 2.01 0.22 11 100 1.88 0-55 12 116 1.86 3.3 13 130 1.86 6.0 14 143 1.86 3.0 16 169 1.86 6-5 Bu hexanoate 83 1.79 8.4 of the boiling points of the homologous lactones (see Table 1) shows the pronounced break at the eight- and nine-membered rings before the conventional parallelism of boiling point and molecular weight is resumed.The corresponding dipole moments show that the smaller ring lactones (four- to seven-membered) possess the cis-arrangement (V) while the larger lactones (above ten-membered) adopt the trans-conformation (VI); the eight-and nine-membered lactones comprise an equilibrium mixture of the two forms containing respectively about 25% and 90% of the trans-conf~rmation.~~ l4 For a complete review of transannular reactions in medium-sized rings see Cope and Martin Quart. Rev. in the press. l5 Prelog and Schenker Helv. Chim. Acta 1952 35 2044. l6 Zavada and Sicher Proc. Chem. SOC.,1961 199. l7 Prelog and Speck Helv. Chim. Acta 1956 38 1786. Prelog and Kiing Helv. Chim.Acta 1956 39 1394. l9 Cope Cotter and Roller 1.Amer. Chem. SOC.,1955,77 3594. Schenker and Prelog Helv. Chim. Acta 1953 36 896. I1 Cope et al. J. Amer. Chem. SOC.,1958 80 2855; 1960 82,6370. 2aQ Barnard and Yang Proc. Chem. SOC.,1958,302. azb Friedman and Schechter J Amer. Chem.Soc. 1961 83 3159. 22C Goering and Closson J. Amer. Chem. Soc. 1961,83 3511. es Huisgen Angew. Chem. 1957,69 341. 24 Huisgen and Ott Tetrahedron 1959 6 253. MARCH1962 A visual demonstration is provided by the p-nitro- phenylhydrazones of the benzocycloalkenones which pale in colour progressively from deep orange in the case of indan-1-one to light yellow for the deriva- tive of benz~cyclo-octenone.~~ In the latter case the hydrazone chromophore is twisted so effectively out of conjugation with the benzene nucleus that the derivative possesses the ultraviolet characteristics of cyclo hexanone p-ni t r opheny 1hydrazone.0;) GO(”,) Transannular interactions of functional groupings in many-membered rings may be revealed by a variety of physical methods. Thus a strong electron interaction of the type shown in (VII) is readily demonstrable by infrared and ultraviolet spectro- scopy by optical rotatory dispersion and by dipole- moment measurements.% In the perchlorate salt of base (VII) no carbonyl absorption is apparent in the infrared region and the salt must therefore be represented as (VIII) with the formation of a full transannular C-N bond. A beautiful example of transannular effects is provided by the tetrazacyclotetradecane (IX) whose abnormal properties of low basicity great stability and high melting point are most satisfyingly rationalised by its unique capability for quadruple transannular hydrogen bonding.27 A great deal of work has been carried out on the transannular interaction of two benzene rings in the cyclophane class of compound.In the paracyclo- phanes represented by the general formulation (x) the spectra and reactivity of the compounds vary in accordance with the length of the junctions between the two benzene nuclei and this phenomenon has been rationalised as the consequence of transannular interaction of the two n-electron clouds.28 As an example Friedel-Crafts acetylation of the para- cyclophanes showed that the smaller the values of rn and n in (29the faster the rate of introduction of the first acetyl group in one ring but the slower the rate of introduction of the second acetyl grouping in the second ring; this finding suggested transannular de- activation of one unsubstituted nucleus by the other (acetylated) nucleus.29 An interesting transannular bond formation was found to occur during the nitra- tion of [2,2]metacyclophane (XI) whereby the tetrahydronitropyrene (XII) was obtained?O Many of the steric restrictions associated with the smaller rings no longer hold with increasing ring size.Thus the applicability of Bredt’s rule ceases with the eight-membered ring,’ and with this ring size the first incursion of geometrical isomerism about a double bond becomes possible?l The cis-cycloalkenes are thermodynamically more stable than the trans-isomers up to cycloundecene at which point the stability relationship is reversed to the more familiar acyclic pattern32 (in the cycloundecene case it is noteworthy that the stability order is derived almost wholly from the entropy change; this aspect becomes even more striking for the next homologue the more stable trans-cyclododecene possessing a higher heat content than the cis-isomer).Analogous more complex examples are found in cis-cis-and cis-trans-cyclodeca-l,3-diene,33trans-trans- and cis- cis-cyclo-octa-1,5-dieneX and cis-trans-trans- and trans-trans-trans-cyclododeca- 1,5,9-triene;= the last three compounds are made by ingenious oligomerisa- tions of b~tadiene.3~~~ 25 Huisgen et al.Annalen 1954,586 1. 26 Leonard et al. J. Amer. Chem. SOC.,1954 76 630 3463 5708; 1955 77 6234 et req.; 1957 79 5476; 1958 80 4858 6042; 1959,81 504; 1960,82,4075. See aIso Kosower et al. ibid. 1961,83 2031. 27 Stetter and Mayer Chem. Ber. 1961 94 410. 28 Cram et al. J. Amer. Chem. SOC.,1959 81 5963 5971 5977 5983 and references cited therein; 1961 83 2204; Baker McOmie and Norman J. 1951 1114. 2@ Cram et al. J. Amer. Chem. SOC.,1955,77 1179 1186 6289; 1958 80 3094 3126. 30 Allinger Da Rooge and Hermann J. Amer. Chem. SOC.,1961,83 1974. 51 Blomquist et al. J. Amer. Chem. SOC.,1952,76 3636 3643; 1953 75 2153; 1955,77 1001; Cope el al. ibid.,1953, 75 3212; 1955,77 1628; Prelog et al.Helv. Chim. Acta 1952,35 1598 2044; 1953,36,471 1181; 1955.38 1776 1786. Cope Moore and Moore J. Amer. Chem. SOC.,1960 82 1744; 1959 81 3153; Svoboda and Sicher Chem. and Ind. 1959 290; Turner and Meador J. Amer. Chem. SOC.,1957,79,4133; Allinger ibid. p. 3443. 33 Blomquist and Goldstein J. Amer. Chem. Soc. 1955,77 998. 34 Ziegler et al. Annalen 1950 567 1 ;1954 589 122. 36 Wilke Angew. Chem. 1957 69 397; J. Polymer Sci. 1959,38,45. 36 Reed J. 1954 1931. 102 PROCEEDINGS The flexibility of the many-membered rings also allows the incorporation of the linear allenic3’ and acetyleniP functions the smallest member of the latter series being cyclo-octyne.= Non-conjugated cyclic poly-ynes of type (XUI)are now readily ob- tainable by interaction of polymethylene dibromides and a mixture of mono- and di-sodium acetylides; similar compounds with junctions of different lengths between the triple bonds are prepared from poly- methylene dibromides and the disodium derivatives of w-diethynyl compounds.39 It is interesting that the first representative of this type the dioxacyclo- decadiyne (XIV) was reported over thirty years ago4* and this work has recently been fully ~onfirmed.~~ A versatile route to cyclic hydrocarbons containing conjugated diacetylenic linkages has developed from the well-established oxidative coupling of terminal acetylenes to ay-diynes.The elaboration by Dr. G. Eglinton in Glasgow of a highly effective homo- geneous reagent which is particularly conducive to cyclic coupling (cupric acetate in pyridine with ether or alcohol as co-solvent) has proved of great value in this For example subjection of tetra-deca-l,l3-diyne to this process gave a mixture of the cyclic monomer* (cyclotetradeca-l,3-diyne)and the cyclic dimer* (cyclo-octacosa-l,3,15,17-tetrayne).43 The yield sometimes attainable in this process is well shown by the intramolecular coupling of but-4- ynyl undec-10-ynoate whereby there was obtained an 88 % yield of the diacetylenic lactone (XV) readily convertible by hydrogenation into exaltolide.u This reaction has been most fruitfully employed by SondheimeI-45 who has shown that intermolecular coupling of relatively short-chain diacetylenes of type HC=C-X.C=CH produces a whole gamut of easily separable cyclic oligomers of type (XVI) ranging from the dimeric tetra! ne to the hexameric I I dodecayne.Macrocycles of very large ring size have thus been rendered attainable (54 members holds the current record) by an essentially one-step procedure. (xv III) In Glasgow the coupling reaction was applied to o-diethynylbenzene in the expectation that at least one of the main products would be the strainless trimer (XVII). In the event46 the only isolatable com- pound was shown conclusively to be the highly- strained dimer (XVIII) and this unexpected result was fully confirmed by X-ray measurements*’ as shown in Fig. 7. As is seen the distortion of the di- acetylene linkages from their normally linear arrange- ment is considerable.The proximity of the un-saturated centres is obviously highly favourable for transannular reactions and these take place under extremely mild circurn~tances.~~ Thus although * The terms “monomer,” “dimer,” etc. are here used as a convenient approximation to denote the cyclic coupled products [C=C.X.C=C-] derived from the true acyclic monomer HCr C.X-C=CH. *’ Ball and Landor Proc. Chem. SOC.,3961 143; Skattebol Tetrahedron Letters 1961 167; Gardner and Narayana J. Org. Chem. 1961,26 3518. Blomquist Burge Liang Bohrer Suesy and Kleis J. Amer. Chem. SOC.,1951,73,5510;Wittig et. al. Chem. Ber., 1961,94,3260 3276. Wotiz Adams and Parson J. Amer. Chem. Soc. 1961,83,373;Hubert and Dale Chem. andlnd. 1961,249,1224. I0 Lespieau Compt. rend.1929,188 502. 41 Sondheimer Gaoni and Bregman Tetrahedron Letters 1960 No. 26 25. 4a Eglinton and Galbraith Chem. and Ind. 1956 737. Eglinton and Galbraith J. 1959 889. 44 Carnduff Eglinton McCrae and Raphael Chem. and Ind. 1960 559; Bergelson Molotkovsky and Shemyakin ibid. p. 558. Sondheimer et al. J. Amer. Chem. SOC.,1956 78 4178; 1957 79 4247 5817 6263; 1959 81 1771 4600 6301; Proc. Chern. SOC.,1957,79,5817. IsBehr Eglinton Galbraith and Raphael J. 1960,3614; Chem. and Ind. 1959 699. Grant and Speakman Proc. Chern. Soc. 1959 231. MARCH1962 catalytic hydrogenation of (XVIII) certainly gave a substantial amount of the expected perhydro-derivative (XX) a considerable portion of the pro- duct consisted of the pentacyclic hydrocarbon (XXI), together with much smaller amounts of the known fluorenacene (XLX) the last two being derived from (XVIII) by different modes of transannular carbon- carbon bond formation.Sodium in liquid ammonia reduced the acetylene (XVIII) in small amount to compounds (XX) and (XXT) but the two main pro- ducts were two steroisomeric hydrofluorenacenes of gross structure (XXII). FIG.7. I z 0””; A (XVIII) was obtainedm with no detectable amount of the tetramer (XXrV). The latter has now been obtainedm by a different route and is noteworthy for the size of its molecular hole about 9 8 square. Further study of proximity effects on these hydro- carbons and related compounds49 is in progress. Until recently the only known representatives of the monocyclic polyolefins of general formula [-CH=CH-].have b=en tha contrasting planar benzene with six identical hybrid carbonxarbon bonds and the multiplanar cyclo-octatetraene with single-double bond alternation round the ring. This .... . . ...._ _..._ ... ~--X (Reproduced withbrmission from Grant and Speakman Proc. Chem. SOC.,1959,231.) As part of an investigation as to the pathway of formation of the acetylene (XVTII) the corresponding “open dimer” (XXITI) was prepared and subjected 2-(XVIII) (XXI I> I 31 t Reagents 1 Pd-C H,. 2 Na in NH,. 3 Pd-C 300’. to the coupling procedure in the confident expecta- tion that the tetramer (XXIV) would result; most surprisingly a good yield of the strained dimer situation has not afforded much scope for the testing of the Huckel prediction5* that in such systems only those possessing a closed shell of (412+ 2) 7r electrons will exhibit those properties known as aromatic.After benzene itself the vinylogue obeying Huckel’s (XXIII) rule most likely to possess the necessary qualification of planarity or near-planarity is cyclo-octade-canonaene (XXVII) with 18n electrons.51 Ona of the most spectacular recent developments in the macro- cyclic field has been the brilliantly conceived syn- thesis by Sondheimer and his colleagues of this key hydrocarbon and other higher vinylogues of benzene.* * Such compounds may be conveniently described as [NJannulenes where N is the number of ring members. 48 Behr Eglinton and Raphael unpublished work.40 Nakagawa and Toda Tetrahedron Letters 1961 51 ; Chem. and Ind. 1959 458; Bull. Chem. SOC.Japan 196Q,33 223; 1961,34 862,874. Huckel 2.Phys. 1931 70 204; 2. Elektrochem. 1937 43 752 827. 61 For discussion see Baker and McOmie Chapter IX in “Non-benzenoid Aromatic Compounds,” ed. D. Ginsburg Interscience Publ. Inc. New York 1959 p. 477. For the synthesis of compound (XXVII) the hexa- acetylene (XXV) (prepared as already described by the oxidative “trimerisation” of hexa- 1,5-diyne) was subjected to a base-catalysed multiple prototropic rearrangement with the production of the fully con- jugated he~aenetriyne~~ (XXVI). Selective catalytic partial hydrogenation of the three triple bonds in the latter compound produced53 the required cyclo- octadecanonaene([1 Slannulene ;XXVII).Analogous syntheses of other benzene vinylogues have been PROCEEDINGS hydrogen atoms (as shown in XXVII) in a planar structure would constitute an impossibly crowded arrangement most plausibly relieved by a molecular deformation involving out-of-plane buckling.59 The X-ray analysis of [18]annulene is in process at the present time and although the refinement is not yet complete “the deviations of the nine independent carbon atoms from a mean plane determined by all of them are of the order of 0.1 A. The carbon-carbon It is and [30]ann~lene.~~*~~noteworthy that the theoretically highly favourabie Hiickel system of [30]annulene has not proved to be notably stable.(XXV) The interesting [18lannulene(XXVII) proved to be a reasonably stable brownish-red crystalline com- pound sublimable at 120-130”/0-5 mm. and decom- posing slowly on being exposed to light and air. However the hydrocarbon is not strikingly more inert than the non-Huckel [20]- and [24]-annulene and the [14]annulene which although a Huckel system cannot be planar. In its reactions [18]an- nulene behaves as a typical conjugated polyene addi- tion taking place with hydrogen bromine and maleic anhydride. All attempts at electrophilic substitution have so far proved fruitless.5s Molecular-orbital cal- culations on [18Jannulene based on the premise of equal bond lengths in a planar ring led to the pre- diction of ultraviolet absorption at 510 580 and 730 mp58 in considerable discord with the reported values53 of 269,278 369,408,422 and 448 mp.This discrepancy has been taken as an indication that there is therefore single-double bond alternation round the ring of [18]annulene. Alternatively it has been strongly suggested that the six intra-annular bond lengths all lie between 1-37 and 1.42 carried out including those of [14]ann~lene,~~ [20]ann~lene,~~ One most significant difference between the [1 6]ann~lene,~~ [24]ann~lene,~~~~ Huckel and the non-Hiickel annulenes is dramatically revealed by nuclear magnetic resonance spectro-scopy. The essential feature of an aromatic system is the presence of a ring of atoms linked so that n-electrons are delocalised right round the ring.In other terms an aromatic compound may be defined as one which will sustain an induced ring current. The magnitude of this ring current as measured by the degree of shielding of protons attached directly to the aromatic nucleus thus provides at long last a quantitative estimation of the hitherto somewhat subjective concept of degree of aromaticity relative to benzene.61 To take one example the proton absorption of cyclo-octatetraene occurs in the normal olefinic region while that of benzene lies at fields lower by about 1-4 p.p.m. (72-73) because of the deshielding effect. Theory predicts further that in contrast to these peripheral protons those intra- annular protons situated at or near the centre of a large aromatic ring should absorb at very high fields.Thus the intra-annular imino-protons in copropor- phyrin-1 are subjected to intense shielding and pro- duce the extraordinarily high value r = 13.98 at a field some 13 p.p.m. higher than that found for the imino-proton of pyrrole. Accordingly an annulene which obeys Huckel’s rule and is of sufficient size to attain planarity should give rise to absorption in two widely disparate regions of the proton spectrum if it is to be regarded as aromatic. These qualifications are amply met by [18]ann~lene~~ which does in fact show two broad bands at r 1-2 and 11-9 the former being due to the twelve peripheral protons and thus being twice as intense as the latter which arises from the six shielded intra-annular protons. The non- 62 Sondheimer Wolovsky Amiel and Gaoni J.Amer. Chem. SOC.,1959 81 1771. 63 Sondheimer and Wolovsky Tetrahedron Letters 1959 No. 3,3 ;Sondheimer Wolovsky and Amiel J. Amr. Chem. SOC..1962,84,260 270,274. 64 Sondheimer and Gaoni J. Amer. Cheni. SOC.,1960 82 5765. 66 Sondheimer and Gaoni J. Amer. Chern. SOC.,1961,83 1259. 66 Sondheimer and Wolovsky J. Amer. Chem. Sac. 1959 81,4755. 67 Sondheimer et al. J. Amer. Chem. SOC.,1960 82 754 755; 1961 83 1686. Gouterrnan and Wagniere Tetrahedron Letters 1960 No. 11 22; Davies ibid. 1959 8 4; Longuet-Higgins and Salem Proc. Roy. SOC.,1960 A ZS7 445. Coulson and Goleblewski Tetrahedron 1960 11 125. Bregman and Rabinovich personal communication. 61 Elvidge and Jackman J. 1961 859. Ep Jackman personal communication.MARCH1962 Huckel [24]annulene presents a completely different picture the proton absorption being confined to the region 2.5-3.2. In the case of the related dehydro- derivatives the intra-annular protons give rise to a band of he structure which makes possible an unam- biguous assignment. Thus in the Huckel structure trisdehydro[1S]annulene* (XXVI) the intra-annular and the peripheral protons absorb at T 8.1 and 1 -5-3.0 respectively compared with the respective values of T 1.75 and 3-6-49 for the analogous pro- tons of the non-Huckel tetradehydro[24]annulene. These observations provide a particularly clear demonstration of the validity of Huckel’s rule. The availability of macrocyclic compounds has for long prompted the idea of the possible existence of interlinked rings to form structures of the “daisy- chain” type.One obvious problem is the devising of some criterion to establish whether such structures have in fact been formed. An ingenious first step in this direction has been recently reported by Wasser- man63 who carried out the acyloin condensation of diethyl tetratriacontanedioate (XXVIII) in the presence of a large excess of deuterated cyclotetra- triacontane (XXIX) C34H63D5.It was found that the acyloin fraction carefully separated chromato-graphically from (XXTX) showed characteristic C-D stretching frequencies in the infrared spectrum corresponding to a content of about 1% of the so-called catenane acyloin (XXX). Further fission of the acyloin by lead tetra-acetate produced isolable amounts of the original deuterated hydrocarbon (XXIX).Thus a new type of isomerism topological isomerism becomes possible and future trends may perhaps be indicated by the observation that an iso- meric molecular knot of type (XXXI) becomes sterically feasible in systems of 50 members or more. In a brief survey of this type many obvious associated topics cannot be discussed in detail. Thus the molecular dissymetry associated with many large ring systems merits a review of its own. The initial study of many-membered ring systems arose in the first place from an investigation on two animal secre- tions muscone and civetone and Nature’s prior claim in this field has considerably expanded since then.Nine- eleven- and particularly ten-membered rings are now commonplace in the terpene fielda and give rise to interesting biogenetic implicati0ns.6~ Cyclic polypeptides alkaloids and macrolides have become equally familiar and even compounds such as lagosin filipin and pimaricin containing con- jugated trans-polyene systems in a large ring surprise our blase faculties only momentarily. The study of many-membered ring systems still provides fruitful CO Et I VdJ (XXXI) and fascinating ground for both speculation and experimentation; for instance the transannular reactions described above possess obvious biological implications with regard to specific enzyme action upon an adsorbed species. Such investigations not only possess intrinsic scientific interest but have also contributed their mite towards the onward march of civilisation.The long-established perfumery use of large ring ketones and lactones is still flourishing. The intriguing cyclode~trines,~~ whose molecular “hole” functions as a Lewis base are used as a pro- tective molecular stockade in inclusion complexes with otherwise easily oxidisable drugs and vitamins. As a final accolade the macrocyclic polyacetylenes now find use as high-energy binders for rocket fuels. * The extra n-electron pairs of the three triple bonds in this structure are in orbitals in the plane of the ring and therefore make no contribution to the “Huckel total.” 63 Wasserman J. Amer. Chern. Suc. 1960 82,4433; Frisch and Wasserman ibid.1961 83 3789. 64 For a review see Sorm Fortschr. Chem. Org. Natursfofle 1961 19 1. 65 Hendrickson Tetrahedron 1959 7 82. French Adv. Carbohydrate Chern. 1957,12,189; Cramer Angew. Chern. 1961,73,55; 1956,68,118; 1952,64,441. PROCEEDINGS CHEMICAL SOCIETY MEETING THE following papers were read and discussed at a Scientific Meeting of The Chemical Society held at Burlington House on January 18th 1962. Anchimeric Assistance by a Neighbouring Tetrazole material was decisive and showed a strong azide Group. By F. L. SCOTT*and M. HOLLAND. stretching band7 at 2120 cm.-l. This suggested that participation can be de- the substance was in fact 5-azido-3-phenyl-1,2,4-NEIGHBOURING-GROUP tected via kinetic effects by stereochemical changes triazole (V) resulting from tetrazolyl anchimerism or by virtue of a product isolated.We have estab- to produce a transition state close in structure to lished the involvement of a tetrazole ring in such a (IV) followed by (or coincident with) N-N bond process by using the last criterion. The kinetic rupture at the point shown by the broken line in (IV) evidence for this is still being accumulated. to yield (V). Compound (V) was synthesised unam- biguously by diazotisation of 5-amino-3-phenyl-The brominationl in acetic acid of benzaldehyde 1,2,4-triazole followed by displacement of the 5-tetrazolylhydrazone leads to the hydrazidic2 diazonium group with azide ion. The involvement of the heteroatom in (I) may be generalised as follows where X may be a phosphate group,* or hydr~gen,~ or as in the present work halogen.1° Each leaving group may have its own range of utility; for example while compound (V) is readily produced from the bromide (I).This loses bromide ion easily (ti ca. hydrazidic bromide (I) as described above we have 85 min.) in 95% ethanolic solution at 25”. The been unable to effect a simifar conversion using lead analogous rn-andp-bromobenzaldehyde 5-tetrazolyl- tetra-acetate.l’ hydrazones are essentially unaffected under these conditions. The major product (60% yield) of this solvolysis (sic) is a substance of empirical formula A New Synthesis of Acetylenes. Part II. The Reaction (C4H3N,)X. The fact that the material was not the of Triphenylphosphine with a-Halogenocarbonyl expected3 dihydrotetrazine (11) was shown by its Compounds.By S. TRIPPETT. molecular weight [Found M (Rast) 179. Calc. for of the stable phosphoranes (I) affords PYROLYSIS CsH6N6 M 1861. a convenient synthesis of the acetylenes RIC:C.R2 Alternative formulations might include its being a nitrilimine* (which should however add solvent under the reaction conditions) or a diazocyclopro- pene5 (UI) or triazolyItetrazole (IV) resulting from N(3) and N(51 closures respectively.6 Objections can be raised to the last two structures but they need not be considered as the infrared spectrum of the * University College Cork. * By analogy with the name “imidic halide” for the system -C(X)=N- we suggest the name “hydrazidic halide” 1 Scott. Monish. and Reilly J.Org. Chem. 1957 22 692. for the system -C(X)= N-N <. 8 See e.g. Chattaway and Irving J. Chem. SOC.,1935 90;and previous papers. Huisgen. Proc. Chem. SOP.,1961 357. 6 See. e.g. Schnitz and Ohme Chem. Ber. 1961 94 2166. 6 Scott Glick and Winstein Experientia 1957,13,183. 7 Cf. Bhllamy “The Infra-red Spectra of Complex Molecules,” J. Wiley and Sons Inc. New York 1954 p. 223. * See Huisgen Sturm and Seidel Chem. Ber. 1961 94 1555 and other papers by Huisgen’s group. 0 Closure is achieved by oxidation with lead tetra-acetate; see e.g. Bower and Doyle J. 1957 727. loCf. Delaby Mandereau and Reynaud Bull. SOC.chirn. France 1961 2065. An interesting generation of a reactive pyridyl system in situ is described by Huisgen Sturm and Seidel (loc. cit. p. 1558).11 The tetra-acetate oxidation of arylidene-aryl-hydraonesis complex (see Iffland Salisbury and Schafer J. ~m~. Chem. Soc. 1961 83 747). MARCH1962 carbonyl group or its equiva1ent.l The simplest route to the phosphoranes (I) is from or-halogeno- carbonyl compounds by quaternisation with tri- phenylphosphine and treatment of the resulting phosphonium salts with alkali. We have now shown that this quaternisation is restricted to compounds of the formula HalCH,CO.R. In general triphenylphosphine reacts with ar-halo- genocarbonyl compounds to give “enol” phos-phonium salts (11). These are analogous to Rydon’s reagents and with alcohols give the dehalogenated ketone triphenylphosphine oxide and the alkyl halide. The formation of phosphonium salts analogous to (11) is used to correlate the reactions of triphenylphosphine with a wide range of other ha1 ides.In the ensuing discussion Sir Alexander Todd suggested that perhaps the initial products in the reactions of triphenylphosphine with all cc-halogeno-carbonyl compounds were enol phosphonium salts which when derived from Hal.CH,-COR then re- arranged to give p-ketoalkylphosphonium salts. Dr. Trippett replied that a reaction sequence in which phosphorus first got hold of oxygen and then let go of it would be remarkable in view of the tremendous oxygen affinity of phosphorus. After a general discussion it was agreed that steric factors probably controlled the point of attack of the triphenylphosphine. Aroyl Peroxides.Part I. The Decomposition of Benzoyl Peroxide in Alkylbenzenes. By W. R. FOSTER H. WILLIAMS. and GARETH THEkinetics and products of the reactions of benzoyl peroxide with isopropylbenzene ethyl- benzene and p-xylene have been studied over a range of initial peroxide concentrations. The kinetics indicate that reactions of order 1 and 1.5 occur simultaneously in all three solvents and the appropri- ate velocity constants have been determined. The first-order reaction corresponds to the primary fission of the peroxide and the reaction of order 1-5 to a radical-induced decomposition which is terminated by reactions of the type 2R- -+products. From the measured values of the velocity con- stants it is possible to calculate the proportion of the total amount of peroxide which decomposes by the primary and induced reactions and hence the pre- dicted total yield of termination products at any initial peroxide concentration.By comparison of these predictions with the measured yields of the various products it is shown that the various dimeric products which must be termination products account for almost the whole of the permitted yield of these products at each concentration. It follows that much of the yield of biaryls and esters which are the products of nuclear substitution of phenyl and benzoyloxy radicals must be formed in reactions other than those of chain-termination that is to say they must to a considerable extent be products of reactions of induced decomposition of the peroxide.The radical largely responsible for the induced de- composition is therefore the substituted phenylcyclo- hexadienyl radical [RArH]. which is formed as an intermediate in the nuclear substitution of ArH by the radical Re. This process of induced decomposi- tion may therefore be formulated as follows LRArH]. + (PhCO.O) -+ RAr + PhCOzH + PhCO.0. The contribution of other possible reactions of induced decomposition is shown to be fairly small by measurement of the yields of the products of these reactions. In discussion Dr. Bryce-Smith suggested that the induced decomposition of benzoyl peroxide might in part result from its direct oxidation of the dihydro- biphenyls RArH, and tetrahydroquaterphenyls which are known to be products of the decomposi- tion of benzoyl peroxide in benzene.He enquired whether the experimental results excluded such alternatives to the proposed free-radical mechanism. Professor Hey said that the work of Foster and Williams was a logical development from the earlier work of Nozaki and Bartlett and of Godin and Bailey but that they had now for the first time made a complete kinetic and product analysis for the reaction of benzoyl peroxide with an aromatic com- pound. The details of this complex reaction were now becoming clear. The corresponding reaction with benzene should in the absence of a side-chain be less complex. This problem had been recently investigated by Mr. M. J. Perkins. Mr. Perkins said that Nozaki and Bartlett had found that the decomposition of benzoyl peroxide in benzene occurred by way of reactions of order 1 and 1.5.Consideration of the reaction scheme pro- posed by Foster and Williams indicated that in this system benzoic acid should be formed only in the induced decomposition. The experimental yields of benzoic acid measured over a range of initial per- oxide concentrations had been found to be slightly greater than those calculated on this hypothesis by using the rate constants determined by Nozaki and Bartlett. Mr. Perkins suggested that this small dis-crepancy might be due to abstraction by benzoyloxy- radicals of hydrogen from the hydroaromatic pro- ducts of the termination reaction 2[RArH]* + Gough and Trippett Proc. Chem. SOC.,1961 302.Products. In evidence for these and other side reactions it had been noted that the yields of these products fell off very rapidly as the initial concentra- tion of peroxide was increased. Replying Dr. G. H. Williams said that if the steady-state hypothesis is applied to the mechanism proposed by Dr. Bryce-Smith then in the absence of any other reactions of induced decomposition the total rate of disappearance of benzoyl peroxide is given by -d[P]/dt = (k + k,’)[P] where k is the rate-constant for the primary decomposition and k,’ is a composite constant. The kinetics show that a considerable proportion of the peroxide decom- poses by a 1-5-order reaction and this must there- fore correspond to an induced decomposition other than that resulting from the direct oxidation of di-hydrobiaryls and tetrahydroquaterphenyl deriva- tives.It is the mechanism of this process which has been discussed; and the main conclusion reached namely that the oxidation of the a-complex is the most important reaction of chain propagation in the 1 -5-order induced decomposition is reinforced if as seems possible some hydroaromatic products are directly oxidised by molecular benzoyl peroxide. Thus direct oxidation if it occurs must contribute to the first-order component of the total reaction and the contribution of the primary decomposition PROCEEDINGS to this component is therefore correspondingly re-duced. Since direct oxidation results neither in the formation nor in the destruction of radicals the permitted yield of termination products is also reduced and the proportion of the products of nuclear substitution which is formed in a chain- propagation reaction must therefore be increased.To this extent therefore such reactions assume an enhanced importance. The contribution of the “direct oxidation” mechanism cannot however be large since most of the first-order component must arise from the pri- mary decomposition as this is the only radical- forming process and must occur to an extent sufficient to account at least for the yield of the dehydrogeno-dimer 4,4’-dimethylbibenzyl. Thus even if the possible occurrence of termination pro- ducts in the residue is neglected it can be calculated that not more than 13% of the peroxide at 0.01~- concentration to 18% at 0.1M-concentration can decompose in this way.The observation that the sparingly soluble fully aromatic quaterphenyl deriva- tives occur in the residue only to a rather limited extent also supports the conclusion that while the “direct oxidation” mechanism is possible in prin- ciple yet if it occurs its actual contribution is rather small. ROBERT ROBINSON LECTURESHIP THECOUNCIL is pleased to announce the endowment of an important lectureship named in honour of Sir Robert Robinson (President 1939-1941). In 1956 to commemorate the seventieth birthday of Sir Robert Robinson a group of former students and friends of many nationalities contributed to a volume “Perspectives in Organic Chemistry,” pub- lished in New York by Interscience Publishers Incorporated under the editorship of Sir Alexander Todd.The authors of this book all agreed that the royalties which might accrue from the publication should be donated to a specially created charitable institution “The Sir Robert Robinson Foundation Incorporated” which was established in the State of New York. The Foundation will shortly transfer all its assets which amount to some $5,000 and any further benefits which may arise from the publishing agreement to the Chemical Society for the purpose of endowing a Robert Robinson Lecture. The Council has been pleased to accept this endowment and also wishes to acknowledge with grateful appreciation two further gifts each of f750 from Imperial Chemical Industries Limited and The Shell Chemical Company Limited to augment the fund.This lectureship will represent one of the senior awards of the Society and will normally be delivered in alternate years on the occasion of the Anniversary Meetings. The Lecturer may review progress in any branch of chemistry and he shall be appointed by the Council without regard to nationality or domicile. It is expected that a scientific Presidential Address will not be given in the same year as a Robert Robinson Lecture and thus each President will in future give only one scientific address during his term of office. It is hoped that the legal formalities involved in the transfer of the funds from U.S.A. may be com-pleted in time to enable the first appointment of a “Robert Robinson Lecturer” to be made in the Presidential term of office 1962-1 964.MARCH1962 COMMUNICATIONS An Infrared Method of Isotopic Analysis of Oxygen in Oxy-acids and their Derivatives By A. LAPIDOT,S.PINCHAS,and DAVID SAMUEL WEIZMANN OF SCIENCE ISRAEL) INSTITUTE REHOVOTH THEisotopic analysis of oxygen in both organic’ and inorganic cowpounds2 is usually hampered by the necessity of converting the oxygen into carbon di- oxide (or oxygen gas) for mass spectrometry. In addi- tion these methods require relatively large amounts of material and are time consuming. A new method of analysis is described here based on the shift in the infrared absorption bands of certain materials due to the difference in mass of l60 and leg.In many substances these peaks are broad with much over- lapping and cannot be used for quantitative work (see however Spence?).On the other hand in com- pounds of the X=0type it has recently been sh0wn~1~ that the isotopic absorption peaks are separated by 20-30 cm.-l. Although interest in the isotopic analysis of compounds of this type is somewhat limited,4 it has been found that many strong oxy- acids and their acid esters react with carbodi-imides6 to form NN’-disubstituted ureas the carbonyl oxygen of which arises from their free hydroxyl group (the mechanism of the reaction is discussed fully in ref. 6) 2R.XO.OH + R’.N :C :N-R’ +R’-NHCO-NH.R’ + (R-XO),O where X = S or P and R = alkyl aryl alkoxy or aryloxy.The urea can then be analysed for its isotopic oxygen content by measuring the optical density of its solution (of about 13 mg. per ml of a solvent made of carbon tetrachloride 75 % and dimethyl sulphoxide 25%) at the peak of the corresponding C=l60stretching band. This optical density (for a 0.2 mm. cell and against a solvent control) is then compared with that of a similar normal sample and the content of the nonnal modification is thus calculated. The optical density of the unknown sample is now corrected for the absorption of the labelled modification at the point of measurement and the actual content of normal urea is finally calculated. The amount of the labelled urea is found by difference since the urea C=l80 bands investigated so far were found to be less suit- able for direct analysis.For di-p-tolylurea the peaks of the C =l60and C =l80bands appear at 1708 and 1688 cm.-l respectively while in dicyclohexylurea they are at 1668 and 1647 cm.-l. The isotopic shift in the case of solid l8O-labelled dicyclohexylurea has been reported by Stewart and Muenster.’ We have examined the use of this method for the isotopic analysis of a number of substances including water (acidified with dry hydrogen chloride). In each case the substance was condensed with an excess of di-p-tolylcarbodi-imide in ether or dioxan solution. The di-p-tolylurea was separated washed several times with dry ether and dried under reduced pres- sure (it had m.p. 275”). About 3 mg.are required for an analysis in an ordinary cell. The results given in the Table show good agreement between the two Oxygen isotopic analyses of various compounds (%). Compound l80by infrared l80by mass spect r ome try H20 + HC1 52 51 Bz*NH*PO(OH) 25 24.5 %> 16 13.9 p-C6H,Me-S0,H 38 38 6 3 9 methods in the intermediate range; at low con-centrations agreement was less close. In addition to the advantage of the small quantities required the new analytical method will distinguish between alkoxyl- and free-hydroxyl-oxygen atoms in mono- and di-alkyl phosphates8 and between bridge-oxygen atoms and free-hydroxyl groups in pyro- phosphates. The applications and limitations of the method are being investigated further. This research was supported in part by a research grant of the U.S Public Health Service.(Received January 30th 1962.) Doering and Dorfman J. Amer. Chem. SOC.,1953,75,5595; Rittenberg and Ponticorvo Internat. J. Appl. Radiation Isoropes 1956 1,208; Halmann and Pinchas J. 1958 3264; Samuel J. 1960 1318. Anbar and Guttmann Internat. J. Appl. Radiation Isotopes 1959 3 233; Anbar Halmann and Silver Analyt. Chem. 1960,32 841. Spencer Biochem. J. 1959,73,442. Braude and Turner J. 1958 2404. Pinchas Samuel and Weiss-Broday J. 1961 3063. Khorana. Chem. Rev. 1953,53 1945. ’Stewart and Muenster Canad. J. Chem. 1961,39,401. a Halmann J. 1959 305. PROCEEDINGS The Activated Initiation of Vinyl Polymerisation by Metal Carbonyls By C. H. BAMFORD and C.A. FINCH (COURTAWLDS RESEARCH MAIDENHEAD, LIMITED LABORATORY BERKS.) and BELYAVSKII~ FREYJILINA have reported the use of In the absence of carbon monoxide the rate of chromium molybdenum tungsten and iron car-reaction for a given [CCI,] is proportional to bonyls dissolved in halogen compounds such as [carbonylli at low [carbonyl] but as the latter carbon tetrachloride and chloroform for the prepara- increases the proportionality breaks down (see tion of telomers of ethylene e.g.,CCI,. [CH,CH,];CI Figure). This suggests a free-radical mechanism with (n = 1-4). We find that with certain halogen com- retardation by the initiator (or derivative) at high pounds these carbonyls form effective initiators for initiator concentrations. Independent evidence for free-radical polymerisation of vinyl compounds to retardation was obtained from experiments with high polymers at -100".Derivatives containing initiation by benzoyl peroxide which for a given -CCI, -CBr groups increase the rate of polymerisa- rate of polymerisation gives higher molecular tion greatly but other halogen compounds tried weights. With carbon monoxide at -600 mm.the (except CHCI,CO,H) are ineffective (see Table). square-root dependence holds to higher carbonyl concentrations (Figure); the concentration of the re Eflect of halogen compounds on metal carbonyl- tarding species is therefore decreased by carbon initiated polymerisation of methyl methacrylate monoxide. This accounts for the effect of the gas on (9.5 ml. of monomer 30 mg. of carbonyl 0.5 ml.of the molecular weight of the polymer. halogen compound; sealed tubes; 30 min.; 100"). Halogen Conver-Halogen Conver-These observations are consistent with the an- compound sion (%) compound sion (%) nexed mechanism. Models of the radical (111) show Cr(C0)6 Cr(CO)6 None 2.8 CHBr 14.8 n CCI 11.2 CH,Br 0.7 CHCI 10.2 Mo(CO), CH2C12 1.8 None 1.1 (CH*Cl) 1.9 CCI 29-3 CC1,COOH 18.1 CHC1 6-8 CHC12.COOH 5.7 CF2CIZ 0.98 CF,COOH Trace CHF2CI 1.1 C6HsCI 2.5 W(CO) o-C,H,CI 2.2 CCI 10.2 Molecular weights of the order of lo6 are readily obtained under conditions of negligible chain-transfer. M + Cr(CO> z=e M-.-Cr(CO) + CO .......(I) 1 I I 1 .,C!. (1) + CC[~-(Complex) -(1) CLM't a? .;:crO 0.5 1.0 j 1.5 2.0 Cl (m + co (a) ...... (2) Polymerisation of methyl methacrylate initiated by Cr(CO)6-CCI at 100". [CCI,] = 0-206 mole Dilatometer experiments no CO added. 0Gravi-With methyl methacrylate the presence of carbon monoxide at -1 atm. markedly increases the mole- metric experiments CO -600 mm. (measured at cular weight of the polymer and reduces the rate of room temperature). polymerisation the effects being most pronounced at high and low carbonyl concentration respectively. that the structure is stereochemically reasonable; the Control experiments showed that these results arise unpaired spin is probably stabilised by conjugation. from interaction of carbon monoxide with either the This radical may be too unreactive to initiate and initiator or some derived species and not with the may retard the reaction.The rates of formation of growing chains. both radicals (11) and (111) would by virtue of Freydlina and Belyavskii Doklady Akad. Nauk S.S.S.R. 1959,127,1027; Izvest. Akad. Nauk S.S.S.R.,Otdel. khim. Nauk 1961 177. MARCH1962 reaction (l) be reduced by increasing the carbon monoxide pressure in accord with experiment. Re action (2) explains simply the efficacy of three halogen atoms one of which is chlorine or bromine linked to one carbon; in dichloroacetic acid the carbonyl group possibly takes the place of a halogen atom. For acrylonitrile and vinyl acetate initiation by metal carbonyls is subject to a similar activating effect of halogen derivatives. (Received October 31st 1961.) The Stereochemistry of Isophotosantonic Lactone By J.D. M. ASHER and G. A. SLM DEPARTMENT GLASGOW, (CHEMISTRY THEUNIVERSITY W.2) -IRRADIATION of a-santonin in aqueous acetic acid yields isophoto-a-santonic lactonel (I) ;much of the stereochemistry however remained unproved. Bro- mination of dihydroisophoto-a-santonic lactone acetate (see following communication) gave a bromo- derivative whose constitution and stereochemistry (apart from absolute configuration) we have defined as (IT) by a detailed crystal-structure analysis. It follows that the stereochemistry of isophotosantonic lactone is as in (1). the absolute configuration shown being known from chemical studies2 Provided that no inversion occurs at position 1I in the transforma- tion of santonin into bromodihydroisophotosantonic lactone acetate (see following communication) our analysis also demonstrates that a-santonin has the stereochemistry shown in (TJI).with the configura- tion of the 13-methyl opposite to that generally accepted. &x&!3 (m 0 0 The fourteenth three-dimensional electron-density distribution over one molecule of bromodihydroiso-a-photosantonic Lactone acetate shown by means of superimposed contour sections drawn parallel to (0011. Bromodihydroisophotosantonic lactone acetate crystallises in the orthorhombic system space group P2,2,2, with four molecules of C,,H,,BrO in a unit cell of dimensions a = 11.05 b = 19.23 c = 7.93 A. Three-dimensional X-ray intensity data were recorded on equi-inclination Weissenberg photo- graphs and were estimated visually; in all 1022 independent structure amplitudes were evaluated.The co-ordinates of the bromine atom were derived initially from Patterson syntheses. There- after the remaining atoms other than hydrogen were located by computing successive three-dimen- sional Fourier syntheses. The x-and z-co-ordinates of the bromine atom are both close to and the resultant spurious symmetry in the early stages of the analysis made the location of atomic sites more difficult than usual. In our first attempts to overcome this we assigned atoms on the basis of the relative peak heights of alternative sites related by the spurious symmetry and made no use of our know- ledge of the constitution of the molecule.After five rounds of structure-factor and Fourier calculations it became obvious that this approach was unprofit- able and we then considered how best to fit known features such as the five- and seven-membered carbo- cyclic rings to the approximate electron-density distribution based on the bromine phases and to subsequent distributions. This worked well and after five further rounds of structure-factor and Fourier calculations the stereochemistry (11) could be as-signed. Three more rounds of structure-factor and Fourier calculations were then performed and the value of R reduced to 20-3%. Subsequent refinement has been carried out by the method of least squares. The value of R is now 14.2% and the essential details of the structure are firmly established.The fourteenth three-dimensional electron-density distribution over one molecule is shown in the Figure. Barton de Mayo and Shafiq J. 1957,929. See Barton Proc. Chern. SOC.,1958 61 ;Helv. Chim. Acta 1959 42,2604 and references cited therein. The cycloheptane ring has a chair conformation. For the extensive On the University DEUCE computer programmes devised byDr. J. S. Rollett3andDr.J. G.Sime4wereemployed. We are grateful to Professor J. Monteath Robert- PROCEEDINGS son F.R.S. for advice and encouragement and to Professor D. H. R. Barton F.R.S. for suggesting the problem and for supplies of material. One of us (J.D.M.A.) is indebted to the Departmcnt of Scientific and hdustrial Research for financial support.(Received,January 9th 1962.) Rollett in "Computing Methods and the Phase Problem in X-Ray Crystal Analysis," ed. Pepinsky Robertson and Speakman Pergamon Press Oxford 1961 p. 87. Sime ref. 3 p. 301. Synthetic Studies in the Geigerin Series By D. H. R. BARTON and R. J. WELLS T. MIKI,J. T. PINHEY COLLEGE, (IMPERIAL LONDON,S.W.7) HYDROGENATION of isophoto-a-santonic lactonel (I ; X = H 13a-Me) and equilibration at position 4 gave dihydroisophoto-a-santoniclactone (11 ; R = X = H 13a-Me) m.p. 150-152" [a]D + 39" (in CHCI,). Acetylation with sodium acetate-acetic an- hydride afforded the acetate (U; R = Ac X = H 13a-Me) which on bromination gave a monobromo-derivative m.p. 117-1 18" (decomp.) [a] -33" (in CHCI,).The constitution and relative stereochem- istry of this compound are defined as in (Ii; R = Ac X = Br 13a-Me) by Asher and Sim's results re- ported in the preceding Communication which reveals also that the configuration of the 13-methyl group is opposite to that generally accepted2 for a-santonin (111; X = H 13a-Me). Since treatment of the dihydro-lactone (11; R = X = H 13a-Me) with potassium t-butoxide was needed to give di- hydroisophoto-fi-santonic lactone (11; R = X = H 13P-Me) (prepared3 from P-santonin) prior inver- sion at position 11 in the preparation of the bromo- ketone is unlikely. The foIlowing syntheses of deoxygeigerin and of geigerin support the new configuration at position 11. 8-Epi-isophotoartemisic lactone acetate3 (I ; X = OAc 13 a-Me) with pyridine-thionyl chloride gave the 1O(15)-anhydro-derivative which on selective hydrogenation afforded the dihydro-derivative (IV; R = Ac).Hydrolysis with aqueous sodium hydrogen carbonate furnished the alcohol (IV; R = H) (re-acetylation confirmed the structure) and chromous chloride reduced this to the lactone (V; X = H la-H 13p-Me). Treatment with 5% aqueous sul-phuric acid on the steam-bath for 4 hr. then gave l-epideoxygeigerin (V; X = H 1a-H 13a-M.e) and thence by 2 % ethanolic potassium hydroxide at room temperature deoxygeigerin (V; X = H lP-H 13a-Me). The configuration of the last compound at position 1 1 was established earlier.* Since l-epide- oxygeigerin oxime is stable in 2 % aqueous potassium hydroxide it must be the l-centre which is inverted by alkali.If we accept that the configurations of artemisin at positions 8 and 11 have been properly e~tablished,~ it must be the 1 l-centre which is in-verted by acid. The 13-methyl group must therefore be a in artemisin and hence5 in a-santonin. Treatment of deoxygeigerin with lead tetra-acetate and boron trifluoride6 gave mainly a monoacetate m.p. 207-213" [a]D + 49" (in CHCI,). By using lead tetra[14C]acetate and isotope dilution with geigerin acetate (V; X = OAc lP-H 13a-Me) the formation of 0.6% of geigerin acetate was detected. The conversion of artemisin into geigerin is thus complete. [Added in proof February 15rh.I Conversion of isophoto-p-santonic lactone through the same series of reactions as for the a-isomer (see above) gave different compounds at each stage.The 13-methyl group is therefore not inverted in this sequence and the revised configuration of a-santonin is thus firmly established. (Received January 9th 1962.) Barton de Mayo and Shafiq J. 1957 929. See Cocker and McMurry Tetrahedron 1960 8 181. See Barton Proc. Chem. SOC.,1958 61 ;Helv. Chim. Acta 1959,42 2604. 4 Hamilton McPhail and Sim Proc. Chem. SOC.,1960 278. Sumi J. Amer. Chem. SOC.,1958 80,4869. 6 Henbest Jones and Slater J. 1961 4472. MARCH1962 113 The Dehydrogenation of Amines to Imhes By R. G. R. BACON,W. J. W. HANNA,D. J. MUNRO, and D. STEWART (DEPARTMENT OF ORGANIC CHEMISTRY QUEEN’S UNIVERSITY BELFAST IRELAND) NORTHERN FROVDED that hydrogen is present on an a-carbon the medium was water or a polar organic solvent atom a possible mode of oxidation for primary and but the necessary omission of alkali which decom- secondary amines is the dehydrogenation >CH-NH-poses this oxidant normally resulted in the direct + >C :N- analogous to that of alcohols.The diffi- isolation of an aldehyde or ketone (30-90% for culty of observing this result is due to competitive secondary amines lo-(u,% for primary amines). It prccesses such as oxygenation at the nitrogen atom is known however that aliphatic imines which are and to the very easy conversion of imines into other believed to be intermediates in these oxidations are products. Such dehydrogenation has recently been stabilised by chain branching and in the case of di-demonstrated for cyclic secondary amines by the (3.5,5-trimethylhexyl)amine argentic picolinate gave conversion of pyrrolidines into 1-pyrrolines with the stable aldimine mercuric acetate,’ and for some branched-chain ali- CMe,-CH,-CHMe.CH,.CH N*CH,.CH,.CHMe* phatic primary and secondary amines by the produc- CH,CMe3 (80:<).The exceptional dehydrogenation tion of imines with t-butyl hydroperoxide.2 We have of mono-(3,5,5-trimethylhexyl)amine to the cyanide observed similar effects with bivalent silver. CMe,-CH,-CHMe-CH,CN (-10%) which oc-The aqueous S,0,2-Ag+ reagent,3 a known source curred with argentic picolinate recalls the observa- of arqentic ions converted primary aliphatic or ali- tion by Bamberger et aL6 of small amounts of cyclic amines under alkaline conditions into the cyanides among the products of oxidation of primary corresponding aldimines or ketimines which were amines by aqueous peroxomonosulphate.Argentic isolated and hydrolysed with acid or were hydrogen- picolinate gave a similar yield to mercuric acetatel in ated to the secondary amine 2RR’CH*NH -+ the conversion of 2,5-dimethylpyrrolidine into the RR’C:NCHRR’ (I); H,O + (I) -+ RR’CO + 1-pyrroline. NH,CHRR’; H + (I) -+ (RR’CH),NH. Yields The conversion of secondary amines into dehydro- were 15-95 % and were notably good for amines products under some oxidation conditions is thus with branched alkyl chains. The response of second- established while analogous products RR’C :NH, ary amines to S,08&-Ag+ oxidation was inferior to are plausible intermediates in similar oxidations of that of primary amines but the crude products primary amines.‘Ihe nature of the oxidants used showed a peak due to C==N in their infrared absorp- suggests that radical mechanisms are involved. The tion spectra and gave an aldehyde or ketone on acidic results do not however preclude as an alternative hydrolysis (RR’CH),NH + RR’C :NCHRR’ -+ to the successive removal of hydrogen atoms a route RR‘CO + NH,CHRR’. Various a-amino-acids in which hydroxylation occurs followed by elimina- were oxidised to aldehydes but it is not known tion of water or ammonia; there is recent evidence whether imino-compounds were intermediates. for the latter type of mechanism in axidations of For oxidation of amines with argentic picolinate,4 a-amino-acids.’ (Received,January 15th 1962.) Bonnett Clark Giddey and Todd J.1959 2087. De La Mare. J. Om. Chem.. 1960. 25. 2114. a Bacon et al.,’J. 19y60 1339,’and earlier papers. Bacon and Hanna Proc. Chem. SOC.,1959 305; Bacon Chem. and Znd. 1962 19. Tiollais Bull. SOC.chim. France 1947 708 716 959. Bamberger et al. Ber. 1901 34 2262; 1902 35 4293 4299. Spenser Crawhall and Smyth Chem. and Znd. 1956,796; Crawhall and Smyth Biochem. J. 1958,69,280; cf. Pitt J. Amer. Chem. SOC.,1958 80 3799. Copper-catalysed Nucleophilic Aromatic Substitutions Effected in Organic Solvents By R. G. R. BACONand H. A. 0. HILL OF ORGANIC CHEMISTRY QUEEN’S NORTHERN (DEPARTMENT UNIVERSITY BELFAST IRELAND) WE report here in summary preliminary results for actions; halogen replacement is effected with the aid a little explored type of nuclear aromatic substitu- of copper compounds,l assisted by polar solvents.2 tion related to the Sandmeyer and Ullmann re- Ready replacement of halogen in aryl halides was Cf.Bunnett and Zahler Chem. Rev. 1951 49 273 and later observations e.g. Edwards and McTndoe Chem. and Ind. 1953 1091 ; Hardy and Fortenbaugh J. Amer. Chem. Soc. 1958 80 1716; Nesmeyanov Sazonova and Drozd, Doklady Akad. Nauk S.S.S.R. 1960 130 153. Cf. Finger et al.,J. Amer. Chem. SOC.,1956,78,6034; 1959,81,2674; Newman et al. ibid. 1959,81 3667; J. Org. Chem. 1961 26 2525; Campbell and Hutton ibid. p. 2480. effected usually in the temperature range 1 10-1 SO" with the aid of cuprous compounds.No catalytic effect was observed with other metal ions metallic copper or cupric salts. Suitable solvents in order of effectiveness were 2-substituted pyridines benzo- nitrile < pyridine y-picoline < tertiary amides < dimethyl sulphoxide. Observed effects may be syrnbolised (a) ArHal + CuX -f ArX; (b) ArHal + cU,O + a nucleophil X-or HX (e.g. a phenol) -+ArX; (c) ArHal + Cu,O + a hydrogen source (e.g. a carboxylic acid or complex hydride) -+ArH. Coupling 2ArHal+ Ar-Ar was not observed. Reaction rates were measured with the aid of vapour-phase chromatography. Under suitable con- ditions halide replacements of type (a) showed second-order rate constants. The reactions were in- hibited by addition of e.g.a lithium halide or a chelating agent such as 2,2'-bipyridyl. Solvent in- fluence was predominant; e.g. a 200-fold difference in rate constant was observed between reactions in quinoline and dimethyl sulphoxide under standard conditions. Some nuclear para-substituents are known3 to alter rate constants for aryl halides in the absence of a catalyst by factors of e.g. l@-109 but effects so far observed for reactions with cuprous salts were extremely small; e.g. there was only a PROCEEDINGS 5-fold increase for Y = NO2,compared with Y = H or OMe for reactions of p-Y.C,H,-Hal. In 1-halo- genonaphthalenes ease of replacement followed the order I > Br > C1 F while the ease of entry of nucleophils followed the order (for X in CuX) C1 > Br > I > CN SPh.The replacements were often quantitative and provided good preparative methods. Similar replacements are being studied for di- azonium fluoroborates and other kinds of nuclear-substituted aromatic compounds. The development of this project is of interest in relation to current knowledge and theories concerning both the Sand- meyer reaction4 and uncatalysed aromatic substitu- tion~.~ Uncertainty about the structure of solute species in solutions of copper compounds in organic solvents adds an extra complication to an already complicated field. We suggest however that substi- tution is preceded by some form of association between the aryl compound and cuprous complexes of varying composition in which the ligands are solvent molecules anions or other nucleophils.The ease of entry of the nucleophil X into the aromatic nucleus appears to vary inversely with the strength of the ligand bond Cu-X as indicated by stability constants for cuprous complexes.6 (Received December 28ti1 1961 .) Cf. Bevan and Bye J. 1954 3091 ; Miller Parker and Bolto J. Anter. Chem. Soc. 1957 79 93. Cowdrey and Davies Quart. Rev. 1952 6 358; Nonhebel and Waters Proc. Roy. SOC.,A 1957 242 16. Bunnett Quart. Rev. 1958 12 1. "Stability Constants. Part 11 Inorganic Ligands," Chem. SOC.Special Pubf.,No. 7 1958. The Mechanism of Electrophilic Hydrogen Exchange in Pyridine Derivatives By A. R. KATRITZKY and B. J. RIDGEWELL (THEUNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) ELECTROPHILIC substitution of pyridine in acidic media is difficult this could be due to reaction taking place either through the free base present in low concentration or through the very unreactive con- jugate acid.We have sought to decide between these alternatives for the tritiation of pyridines in aqueous sulphuric acid. Portions (1-2 c.c.) of the base-acid- (tritiated water) mixtures of known composition and H" were heated at constant temperatures for known times in sealed tubes. The contents were diluted acid was removed by ion-exchange chromatography base precipitated as picrate the picrate burnt and the tritiated water collected weighed (yield 90-100 %) and counted in a liquid-scintillation spectrometer. No exchange was observed for pyridine under conditions varying up to 40 hours' heating at H" -12 at 207".However 2,6-lutidine 2,4,6-collidine and 1,2,4,6-tetramethyIpyridiniumsulphate showed exchange of approximately 2/9 2/11 and 2/14 respectively of the hydrogen content indicating that exchange was occurring at positions 3 and 5. Plots of log, [(equil. count.)/(equil. count -count)] against time gave reasonably straight lines. Repre- sentative first-order rate Collidine (1 82") H" k (hr.-l) -7.1 0.0098 -7.6 0.024 -7.9 0.039 constants are tabulated. Tetramethyl-p yridinium sulphate (I 82") H" k (hr.-l) -7.1 0.018 -7.6 0.050 -7.9 0.075 Plotting log, k against H" gave reasonably straight lines of gradients of 0.60 for 2,4,6-collidine and 0.82 for the tetramethylpyridinium sulphate.These results indicate that acid-catalysed hydrogen exchange of collidine proceeds by way of the con- jugate acid. Proton resonance studies support this conclusion. We thank Dr. J. Ridd for helpful discussion. (Received February lst 1962.) MARCH1962 115 A Synthesis of N-(5-Amino-l-~-~-ribf~anosyl-4-imidazolyl~~nyl)-~-as~~ic Acid 5'-0-Phosphate By G. SHAW and D. V. WILSON (INSTITUTE OF TECHNOLOGY 7) BRADFORD THEimidazole nucleotide peptide (I) (SAICAR) is We now record a synthesis of compound (I). The an intermediate in the biosynthesis of purine nucleo- isopropylidene ester2 (111) was hydrolysed with tides de novo and may be prepared from the amino- aqueous-alcoholic alkali and the pyridine salt of the imidazole ribotide (Ha) adenosine triphosphak resulting acid treated in pyridine successively with magnesium ions L-aspartic acid and carbon dioxide dicyclohexylcarbodi-imide and dimethyl L-aspartate in the presence of an enzyme fraction of avian 1iver.l and with 2-cyanoethyl phosphate4 and a further H,N-CO.NHCH-CO,H quantity of dicyclohexylcarbodi-imide.The product I was heated with acetic acid to remove the isopropyl- H20,P*O-CHp CH 2*COZH idene group and then kept at 100" with 0.5~-lithium hydroxide. This gave the acid (I) which was purified by chromatography on Amberlite CG-400 (Br- form) resin in a manner analogous to that used for (0 &i H,qP-O*CH H2y-X the isolation of naturally occurring material' and was obtained as a barium salt in an overall yield of (na X=H) about 15% from the ester (111).@b X=C02H) The identity of the synthetic material was con- bN4 (DC x= CO.NH,) HO OH firmed by analysis by vigorous hydrolysis to aspartic acid and glycine by its ultraviolet absorption spectra at various pH values identical with values quoted for the natural material by a characteristic instability of the diazonium salt in the Bratton-Marshall test and by direct paper-chromatographic comparison with 4,b (m> an authentic specimen. In addition our synthetic CMe material was converted into the carboxyamide (Ilc) An intermediate in this reaction is the carboxylic (identified spectroscopically) in a phosphate buffer acid (IIb) which we have recently synthesised.2 The in the presence of adenylosuccinase.nucleotide (I) also accumulates in cultures of several adenine-requiring mutants of Escherichia coli and Salmonella typhimurium because of mutational loss We thank Dr. Joseph S. Gots Department of of a bifunctional enzyme (adenylosuccinase) which Microbiology University of Pennsylvania for gifts catalyses the cleavage of the acid (I) into the carboxy- of SAICAR and of adenylosuccinase and the amide (IIc) and of adenylosuccinic acid into adenylic Medical Research Council for a maintenance grant acid so providing the unusual case of a double block (to D.V.W.). in a common biosynthetic pathway? (Received February lst 1962.) Lukens and Buchanan J. Biol. Chem. 1959,234 1791. Shaw and Wilson Proc. Chem. SOC.,1961 381. Gots and Goilub Proc.Nat. Acad. Sci. U.S.A. 1957,43 826; Miller Lukens and Buchanan J. Biol. Chem. 1959 234 1806. Tener J. Amer. Chem. SOC.,1961 83 159. Dioxygenyl Hexafluoroplatinate(v) O,+[PtFJ By NEIL BARTLETT and D. H. LDHMANN (DEPARTMENT OF CHEMISTRY THEUNIVERSITY OF BRITISHCOLUMBIA VANCOUVER 8 B.C. CANADA) IN an earlier communication' we described a penta- fluoride has been difficult to obtain pure because of fluoride of platinum and an oxyfluoride which we its ready disproportionation to the hexafluoride and then identified as platinum oxide tetrafluoride. Both tetrafluoride subsequent analytical data have con- fluorides are produced when platinum or platinum firmed our earlier conclusion. Analysis of the oxy-salts are fluorinated at high temperatures (200-350") fluoride which is easily purified by vacuum-in glass or silica apparatus.Although the penta- sublimation at lo",proved more difficult. Bartlett and Lohmann Proc. Chern. SOC.,1960 14. A complete and reliable analysis has shown our earlier conclusion concerning the oxyfluoride to be incorrect and has proved the empirical formula to be F,O2Pt (Found F 32.4; 0,10.4; Pt 57.5. F,O,Pt requires F 33.4; 0 9.4; Pt 57.2%). Fluorine was determined by a modified pyrohydrolytic met hod,2 and platinum by ignition in hydrogen of the hydroxide produced in the hydrolysis. Independent analysis was made for platinum by ignition of the solid in hydrogen (Found Pt 57.4 %) and for fluorine by fusion of a sample with sodium in a Parr bomb (Found F 32.7%).Oxygen was determined by displacement of the gas with bromine trifluoride. Hydrolysis of the solid by water vapour liberated 1.3 moles of oxygen per mole of oxyfluoride the other hydrolysis products being hexafluoroplatinic- (IV) acid and hydrated platinum dioxide. The quantity of oxygen evolved is close to that required by the equation F60,Pt -k H@ -+ PtF6*-+ 2H+ + li02.The presence of hexafluoroplatinic acid as one of the hydrolysis products indicates that the six fluorine atoms of the oxyfluoride are bonded to the platinum since the acid cannot be synthesised in aqueous m;dia. X-Ray powder photographs of the oxyfluoride have been indexed on the basis of a cubic unit cell a = 10.032 + 0.002 A U = 1010 A3 Dn= 4-20 (by CCl displacement) Z = 8 Dc = 4.48.The powder photograph shows a close resemblance to that of nitrosy1 hexafluoro-osmate(v) NOOSF, a = 10.12 A 2 = 8 U = 1038 A3 which has been pre- pared recently in this laboratory. Both patterns closely resemble that of potassium hexafluoro-antimonate(v) KSbF, a = 10.15 = 8 U = 1046 A3 the structure of which has been described by Bode and VOSS.~ If the fluorine atoms are assumzd to occupy approximately the same volume in all three unit cells and the platinum osmium and antimony atoms occupy little more than octahedral holes in the close- packed fluorine-atom arrangement then the 0,and NO must occupy approximately the same volume as a potassium ion. If as recommmded by Zachariasen, the effective volume of a fluorine atom is taken as 18 A3,then O2and NO would each occupy -20 A3.This smill volume implies that they are cations O,+ and NO+ (Zachariasen's value for the volume of the K+ is 21 A3). A structure determination of the platinum com- pound has been undertaken with the atoms in the following positions of space group Th7-Ia3 8 Pt in PROCEEDINGS 8(a):O,O,O;16 0 in 16(c) n n n etc. 48 F in 48(e) x y z etc. Good agreement between calculated and observed intensities is obtained with n = 0.215 f 0-005,x = 0.09 y = 0.135 z = 0.mThe Pt-F bond distance is -1.8 A and the 0-0 bond distance 1-17 f0.17 A. The limited intensity data available have not enabled us to make precise light-atom locations but it is clear that discrete 0 and PtF species exist in the lattice.The magnetic susceptibility of the oxyfluoride follows the Curie-Weiss law (8 = -6") over the temperature range 88-294"~. The magnetic moment peff = 2-46 B.M. at 20" is compatible with two un- paired electrons one associated with an O,+ ion the other with the d5system of an octahedral hexafluoro- platinate(v) ion. In its chemical properties the oxyfluoride behaves as a derivative of five-positive platinum. Potassium hexafluoroplatinate(v) (Found F 32-0. KPtF requires F 32.7%) is formed when the oxyfluoride vapour is passed over hot potassium fluoride and when potassium fluoride is mixed with the oxy- fluoride in iodine pentafluoride solution. Potassium hexafluoroplatinate(v) has a rhombohedra1 unit cell with a = 4.97 A o! = 97-5" and is isomsrphous with its ruthenium osmium and iridium analogue^.^ Dis-solution of the oxyfluoride in chlorine trifluoride and in iodine pentafluoride yields 1:1 platinum penta- fluoride-solvent adducts.Formulation of the compound as dioxygenyl hexafluoroplatinate(v) O,+[PtF,]- is compatible with all this evidence. Weinstock Malm and Weaver6 have shown that platinum hexafluoride is thermally unstable and dis- sociates to a lower fluoride and fluorine. In view of this capacity of the hexapositive platinum to oxidise combined fluorine to the elemental form it is not surprising that it is also capable of oxidising the oxygen molecule. A similar oxidation by ruthenium and rhodium hexafluorides is to be looked for.[Added in proof.] O,PtF has been synthesised by mixing oxygen gas with an equimolar quantity of platinum hexafluoride at 21 '. The authors thank the National Research Council. Ottawa and the Research Corporation for financial assistance and one of us (D.H.L.) thanks the Con- solidated Mining and Smelting Company of Canada Ltd. for a Fellowship. (Received December 4th 1961 .) Welsh and Parker U.K.A.E.A. unclassified report WSGR-36 1959. 8 Bode and Voss 2. anorg. Chem. 1951,264 144. 4 Zachariasen J. Amer. Chem. SOC.,1948,70 2147. 6 Hepworth Jack and Westland J. Inorg. Nuclear Chem. 1956 2 80. 6 Weinstock Malm and Weaver J. Amer. Chem. Soc. 1961 83 4310. MARCH1962 117 The Biosynthesis of Extended Quinones By SHEILA M.BOCKS,B. R. BROWN,and A. H. TODD (DYSON LABORATORY OFOXFORD) PERRINS UNIVERSITY SEVERAL naturally occurring extended quinones e.g. hypericin? the erythroaphins,2 and 4,9-dihydroxy- perylene-3,10quinone,3 are symmetrical and there- fore derivable from two identical molecules. Further it has been suggested that the first4 and third5 of these arise in Nature in this way by oxidative coupling of phenolic precursors. Wood-ro tting fungi (e.g. Polyporus versicolor) when grown on a solid agar medium which contains phenols are known to produce dark zones around the fungal colonies.6 An enzyme acting on phenols appears in the liquid culture medium on which P. versicofur is grown. The same activity can be ob- tained from extracts of the mycelium.When 2,Qdi- methoxyphenol is the substrate the enzyme has an op:imum pH around 4.0. Activity is lost if the cell- free enzyme solution is boiled for five minutes. The activity of the enzyme is inhibited by sodium azide but dialysis against sodium acetate buffer (0.00 1M; pH 4.0) has no effect. The cell-free enzyme solution converts 2,6-di-methoxyphenol (I; R = OMe) in 0.1% solution in acetate buffer (PH 4.0) at 30”into 3,5,3’,5’-tetra- methoxydiphenoquinone (coerulignone) (II; R = OMe) identified by its ultraviolet and infrared spectra in 90% yield and 2,6-dimAhylphenol (I; R = Me) similarly into 3,5,3’,5’-tetramethyldipheno-quinone (11; R = Me) (30%). An oxidative coupling of this kind has not previously been reported for monophenol oxidase systems; the enzyme solution does not require added hydrogen peroxide for its action so that it is unlikely to be peroxidase which however is known to cause oxidative coupling of phenols7 (Received January 9th 1962.) Brockmann Falkenhausen and Dorlars Naturwiss.1950 37 540. Brown Calderbank Johnson Joshi Quayle and Todd f. 1955,959. Anderson and Murray Chem. and Ind. 1956,376. Brockmann and Eggers Angew. Chem. 1955 706. Bu’Lock and Allport Proc. Chem. SOC.,1957 264. Fiihraeus KunKl. Lantbr.-Hogsk. Ann. Uppsala 1949,16 618. Booth and Saunders f. 1956 940. New Aspects of the Meerwein Arylation Route to cc-Amino-acids By R. FILLER,L. GGRELIC, and B. TAQUI-KHAN OF CHEMISTRY INSTITUTE CHICAGO (DEPARTMENT ILLINOIS OF TECHNOLOGY 16 ILL.U.S.A.) OURapplication1 of Meerwein arylation2 as a route to ,&aryl-a-alanines (I; X = C1; in aqueous acetone; cupric catalyst) has been used (X = Br) for the synthesis of 0- rn- and p-~hlorophenylalanine.~ Mechanistic studies by Kochi4 have indicated that acetone reduces copper(I1) to copper(I) the latter being the catalyst. (1) Ar.N$X-+CH,:CH.CO,H -+ Ar.CH,.CHX.CO,H+N -+ Ar.CH,.CH(NH,).CO,H We now report our studies of the effects of varia-tions of solvent and of structure of the unsaturated compound. A low acetone :water ratio was advantageous for the hydrolysis of the diazonium salts to phenols whereas high acetone contents enhanced the Sand- meyer reaction. It has therefore been necessary to determine intermediate solvent ratios for individual cases in order to minimise these side reactions in favour of the Meenvein addition.1-Methylpyr-rolidone but not y-butyrolactone may serve in place of acetone. Jn agreement with a previous st~dy,~ buffering was not necessary and a pH near 1.0 was generally used. The most significant variation was the substitution of methyl acrylate or acrylonitrile (3 mol. excess) for acrylic acid methyl a-chloro-p-aryl-propionatesor -propionitriles were then isolated in 55-65 % yield; Filler and Novar Chem. and Ind. 1960,468; J. Org. Chem. 1961,26 2707. Rondestvedt jun. Org. Reactions 1960 11 189. Cleland J. Org. Chem. 1961 26 3362. Kochi J. Amer. Chem. SOC.,1955,77 5090; 1956,78 1228; 1957,79 2942. yields of only 0-40% were obtained with acrylic acid.It was not necessary to conduct the reaction in a nitrogen atmosphere [to prevent oxidation of copper(r)]. The ester or nitrile was then hydrolysed in 85-95% yields to the corresponding a-chloro- acid with a 2 :1 V/V 90 % formic acid+xmcentrated hydrochloric acid.5 Ammonolysis of the chloro- acids with liquid ammonia in a sealed tube gave the a-amino-acids in 80-95 % yield. We thus converted the following arylamines into a-amino-acids in the overall yields indicated aniline PROCEEDINGS to DL-phenylalanine (48-50 %) ; 2-naphthylamine into ~~-/3-2-naphthylalanine (4649%); rn-trifluoro-methylaniline into m-rn-trifluoromethylphenylalan-he (42%). We believe that with these improvements the route may be the method of choice for the synthesis of a number of p-aryl-a-amino-acids.This work was supported by a grant from the National Cancer Institute National Institutes of Health U.S. Public Ekalth Service- (Received,January 8th 1962.) Dombrovsky Yurkevich and Terent’ev J. Gen. Chem. (U.S.S.R.),1957 27 3381. A Rearrangement Caused by Reduction with Hydriodic Acid By G. R. DELPIERRE and M. LAMCHEN (DEPARTMENT UNIVERSITY OF CHEMISTRY OF CAPETOWN,SOUTH AFRICA) THEaction of hot hydriodic acid with or without the addition of red phosphorus and with or without subsequent reduction with a metal-acid combination is a time-honoured method of replacing a hydroxyl group by hydr0gen.l To our knowledge there is no recorded case of rearrangement during this reduction which is frequently used in structural investigations.We have used this method to convert the amino- glycols (I) and (11) into the 2-alkylpyrrolidines expecting to get compounds (111) and (IV) respec-tively both of which we have previously unam- biguously synthesised.2 The amino-glycols were synthesised as follows reaction of the nitrone (V) with allylmagnesium bromide gave the hydroxylamine (VI) which on hydroxylation with performic acid followed by reduction yielded the glycol (I) ;bishydroxymethyla-tion of the reactive methyl group of the nitrone (VII) with paraformaldehyde followed by complete reduc- tion of the nitrone system gave the amino-glycol (TI). The amino-glycol (I) gave the expected 2-propyl- pyrrolidine (ILI) but the isomeric 1,3-glycol (LI) gave only a small quantity of the expected 2-iso-propylpyrrolidine(IV) isolated and identified as the picrolonate.Instead the major product was the 2-propylpyrrolidine (III) which was isolated and identified as its oxalate. Me2 ty Me2r)CH2-CH=hJ CH (v 0- i)H (Vt) Me2pMe 0-(Vll) Therefore since the isopropyl side-chain is re arranged to a n-propyl side-chain by the action of hot fuming hydriodic acid it is clear that results obtained by such a treatment of 1,3-glycols must be viewed with suspicion and cannot be taken on their own as confirming or disproving a structure. 7he conclusions drawn about the structure of the cycloaddition product of 5,5-dimethyl-1 -pyrroline 1-oxide and ethyl acrylate as reported by the authors,2 which were based on reduction of an amino-glycol by hydriodic acid thus needed re-investigation.An unambiguous synthesis of the amino-glycol (I) and its proved identity with the amino-glycol obtained from the cycloaddition pro- duct however proved the conclusions to have been correct. We believe that this rearrangement is probably limited to 1,3-glycols only but further work will be reported later. (Received January 9th 1962.) Hess and Weltzien Ber. 1920 53 149; Koenigs Ber. 1899 32 223; 1898 31 2375. Delpierre and Lamchen Proc. Gem. Soc. 1960 386. MARCH1962 119 The Photochemical Synthesis of 1,SDiketones and their Cyclisation a New Annulation Process By P. DE MAYO,H. TAKESHITA, and (in part) A.B. M. A. SATTAR (DEPARTMENT UNIVERS~ LONDON CANADA) OF CHEMISTRY OF WESTERNONTARIO IRRADIATION of mixtures of alkenes with acetyl- acetone gives 1,Sdiketones in good yields and acid- or base-catalysed cyclisation then affords a substance with a cyclohexenone ring in place of the original isolated ethylenic linkage; the utility of this process for terpenoid synthesis is illustrated as follows Irradiation of a 12% solution of acetylacetone in cyclohexene by an immersed 80 w lamp for 45 hours gave the diketone 01) (78%) which was cyclised to a 5 :3 mixture of compounds (III) and (IV) (separable by gas-liquid chromatography) (95 %). These struc- tures were established by reduction with sodium borohydride and dehydrogenation to 2-and I-methylnaphthalene respectively.* Irradiation of cyclopentene gave the corresponding diketone which could be similarly cyclised.Irradia- tion of oct-1-ene gave a 3:2 mixture (50%) of the diketones (V; R = C6HI3,R’ = H; and vice versa). Analogous reactions have been performed on 1-methylcyclohexene and on isopropenyl acetate. In the latter case base-catalysed cyclisation of the di-ketone gave with elimination of acetic acid m-5-xylenol (characterised as the tribromo-compound). The reaction is not limited to ethylenic substances which can be used as the solvent. Irradiation of cyclo-hexene for instance proceeds equally well in dilute solution (ca. 1%) in an inert solvent such as cyclo- hexane. Although the detailed mechanism has not yet been elucidated it seems probable that intermediates such as (I) are involved.The initial irradiation product shows very strong hydroxyl absorption in the infra- red region which disappears on slight warming. The retro-aldol reaction indicated (I; arrows) would be expected to occur very easily whilst there is ample analogy for the photochemical step.l The authors acknowledge the support of the U.S.A.F. (Received January 26th 1962.) * A similar cyclisation was reported*to give a single product. Re-examination of this work,by using gas-liquid chromatography has shown that a mixture is obtained. Inter alia Buchi and Goldman J. Arner. Chem. Soc. 1957 79 4741; Grovenstein and Rao Tetrahedron Letters 1961 148. * Barret Cook and Linstead J.1935 1065. Relative Couplings between Free Radicalsand Hydrogen and FIuorine Nuclei by the Overhauser Effect By R. E. RICHARDS and J. W. WHITE (PHYSICAL LABORATORY OXFORD) CHEMICAL THEUNIVERSITY WHENthe electron resonance in a solution containing a paramagnetic substance is excited strongly signi- ficant changes may be induced in the nuclear resonance spectra.l This so-called “Overhauser effect”2 arises from magnetic coupling between the unpaired electrons of for example a radical and the nuclei of other species in the solution. This coupling may occur in two ways? One mechanism is the spin-spin interaction transmitted through chemical bonds which gives rise to spin multiplets in nuclear resonance spectra and hyperfine multiplets in electron-spin resonance spectra.The other is the simple magnetic dipolar coupling which is responsible for the broadening of nuclear resonance lines in solids and for much of the nuclear spin lattice relaxation in liquids for nuclei with spin quantum number = 8. APfagam “Nuclear Magnetism,” Oxford Univ. Press 1961; Varian Associates “N-M-R and E-P-R Spectro-scopy Pergamon Oxford 1960 p. 268. * Overhauser Phys. Rev. 1953 92,411. 8Abragam,Phys. Rev. 1955,98 1729. The nature of the coupling between the free electrons and the nuclei affects the changes which are brought about in the nuclear resonance spectra when the electron resonance is saturated? For dynamic dipolar coupling which is often the most important in solutions the nuclear resonance is reversed and increased in intensity when the electron resonance is excited.We have foundunusual effects with some fluorinated substances. When solutions of the radical 2,5-di-t- butyl-semiquinone in CHF2-CF,CF,CF,.CH,.OH CF,.CH,.OH or CHF2CF,-CH2.0Hare irradiated at the electron resonance frequency at a certain power the hydrogen nuclear resonance is inverted and the signal :noise ratio increased twenty-fold. The fluorine resonance is however not reversed; it is enhanced by a factor of about 1.7. An example of this effect is given in Fig. 1 when the microwave power used was considerably reduced. Fluorine FIG.1. IH andlgF resonances in aqueous CF,-CO,Na (a) microwave power OF, (b) microwave power on. On the other hand when a solution of the same radical in CCIF,-CI,CF was used the fluorine resonance was reversed in the normal manner and increased in intensity about ten times.It was felt that the effect might be connected with the spin-spin coupling between fluorine and hydro- gen atoms in the first three compounds so the experi- ment was repeated with aqueous sodium trifluoro- acetate containing the radical. In this case there is no electron-coupled spin-spin interaction between fluor- ine and hydrogen nuclei. Fig. 2 shows the dependence of the hydrogen and the fluorine nuclear resonance on the microwave power applied to this solution. The hydrogen resonance is reversed and increased twenty- fold in intensity and the fluorine nuclear resonance is enhanced by a factor of about 1-75.These results require that the protons are most strongly coupled by dipolar interaction to the un- PROCEEDINGS paired electrons of the radical; the rapid pumping of the protons among their energy levels must then be producing a small polarisation of the fluorine nuclei through a dynamic dipolar coupling. This implies that the dipolar coupling of protons to the unpaired eIectrons is much stronger than that of fluorine because the normal reversal of the fluorine resonances is more than overcome by the proton-fluorine inter- action. This is not unexpected because the radical is negatively charged and would be expected to make closer encounters with the protons of the solvent than with the fluorines of the negatively charged trifluoroacetate ions.Micmw power (W) 19 FIG.2. Power dependence of lH and 19Fresonances in aqueous CF,CO,Na. (Magnized ordinate scale for 19F in parentheses.) The solutions in fluorinated alcohols contained the radical alkali and some methanol; so the proton enhancement refers to the total hydrogen content; chemically shifted protons were not distinguished in these experiments; the interactions are more com- plex than in trifluoroacetate solutions. It is most unlikely that scalar coupling could occur between the fluorine nuclei and the free electrons in any of these solutions; if it did enhancement of the fluorine resonance could occur. Effects of this kind are clearly of great significance in connexion with the use of the Overhauser effect to enhance nuclear resonance signals and in the study of molecular interactions.These experiments were performed in magnetic fields of about 3000 gauss with 3 cm. microwave radiation. (Received January 18th 1962.) MARCH1962 121 The Significance of the Critical Potential in the Kolbe Reaction By B. E. CONWAYand M. DZIECIUCH (DEPARTMENT OF OTTAWA OTTAWA OF CHEMISTRY,UNIVERSITY CANADA) THEyield of Kobe products R from an aliphatic acid RCO,H has been fo~ndl-~ to be a critical function of potential and the reaction occurs sig-nificantly only above a certain limiting value of the electrode potential e.g. that for appreciable rates of oxygen evolution1v2 in the absence of the carboxylic acid.The exact significance of these potentials has been little discussed. We have found that at platinum gold or pallad- ium in pure anhydrous trifluoroacetic acid containing potassium trifluoroacetate as electrolyte and saturated with carbon dioxide high Faradaic yields (96%) are obtained of the Kolbe coupled product C2F6 (cf. ref. 4) and no detectable oxygen evolution. This re-action is thus specially suitable for quantitative electrochemical kinetic study. Current-potential curves (see Fig. 1) indicate that a critical potential is I f ld= I i , ,II I 1 I I I -5 ”-4 -3 -2 -1 Log (Current density)(amp. cm-2 FIG. 1. Current-potential curves (Tafel lines) for anodic polarisation of the platinum electrode in (A) M-CF,CO,K in pure CF,CO,H (b = 0.26) and (B) M-HCO,K in pure H.CO2H (b = 0.14) at 5”.reached at a limiting current density of about a. cm.-2 in N-potassium trifluoroacetate in pure trifluoroacetic acid and lo4 a. cm.-2 in N-potassium formate in pure formic acid or in water. The sig- nificance of the break in the curve and of the associated critical potential has been examined by the observation of galvanostatic potential transients on anodic polarisation and reverse cathodic dis- charge (Fig. 2). Both types of measurements indicate the formation of a surface film of intermediates. The charge associated with the arrest region in Fig. 2 * Glasstone and Hickling J. 1934 1878; 1936 820. Pande and Shukla Electrochim.Acta 1961 4 215. corresponds for a one-electron transfer to forma- tion of a layer having a fractional coverage of 0-34-1 (based on true surface area5) depending upon current density.The pseudo-capacity of the film at platinum varies from about 30 to 125 p~ern.- depending on current density. Films of 10-100 molecular layers are formed at palladium (depending on the time of previous polarisation) when anodic decarboxylation of formate ions in formic acid is occurring and pseudo-capacities are between 700 and 4300 p~ cm.-,; similar current-potential curves are observed (Fig. 1). The inflections in Figs. 1 and 2 are not due to depolarisers and are also observed in anodic oxide film formation e.g. in passivation of metals (cf. the Flade potential). We suggest there- fore that the critical potentials previously mentioned I I I Time -FIG.2. Galvanostatic cathodic discharge curves forlowing prior artodic polarisation for the indicated conditions (A) P~,M-CF,CO,K€H,CO,H 6.1 X lohs a. cm.-Z 310 sec. anodic followed by cathodic transient. (B) Au,M-CF,-CO~K-CF,-CO,H,7.2 x a. cm.-2 304 sec. anodic etc.; (C) Pd,M- HCO,K-HCO,H 5.9 x a. crn.-, 314 sec. anodic etc. involve formation of passive films of a metal “Car-boxylate” on the electrode and that the transition region in Figs. 1 and 2 corresponds to formation and removal,6 respectively of this film which is then a pre- Preuner and Ludlam 2.phys. Chem. 1907,59,682; Shukla and Walker Trans.Farczhy Soc. 1931,27,727; Vasilev, Doklady Akad. Nauk U.S.S.R.,1960 134 879.Swarts Bull. SOC.chim. belges 1933 42 102. Bockris and Conway J. Chem.Phys. 1958,28 707. Conway and Dzieciuch Nature 1961 189 914. PROCEEDINGS requisite for subsequent steady-state occurrence of the anodic reaction in aqueous formate solution is the Kolbe decarboxylation but it must be noted only a decarboxylation the critical potential is not that C2F6 is still a product of the reaction below itself specially related to hydrocarbon formation in the transition region. The critical potentials are the coupling reaction. observed in aqueous as well as non-aqueous Calculations of the relevant reversible potentials formate and trifluoroacetate solutions and are hence for decarboxylation of aqueous formic and acetic not related to a critical condition for discharge of acid show that the critical potentials cannot be hydroxyl from water or OH-ions to form hydrogen identified with the corresponding reversible potentials peroxidel or alkyl oxidation products.Also since and in fact exceed them by some 0.6-1.0~. (Received December 16th 1961 .) Two Novel Rearrangement Reactions By E. BULLOCK and A. W. JOHNSON B. GREGORY (DEPARTMENT THE UNIVERSITY OF CHEMISTRY NOTTINGHAM) and P. J. BRIGNELL ULLI EISNER and H. WILLIAMS (DEPARTMENT SIRJOHN CASS COLLEGE OF CHEMISTRY LONDON,E.C.3) BENARY~ found that treatment of the dihydro-The light absorption of compound (A) (Amax. 229 pyridine (I; R = C1) with potassium cyanide in boil- 326 mp; log E 4-18,4.19) was abnormal with respect ing aqueous alcohol afforded a mixture of the pyr- to its precursor the chloride (I; R = C1) (Amax.231 role (11) and a product (A) which he formulated as 349 mp; log E 4.29 3-88) and related dihydro- the derived cyanide (I; R = CN). The compound pyridines;6 also the lack of fluorescence in ultra- (A) was converted into the pyrrole (11) by the violet light and the extreme lability to acid6 are at action of alkali. We have repeated this work and variance with the dihydropyridine structure postu- have shown that the conversion of the chloride lated for it. Furthermore difficulty in formulating a (I; R = Cl) into product (A) is quantitative at satisfactory reactionmechanism to account for the for- room temperature. mation of a pyrrole ester (111; R = C0,Et) led us to The lack of reactivity2 of the pyrrole (11) and its postulate rearrangement of the chloride (I; R = C1) spectroscopic properties3y4 suggested that it was in on treatment with cyanide affording the dihydro- fact the known5 compound (111; R = C0,Et).This azepine (IV). Similar ring expansions have recently was confirmed by a mixed m.p. determination with been described.' Infrared and nuclear magnetic an authentic specimen and by its degradation to a resonance spectra are consistent with structure (IV). cyanide (111; R = H) which was synthesised from Spectroscopic evidence indicates that reaction of the 2,5-dimethylpyrrole by standard methods. Ethyl chloride (I; R = C1) with other nucleophiles (N3- acrylate identified by gas chromatography and infra- OH- OAc- OMe- but not I-or Ph.SO,-) is red spectrum is also produced in the reaction of accompanied by an analogous rearrangement pre- product (A) with alkali and accounts for the rest of sumably involving a carbonium intermediate.the molecule. Support for the above mechanism is derived from H CH,R the fact that the homologous dihydropyridine (I;R= CH2Cl) m.p. 136-137" Amax. 234,347 mp MeUJCzE (log E 4-27 3-90) reacts with potassium cyanide only H (0) under forcing conditions (addition of acetamide H ,CN heating at 90" for 7.5 hr.) affording a product m.p. 114-1 15" the ultraviolet (Amax. 234 347 mp; log E 4.27,3.90) and infrared absorption of which indicate that it is the dihydropyridine (I; R = CH2CN). l Benary Ber. 1920 53 2218. * Cf. Fischer and Miiller 2.physiol.Chem. 1937 246 31; 1938,257 61. * Eisner and Gore J. 1958 922. Eisner and Erskine J. 1958 971. Bilton and Linstead J. 1937 922. Cf. Traber and Karrer Helv. Chim. Acta 1958 41 2066. ' Nelson Fassnacht and Piper J. Amer. Chem. Soc. 1961,83,206; Bergmann and Rabinovitz J. Ore. Chem. 1960, 25 827 828; Craig Lester Saggiomo Kaiser and Zirkle J. Org. Chem. 1961 26 135 and references cited therein; Whitlock Tetrahedron Letters 1961 No. 17 593. MARCH1942 The dihydropyridine structure for product (A) was finally eliminated by an unambiguous synthesis (from the potassium salt of cyanoacetaldehydes and ethyl ,8-aminocrotonate in acetic acid) of the authentic compound (I; R = CN) m.p. 141-143" Amax. 231 349 mp (log E 4-28 3.89).The annexed mechanism is visualised for the ring contraction (IV) -+ (111; R = C0,Et). A rigorous proof of the structure (IV) and the kinetics of the rearrangements are under investiga- tion. We are indebted to Dr. L. M. Jackman for helpful discussions and for preliminary nuclear magnetic resonance measurements to Professor C. Rimington F.R.S. for affording facilities to one of us (U.E.) during the early stages of this work and to D.S.I.R. for maintenance grants (to B.G. and P.J.B.). (Received January 26th 1962.) NEWS AND ANNOUNCEMENTS Liaison Officers.-The following Fellows have agreed to act as Chemical Society Liaison Officers Rutherford College of Tech- nology Newcastle-upon- Tyne . . .. . . Dr. R. Hemming Sunderland Technical Col- lege .... . . Dr. W. R. Longworth The Corday-Morgan Medal and Prize.-The Council of the Chemical Society has awarded the Corday-Morgan Medal and Prize to Professor R. N. Huszeldine Professor of Chemistry at the Man-Chester College of Science and Technology in con- sideration of his outstanding contributions to the chemistry of fluorine. The award is made in respect of the year 1960. This Award consisting of a Silver Medal and a monetary Prize 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 the most meritorious contribution to experimental chemistry and who has not at the date of publication attained the age of thirty-six years.Copies of the rules governing the Award may be obtained from the General Secretary of the Chemical Society Burling- ton House London W.l. Applications or recom- mendations in respect of the Award for the year 1961 must be received not later than December 31st 1962 and applications for the Award for 1962 are due before the end of 1963. Dr. E. de Barry Barnett Memorial.-A Committee has been formed to appeal for funds for a Memorial to the late Dr. Barry Barnett which it is proposed will take the form of an Exhibition tenable at Sir John Cass College. Dr. Barnett joined the College as Lecturer in Organic Chemistry in 1919 subsequently became Head of the Department and retired in 1947 as Deputy Principal.It is thought that many who were associated with Dr. Barnett will wish to con- tribute to the fund and donations should be sent to Dr. S. D. Ross the Appeal Treasurer at 135 Hendon Way London N.W.2. D.S.I.R. Awards for Study Abroad.-Up to 100 awards for study overseas will be offered this year to scientists and technologists by the Department of Scientific and Industrial Research either through its own scheme of awards or through the N.A.T.O. Science Studentship and Fellowship Scheme. These awards may be at either postgraduate studentship or postdoctoral fellowship level and will normally be tenable for two to three years at univer- sities colleges or other approved institutions in any part of the world. Their values are f400 p.a.and E800-950 p.a. respectively but they may also attract additional allowances. Full details are given in the booklet "D.S.I.R. Studentships and Fellow- ships 1962," available through H.M.S.O.(price 2s.). Application forms are available now from D.S.I.R. State House High Holborn W.C.l and interviews for the awards will be held in April. Election of New Fellows.-1 66 Candidates whose names were published in Proceedings for January have been elected to the Fellowship. Symposia etc.-The Golden Jubilee Celebration of the South African Chemical Institute will be held in the Johannesburg Pretoria and Vereeniging areas from July 2nd to llth 1962. An invitation to Fellows to register as delegates has been extended. Further enquiries should be addressed to The South African Chemical Institute P.O.Box 3361 Johannesburg Transvaal. The Third International Congress on Catalysis organised by the Royal Netherlands Chemical Society will be held in Amsterdam on July 20-25th 1964. Further enquiries should be addressed to Dr. D. M. Brouwer Secretary Third International Congress on Catalysis P.O. Box 3003 Amsterdam Net herlands. A Meeting of the Polish Chemical Society on “Chemistry and Technology of Chlorine and Chloro-derivatives” will be held in Szozecin Poland from June 4th to 6th 1962. Abstracts of the papers presented will be sent free of charge to interested persons in April 1962. Further enquiries should be addressed to the Organisation Committee Chair- man Dr. Antoni Z.Zielinski 10 Pulaski St. Szozecin 3 Poland. Deaths.-We regret to announce the deaths of the following Professor Dr. J. Dedek (9.2.62) Scientific adviser to the Tirlemont Refinery; Mr. F. R. Dodd (11.2.62) a Fellow for over sixty years; Mr. G. R. Marshall (18.7.61) Chief Chemist Metafiltration Co.,Ltd. ; Dr. H. W. Webb (8.2.62) Ceramics con- sultant; and Professor F. P. Worley (8.12.60) formerly of University College Auckland. Personal.-An award under the Royal Society and Nuffield Foundation Commonwealth Bursaries Scheme has been made to Mr. H. R. Arthur Senior Lecturer in Organic Chemistry University of Hong Kong to assist him to visit Oxford and Manchester in 1962 to study new research techniques. Dr. P. Borrell and Dr. D. Cohen have been appointed to Lectureships at the University College of North Staffordshire.Dr. A. B. Callear and Dr. D. W. Cameron have been appointed to Title “A” Fellowships at Churchill College Cambridge. Dr. R. C. Cambie of Auckland University has been awarded a Pressed Steel Research Scholarship tenable in the Dyson Perrins Laboratory Oxford University. Dr. S. Cofey has retired from his post as Assistant PROCEEDINGS to the Research Director Imperial Chemical In-dustries Limited Dyestuffs Division after 36 years’ service. Dr. R. F. Curtis and Dr. G. H. R. Summers have been appointed Senior Lecturers in Chemistry at the University College of Swansea. Dr. B. D. England is visiting Great Britain while on sabbatical leave from the Victoria University of Wellington.Dr. A. Fisher has returned to the Chemistry Department University of Canterbury after spend- ing a year at the California Institute of Technology on a post-doctoral fellowship. The University of Birmingham has conferred the Honorary Degree of D.Sc. on Sir Charles Goodeve and the Honorary Degree of LL.D. on Professor E. L. Hirst. Dr. P. K. Grant has joined the staff of the Univer- sity of Otago as Lecturer in Chemistry. Dr. J. Grimshaw and Dr. W. R. Jackson have been appointed to supernumerary lectureships in Organic Chemistry at the Queen’s University Belfast. Dr. G. Harris has received the award 0f.a D.Sc. degree by the University of London for his work in the field of fermentation. Dr. R.W.Hay has joined the staff of the Victoria University of Wellington as Lecturer in Chemistry. Mr. N. E. F. Hitchcock has been appointed Group Laboratory Manager of Castrol Limited. The title of Professor of Electrochemistry has been conferred on Dr. D. J. G. Ives in respect of his post at Birkbeck College from October lst 1962. Professor J. Packer of the University of Canter- bury has been elected President of Section B of the Jubilee Congress of A.N.Z.A.A.S. for 1962. Dr. J. E. Packer has been appointed to the staff of Auckland University as Lecturer in Chemistry. Dr. R. Truscoe Senior Lecturer in Biochemistry at the Victoria University of Wellington has been promoted to Associate Professor. Professor F. H. Westheimer Morrell Lecturer at Harvard University from October lst 1962 has been elected to an Overseas Fellowship at Churchill College Cambridge.FORTHCOMING SCIENTIFIC MEETINGS London Thursday May loth at 7.30 p.m. Tilden Lecture “Stereoselectivity in the Reactions of Cyclic Compounds,” by Professor H. B. Henbest D.Sc. Ph.D. F.R.I.C. to be held in the Large Chemistry Theatre Imperial College of Science and Technology South Kensington S.W.7. Birmingham Friday May llth at 4.30 p.m. Lecture “Developments in Magnetic Resonance,” by Dr. R. E. Richards M.A. F.R.S. Joint Meeting with the University Chemical Society to be held in the Chemistry Department The Univer- sity. MARCH1962 Cambridge Monday May 7th at 5 p.m. Lecture “Optical Rotary Dispersion as a Tool in Structural Organic Chemistry,” by Professor W.Klyne M.A. Ph.D. D.Sc. to be given in the University Chemical Laboratory Lensfield Road. Durham Wednesday May 2nd at 5 p.m. Lecture “Recent Results on Metal n-Complexes of Unsaturated Hydrocarbons,” by Professor E. 0. Fischer Dr.rer.nat. Joint Meeting with the Durham Colleges Chemical Society to be held in the Science Laboratories The University. Edinburgh Tuesday May 8th at 4.30 p.m. Lecture “Neutron Activation Analysis,” by Profes- sor H. Irving M.A. D.Phi1. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Keele Tuesday May lst at 8.30 p.m. Lecture “Science in Art and Archaeology,” by Dr. A. E. A.Werner M.A. A.R.I.C. Joint Meeting with the University College Science Society and the Royal Institute of Chemistry to be held in the Department of Chemistry University College of North Staffs. Leicester Monday April 30th at 3.30 p.m. Lecture “Quantitative Studies in Aromatic Substi- tution with the aid of Gas Chromatography,” by Dr. R. 0. C. Norman M.A. Joint Meeting with the Colleges of Art and Technology Chemical Society to be held Sthe Colleges of Art and Technology. Manchester Tuesday April loth at 10 a.m. Symposium “New Physical Methods of Structural Investigation.” Joint Meeting with the Society of Chemical Industry the Royal Institute of Chemistry and the Institute of Petroleum to be held in the Large Chemistry Lecture Theatre The University.St.Andrews and Dundee Friday April 13th at 5.15 p.m Lecture “Chemotherapy and the Organic Chemist,” by Dr. F. L. Rose O.B.E. F.R.S. Joint Meeting with the University Chemical Society to be held in the Chemistry Department St. Salvators College St. Andrews. Friday April 27th at 5 p.m. Lecture “Principles of Radiation Chemistry,” by Professor F. S. Dainton Sc.D. F.R.S. Joint Meeting with the Royal Institute of Chemistry to be held in the Chemistry Department Queen’s College Dundee. Friday April 27th at 5.15 p.m. Lecture “Applications of Nuclear Magnetic Reson- ance in Structural Organic Chemistry,” by Dr. L. M. Jackman. Joint Meeting with the University Chem- ical Society to be held in the Chemistry Department St.Salvators College St. Andrews. Southampton Thursday April Sth at 7 p.m. Lecture “Analytical Research,” by Dr. J. Haslam. Joint Meeting with the University Chemical Society to be held in the College of Technology Portsmouth. Friday May 1 lth at 5 p.m. Tilden Lecture “Stereoselectivity in the Reactions of Cyclic Compounds,” by Professor H. B. Henbest D.Sc. Ph.D. F.R.I.C. 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Flmt Frances Heather B.A. Pharmacology Department Oxford. MARCH1962 Font Jose B.Sc. Departamento de Quimica Organica Patronato Juan de la Cierva Universidad de Barcelona Barcelona Spain. Frank Geoffrey B.A. The Queen’s College Oxford. French Alan Sidney BSc. 5 Scotts Road Ware Hem. Friedman Paul B.S.M.A. 1269 E. 98th Street, Brooklyn 36 N.Y. U.S.A. Fung David Ping Chi B.Sc. Assumption University Windsor Ontario Canada. Furniss Kenneth. 84 Stanwood Road Sheffield 6 Yorks. Garforth John David A.R.I.C. I.C.I. Akers Research Laboratories The Frythe Welwyn Herts. Gay Ian David M.Sc. Chemistry Department Imperial College London S.W.7. Gemmill George Graeme B.A. Department of Pharma- cology South Parks Road Oxford. Giam Choo-Seng M.Sc. A.R.I.C. Chemistry Depart- ment University of Saskatchewan Saskatoon Sas- katchewan Canada. Gilbert David Stone. 113 Mere Road Leicester. Glentworth Peter Ph.D. Chemistry Department Leeds University Leeds 2. Goldstein Irwin J. Ph.D. Department of Biochemistry, University of Buffalo School of Medicine 3435 Main Street Buffalo 14 N.Y.U.S.A. Graham Elinor Margaret B.Sc. Chemistry Department The University Glasgow W.2. Grassi Robert John B.Sc. Chemistry Department University of Southern California University Park Los Angeles 7 California U.S.A. Griesmeir Walter. Schwabmuenchen Frauenstrasse 18 Germany. Grigor Bruce Anthony M.Sc. Department of Chemistry, The University Leicester. Grover Pyara Krischen Ph.D. The Worcester Founda- tion for Experimental Biology Shrewsbury Massa- chusetts U.S.A. Grundy Kenneth Henry MSc. Department of Chemis- try University of Manckester Oxford Road, Manchester 13. Gurst Jerome Edwin A.B. Department of Chemistry Stanford University ,Stanford California U .S.A. Guy Robert William BSc. 25 Walker Street Somerton South Australia.Hajos Zoltam George. Hoffmann-La Roche Inc., Nutley 10 New Jersey U.S.A. Hards tone John David B. Sc. Chemistry Department , Washington Singer Laboratories University of Exeter Exeter. Harvey David John. The Vicarage Looe Cornwall. Hassid Menahem Joseph. 9 Hillcrest Avenue London N.W.11. Hayes John William B.Sc. Department of Analytical Chemistry University of New South Wales Box 1 Kensington N.S.W. Australia. Hellmuth Walter Wilhelm B.S. Box 36 Chemistry Department University of Connecticut Storrs, Connecticut U.S.A. Hendess Raymond William B.S. 218-B Harrison Street Princeton New Jersey U.S.A. Henson Roger Michael. 889 Scott Hall Road Leeds 17. Hiraoka Hiroyuki Ph.D. Department of Chemistry University of California at Los Angeles Los Angeles 24 California U.S.A.Hirsch Hans Ph.D. A.R.I.C. D.I.C. 32 Donnington Road Kenton Harrow Middlesex. Hollander Gary T. B.S. Department of Chemistry, University of Washington Seattle 5 Washington, U.S.A. Hughes Graham Keith Ph.D. Department of Chemistry, University of Alberta Edmonton Alberta Canada. Hughes Leonard BSc. 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Maxwell Catherine B.Sc. Chemistry Department The University Glasgow W.2.Mazza Robert John B.Sc. The Isotope Unit Queen Elizabeth College Campden Hill Road London W.8. Mehrotra Bam Deo M.Sc. Chemistry Department Indiana University Bloomington Indiana U.S.A. Michelman John Sigmund B.S. 33 Perkins Hall, Harvard University Cambridge 38 Massachusetts, U.S.A. Montanari Fernando. Istituto Chimica Organica-Universita Via A. Vivaldi 70 Modena Italy. Monteriolo Susana Cerquiglini. Laboratorio di Chimica Istituto Superiore di Sanita Viale Regina Elena 299, Roma Italy. Moore Alan William Ph.D. Copse House Rathdrum Co. Wicklow Ireland. Moore Kenneth William. 68 West End Park Street Glasgow C.3. Moreland Peter John. 33 Menin Road Tipton Staffs. Morton William David B.Sc. 357 Wigan Lane Wigan Lancs. Muir Kenneth Walter.88 Duntocher Road Bearsden Dumbartonshire Scotland. Murti V. V. S. M.Sc. D.Sc. Department of Chemistry, University of Delhi Delhi-6 India. Nishida Shinya Ph.D. Department of Organic Chemis- try Imperial College London S.W.7. Notaro Vincent A. B.S. 206 Dix Drive North Versailles Twp. East McKeesport Pennsylvania U.S.A. Ogden Anthony Barry. 10 York Avenue Coppice Oldham Lancs. Othman Adil Ali B.Sc. 50 Grove Avenue Moseley Birmingham 13. PROCEEDINGS Park Chug Ho B.S. Room 6-328 M.I.T. Cam-bridge 39 Massachusetts U.S.A. Parker Edward Keith. 38 Kennedy Road Sheffield 8. Pasquon Italo Dr.Ing. Via Donatello 22 Milano Italy. Perlmutter. Howard David. B. A. DeDartment of Chemis-try New York University University Heights, Bronx 53.N.Y. U.S.A. Phenix Douglas William. “Linnwood,” 2 Manse Road North Mount Vernon Glasgow E.2. Phillips Jacob Raphael. 50 Friars Walk Southgate London N. 14. Pitkethly William Nicholson B.Pharm. M.P.S. 5 Willowfield Avenue Newcastle-upon-Tyne 3. Poutsma Marvin L. Ph.D. Union Carbide Research Institute Box 278 Tarrytown New York U.S.A. Power Leslie Frederick B.Sc. University College of Townsville P.O. 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Limited General Chemicals Division Widnes Laboratory Widnes Lancs. Richardson Kenneth BSc.4 North Lane Portslade Sussex. Ridlev. Daniel. 9 Lawrence Street. Chester-le-Street. Co Durham. Roberts Roger Charles B.Sc. 14 Marcia Street Moss Side Manchester 14. Robertson William Gibson. “Milford,” Paisley Road Barrhead Renfrewshire. Robson. Edwin. B.Sc. 5 Grange Crescent Road. -Sheffield 11. ’ Rodgers. Peter John. Keble College. Oxford. Rosgnthal David Ph.D. 400 LiGngston Avenue New Brunswick New Jersey U.S.A. Roy Noel John. 13 Newton Lane Chester Cheshire. Rudge Anthony John. 9 Avondale Street Bramley Leeds 13 Yorks. Rutherford. David. M.Sc. 33 Marchmont Crescent, Edinburgh 9. ‘ Sack. Milton. Ph.D. 860 Lancaster Avenue Syracuse 10, .-New York; U.S.A. Sahyun Melville Richard Valde A.B. Department of Chemistry University of California Los Angeles 24, California U.S.A.Schapiro Janice C. M.S. Department of Chemistry University of Illinois Urbana Illinois U.S.A. MARCH1962 Scheppele Stuart Edward B.S. Department of Chemis- try Michigan State University East Lansing, Michigan U.S.A. Schofield William Granville Ph.D. Ingleby Manor Ingleby Greenhow Great Ayton Middlesbrough, Y orks . Scott Bryan Conelly. Balliol College Oxford. Senciall Ian Robert B.Sc. Fisons Pest Control Ltd. Chesterford Park Research Station Saffron Walden Essex. Senior Colin Henry. Balliol College Oxford. Shah Navinchandra Vandravandas B.Sc. 7 Hague Road Withington Manchester 20. Sharpe Geoffrey Thomas Jr. 8 Rokeby Square Merry Oaks Durham. Sheppard Chester Stephen Ph.D.2763 Sheridan Drive Tonawanda New York U.S.A. Silverstein Richard B.A. Department of Chemistry, Florida State University Tallahassee Florida U.S.A. Singer Lawrence Alan B.A. Chemistry Department University of California Los Angeles 24 California U.S.A. Smart Graham Michael. 61 Highfield Road Blackheath Birmingham. Smith Edward Richard D.Chem. 14 Lord Street, Fallowfield Manchester. 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PROCEEDINGS OBITUARY NOTICES RALPH FRANCIS NAYLOR 192 1-1 96 1 THEdeath occurred on August 6th 1961 of Ralph Francis Naylor Professor of Chemistry at the Royal College Nairobi Kenya. He was killed in a car accident at Mkushi in Northern Rhodesia. Born on August 22nd 1921 in London he was educated at Emanuel School and at Imperial College London.After graduation in 1942 he worked with the British Rubber Products Research Association on aliphatic sulphur compounds and reactivity of olefins. He published some 12 papers on this work between 1943 and 1949 including several in the Journal. His next appointment was at Makerere College Kampala Uganda when he became a Lecturer in Organic Chemistry in 1949. The College had just begun B.Sc. degree work as a University College in special relation with the University of London. In 1954 Naylor as Senior Lecturer became Acting Head of the Chemistry Department. His flair for organising and planning was given full scope during the next two years. One Chemistry building had just been completed and it fell to him to plan the second one.Shortly before this time he had spent nine months at Harvard learning bacteriological techniques. He now embarked on research into the chemotherapy of leprosy. This involved visiting leper colonies in Uganda and adjacent countries and carrying out tests there. He was a member of the Board of Governors of the Leprosy Settlement at Kumi. Later he set up a radiochemical laboratory at Makerere and used tracer techniques to study the uptake of leprosy drugs in organisms related to hi. Ieprae which could be cultured. He described this work in a paper which he read at the VIIth International Congress on Leprosy held in Tokyo in 1958. Ralph Naylor had wide interests and deep religious convictions. He had been President of the Uganda Mountain Club and a Trustee of the East Africa Outward Bound organisation.His ascents included Kilimanjaro Elgon and the difficult ice- clad Ruwenzoris the legendary Mountains of the Moon. He was also President of the Uganda Amateur Athletic Association. Naylor had been a Resident Tutor and Acting Warden of one of the Student Halls of Residence at Makerere. He spent much time looking after his student tutorial groups and played a full part in College committee work. His lectures were models of clarity and his practical classes meticulously organised. The East Africa Section of the Royal Institute of Chemistry which was set up in 1956 owed a great deal to his energy and initiative. He was Secretary until the time of his death.The Royal College Nairobi acquired University Collzge status in January 1961 with Naylor as its first Professor of Chemistry. He was also Dean of the Faculty of Science. One of his first tasks was to plan the College’s new Chemistry building. His death is a blow to that College to all his many friends and to East African scientific education general1y . M. CRAWFORD. JAMES MURRAY 1923-1961 THEdeath of James Murray in a motor accident at Dunedin New Zealand on June 24th 1961 was a grievous loss to the University of Otago and to New Zealand Science. In a time of increasing speciafisa- tion he was a man of unusually wide interests and attainments. His work on the borderline of chemistry and botany was just beginning to develop fruitfully in the way which has so often occurred in the sciences.He had completed the long apprenticeship needed before work of significance to two subjects could reach the stage of publication and his wide knowledge of chemistry combined with his en-thusiasm for certain aspects of botany promised a cross-fertilisation from which results of great value could be expected. Born at Forest Hills Southland New Zealand on April 3rd 1923 the son of a farmer he was educated at the Otago Boys’ High School where he was dux in 194 1 and won a University National Scholarship. He graduated Master of Science in Chemistry from the University of Otago in 1945 and was appointed Assistant Lecturer in Chemistry. With the award of a National Research Fellowship in 195 I Dr.Murray proceeded to Cambridge where he gained the degree of Ph.D. in chemistry. His principal research interest was in the chemistry of New Zealand plant products and he had published some fifteen chemical papers in this field. From his chemical investigations of New Zealand lichens arose a keen interest in their botany. In 1959 he was awarded a NuEeld Foundation Travelling Fellow- ship in Science for study in London at Imperial MARCH1962 College and at the British Museum. He Visited some of the great herbaria in Europe and returned to New Zealand to embark on a series of papers on New Zealand lichens of which three have been published. In twelve years of collecting Dr. Murray gathered some 10,ooO lichen specimens all of which he had sorted and classified with meticulous care.He had some fifteen papers on various lichen genera in preparation including a key to New Zealand lichens. He had also begun the even more important task of writing in collaboration with a lichenologist at the British Museum a world monograph on the lichen genus Sticta. All this he had carried out while still carrying the considerable load of lecturing demon- strating and research supervision that is the usual lot of a university teacher. At the time of his death Dr. Murray was Senior Lecturer in the Department of Chemistry. There and in the University generally he won the respect and friendship of colleagues and students alike. Blessed with a remarkably retentive memory he had a wide and detailed knowledge of all branches of chemistry.Those research students who worked under his supervision quickly came to appreciate his quality and equally quickly became his friends. He gave freely of his wide knowledge and ability to other investi- gators. Indeed unselfish co-operation was a key-note of his character. He was for many years secretary of the Otago branch of the Royal Society of New Zealand. He read easily in several languages and was deeply interested in all aspects of library work. The task of making the literature of science more accessible to research workers was close to his heart and his work as Departmental Librarian was an expression of this. Dr. Murray was a family man.His wife whom he married in 1949 was formerly a member of the staff of the Chemistry Department and there are three children. He was a man of great vitality and despite his many activities never lacked time to share the en- thusiasms of others. The University community and the community at large can ill afford to lose a man of such high ability and character at the height of his creative capacity. R. E. CORBETT. LEV1 MELLOR HILL 1891-1961 LEVI MELLORHILLwas educated at the Verdin Grammar School Winsford Cheshire and left there at the age of 15 to take up employment with the firm of Brunner Mond and Co. at Northwich the pioneers of the Ammonia Soda Process in this country. After a year of routine chemical testing for process control he was selected to join the Research Department established in 1907 under the leader- ship of Mr.F. A. Freeth later Dr. Freeth F.R.S. The main line of work in this Department for many years was the exploration of the solubilities of mix-tures of inorganic salts in water by using Willard Gibbs’s phase rule as a guide and the application of this knowledge to the design of industrial processes. This was the first use of Gibbs’s work in industry. L. M. Hill took part in this work and eventually became one of the leading spirits. He was promoted to managerial status in 1928 by which time Brunner Mond and Co. had merged with other firms and become the Alkali Division of Imperial Chemical Industries Limited. Hill’s work as a mature scientist was concerned largely with the more complex aspects of the am- monia soda process and other alkali processes and his published researches are only very simple examples of his major work.To illustrate his standards it is best to go back to work in which Hill took part in only a junior capacity-the work done by Freeth and others on processes for the manufac- ture of ammonium nitrate during the first World War. Several processes were invented and worked up to the production Scale because ammonium nitrate was urgently needed for munitions. All of them depended on the subtle use of solubility relationships to produce one salt from others but the last process to reach the full scale the production of ammonium nitrate (and sodium sulphate) from sodium nitrate and ammonium sulphate showed these subtleties to the highest degree.In this reaction the danger of obtaining useless double salts is great and a process involving heating and cooling of solutions together with dilution evaporation and strictly specified compositions based on a detailed knowledge of the underlying solubility relationships is necessary to obtain the desired products. This is an example of a general technique which has been an important result of the work of Freeth and his co-workers. An impressive account of the many possibilities opened up by the technique has been given by Hill in an article in “Thorpe’s Dictionary of Applied Chem- istry.” Hill was well prepared for writing this article having taught the technique to successions of col-leagues who gratefully remember his ability to bring out the life and interest in a subject which is often made to appear dull.Levi Hill was a quiet helpful man. He was a faithful worshipper and Sunday School teacher in the Church of England. Sport played no part in his life but he was a keen railway enthusiast. E. BLUMENTHAL ADDITIONS TO THE LIBRARY E.The condensed chemical dictionary. Edited by A. and Rose. 6th edn. 9. 1256.Reinhold. New York. 1961. Ultraviolet and visible absorption spectra index for 1955-1959. Compiled by H. M. Hershenson. Pp. 133. Academic Press. New York. 1961. An introduction to infrared spectroscopy. W. Brugel. (Translated from the German by A. R. Katritzky and A. J.D. Katritzky.) Pp. 419. Methuen. London. 1962. Ultraviolet and visible spectroscopy chemical applica- tions. C. N. R. Rao. Pp. 164. Butterworths. London. 1961. An introduction to spin-spin splitting in high resolu- tion nuclear magnetic resonance spectra. J. D. Roberts. Pp. 116.W. A. Benjamin Inc. New York. 1961. Atomic-absorption spectrophotometry. W.T. Elwell and J. A. F. Gidley. Pp. 102. Pergamon Press. Oxford. 1961.(Presented by the publisher.) Calculations in physical chemistry. W. V. Hawes and N. H. Davies. Pp. 203. English Universities Press. London. 1962.(Presented by the publisher.) Valence. C. A. Coulson. 2nd edn. Pp. 404. University Press. Oxford. 1961. Crystallometry. P. Terpstra and L. W. Codd. Pp.420. Longmans. London.1961. Refractometry and chemical structure. S. S. Batsanov. (Translated from the Russian by P. P. Sutton.) Pp. 250. Consultants Bureau. New York. 1961. Dynamic physical chemistry a textbook of thermo- dynamics equilibria and kinetics. J. Rose. Pp. 1218. Pitman. London. 1961. Chemical thermodynamics. J. G. Kirkwood and J. Oppenheim. Pp.261. McGraw-Hill. New York. 1961. The determination of stability constants and other equilibrium constants in solution. F. J. C.Rossotti and Hazel Rossotti. Pp. 425. McGraw-Hill. New York. 1961. The electronic theory of acids and bases. W. F. Luder and S. Zuffanti. 2nd edn. Pp. 165. Dover. New York. 1961. Polyelectrolyte solutions. S. A. Rice and M. Nagasawa. Pp. 568. Academic Press. London. 1961. Atomic radiation and polymers.A.Charlesby. Pp,556. Pergamon Press. Oxford. 1960. Toxicity of beryllium compounds. L. B. Tepper H. L. Hardy and R. I. Chamberlin. Pp. 190.Elsevier. Amster- dam. 1961. Inorganic chemistry. J. Kkinberg W. J. Argersinger and E. Griswold. Pp. 680.Heath. Boston. 1960. The surface chemistry of solids. S. J. Gregg. 2nd edn. Pp. 393.Chapman & Hall. London. 1961. Comprehensive inorganic chemistry. Edited by R. C. Brasted. Vol. 8. Sulfur selenium tellurium polonium and oxygen. Pp. 306. Van Nostrand. New Jersey. 1961. (Presented by the publisher.) The rare earths. Edited by F. H. Spedding and A. H. Daane. Pp. 641.John Wiley & Son. New York 1961. Advanced organic chemistry. L. F. Fieser and M. Fieser. Pp. 1158.Reinhold. New York. 1961. Chemistry of organic fluorine compounds. M. Hud- licky. Pp. 536.Pergamon Press. Oxford. 1961.(Presented by the publisher.) Einfuhrung in die theoretische organische Chemie. H. A. Staab. 2nd edn Pp.760. Verlag-Chemie. Weinheim. 1960. Rapid radiochemical separations. Y.Kusaka and W. Wayne Meinke. Sponsored by the United States Atomic Energy Commission. (Nuclear Science Series; Radio-chemical Techniques HASNS 3104.) Pp. 125. Sub-committee on Radiochemistry. Washington. 1961. (Presented by the publisher.) Physical methods in chemical analysis. Edited by W. G. Berl. Vol. 4. Pp. 76.Academic Press. New York. 1961. Reagent chemicals and standards. J. Rosin. 4th edn. Pp. 557.Van Nostrand. New Jersey. 1961.(Presented by the publisher.) Neuere Verfahren der Uranindustrie.G. A. Fester. (Sammlung chemischer und chemisch-technischer Beitrage. No. 58.) Pp. 88.Enke. Stuttgart. 1962. Die atherischen ole. Gildemeister and Hoffmann. Vol. 7. 4th edn. Pp. 806. W. Treibs et al. Akademie Verlag. Berlin. 1961. Textbook of biochemistry. E. S. West and W. P. Todd. 3rd edn. Pp. 1422. Macmillan. New York. 1961. The chemical analysis of foods. H. E. Cox. 5th edn. D. Pearson. Pp.464.Churchill. London. 1962. Clinical enzymology; enzymes in pathogensis diag- nosis and therapy. R. Abderhalden. (Translated by P. Oesper.) Pp. 448. Van Nostrand. New Jersey. 1961. (Presented by the publisher.) Industrial microbiology. A. H. Rose. Pp. 286. Buttenvorths. London. 1961. The biosynthesis of proteins.H. Chantrenne. Pp. 220. Pergamon Press. Oxford. 1961. The chemistry and technology of rayon manufacture. F. D. Lewis. Pp. 263.Lewis. Reigate Surrey. 1961. Ceramics physical and chemical fundamentals. H. Salmang. (Translated from the Gem by M. Francis.) Pp. 380. Butterworths. London. 1961. Adhesion. Edited by D. D. Eley. Pp. 290. University Press. Oxford. 1961. Anodic oxide films. L. Young. Pp. 377. Academic Press. London. 1961. Biological structure and function proceedings of the First IUB/IUBS International Symposium Stockholm. 1960. Edited by T. W. Goodwin and 0.Lindberg. Vol. 2.Pp. 665.Academic Press. London. 1961. The structure and biosynthesis of macromolecules symposium held in London 1961 to commemorate the fiftieth anniversary of the Biochemical Society; organised and edited by J.K. Grant and D. J. Bell. (Biochemical Society Symposia No. 21.) Pp. 132. University Press. Cambridge. 1962. (Presented by the Biochemical Society.) Inorganic polymers lectures delivered at an Inter-national Symposium held at Nottingham 1961; organised jointly by the University of Nottingham and the Chemical Society. (Chem. SOC. Special Publ. No. 15.) Pp. 146.Chemical Society. London. 1961. NEW JOURNALS Angewandte Chemie International Edition from 1962,l. Biochemistry from 1962 1. Chemical Processing from 1962,8. European Chemical News from 1962,l.
ISSN:0369-8718
DOI:10.1039/PS9620000097
出版商:RSC
年代:1962
数据来源: RSC
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