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Proceedings of the Chemical Society. October 1963 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue October,
1963,
Page 293-324
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PROCEEDINGS OF THE CHEMICAL SOCIETY OCTOBER 1963 HUGO MULLER LECTURE* The Biogenesis of Phenolic Alkaloids By D. H. R. BARTON DEPARTMENT COLLEGE S.W.7) (CHEMISTRY IMPERIAL LONDON Thou has the keys of Paradise 0just subtle and mighty opium! @e Quincey) Faire Daffadills we weep to see you haste away so soone. (Herrick) THEstudy of the biogenesis of plant alkaloids is already much too large for compression into a single lecture. Since the general background has been treated recently by Battersby1s2 in an authoritative manner no further exposition is needed at this time. Indeed for the sake of brevity we shall be con- cerned here with only two groups of alkaloids the morphine and the Amaryllidaceae alkaloids and in particular with the final steps in the biosynthetic sequence after the basic carbon skeletons have already been assembled.The earlier stages of bio-synthesis have been discussed already by Battersby2 and by Leete.3 In the constitutions of the morphine and Amaryl- lidaceae alkaloids we can discern an interesting rela- tionship between a reaction mechanism and bio- synthesis.* The mechanism we examine is that of phenol oxidation to furnish phenolate radicals (as I). If we assume that such radicals disappear by coupling in pairs to furnish molecular products then certain restrictions are imposed on the mode of coupling. Equally if we assume that such radicals are also involved in biogenetic pathways5 then interesting restrictions are imposed on the precursors and pro- ducts in the biogenetic sequence.(1) One must distinguish in principle between the coupling process and the substitution of a phenolate radical into a molecule of phenol followed by further oxidation. Both mechanisms predict ortho-para type s~bstitution,4~*~~ but have different implications for biogenesis. The substitution mechanism is less restric- tive than the coupling mechanism. We favour the latter. If p-cresol a phenol whose oxidation has been thoroughly studied:^^ be oxidised in the presence of a ten-fold excess of veratrole no veratrole is incor- porated into the phenolic products>* Similarly oxidation of the monophenol (11 R = Bz) gives no monomeric coupling product whereas the corres- * Delivered before The Society at the Manchester College of Science and Technology on May 2nd 1963; at the Royal Institution London on May 9th; and at the University of Birmingham on May 10th.Battersby Quart. Rev. 1961 15 259. Battersby Tilden Lecture Proc. Chern. Soc. 1963 189. Leete in Bernfeld “The Biogenesis of Natural Compounds,” Pergamon Press Oxford 1963 p. 739 et seq. Barton and Cohen “Festschrift A. Stoll,” Birkhauser Basle 1957 p. 117. Cf. Waters “The Chemistry of Free Radicals,” Oxford University Press London 1946 Chap. XII. Erdtman and Wachtmeister “Festschrift A. Stoll,” Birkhauser Basle 1957 p. 144. ’Barton Fourth Welch Foundation Conference Houston Texas Nov. 1960 in press. Barton Deflorin and Edwards J. 1956 530; and references there cited. ’Haynes Turner and Waters J.1956 2823; and references there cited. lo Barton Cox and Kirby unpublished observations. 293 ponding dihydric phenol (11 R = H) is smoothly cyclised.ll In so far as -0Me or -0Bz can be equated with -OH for the process of radical coupling a substitution mechanism seems improbable. We can- not however yet exclude radical substitution into a phenoate anion.12 Phenol coupling can of course be I HO& / (a) (m carried out in neutral or acidic pH and under these conditions the anion substitution process can hardly be important. For the remainder of our discussion we shall accept radical coupling without further qualification. The morphine alkaloids have been of interest to organic chemists since the beginning of the last century.The brilliant conception that the morphine molecule was constructed in Nature by the oxidative cyclisation of a benzylisoquinoline led Sir Robert Robinson to the first correct formulation of the morphine alka10ids.l~ Many biogenetic speculations have been advanced to explain the details of morphine biogenesis but owing to recent tracer studies only one theory has stood the test of experiment. It was proposed4 that the benzylisoquinoline (IV) was the true morphine precursor. If the intramolecular oxidative coupling of this substance were analogous to the union of p-cresolate radicals to form “Pummerer’s ketone” (111) then the sequence through the dienone (V) the enone (VI) and its reduction product (IX) would lead to the alkaloids thebaine (VIII) codeinone (X) codeine (XI R = Me) and morphine (XI R = H).* An important variant of this scheme was proposed by Battersby14 and by Ginsburg.15 These authors have suggested that the dienone (V) is reduced to the dienol (VII) rather than cyclised to the enone (VI).Although on the basis of our prior work8 we were PROCEEDINGS at first opposed to this alternative recent experi- mental work in our laboratory has shown that it is correct. Thus we have been able to prepare the beautifully crystalline dienone (V) m.p. 197” [a]* + 11 1 O (c. 1-69in ethanol) from thebaine. It exists solely in the “open” form (V) rather than the “closed” form (VI). Reduction by sodium borohydride affords two stereoisomeric alcohols (VII).Both of these alcohols under extremely mild acid conditions (aqueous solutions at pH3-pH4) are converted spontaneously at room temperature in fair yield into thebaine (VIII). Earlier experimental evidence by Battersby Leete Mothes Rapoport and their respective collaborators summarised by Battersby,112 is in accord with the biogenetic scheme given above. We have shownl6?l7 that the precursor (IV) labelled with 14C and tritium as indicated (ratio 2*0:1) affords thebaine (VIII) with the labels in a similar ratio (2.6:1). The plant used was Papaver somniferum and the percentage incorporation (0.14%) was greater than that obtained with tyrosine (0-08%). We have also synthesised18 (IX) with five different posi- tions labelled (see MI). We are confident that this will afford thebaine with all five labels in the same positions and in the same ratio.We have also pre- * No stereochemical significance is to be attached to any of the formulz given in this lecture. Thickened bonds are used only for convenience in designating constitutions. li Afzal and Kirby personal communkation. lP Beecken Gottschalk Gizycki Kramer Maassen Matthies Musso Rathjen and Zahorszky Angew. Chem. 1961 73 665. l3 Gulland and Robinson Mem. Proc. Munchester Lit. Phil. Soc. 1925,69 79; as quoted by Battersby in ref. 2. l4 Battersby Summer School on “Biogenesis,” Milan Italy Sept. 1962 in press. l5 Ginsburg “The Opium Alkaloids,” Interscience Publishers New York 1962 p. 91. l6 Barton Kirby Steglich and Thomas Proc. Chern.Soc. 1963 203. Barton Kirby and Thomas Summer School on “Biogenesis,” Milan Italy Sept. 1962 in press. Barton Kirby and Thomas unpublished observations. OCTOBER 1963 295 pared (V) with tritium labelling para-to the phenolic hydroxyl as well as the two alcohols (VII) with tritium labelling at the same position and at the secondary allylic position.13 We shall therefore have no difficulty in confirming the biogenetic sequence (IV) -+ (V) -+ (VII) -(VIII) during the current growing season. The sequence thebaine (VIII) > codeine (XI R = Me) -z morphine (XI R = H) has already been firmly es tablished.20 The postulated intermediacy of codeinone (X) still remains to be demonstrated. Having available a supply of the precursor (IV) radiochemically labelled with tritium (but without N-methyl labelling) we were interested to study its oxidation in vitro to the dienone (V) for this would constitute a total synthesis of morphine alkaloids by the biogenetic route.We had studied this at some length in Glasgow in collaboration with Drs. K. H. Overton and M. K. Jain,2l but it was not possible to isolate any product corresponding to (V) or (VI). The oxidation of the radioactive precursor has marked advantages because dilution of the crude oxidation product with dienone (V) gives after adequate puri- fication an exact measure of the yield of dienone (V) resulting from the oxidation. The yield of dienone (V) in our fist oxidation (manganese dioxide in chloro- form) was 0.O12%.lsThis was confirmed by further processingto give thebaine (VIII) with the same level of activity.Since the precursor (TV) was racemic the yield of racemic (V) must have been 0.024%. The dilution with optically active (V) constitutes of course a resolution. If one will accept a yield of pro- duct measured only by radioactivity then we have attained a long sought objective22-the total syn- thesis of morphine alkaloids by the biogenetic route. There are of course already two excellent but non- biogenetic total syntheses of morphine alkaloids reported in the literat~re.~~ The Amaryllidaceae alkaloids are a large group of natural products24 which at first glance are of widely divergent function and type. In fact all of these compounds can be regarded as derived from a single precursor norbelladine (XIII R = H) by phenolate radical ~oupling.~ Three main skeletal types can be recognised with sub-groups of alkaloids derived therefrom.We shall consider here the minimum number of alkaloids which represent the main skeletal types. We commence with the alkaloid galanthamine (XVII) which we regarded as biosynthesised from norbelladine ON-dimethyl ether (XIV R = Me) by oxidation to the dienone (XV) ring closure to the enone (XVIII) and reduction to the latter to the allylic alcohol (XVII) (galanthamine). At the time when this scheme was put forward4 it must be realised that belladine25 (XIXI R = Me) was not known and that the alkaloid narwedine26 (XVIII) had not been characterised.The formula for OH ow (XVI I) (XVIII) 11 0 OH LO Barton Kirby and Steglich unpublished observations. Lo Rapoport Stermitz and Baker J. Amer. Chem. Soc, 1960 82 2765; Stermitz and Rapoport Nature 1961 189 310; J. Amer. Chem. Soc. 1961 83,4045; Battersby and Harper Tetrahedron Letters 1960 No. 27 21. See Jain PhD. Thesis Glasgow 1958. 22 Sir Robert Robinson “The Structural Relations of Natural Products,’’ Oxford University Press London 1955. J3 Gates and Tschudi J. Amer. Chem. SOC.,1952,74 1109; 1956,78 1380; Elad and Ginsburg ibid. 1954,76 312; J.. 1954 3052. Wildman “The Alkaloids,” co-ed. Manske and Holmes Academic Press New York 1960 Vol. VI 290. p5 Warnhoff Chem. andInd. 1957 1385. 26 Boit Dopke and Beitner Chem. Ber. 1957 90 2197.PROCEEDINGS galanthamine was uncertain. The correct formula (XVII) was in fact chosen on the basis of the pro- posed biogenesis. Of course the constitution of galanthamine has been placed beyond question by a total synthesis based on the biogenetic scheme.27 It is of interest that in this case the enone (XVIII) is much more stable than the dienone (XV). The equi- librium between (XVIII) and (XV) can however be detected easily by the facile racemisation of nar- wedine (XVIII). The alkaloid haemanthamine (XX) can be regarded as produced from norbelladine O-methyl ether (XIV R = H) by oxidative coupling to the dienone (XVI) which isomerises to the enone (XIX). There is good experimental evidence for this step and for its re- versibility in analogous systems.28 Later steps of reduction methylation and hydroxylation then lead to haemanthamine (XX).The aliphatic hydroxyl group might of course be introduced at an earlier stage in the biosynthesis. The origin of the methylene- dioxy-group is discussed further below. The alkaloids galanthine (XXII) and lycorine (XXIII) can also be regarded as derived from O-methylnorbelladine (XIV R = H). Here oxidative coupling is directed to give initially the medium-ring intermediate (XXI). Dienones are of course obliga- tory initial products of phenolate radical coupling. When the dienone is separated from phenol solely by migration of hydrogen we normally assume a very rapid prototropy of dienone to phenol but have not written such an obvious step into previous formulse.The bis-dienone (XXI) is however according to our assumption a special case in that the medium-size nitrogenous ring has a special conformational driving force for closure.29 If we can accept that this driving force is sufficient then we can understand that closure of the ring gives by vinylogous @-addi- tion the enone structure (XXIV). The lower dienone ring of (XXI) attains aromaticity in the usual way. The formation of the Pyunsaturated enone rather than the a@-unsaturated isomer is expected under kinetic control.30 The introduction of allylic hydroxyl or methoxyl at a later stage in the scheme represents a minor divergence from earlier ~chemes.~?~ Such a step would have the conceptual advantage of a single oxygenation pattern in the precursor for all the Amaryllidaceae alkaloids so far discussed.Some recent results kindly communicated to us by Prof. A. R. Battersby would support this point of view. The results of tracer studies on the biogenesis of Amaryllidaceae alkaloids have already been very competently summarised by Battersby2 and we shall refer here only to a few of the very recent results in any detail. In brief the work of Battersby?l Wild- man Suhadolnik Jeffs and their respective col- laborators with additional contributions from the Imperial College group has proven the incorporation of O-methylnorbelladine and its N-methyl derivative intact into the various types of Amaryllidaceae alkaloids. The structural aspects of our theory4 have thus been firmly proven.Proof that the mechanism of coupling really involves two phenolate radicals is difficult to secure by direct experiment but so far as circumstantial evidence will go the theory is supported. The use of whole plants for alkaloid studies has disadvantages and the isolation of the individual enzymes which catalyse the successive steps of the biosynthesis would certainly be a great advance. In a Communication which will appear shortly Fales Mann and M~dd~~ have characterised an enzyme which converts specifically norbelladine (XIII, R = H) into O-methylnorbelladine (XIV R =H). Similar work by Suhadolnik and his collaborators is also in course of publication.% Most of our worka on the biogenesis of Amaryl- lidaceae alkaloids has been carried out with the King Alfred daffodil.This is not only a very beautiful plant it also obligingly produces as the main alkaloids galanthine (XXII) galanthamine (XVII) and haemanthamine (XX) each representative of a major group of alkaloids. The incorporation of ON-dimethylnorbelladine (XIV R = Me) labelled in the two methyl groups and at the position indicated into galanthamine showed that the whole molecule was utilised without any O-or N-de-methylation. Since we had also shown that O-methylnorbelladine (XIV R = H) was a precursor of haemanthamine (XX) it was immediately an attrac- tive hypothesis that the methylenedioxy group of haemanthamine was formed by cyclisation of an ortho-methoxy phenol.A concise e~periment?~ in which O-methylnorbelladine (XIV R = H) labelled in the O-methyl group and in the carbon skeleton at 27 Barton and Kirby Proc. Chenz. SOC. 1960 392; J. ,1962 806. 28 Goosen John Warren and Yates J. 1961,4038. 29 Cf. Anet Bailey and (Sir Robert) Robinson Chem. and Ind. 1953 944; Leonard Fox Oki and Chiaravelli J. Amer. Chem. SOC. 1954 76 630 3465 5708 and 6421; Leonard Chimia 1960,14 231. 30 Cf. Birch J. 1950 1551 2325; Ringold and Malhotra Tetrahedron Letters 1962 No. 15 669. 31 Archer Breuer Binks Battersby and Wildman Proc. Chem. SOC. 1963 168. 32 Fales Mann and Mudd J. Amer. Chem. Soc. 1963 in press; we thank Prof. A. R. Battersby for kindly informing us of this important work. 33 Personal communication from Dr.Suhadolnik. 34 Barton Kirby Taylor and Thomas Proc. Chem. Suc. 1961 254; 1962 179; J. 1963 4545. 35 Barton Kirby and Taylor Proc. Chem. Suc. 1962 340. OCTOBER 1963 297 the position indicated was fed to the King Alfred daffodil gave haemanthamine (XX) in which the methylenedioxy-group and the corresponding ring carbon were labelled in exactly the same ratio as in the precursor. The cyclisation hypothesis was thus firmly proven. It is of interest that the isomeric O-methylnor- belladine (side-chain labelled) with the methoxyl group meta to the side chain -CH,-NH-is not incorporated into galanthamine galanthine or haemanthamine. So far as alkaloid biogenesis is concerned it is metabolically inert.% (xxrv) 1 n Amongst the minor alkaloids of the King Alfred daffodil are lycorenine (XXVI R = H,OH) and homolycorine (XXVI R = 0).The biosynthesis of these compounds can be regarded7 as proceeding from (XXIV) through (XXV). In this case norbel- ladine (XIII R = H) or 0-methylnorbelladine (XIV R = H) should be the correct precursor. Alternately one could visualise that the ON-dimethylnorbelladine (XIV R = Me) is the precursor so that cyclisation of the medium-sized ring intermediate is accom- panied by quaternisation of nitrogen. In fact homo- lycorine (XXVI R = 0) is formed from norbel- ladix~e~~ (XIII R = H) (side-chain labelled) with 0.05 % incorporation. No significant amount of labelled homolycorine or lycorenine was produced when ON-dimethylnorbelladine (XIV R = Me) with N-methyl labelling was fed.The scheme given above (XXIV) -(XXV) (XXVI) is therefore, -+ supported. The biochemical cyclisation of ortho-methoxy phenols referred to above may well have wider implications in biogenesis. For example the ‘ber- berine’ carbon [marked with an asterisk in the berberine formula (XXVII)] which has played such an important role in the speculations of Sir Robert Robinson22 and others may (at least in some cases) be derived from the oxidative cyclisation of an N-methyl group.* To illustrate this general theme with one example the precursor of thebaine (see above) can be written as in (XXVIII). Dehydrogena-tion to the imine (XXIX) and cyclisation would furnish the phenol (XXXI).Oxidative cyclisation of the latter and ring opening would give protopine (XXX). Of course the order in which the various cyclisations occur is not determined and the three / other isomeric ortho-methyoxyphenols corresponding to (XXVIII) might in principle be used by Nature for the synthesis of protopine. Experiments are in hand in collaboration with Mr. R. H. Hesse to con- firm the origin of the ‘berberine’ carbon. The ‘berberine’ carbon of indole alkaloids could in principle be derived in an analogous manner. * This suggestion was first made (at Imperial College) by Dr. G. W. Kirby in the course of mutual discussion of the ‘berberine’ carbon. The idea was presented at the Summer School on Biogenesis in Milan,17 At that time Professor A. R. Battersby kindly informed us that he had independently reached the same conception.He has presented his views subsequently in his Tilden Lecture.2 36 Barton Kirby and Tiwari unpublished observations. 37 Barton Kirby and Prager unpublished observations. PROCFEDINGS Another theoretical idea employed in our earlier speculations,4 was the suggestion that in order to explain the constitutions of the aporphine alkaloids anonaine (XXXVI R = H) and roemerine (XXXVZ R = Me) (see also nuciferine and nornuciferine%) the precursor (XXXII R =H or Merespectively) was Me0 \ (XXXII) (XXXIII) (xxxrv) I e, 0 ~~ (XXXVI) oxidised in the usual way to the dienone (XXXIII R = H or Me respectively). Reduction to the dienol (XXXIV R = H or Me respectively) and acid- catalysed rearrangement (see arrows) would then furnish anonaine (XXXVI R = H) and roemerine (XXXVI R = Me).Of course in 1956 the dienol- benzene rearrangement39 had not been generally recognised. The later work cited and in particular the aromatisation of prephenic acid,4O make such speculation much more acceptable. Battersby2 has used the dienol-benzene rearrangement to advantage to explain the structures of several “abnormal“ aporphine alkaloids for which we had previously* used a dienone-phenol rearrangement. Battersby‘s treatment seems superior to our earlier ideas. Either a dienone-phenol or a dienol-benzene rearrange- ment should be involved in the biogenesis of the interesting alkaloid cryptopleurine (XXXV).*l It is clear that biogenetic studies with alkaloidal compounds are at the very interesting stage of development where hypothesis and experiment can be synergistically combined.In this connection we would add that very much more has been omitted from this lecture than has been included. No reference has been made to the stimulating specula- tions of Wenkert or to the pioneering investigations of Marion Leete and others on other types of alkaloids simply because of lack of relevancy to this specialised topic. I wish to express my appreciation to Drs. R. H. Prager W. Steglich and J. B. Taylor and Messrs. G. H. Thomas and H. P. Tiwari for the wonderful contributions they have made to the work reported. Especial thanks are due to Dr.Gordon Kirby for his participation in the programme at all levels of theory experiment and supervision. I have truly acted as a spokesman for this group rather than for myself. Dr. D. W. Turner has very kindly helped us at all times with advice on radiochemical counting techniques. We thank also Professor A. R,Battersby for friendly discussion and Professor W. C. Wildman for his many generous gifts of alkaloids. 38 Tomita Watanabe and Furukawa J. Pharm. SOC.Japan 1961,81 1202. 3* Gentles Moss Herzog and Herschberg J. Amer. Chem. SOC.,1958 80 3702; Plieninger and Keilich Chem. Ber. 1958,91 1891.. 40 See Plienmger Angew. Chem. Internat. Edn. 1962 1 367. 41 Gellert and Riggs Australian J. Chem. 1954 7 113; Fridrichsons and Mathieson Acra Crysf.1955 8 761; Bradsher and Berger J. Amer. Chem. Soc. 1957,79,3287; cf. tylophorine Govindachari Lakshmikanthan Nagarajan and Pai Chem. and Znd. 1957 1484. The Journal and The Proceedings of The Chemical Society Publication of Accounts of Two-dimensional X-ray Analyses INrecent months it has become necessary to con- sider the standard of work that should now be required in papers and communications dealing with the results of two-dimensional X-ray analyses. As a result of accumulated experience and advice from crystallographers and chemists the Publication Com- mittee has accepted the following as advice to authors and referees An analysis based only on two-dimensional pro- jections may form the subject of a short paper pro- vided that it leads to firm conclusions of substantial chemical interest or that it solves the phase problem in a structure of chemical interest.But only in exceptional cases where the structure is two-dimensional or otherwise simple and the pro- jections are well resolved is a detailed quantitative discussion of molecular dimensions justified. The methods commonly used for assessing accuracy are not reliable for imperfectly resolved projects. The publication of molecular dimensions with alleged standard deviations may then seriously mislead the casual reader. A standard deviation is now commonly given but the meaning of & is not always understood by the lay-chemist. For example C-C = 1.35 =k 0.05 A (where rt 0-05 is properly estimated) means that OCTOBER 1963 there is a 68% probability that the true result lies within these limits and a 99.9% probability that it lies between 1-20 and 1.50 A.(Except perhaps statistically therefore the above result might have little chemical significance; and the justification for publishing it might be questionable.) Nevertheless some readers will suppose the C-C distance to have been fixed between 1.30 and 1-40A. The situation is even more misleading when the rt 0.05 have been optimistically underestimated. Recording and Nomenclature of Circular Dichroism By CARLDJERASSI and E. BUNNENBERG (DEPARTMENT OF CHEMISTRY STANFORD UNIVERSITY STANFORD CALIFORNIA) THEwidespread use of optical rotatory dispersion in organic chemistry necessitated the introduction1 of a nomenclature system somewhat different from that employed by physical chemists so that the shape and magnitude of the rotatory dispersion curve could be expressed simply and unambiguously in terms not already used by organic chemists for other purposes.For that reason the words “peak” and “trough” were suggested1 to define the extrema of a Cotton effect (see Fig. l) since the terms “maximum” and “minimum” have a specific connotation in absorp- tion spectroscopy and the position of the absorption maximum coincides (roughly) with the mid-point CD POshve Moximurn FIG. 1 between the extrema of the Cotton effect. This nomenclature and certain accompanying definitions1 have simple counterparts in most of the principal scientific languages* and have found wide acceptance.Since the frequent reproduction of full rotatory dispersion curves in journals is hardly feasible a notation for the recording of experimental data was suggested that has also been accepted by most organic chemists. Recently instruments have become available3 for the convenient measurement of circular dichroism with the consequent rapid increase in such deter- minations for organic substances. As pointed out recently,q the intimate relation between optical rotatory dispersion and circular dichroism permits interchangeable application of these two physical tools for most organic chemical applications notably in stereochemistry. It is important therefore that for concise reporting of circular dichroism data a nomenclature system should be used that fulfills the same criteria as those established earlier1 for optical rotatory dispersion measurements.Although the terms “peak” and “trough” were introducedl for rotatory dispersion extrema to differentiate them from absorption “maxima” and “minima” it is suggested that the nomenclature of absorption spectroscopy be again utilized to designate the extrema of circular dichroism curves. Since circular dichroism extrema are necessarily quantities requiring sign-in contrast to absorption spectroscopy-it is obligatory that the circular dichroism data reflect this by use of the terms “positive (or negative) maximum” “positive (or negative) minimum” and “positive (or negative) point of inflection.” Particular details of this nomenclature are illustrated in Figs.1 and 2 and are self-explanatory except for one feature indicated in Fig. 2. In the latter there are depicted the circular dichroism curves of three hypothetic substances Djerassi and Klyne Proc. Chem. Soc. 1957 55. Inter al. Russian translation (by Yashunskoso and Demyanovich) of C. Djerassi “Optical Rotatory Dispersion Applications to Organic Chemistry,” McGraw Hill New York 1960 Foreign Literature Publishing House Moscow 1962 pp. 24-32; Japanese translation (by Nakanishi and Yamazaki) Tokyo Kagaku Dojin Co.Ltd. Tokyo. 1961 pp. 10-16; Ohloff Osiecki and Djerassi Chem. Ber. 1962,95 1400; Djerassi Bull. Soc. Chirn. France 1957 741. Mitchell “Unicam Spectrovision,” 1958 No.6 6; Badoz Billardon and Mathieu Cumpi. rend. 1960,251 1477; Grosjean and Legrand ibid. 2150; Holzwarth Gratzer and Doty J. Amer. Chenz. SOC.,1962,84,3194; Mason J. Chem. Soc. 1962 3285. * Djerassi Wolf and Bunnenberg J. Amer. Chem. Soc. 1962 84 4552. which differ only in the 300 mp region as indicated by the letters x y and z. Point z represents a “positive minimum” which results from the incomplete isolation of the two absorption bands. This terminology is not applicable to point x where the two absorption bands are completely isolated as was actually observed in the actual example given in Fig. 1 [point marked (3)]. Also the curve containing pointy (Fig. 2) represents a situation of multiple adjacent optically active absorption bands of alternate signs.The term “negative minimum” would be completely inappro- riate since point y actually represents a “negative maximum.’’ Finally although not depicted in Fig. 2 it should be noted that points of inflection may exist and these should be tabulated and properly signed. Circular dichroism curves have been plotted in terms of or de* but for the purposes of both the organic and the theoretical chemist the use of molecular ellipticity units [6] is clearly preferable.’ All our comparative rotatory dispersion-circular dichroism results4r8 have been plotted in molecular rotation [#] and molecular ellipticity [6] units and as illustrated in Fig. 1 the use of such units has the enormous advantage that approximately equal orders of magnitude are always encountered.Since organic chemists are accustomed to molecular rotation magnitudes molecular ellipticity values immediately become meaningful. Furthermore flieir use eliminates the multiscalar graphs found in the earlier literature9. €n view of the relation7 [8] rJ_ 2.303(4500/n)(~~-e~) the E$-E,. values PROCEEDINGS earlier employed 5s6p9can be converted easily into molecular ellipticity units by multiplying them by the factor 3300. It was suggested1 that when optical rotatory dispersion curves cannot be reproduced the molecular rotation at 589 mp (sodium D line) the various extrema and the last-measured wavelength be reported. With circular dichroism curves it is probably sufficient to report only the position of each circular dichroism maximum together with the termination points of each circular dichroism band as well as the solvent concentration and temper- ature.Thus the first positive circular dichroism band in Fig. 1 can be described in the experimental portion of an article without reproducing the curve by listing the points marked 1 2 and 3 in Fig. 1 [&O 0,[sJ,,o + 25,500 [sJ380 0,while the second (negative) one would then be defined by giving the corresponding values for points 3,4 and 5 in Fig. 1. From the standpoint of the theoretical chemist interested in ro tational-s trength calculations it would be desirable to give also the area under the circular dichroism curve but past experience in other spectroscopic fields indicates the unlikelihood that this will be done in general organic chemical studies.As an alternative when circular dichroism curves are not reproduced the band-width7sSa at half maximum should be reported. This is illustrated in Fig. 2 through the use of the symbol l“; in situations where the band is not well isolated it is suggested that l”/2 be reported as indicated for the 275 mp band in Fig. 2. Finally it should be empha- sised that whenever circular dichroism data are recorded they should be accompanied by a citation of the relevant absorption spectral maxima (A max. abs. 454 and 317 mp in Fig. 1) obtained in the same solvent. These nomenclature suggestions have been circulated among American and British investigators interested in applications of circular dichroism to organic chemistry and have met with substantial approval.We are indebted to the following individuals for correspondence and comments many of which were incorporated into the present final version :E. R. Blout (Harvard University) R. C. Cookson (University of Southampton) M. Good- man (Brooklyn Polytechnic Institute) W. Klyne (Univer- sity of London) S. F. Mason (University of Exeter) K. Mislow (New York University) A. Moscowitz (University of Minnesota) A.I.Scott (University of British Columbia) U. Weiss (National Institutes of Health Bethesda) and D. H. Whiffen (National Physical Laboratory Tedding- ton). fa) McCapra Scott Sim and Young Frm. Ckm. SOC.,1962 185; (b) e.g. Mason Proc.Chem. Soc. 1962 362; McCaffery and Mason Trans. Faraday Sm. 1963,554 1 and other papers from Exeter University. Velluz and Legrand Angew. Chem. 1961 73 603 and subsequent articles from the Roussel-Uclaf Laboratories. Moscowitz in Djerassi (ref. 2a) Ch. 12 p. 155. Bunnenberg Djerassi Mislow and Moscowitz J. Amer. Chern. Soc. 1962,84,2823; Djerassi Wolf and Bunnenberg ibid. 1963 85 324; Mislow Bunnenberg Records Wellman and Djerassi ibid.,p. 1342 ;Wellinson Bunnenberg and Djerrasi :bid.,p. 1870. (a) e.g. Kuhn Ann. Re)?.Ph~s.Chem. 1958,9,417 and earlier papers; (b) Mitchell and Schwarzwald J. Chem. Suc., 1939 889. OCTOBER 1963 301 COMMUNICATIONS Conformational Equilibria in trans-2-~~yclohexanol and trans-Cyclohexane-1 ,Zdiol By J. PITHA J.SICHER,F. $1~08,M. TICH~, and S. VASEKOVA (INSTITUTE AND BIOCHEMISTRY, OF ORGANICCHEMISTRY CZECHOSLOVAK OF SCIENCE, ACADEMY PRAGUE) WE report values for the conformational equilibria in trans-2-aminocyclohexanol(Iee + Iaa) and trans-cyclohexane-l,2-diol (IIee $‘IIaa).* The equilibrium is very largely shifted towards the ee side making experimental evaluation very difficult. This difficulty is circumvented by using the “auxiliary” compounds (111) and (IV) in which the isopropyl acts as an “equilibrium-restoring group,” and subsequently correcting for its presence.l The conformational equilibrium in (111) and (IV) was determined by cor- relation of the absorptivities of “bonded” hydroxyl groups (at 3525 and 3600 cm.-l respectively) in these two compounds with the absorptivity (at the same wavenumbers) of the conformationally homo-geneous 4-t-butyl-substituted amino-alcohols (V) and (VI) and the diols (VII) and (VIII) respectively.ti The assumption underlying this approach is that the spectrum in the OH-stretching region of the amino- alcohol isomer (VI) is identical with that of the aa conformer of (111) while that of the amino-alcohol isomer (V)is identical with that of the ee conformer of (111) the same holding for the corresponding diols.0 The equilibrium in (111) and (IV) (Table) favours the ee isomers both in the amino-alcohol and the (IILe) + (IIIua) T AG AH AS (“c) (kcal.mole-l) (e.u.) 32 45 56 0.34 We can estimate AG for the conformational equilibria in trans-Zarninocyclohexanol (I) and X - (1 ee X-NH,) (II ee x-OH) (Ilua:X-OH X Pr‘ @; (mee :X-NH,) (III uu :X-NH,) (Wee X-OH) (IVm :X-OH ) OH I (v :x= NH,) (V1 :X=NH,) (VII x-OH) (Vlll :x-OH ) Weel + ([Vaa) T AG AH As (“c) (kcal.mole-l) (e.u.) 33 0*33]1.8 4.9 60 0.19 * The standard error of the mean in dG is lower than 0.05 kcal. mole-’. diol (71 and 64% respectively at 30”). There are appreciable entropy terms favouring the aa con-formers; this is probably due to loss of rotational freedom of the functional groups as well as to specific solvent effects in the ee conformers resulting from hydrogen-bond formation. trans-cyclohexane-1,2-diol (11) from the AG data for (111) and (IV) by adding the A-value of the isopropyl group.Taking this as 2.1,5we get 2-6 and 2.4 kcal. mole-l for AG of the equilibria (Iee) ;=I (Iaa) and (Ilee) ;=I (II,J respectively. In the absence of inter-actions between the equatorial functional groups * Boat forms are believed to be practically absent in the compounds examined; for discussion see TichJi SipoS and Sicher Coll. Czech. Chem. Comm. 1962 27 2907. 7 Measured on a Unicam SP 100 spectrometer in tetrachloroethylene (c = 2-9 x 10-3~); 5 to 9 absorptivity measurements were made for each compound. f Compounds (V) (VI) and (VIII) have been described (TichJi SipoS and Sicher Coll. Czech. Chem. Comm. 1962, 27 2907; LeBel and Czaja J. Org. Chem. 1961 26 4768); preparation of compounds (111) (IV) and (VII) will be reported subsequently .8 This assumption is supported by the fact that the 3p spectrum of (V) is practically identical with that of truns-2-amino-trans-4-isopropylcyclohexanol as well as trans-2-amino-trans-4-t-butylcyclohexanol. Tichf Jona and Sicher Cull. Czech. Chem. Comm. 1959,24 3434. Gramstad Spectrochim. Acta 1963 19,497. Allinger Freiberg and Hu J. Amer. Chem. SOC.,1962 84,2836. dGfor the equilibrium (Ice) F1 (Iaa)would be approxi- mately the sum of the A-values of the two groups,*s5 i.e. AoII + A, = 0-8 + 1.2 = 2.0; for the equi- libriurn (IIee) + (Iluu) analogously by 2AoH = 1-6. The differences between the values thus computed and those determined experimentally 0.6 kcal. PROCEEDINGS mole-l for (I) and 0.8 kcal. mole-l for (11) represent crude estimates of the net diequatorial interactions of the groups involved which thus are attractive overall and of the same order of magnitude for the two cases.(Received August 29th 1963.) Eliel Della and Williams Tetrahedron Letters 1963 No. 13 831. Eliel J. Chem. Educ. 1960 37 126. Oxidative Dimerisation of 2,3-Dihydrohexamethylpyrazine By M. LAMCHEN and T. MITTAG (DEPARTMENT UNIVERSITY OF CHEMISTRY OF CAPE TOWN SOUTH AFRICA) THE ready oxidation of 2,3-dihydropyrazines to pyrazines' severely limits the use of these compounds. When the 2 and 3 positions are fully substituted this oxidation cannot occur and with this in mind we prepared the 2,3-dihydrohexamethylpyrazine(I) by condensing 2,3-diamino-2,3-dimethylbutane and butane-2,3-dione.Even this product was very unstable but by work- ing in dry nitrogen it was possible to isolate the compound (I) a pale yellow solid m.p. 46",h,, 231 and 358 mp (E 9500 and 1200 resp.) Vmax 1665 and 1605 cm.-l which even under nitrogen decom- posed within 3 days. Catalytic hydrogenation occurred in two distinct steps (the first fast the second slow) to give a hexamethylpiperazine. Oxidation by air in the presence of hydrochloric acid rapidly produced a stable deep purple non-crystal- line solid C,,H,,ClN, the chlorine being present as chloride ions. Oxidation of the dihydropyrazine (I) with one equivalent of iodine in dry ether gave a quantitative yield of an iodide C,,H,,IN,. The same iodide was precipitated by dissolution of the chloride in aqueous potassium iodide.When hydrogenated over platinum or Raney nickel the chloride absorbed hydrogen with loss of colour which was very rapidly restored on exposure to air. Aqueous alkali decomposed the purple com- pound with the formation of tars. On chemical and in particular on spectral evidence we have assigned the dimeric structure (IV; X = C1) to the purple chloride. The ultraviolet spectrum showed maxima at 230 and 270 mp (e 1250 and 850 respectively) and the visible spectrum had a single absorption band which is dependent on pH being 515 mp (E 14,000) at pH 8 and 550 mp (E 14,000) at pH 1. The bathochromic shift at higher acidity is probably due to increased protonation of the C-N groups.The infrared spectrum (potassium chloride disc) showed bands at 3438 3068 2800-2556 Ishiguro and Matsumura Chem. Abs. 1958 52 11862. (series) 1624 and 1508 cm,-l. The N-H and +N-H stretching bands were confirmed by deuteration. The proton magnetic resonance spectrum in deuterium oxide had chemical shifts at r 8.7 (gem-dimethyl) 8.6 (gem-dimethyl) 7.3 (N=C-CH,) and 3.2 (olefinic proton) with relative intensities of 6 6 3:1. 0V) Structure (IV) could form from the dihydro- pyrazine (I) by initial oxidation to the free-radical cation (11) ; dimerisation followed by reversible re- arrangement (IIT) -(TV) would complete the process. We are indebted to Dr. C. Chapman Cambridge and Dr. K. Pachler C.S.I.R.,Pretoria for the proton magnetic resonance spectra.(Received August 7th 1963.) OCTOBER 1963 303 A Wave Function and Chemical Formula for Benzene By P. B. EMPEDOCLES and J. W. LINM~~"~ (INORGANIC LABORATORY, CHEMISTRY OXFORD) IT has been suggested1v2 that a successful description might be provided for many molecules by assigning each electron to a different orbital. This proved worthwhile2 for the electrons of the v-system of C3H5+ C3H5 and C3H5- and other molecules and ions have also been treated successfully in the same way.3~~ When this is extended to the six electrons of the n-system of benzene in which there are six C-C bonds each electron will be assigned to a separate orbital formed by the combination of two atomic orbitals. That is the six orbitals accommodating the six electrons will be (a + kb) (b + kc) (c + kd) (d + ke) (e + kf) and Gf + ka) where a-f repre-sent the six carbon 2r-atomic orbitals and k is a constant.In order to obtain functions for which the spin quantum number Sz = 0 three a-and three ,&spin functions must be combined with the six space functions (a + kb) etc. There are twenty different ways of distributing these (::::;).-To obtain wave functions of the required symmeky antisym- metrised determinants based on (a + kb) etc. must be combined with a similar set of twenty based on (ka + b) etc. There are two combinations of these forty determinants which have the symmetry lAlS. If k = 1 there are only twenty determinants to be combined. Previous calculations of this kind have been carried out for C3H5+ C3H5 and C3H5- (ref.2) and for C4H,+ and CpH (ref. 3). These suggest that lowest energies are obtained with k close to 3. Energies have therefore been calculated with the help of a Ferranti Mercury computer both for the simple function having k = 1 and for that having k = 3. The results are shown in the Table where comparison is made with a single-configuration Huckel molecular-orbital treatment in which the same 2pn-atomic orbitals were used as the basis. It can be seen that the non-pairing function2 with k = 3 Function Energy (ev) Huckel molecular orbital 114.1 Non-pairing (k = 1)* 1 14.6 Non-pairing (k = 3)* 118.3 * Two independent sets of configurations. Linnett J. Arner. Chem. SOC.,1961 83 2643.Hirst and Linnett J. 1962 1035 3844. leads to an energy 3.9 ev (90 kcal./mole) below that obtained by using the Huckel function. This is a significant decrease; it is approximately half as much again as the heat of hydrogenation of benzene and its magnitude is roughly that of the quantum for h = 3000 A. These calculations were made by the method of Goeppert-Mayer and Sklar by using the Hamiltonian R i= 1 j=l i>j i= 1 [ V,(O + Vdi) + V&) + V&) + V&) + VXi]' where rf3are the inter-electron distances and V,(i), etc. are the potential of the electron i in the fields of the C+ centres a 6.. .. At the present time the calculation involving the non-pairing function is lengthy but this does not affect the valuable general conclusion that this way of disposing the electrons spatially produces a most encouraging result.There are three possible types of distribution of the spin functions among the six space orbitals; one member of each type is shown diagrammatically as (1-111). The relative weights of the individual members of the different types are 8.64:3-82:1-00 respectively. (1) (11) (IIQ Using a simple argument based on the introduction of electron correlation into the simple molecular- orbital function we had concluded previously that the relative weights for the simple function (k = 1) should be 9:4:1. The general conclusion from this examination is that a most satisfactory function for the electron distribution in the n-system of benzene is obtained by regarding each C-C bond as being made up of Empedocles Thesis Oxford 1962.Gould and Linnett Trans. Furuday Soc. 1963 53 1001; also unpublished calculations by G. Frank J. Farren, B. J. Duke M. Barber and D. M. Hirst. Goeppert-Mayer and Sklar J. Chem. Phys. 1935,6 645. PROCEEDINGS three electrons (two in a a-orbital and one in a n-orbital). The formula may therefore best be written as (IV). We thank the D.S.T.R. for a Studentship to P.B.E. (Received July 23rd 1963.) Reaction of Aluminium with Carbon Dioxide at 400-650" By R. J. BREAKSPERE and H. F. LEACH S. J. GREGG (DEPARTMENT THEUNIVERSITY, OF CHEMISTRY EXETER) ALUMINIUM is well known as a metal which under- goes "protective oxidation" in oxygen i.e.the film of oxide reaches a limiting thickness and then oxidation virtually ceases. It was thought of interest to study the behaviour of sheet aluminium when exposed to carbon dioxide at elevated tem- perature because of the possible deposition of carbon-a feature which is known to exert consider- able influence on the oxidative behaviour of both magnesium1 and beryllium.2 The reactions thermodynamically possi bfe are 2Al + 3c0 -+AI,O + 3CO (1) 4AI + 3CO2 -+ 2AI20 + 3C (2) with further reaction of the carbon monoxide produced in reaction (1) as follows 2AI + 3CO -+ 2A120 + 3C (3) In addition the carbon formed in reactions (2) and (3) could react with aluminium to form the carbide A14C3. be detected at 400" or 450". When however a bulb containing copper oxide heated at 350" was attached to the system (so as to convert into carbon dioxide the monoxide produced) no deposition of carbon could be detected at any temperature.It thus seems that the carbon is formed as a result of reaction (1) followed by (3) and not directly in reaction (2). The curves of total weight gain of the specimen (from formation of oxide + deposition of carbon) against time have been obtained at temperatures from 400" to 650" at 50" intervals together with corresponding curves with oxygen as oxidant by way of comparison;a vacuum-microbalance sensi- tive to 1 pg was used. Some examples of the curves are given in the Figure. It seems clear that the presence of carbon in the oxide film has a two-fold effect; it slows down the overall rate of film growth in the early stages and accelerates it in the later stages.The formulation of a detailed explanation must await the results of work Time (hours) Curves of weight gain against time for oxidation oj aluniiniuin at 400" and 600". Full lines in carbon dioxide. Broken lines in oxygen. By use of carbon dioxide labelled with 14C the amount of carbon deposited on the aluminium specimen being estimated2 by direct counting by autoradiography and by calculation from the reduction of counts in the gas phase it has been found that small amounts of carbon are deposited in the temperature range 500-650"; no carbon could still in progress. Meanwhile it seems that the presence of carbon (perhaps in the form of impurity defects) in some way interferes with the recrystallisation of the '6amorphous'' film of alumina a process which has been suggested as the cause of the sharp bend- over of the curves in oxygen3 (see Figure).(Received,July 24th 1963.) Antill Castle Gregg and Jepson J. Nuclear Materials 1962 5 254. Gregg Hussey and Jepson J. Nuclear Materials 1960 2 225. Aylmore Gregg and Jepson J. Inst. Met& 1959 88 205. OCTOBER 1963 305 Monomeric Quadricovalent Chromium Compounds By J. S. BASI and D. C. BRADLEY (CHEMISTRY UNIVERSITY ONTARIO, DEPARTMENT OF WESTERN LONDON,ONTARIO CANADA) and YAMAZAKI~ HAGIHARA briefly reported the isolation of tetra-t-butoxychromium(1v) after re-action of dibenzenechromium with di-t-butyl per- oxide.In attempting to prepare trisdiethylamino- chromium(Ir1) from the trichloride with lithium di- ethylamide in tetrahydrofuran we obtained tetra- kisdiethylaminochromium(1v) as a volatile viscous green liquid (-12 % yield based on CrCI,). This is extremely readily hydrolysed and reacts with hydroxylic compounds liberating diethylamine and providing a valuable method for preparing quadri- covalent chromium compounds. For example addi- tion of tertiary alcohols gave chromium tetra-alkoxides Cr(OCMe,Et,-,) where x = 1-3 in excellent yields. Similarly the addition of trialkyl-silanols gave tetrakistrialkylsiloxychromium(Iv) compounds. The chromium(1v) tertiary alkoxides are volatile monomeric blue compounds less readily hydrolysed than the corresponding titanium compounds.They are paramagnetic (p 2.79-2-82 B.M. at 25") and have infrared spectra very similar to those of the corresponding titanium and vanadium compounds. In addition to intense ultraviolet absorption bands characteristic of compounds M(OR) there are rather broad bands at 600-700 mp with maximum intensities at 635-660 mp (E 550-600) due to d-d-transitions in these d2-tetrahedral complexes. Chromium(1v) tertiary butoxide did not react with t-pentyl alcohol but with triethylsilanol it gave tetra- kistriethylsiloxychromium and t-butyl alcohol. With primary or secondary aliphatic alcohols the appropri- ate chromium(n1) alkoxide and aldehyde or ketone and t-butyl alcohol were obtained.With acetyl- acetone the chromium was also reduced giving Cr(acac), acetone and t-butyl alcohol. Chromium(1v) t-butoxide has also been obtained by other methods notably the oxidation of chrom- ium(@ t-butoxide [obtained by treating trisdialkyl- aminochromium(m) compounds2 with t-butyl al- cohol] in an excess of t-butyl alcohol in 40% yield (based on the original chromium trichloride). Instead of molecular oxygen oxidising agents such as bromine lead tetra-acetate di-t-butyl peroxide or t-butyl chromate may be used. We thank the National Research Council Canada the Research Corporation and the Anderson Chemical Division of the Stauffer Chemical Corn-PanY for SUPPO*. (Received September 2nd 1963.) Hagihara and Yamazaki J. Amer. Chem. Soc.1959 81 3160. Basi and Bradley unpublished results. Chemiliuminescencefrom Dissolved Oxygen By E. J. BOWEN and R. A. LLOYD (PHYSICAL LABORATORY, CHEMISTRY OXFORID) NEARLY sixty years ago it was noted that polyhydric phenols in strong alkali when treated with hydrogen peroxide emit a strong red glow resembling that from a hot coal.lP2 A typical mixture consists of SO ml. of 10%pyrogallol solution 20 ml. of 40% potassium hydroxide solution and SO ml. of "formalin," treated with 30 ml. of 30% hydrogen peroxide. We find using a photomultiplier-spectro-graph combination that the emission spectrum con- sists of a narrow band at about 630 mp identical with a weaker emission found for mixtures of hypo- chlorite solutions and hydrogen peroxide.2 Khan and Kasha3 have identified this emission as the 0,O band of the forbidden '2;4"2;transition of molecular oxygen in the dissolved state.For the gaseous state the 0,O band is at 760 mp indicating considerable solvent interaction with the upper excited level. We have not so far detected an emission from the escap- ing gas (the reaction mixture froths in bubbles) but whether this is due to the long-wave insensitivity of the photomultiplier or to a greater forbidden nature of the gas transition cannot be stated. By the use of a pulse-counting amplifier and photo- multiplier combination of very high sensitivity we Trautz and Schorigen 2.wissen. Photogr. Photochem. 1905 3 121; Grinberg J. Russ. Phys. Chem. SOC.,1920, 52 151. Seliger Analyt.Biochem. 1960 1 60. 'Khan and Kasha private communication and in press. PROCEEDINGS have also detected long-wave emission (> 550 mp) indicate the production of traces of electronically from dilute reacting solutions of potassium per- excited oxygen molecules from intermediate reaction manganate and oxalic acid which would seem to states. (Received September 1Oth 1963.) Steric Effects in Proton Transfer Reactions By J. A. FEATHER and V. GOLD OF LONDON STRAND, (UNIVERSITY KING’SCOLLEGE W.C.2) THE hydrolysis of acetic anhydride is powerfully catalysed by pyridine whereas pyridine bases with methyl substituents in a-positions are without noticeable catalytic effect.l It has been concludedl that a steric effect of this size due to obstruction of the basic site of the catalyst is incompatible with base catalysis (in the Bronsted sense) and that the mechanism instead involves formation of an acetyl- pyridinium intermediate.This conclusion has since been confirmed by other evidence.l9 However the argument was in a sense incomplete since as one of us has discussed in detail little is known about steric effects on the kinetics of proton tran~fer.~ The examples of base catalysis). Some of our results ex- pressed as departures from the Bronsted catalysis law are given in the Table where d log k = log k -GK,-B G and being parameters of the Bronsted catalysis law deduced for a particular ketone from measurements on pyridine and 4-picoline K the acidity constant of the substituted pyridinium ion7 and k the corresponding catalytic coefficient.The results fall into a pattern illustrating not only the role of a-substituents in the catalyst but also the effect of the size of group R in a ketone R-CH,CO.R’ on the susceptibility of the compound to steric hindrance of ionisation of the C-H bonds Values oj Alogk R R Ketone 2-Me 2-Et 2,4-Me 2,5-Me 2.6-Me 2,4,6-Me3 Pyridine substituents 3-Me 3,4-Me2 3,5-Me H Me -0.12 -0.21 -0.14 -0.11 CH Et -0.14 -0.28 -0.22 H CHMe -0.22 -0.30 -0.28 -0.23 H CMe -0.60 --*[CH,],* -0.27 -0.40 -0.26 -0.24 same point has recently been made by Covitz and Westheimer who added experimental data to show that the presence of a-substituents in pyridine bases reduces their catalytic activity in the mutarotation of glucose and in the hydrolysis of methyl ethylene ph~sphate.~ They also noted similar steric hindrance in the acid catalysis of the racemisation of menthone by the 2,6-lutidinium ion.We have systematically studied the role of steric hindrance in base catalysis using as main examples the iodination of ketones. This reaction is well known6 to involve a single proton transfer as the rate-controlling step without possible complications from other protolytic reactions or equilibria (such as could conceivably arise in Covitz and Westheimer’s -0.84 -1.12 +0*07 -0.08 t0.03 -1.05 -1.38 +0*13 -0.04 f0.04 -1.01 -1.26 40.10 -0-01 +0.05 -1.38 - +om02 - - -1.49 -1.69 -+O*lI +O@1 +O.10 indicated. The observed regularities establish the steric origin of the effect of a-substituents in the base.It is also evident that the effect is considerably smaller than that in the hydrolysis of acetic an- hydride or in other reactions subject to nucleophilic catalysi~,~ in accordance with the earlier conc1usions.l The largest effect now found (2,4,6-collidine cata- lysis in the iodination of cyclohexanone) corresponds to a fifty-fold rate reduction. The quantitative evaluation of the steric effect from the d log k values requires a more detailed inter- pretation of substituent effects not only in 2- but also in the 3- and 4-positions. (Received September 7th 1963.) Butler and Gold J. 1961 4362; Gold and Jefferson J. 1953 1409. Gold and Jefferson J.1953 1416; Bunton Fuller Perry and Shiner Tetrahedron Letters 1961 458; Butler and Gold J. 1962,976; Johnson J. Phys. Chem. 1963,57,495. Gold “Progress in Stereochemistry,” Vol. 3 Buttenvorths London 1962 p. 169. Bell GeIles and Moller Proc. Roy. Soc. 1949 A 198 308; Pearson and Williams J. Amer. Chem. SOC., 1953, 75 3073; Bell Rand and Wynne-Jones Trans. Faraday SOC. 1956 52 1093; Bell and Jensen Proc. Roy. Soc. 1961, A 261 38. Covitz and Westheimer J. Amer. Chem. Soc. 1963 85 1773. Bell “Acid-Base Catalysis,” Oxford University Press Oxford 1941. Andon Cox and Herington Trans. Faraday SOC. 1954 50 923. OCTOBER 1963 307 The lA2 State of Thiophosgene J. H. CALLOMON, By J. C. D. BRAND D. C. MOULE and J. TYRRELL OF CHEMISTRY,THEUNIVERSITY, (DEPARTMENT GLASGOW and OF CHEMISTRY COLLEGE, DEPARTMENT UNIVERSITY LONDON) THE visible bands of thiophosgene are attributed to The origin of the singlet system is close to 5340 A.transitions from the ground state to the singlet (,A2) The assignment lA2 -lA1 for the electronic transi- and triplet (3A2) states of the first excited electronic tion is established by the fact that the zero-point level c0nfiguration.l As the A2 states of formaldehyde are of the excited state does not combine with the ground pyramidal2 some interest attaches to the question state only with levels which have v4” = 1,3 . . . whether the states of thiophosgene are planar or non- The stronger bands in the system can be fitted to planar since the answer may throw light on the progressions of 2-6 members in three upper state manner in which the 3p chlorine orbitals contribute vibrations whose behaviour is nearly harmonic and to the molecular n-orbitals.The barrier to planarity a fourth vibration that is strongly anharmonic so in the lA2 state of formaldehyde (a few hundred that its quanta are alternately small and large (see crn.-l) vanishes or nearly vanishes in the correspond- Table 1). The isotope effect ties down the anharmonic ing states of acraldehyde and pr~pynal,~ so that the vibration to the mode in which the carbon nucleus barrier is definitely sensitive to conjugation in the moves roughly at right angles to the plane of the familiar sense. heavier nuclei ;thus the all-planar configuration cor- TABLE1. Vibrationfreqaencies of thiophosgene.lA1 (ground) state lAZ(excited) state 35c1,cs 35CP7ClCS vl(al) CS stretching 114W 907*2b 906@ vz(al) CC1 stretching 505 480.0‘ 476.7‘ ~3(al) El2 deformation 294 247-6‘ 245*8c 35ClZCS 35c137c1cs ~4(bl)Out-of-plane v4 = 1 471-0 470.6 0.5 05 2 941.8 941.0 279.6 278-4 3 1412.6 141 1.5 292.5 291.3 4 1884 1882 _. -5 -587.0 584.6 * From the infrared spectrum; b Attached to the zero-point level; c Attached to first quantum (0-5 cm.-l) of Y;. For the present purpose the band systems of thio-responds to a potential maximum and the equilibrium phosgene in the region 4000-6000 A were re-structure must be pyramidal. In combination with examined under high resolution with paths ranging vl’ and v3’ the anharmonic splittings are observed to up to 1 m.atm. The overlapping singlet and triplet undergo a small decrease and a large increase respec- systems are distinguishable by differences in band tively a situation not unlike that recorded in the contour. The key to the vibrational analysis of the vibrational structure of ammonia. singlet system is that a large proportion of bands An anharmonic double-minimum potential can be above 5000 A are “hot”; and that nearly all these represented by the function V(Q) = *xQ2 + “hot” bands emanate from levels of the out-of-plane A exp(-a2Q2) in which Q is a mass-adjusted co- vibration v4 (b,) which in agreement with a recent ordinate and x a and A are parameters5 By arbitrar- study by Downs,4 can be separately identified as an ily imposing the further condition that V(Q)shall be infrared fundamental at 471 cm.-l.Transitions from parabolic at its minima (a3V/aQ3)miq = 0 one the v4” stack are observed up to v4” = 4 providing obtains a relationship between A a and A which a strong argument in favour of a pyramidal structure reduces the number of independent parameters to in the excited state. two. The theoretical levels of v4’ based on this two- Burnelle Acad. roy. Belg. Classe sci. MPm. 1958 30 no. 7. ’Brand J. 1956 858. Robinson and DiGiorgio Canad. J. Chem. 1958,36 31. DiCiorgio and Robinson J. Chem. Phys. 1959 31 1678. Brand Callomon and Watson Discuss. Faraday SOC. 1963 35 173. Brand and Williamson ibid. p. 184. Downs Spectrochim. Ada 1963 19 1165. Coon Cesani and Loyd Discuss. Faraday Soc..1963 35 100. PROCEEDINGS parameter function (0 0.9 279 296 and 582 cm.-l for v/ = 0 1 2 3 and 5 of the 35C12CS isotope) reproduce the observed values with a mean square deviation of < 3 cm.-? The potential barrier (maxi- mum to minimum) opposing planarity is calculated to be about 600 cm.-I its summit lying roughly half- way between the levels with vi= 3 and 5. Structural changes accompanying the n-n transition are there- fore very similar in thiophosgene and formaldehyde and indicate that the chlorine atoms do little to stabilise the excited state in a planar configuration. we thank D.S.1.R. and the National Research Of Canada for (Received September 9th 1963.) Acetylacetone as a Neutral Ligand :I)ioxobis(acetylacetone)molybdenum(~v) By D.GRDENIC (LABORATORY AND INORGANIC FACULTY OF GENERAL CHEMISTRY OF SCIENCE ZAGREB) THEUNIVERSITY AND B. KORPAR-~LIG (DEPARTMENT AND INORGANIC CHEMISTRY, OF STRUCTURAL RUDER BOSKOVIC ZAGREB, INSTITUTE YUGOSLAVIA) MOLYBDENYL(VI) when ACETYLACETONATE,~ dis-solved in hot acetylacetone was smoothly reduced by zinc powder to a brown substance2 deposited as microscopic flat needles. Recrystallised from acetyl- acetone this had m.p. 185-192” (decomp.) (Found C 37-1;H 4.7;Mo 29.1.Calc. for C,,H,,MoO, C 36.8;H,4-3;Mo,29.4%) and was considered a dihydroxobis(acetylacetonato)molybdenum(Iv) (I). The quadrivalency of molybdenum was confirmed by quantitative separation of molybdenum(1v) oxide monohydrate on treatment with aqueous alkali.Unexpectedly the characteristic infrared absorp- tion bands for 0-H as well as for H ‘ * 0-H in the region 3600-3200 cm.-l were entirely absent. The bands at 1188 and 728 cm.-l which appeared in the spectrum of molybdenyl (VI) acetylacetonate and are characteristic for all “normal” acetylacetonates owing to the in-plane and out-of-plane y(C-H) deformation vibrations were also absent. Conse- quently a structure with acetylacetone as a neutral ligand (11) is postulated analogous to dichlorobis- biuretzinc whose structure was determined recently by X-ray crystal structure analysis? Direct evidence of y(CH,) in the molybdenum(1v) compound could not be obtained from infrared spectra because the corresponding deformation band5 at 1440cm.-l fell in the most complex region of the spectrum.All the results point to identity of the substance with that described by Larson and Moore as the “brown modification” of molybdenyf(vI) acetyl- acetonate. The low solubility has so far prevented reliable determination of the molecular weight. The com- pound is diamagnetic xg = -units at 23”. OH 0.31 x 10- c.g.s. (I 1 (a) Dioxob i s-(1,3-dip hen yl p r op a ne -1,3 -dione) molybdenum(1v) and dioxobis(cyc1ohexane-1,2-dione)motybdenum(Iv) were prepared by replacing acetylacetone with the appropriate diketone. The former of these complexes was also prepared from the corresponding molybdenum(w) compound by reduction with zinc powder and has the same properties as the “black form” of the molybdenum (VI) compounds described by Larson and Moore.6 We were successful in replacing acetylacetone in dioxobis(acetylacetone)molybdenum(Iv) by several other ligands.Replacement of acetylacetone by a diketone which does not enolise was never quanti- tative. Only 3,3,6,6-tetramethylcyclohexane-1,2-dione gave a crystalline compound [composition very close to Mo02(CloHl,0,)]. Attempts to replace acetylacetone by carbon monoxide triethyl- phosphine triphenylphosphine triphenylarsine oxide or phenyl isocyanide have not been promising so far because only impure and insoluble products were obtained probably owing to polymerisation. The authors are grateful to Dr. Cirila DjordjeviC for a helpful discussion of infrared spectra which will be the subject of a separate paper.(Received July 30th 1963.) Fernelius Terada and Bryant Inorg. Synth. 1960 6 147. Grdenid and Korpar-Colig 1st Yugoslav Congress for Pure and Applied Chemistry Zagreb June 1960 Abs. Papers p. 130; B. Korpar-blig Doctor of Chemistry Thesis Zagreb 1961. DjordjeviC Lewis and Nyholm J. 1962. 4778. .INardelli Fava and Giraldi Actu Cryst. 1963 16 343. Cross “Introduction to Practical Infra-Red Spectroscopy,” Butterworths Scientific Publns. London 1960 p. 62. * Larson and Moore Znorg. Chem. 1962 1 856. OCTOBER 1963 309 Hydrolysis of Phosphate Diesters Eff-of a Neighbouring Hydroxyl Group By D. M. BROWNand D. A. USHER (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) A LARGE literature1 testifies that while phosphate diesters are extremely stable to base a neighbouring hydroxyl group has a marked labilising effect.This effect has in the cases previously studied been accounted for by displacement (a). We have now distinguished an alternative base-catalysed decom- position. For example ester (I; R = cyclohexyl) 0- attack on carbon or phosphorus are eliminated and it is therefore clear that the reaction is one of epoxide formation (route b).z Methyl substitution in the glycol residue gives the results shown in Table 1 (R = cyclohexyl). It can be seen that there are marked effects on the relative rates of the competing reactions. Thus with gives on alkaline hydrolysis 67% of cyclohexyl the diester (II; R1 = H R2 = R3 = Me) the epoxide dihydrogen phosphate and 33% of the normal pro- route becomes essentially exclusive.It is observed ducts. Both modes of breakdown are of first order that throughout the course of the hydrolysis of this in substrate and in hydroxide ion. and of the isomeric diester (II;R1= Me R2 = R3 = Hydrolysis (N-NaOH ; 100O) of cyclohexyl erythro-H) constancy of the rate and product ratio is main- -3-hydroxy-2-butyl hydrogen phosphate gives stereo- tained showing that no migration of the alkyl- chemically pure meso-butane-2,3-diol and when the phosphoryl group occurs (cf. ref. 6). hydrolysis is conducted in water enriched in oxygen- The effect of changing the ester function is seen in 18 the cyclohexyl phosphate formed is isotopically Table 2 in which rates of hydrolysis of some esters normal.Mechanisms involving initial hydroxide of 2-hydroxypropyl phosphate are compared. In con- TABLE1. Rates of hydrolysis of RO~PO(OH)~OCR~-CRzR3~OH (11). (As. NaOH at 100”; k in 1. mole-l sec.-l) Compound Formation of RO*P03H2 Formation of ROH (106k) (106k) R2 = R3 = H 2.9 (67)* 1.4 (33)* R2 = H R3 = Me 16.6 (86.5) 2.6 (13.5) H R2 = R3 = Me 65 (97.5) 1.7 (2.5) Me R2 = R3 = H 135 (26.5) 373 (73.5) * mole-% of products. TABLE2. Hydrolysis of RO-PO(OH).O CH ,CH(OH).CH (Aq. NaOH at 80”; k in 1. mole-l sec.-l) Formation of RO.PO3Hz Formation of ROH loSk lO-”Z Ea 106k 10-Bpz E CyclohexyI 3.0 (84)* 2-3t 22.4: 0.55 (16)* 1*6t 20.1 Methyl 9.8 (7) 6-0 22.2 127 (93) 1.4 16.2 Phenyl --74,000 (100) 23 13.7 * mole-%of products.t In 1. mole-l sec.-l $ In kcal. mole-l. See Brown in “Advances in Organic Chemistry,” ed. Raphael Taylor and Wynberg Interscience New York 1963 pp. 81-83. It has been observed earlier that methyl3 and benzyl* glycerol phosphates afforded 8-10% of the corresponding alkyl phosphate on hydrolysis and the triester dibenzyl trans-2-hydroxycyclohexylphosphate gave 30 % of cyclohexene ~xide.~ Fleury Lecocq and Le Dizet Bull. SOC.chim.France 1956 1193. Brown Hall and Higson J. 1958 1360. Brown and Hamer J. 1960,406. Brown Magrath Neilson and Todd Nature 1956 177 1124. 3 10 sidering process (a),involving displacement of RO- we note that differences in the rates of hydrolysis are largely due to differences in activation energy.Further in a more extended series of esters a linear relationship has been found between log k and the pK values7 of the esterifying alcohols. The equation of the curve is log k =; -0.555 pKa + 4.43 PROCEEDINGS where linearity is maintained over a range of lo7in k and l0l2 in Ka. We are grateful to Drs. D. Samuel and B. Silver of the Weizmann Institute of Science for carrying out the oxygen-18 analyses and to D.S.I.R. for a maintenance grant (to D.A.U.). (Received August 13th 1963.) Ballinger and Long J. Amer. Chern. Soc. 1960,82 795; Bruice Fife Bruno and Brandon Biochemistry 1962,1 7. Dienoic Acid and Phenols A Novel Cyclisation Reaction By G. P. CHIUSOLI and G. AGN~ RESEARCH MONTECATINI NOVARA, (DONEGANI INSTITUTE COMPANY ITALY) 2,5-DIENOIC ACIDS which have recently become generally available from allylic compounds acetylene and carbon monoxide,l are easily cyclised to phenols.We recently reported2 that hexa-2,5-dienoic acid (I; R = H) cyclises to phenyl acetate when heated with acetic anhydride containing small amounts of acidic compounds such as zinc chloride aluminium chloride stannic chloride or sulphuric acid. Phenol is also obtained directly although in lower yields by reacting the hexadienoic acid with acidic catalysts in the absence of acetic anhydride. No difference was noted in the reactions of the cis-and trans -acids. The 3,5-dienoic acid reacts under the above conditions in an analogous way but with lower yield probably owing to poly- merisation.o-Cresol was also obtained in good yields (94 %) from 5-methylhexa-2,5-dienoicacid. Attempted extension of the method to w-alkyl- hexadienoic acids gave mainly tars and only small amounts of phenols. In these cases however refluxing the acids with solutions of basic catalysts such as sodium or potassium acetate in acetic anhydride preferably diluted with acetic acid provided a very efficient method of cyclisation to aryl acetates. o-Cresol was obtained from hepta-2 5(or 3,5)-dienoic acid (yield 65 %) ; biphenyl-2-01 (70%) from 6-phenylhexa-2,5(or 3,5)-dienoic acid; o-neopentylphenol (a new compound m.p. 37-38") (83%) from 8,8-dimethylnona-2,5(or 3,5)-dienoic acid; and saligenin mainly as polymer from 7-acetoxyhepta-2,5 (or 3,5)-dienoic acid.We observed also a double cyclisation of the acid (11) to naphthalene-l,5-diol (yield 69 %). The reactivity of the 2,5- and 3,5-tautomers are similar isomeri- sation of the 2,5- to the 3,Sdienoic form being catalysed by bases.l Cyclisation is prevented if isomerisation to the 2,4-form takes place first as in the case of hexadienoic and 5-methylhexadienoic acid. If however a carboxyl group is present in the terminal position as in hepta-3,5-diene-l,7-dioic acid3 (I; R = C02H) both basic and acidic cycli- sation give good results. From this acid a direct synthesis of aspirin was achieved (yield 61% with bases and 87% with acids). From a mechanistic point of view the results suggest that electronic effects are largely responsible.If substituents confer sufficient stability on the 3,Sdienoic form basic cyclisation is possible. Acid cyclisation seems to require an electron shift towards the 6-position. From a biochemical point of view the relation between fatty acids and phenols4 finds a new chemical parallel. We thank Professor A. Qujlico for his interest. (Received August 7th 1963 Chiusoli Chimica e Industria 1959 41 503 506 512 762; Angew. Chem. 1960 72 74; Chiusoli and Merzoni Chimica e Industria 1961 43 256 259; 1963 45 6; Chiusoli Bottaccio and Cameroni ibid. 1962 44 131. Chiusoli and Agnes 2.Naturforsch. 1962 17b 852. Grundmann Ber. 1937 70 1148. Birch Proc. Chem. SOC.,1962 4. OCTOBER 1963 31 1 The Reaction of Cobalamins with Thiols an Alternative Synthesis of Alkyl-cobamide Coenzyme Analogues By D.H. DOLPHIN and A. W. JOHNSON (DEPARTMENT UNIVERSJTY OF CHEMISTRY OF NOTTINGHAM) STUDIES the biosynthesis of the vitamin B,, of coenzyme112 (I; R = 5'-deoxyadenosyl) from hydroxocobalamin (vitamin B12b) (I; R = H,O) have established that the 5'-deoxyadenosyl group is derived from adenosine triphosphate (ATP) and that necessary co-factors for the reaction are a thiol (glutathione and 2-mercaptoethanol were exempli- fied) reduced flavin (FADH,) and manganese ions. The in vivo reaction therefore does not parallel the in vitro partial synthesis of the coenzyme from hydroxocobalamin,3s4 which involves a preliminary reduction to the so-called vitamin B126,a cobalt h~dride.~-~ We have examined the reaction of hydroxoco- balamin with a variety of thiols including glutathione 2-mercaptoethanol thioglycollic (mercaptoacetic) acid cysteine homocysteine ethanethiol toluene- w-thiol and sodium hydrogen sulphide (present in aqueous solutions of sodium sulphide) and in all cases the initial colour change is from red to violet.When methyl iodide is added to the mixture of aqueous hydroxocobalamin and any one of the above thiols with exclusion of light methylcobalamin is formed (identified by chromatography and spectra3). In the case of sodium hydrogen sulphide the yield of methylcobalamin is very high (ca. 90%) and the product is easily isolated in the crystalline form. This reaction has been examined in detail and it has been shown not to be a simple displacement reaction of type (A).OH -SR Me J. 4 I (A) CO~II-+ Co~l~ Colil -+ (11) In fact the reactive intermediate in the formation of methylcobalamin was not the violet product which is believed to be the species (11) but a second- ary brown compound formed by further reduction of (11) by sulphide. The spectrum of the brown com- pound is similar to that of vitamin BlZr,'a reduction product of vitamin B, containing bivalent cobalt (see however Hill et d6).Solutions of the brown compound react very rapidly with methyl iodide to yield methylcobalamin and the overall reaction is markedly faster if the hydroxocobalamin and sodium hydrogen sulphide solutions are allowed to react to the brown stage before addition of methyl iodide.The brown intermediate can also be prepared directly from vitamin B1,r by adding a degassed (i.e. oxygen-free) aqueous solution of sodium sul- phide but the product is not sufficiently stable to be isolated in the solid state. Vitamin Bl2r does not react with methyl iodide in the absence of sulphide ions and it is probable that the reactive brown inter- mediates are complexes (111) of bivalent cobalt. This implies a final oxidation step although it has been ,NH r.Nt "2 tH2 \ observed that the rate of reaction of hydroxoco- balamin sodium sulphide and methyl iodide to form methylcobalamin is faster in the absence of oxygen mm.) than the similar reaction with oxygen present. The precise nature of the oxidation step has not been elucidated.The cycle is reversed when the final solution is irradiated as methylcobalamin is rapidly photolysed to re-form hydroxocobalamin. hv Brady Castanera and Barker J. Biol. Chem. 1962,237 2325. Weissbach Redfield and Peterkovsky J. Biol. Chem. 1962 237 3217. Smith Mervyn Johnson and Shaw Nature 1962 194 1175;J. Chem. Soc. 1963 in the press. Bernhauser Muller and Muller Biochem. Z. 1962 336 102 299. Smith and Mervyn Biochem.J. 1962,86 2~. Hill Pratt and Williams J. Theor. Biol. 1962 3 423. Diehl and Murie Iowa State Cull. J. Sci. 1952 26 555; Jaselkis and Diehl J. Amer. Chem. SOC.,1954 76 4345; Beaven and Johnson Nature 1955 176 1264. Hogenkamp Barker. and Mason Arch. Biochem. Biophys. 1963 100 353. The displacement of the sulphur ligand by an alkyl group is more susceptible to steric hindrance than the corresponding hydride displacement and PROCEEDINGS methyl toluene-p-sulphonate 1 ehloro- 1-bromo- and 1 -iodo-propane 1 -iodobutane chloroacetic acid p-chloropropionic acid and acetyl chloride.The Red Compound Formed in the Colorimetric Determination of Tin and Some Related Compounds By R. C. POLLER ELIZABETH CAMPDEN W.8) (QUEEN COLLEGE HILL ROAD LONDON REDUCTION of benzene- 1,2-disulphonyl chloride with tin and hydrochloric acid gives an insoluble red compound of high melting point1 for which structure (I) has been proposed.2 A similar compound is widely used in the colorimetric determination of tin toluene-3,4-dithiol being the favoured reagenL3s4 In a study of ring systems containing tin and sulphur the structure of the red compound obtained by treatment of the disodium derivative of toluene- 3,4-dithiol with stannic chloride has been re-examined.Despite statements to the contrary5 tin@) is necessary for the formation of this material :tin(@ gives an unstable yellow compound. The red product is insoluble in the common organic solvents but dissolves in sodium hydroxide solution and in organic bases with loss of colour. The pale yellow crystalline pyridine and dimethylformamide derivatives were isolated and shown to be 2 1 complexes corresponding to formula (11). These complexes are unstable and on prolonged exposure to air orwhen heated become redwith lossof the ligand.The red compound is clearly polymeric the tin atom probably showing co-ordination number 6 and the properties of this material are more readily understood in terms of a structure such as (111). The compound was purified through its dimethyl-formamide derivative then having m.p. 300-305 O and its reflectance spectrum (Am, 515 Amin 400 mp) agreed with that published4 for the dispersed material obtained in the colorimetric determination of tin (Amax 530 Amin. 400 mp). A monomeric spirocyclic compound containing Sn-S bonds in which tin is 4-covalent (IV; m.p. 1 82-1 83 "),and anumber of related cyclic compounds (V; m.p. 155O) and (VI; n =2 R =Bu; m.p. 59-60" n = 2 R = Ph m.p. 108-109°; n = 3 R = Bu m.p. 63-64'; n = 3 R = Ph m.p.103-104") have L (1) (n ,L=pyridice OF d imethy lfor mamide) H2C-S ,S-CH, I Sn I I t H2C-S' bCH2 (IV) now been prepared by similar methods. These compounds are all colourless and soluble in many organic solvents ; their reactions are under investi- gation. The author thanks Mr. A. A. Sarsfield for technical assistance. (Received August 16tk 1963.) Pollak Monarsh. 1913,34 1673;Guha and Chakladar J. Indian Chenz. Soc. 1925,2 318. a Brown and Austin J. Arner. Chern. Sac. 1940 62 673. Clark Analyst 1936,61,242;1937,62 661. * Farnsworth and Pekola Analyt. Chern. 1954 26 735. Following Clark (ref. 3) all the published analytical procedures call for addition of rnercaptoacetic acid whose function is said to be to reduce tin(rv) to tin@).OCTOBER 1963 313 The Structure of Ergwhrysin SecaIonic Acid and ChrysergoNcAcid By J. W. APSMON,A. J. CORRAN W. MARLOW N. G. CREASEY W. B. WHALLEY, and (in part) K. Y.SIM (THESCHOOL UNIVERSITY OF PHARMACY OF LONDON) DURING continuing studies of the ergot pigments,l we have derived the structure (I) for ergochrysin2 and (11) (without stereochemical assignments) for secalonic3 and chrysergonic acid3. Ergochrysin C29H2,01z(C02Me) [a],-68" m.p. 285O (decomp.) contains an acidic p-diketone residue and exhibits infrared absorption at 1802 (7-lactone) 1761 (ester with oxygen as an a-sub- stituent) and 1639 (chelated aromatic C =0)cm.-l. Fusion with alkali yields m-cresotinic (3-hydroxy- 5-methylbenzoic) acid; oxidation with potassium permanganate affords (f)-methylsuccinic acid.Hot pyridine converts ergochrysin into isoergo-chrysin m.p. 250" (decomp.) [alD + 59" Vmax 1802 and 1754 cm.-l by inversion at position 9. Ergochrysin and isoergochrysin mutarotate in pyridine furnish methyl m-cresotinate on pyrolysis and yield the same dimorphic tri-0-methyi Ether (1; R = Me) m.p. 179" and 260" [a],-19.1" vmax 1802 and 1752 cm.-l. The nuclear magnetic resonance spectrum (all in CDCl,) of this ether includes a doublet at T 8-80(J6 c./sec.) (XHMe; 6 protons) and two pairs of doublets at r 2.36 and 3-04 (J 8 c./sec.) and T 2-51and 2.88 (J 9 c./sec.) (two pairs of ortho-aromatic protons). Oxidation of the ether (I; R = Me) (with Jones's reagent4) and degradation of the resultant penta- ketone by alkali furnishes 3,3'-diacetyl-4,4'-dihy-droxy-2,2'-dimethoxybiphenyl(cf.ergoflavinl). Mild acetylation of ergochrysin forms the expected enol hexa-acetate but vigorous acetylation of ergo- chrysin or isoergochrysin produces the benzophenone (111) m.p. 245" (decomp.) [a],+ 15".The nuclear magnetic resonance spectrum of the en01 acetate has a doublet at r 8.61 (J 6c./sec.) (:CHMe; 6 protons) and that of the benzophenone (111) includes six aromatic protons a singlet at 7 8.40 (C-Me attached to an aromatic ring; 3 protons) and a doublet at T 8.96 (J 6 c./sec.) (XHMe; 3 protons). Degradation of the benzophenone (111) with acid produces carbon dioxide m-cresotinic acid and the phenol (IV; R = H) m.p.220",[a] +66. 9' in which the unit B is identical with the C1 unit of ergoflavin'. Potassium permanganate oxidises this product (IV; R = H) to (-)-methylsuccinic acid (cf. ergoflavinl). Oxidation of the tetraether (IV; R = Me) gives the corresponding diketone which forms oxalic acid and 3-acetyl-4-hydroxy-2,2',4'-trimethoxybiphenyl m.p. 94",on alkali degradation (cf. ergoflavinl). These facts may be rationalised in terms of formula (I; R = H) for ergochrysin. C0,Me rm\ "-Me The similarity between ergochrysin and secalonic3 and chrysergonic acid3 is illustrated by e.g. their mutarotation in pyridine3 and the formation from each of methylsuccinic acid and 2,4,2' ,4'-tetra- hydroxybiphenyl on alkali fusion3. We have established that secalonic and chrysergonic acid are isomers C,,H240,,(C0,Me)2 (contrast Franck Apsimon Corran Creasey K.Y. Sim and Whalley Proc. Chem. Soc. 1963 209; cf. Asher McPhail Robertson Silverton and G. A. Sim Proc Chem. SOC.,1963 210. Bergmann Ber. 1932 65 1486 1489. Stoll Renz and Brack Helv. Chim. Am 1952 35 2022. Bowers Halsall Jones and Lemin J. 1953 2548. PROCEEDINGS et aL5) and are not lactones or acids but acidic chrysergonic acid have the same stereochemistry as bis-p-diketones (cf. ergochrysin). Each pigment that of unit A in ergochrysin (I; R = H); the second exhibits a negative Gibbs test,6 contains two methyl CI5 moiety in chrysergonic acid probably has the ester residues (vmax. 1754 cm.-l) yields methyl stereochemistry of unit A in isoergochrysin.m-cresotinate on pyrolysis and in contrast to [a] above are for pyridine solutions. previous observations3 gives the same optically We thank Messrs. Burroughs Wellcome & Co. inactive bibenzophenone (V) m.p. 206" on vigorous and T. & H. Smith Ltd. for the provision of crude acetylation. We conclude that secalonic and pigment concentrate Dr. J. Renz of Sandoz for a chrysergonic acid are diastereoisomers of formula (11). generous gift of secalonic and chrysergonic acid and The molecular rotational data suggest that both the Wellcome Trust for financial support. C, units of secalonic acid and one C15 fragment of (ReceivedAugust 8th 1963.) Franck Thiele and Reschke Chem. Ber. 1962 !B 1328. King King and Manning J. 1957 563. Replacement of Methanesulphonyloxy-groups the Conversion of the D-gluco-into the D-gulactu-Configuration By J.HILL,L. HOUGH,and A. C. RICHARDSON (DEPARTMENT CHEMISTRY BRISTOL) OF ORGANIC THEUNIVERSITY DISPLACEMENTS of sulphonyloxy-groups at secondary = Bz R = OBz) as the only product thus carbon atoms of carbohydrates by nucleophilic excluding neighbouring acyloxy-group participation. reagents such as sodium benzoate in NN-dimethyl-Thus the equatorial 4-sulphonyloxy-group of the formamide have been achieved in circumstances glucoside is replaced by an SN2 process as readily as favourable to either an SN2 reaction or neighbouring- the axial 4-sulphonyloxy-group of the galactoside group participati0n.l Direct replacements of sulpho- contrary to a previous view.7 nates attached to a pyranose ring are rare.Reist et al. Replacement with sodium azide in dimethylform- have prepared 4-azid0-4-deoxy-~ and 4-0-benzoyl-~- amide very rapidly (3 hr. at 150-155") gave in 70% gl~copyranosides~ from methyl 2,3,6-tri-O-benzoyl- yield the 4,6-diazido-4,6-dideoxy-~-galactoside 4-0-methanesulphonyl-cc-D-galactopyranoside by (11; R = Bz and Ac R' = N& as revealed by treatment with sodium azide and sodium benzoate proton magnetic resonance @.m.r.) spectroscopy respectively in dimethylformamide an approach and this derivative was converted into syrupy methyl that led to the synthesis of amosamine (4,6-dideoxy- 4,6-diamino-4,6-dideoxy-a-~-galactopyranoside 4-dimethylamino-~-glucose).* We have prepared (11; R = H R' = NH,) characterised as the the 2,3-diacetate and the 2,3-dibenzoate of methyl crystalline di-N-acetyl (11; R = H R = NHAc) 4,6-di-O-me t hanesulp honyl-a-~-glucopyranoside tetra-acetyl (11; R =* Ac R' = NHAc) and (I; R = Ac and Bz respectively) with a view to tetrabenzoyl(I1; R = Bz R' = NHBz) derivatives.examining the nucleophilic displacements of the The 4,6-dideoxy-4,6-dithiocyanato-derivative(11; primary and secondary sulphonates. Whilst the R = Bz R' = SCN) was similarly prepared in 40% departure of the 4-methanesulphonyloxy-substituent yield by the use of potassium thiocyanate in was unlikely5 to be facilitated by participation of the dimethylformamide (1 30" for 48 hr.) the ~-galacto- vicinal trans-acyloxy-group via a cyclic cation an configuration being assigned by p.m.r.spectra. analogous reaction of methyl 3-acetamido-2-O-Treatment of the dithiocyanate with either sodium acetyl-3-deoxy-4,6-di-O-methanesulphonyl-a-D-glu-ethoxide8 or ethanolic sodium sulphideg led with copyranoside with iodide led to a 4 6-di-iodo- simultaneous de-O-benzoylation to the dithiolate derivative probably as a result of acetamido-group (11; R = H R' = S-) which on de-ionisation participation. However reaction of the glucoside underwent rapid atmospheric oxidation to the (I; R = Bz) with sodium benzoate in dimethyl- crystalline 4,6-disulphide (111) (Found M 226 225 requires M 224). This is the first example formamide at 140" for 20 hr. gave methyl 2 3 4 C7HlZO4S2 6-tetra -0-benzoyl-a-D-gatdctopyranoside (I1; R of an intramolecular disulphide in the carbohydrate Baker and Haines.J. Om. Chem. 1963 28,438. Reist Spencer Baker and Goodman Chem. and Ind. 1962 1794. Reist Spencer and Baker J. Org. Chem. 1959 24 1618. * Stevens Blumbergs and Daniher J. Amer. Chem. Soc. 1963 85 1552. Richardson,Proc. Chem. Soc. 1963 131. Jeanloz and Jeanloz J. Amer. Chem. SOC.,1958 80 5692. Reist Goodman Spencer and Gueffry 19th I.U.P.A.C. Congress London 1963 Abstract A3-45. Muller and Wilhelms Ber. 1941 74 698. @ Panchenko and Smirnov. J. Gen. Chem. (U.S.S.R.) 1932 2 193; Takiura and Takino J. Pharm. SOC. Japan 1954, 74 839. OCTOBER 1963 315 field. Desulphurisation of the disulphide (111) or triphenyl phosphite methiodide for removal of dithiocyanate (11; R = Bz R’ = SCN) by Raney the 4,6-hydroxyl groups of a suitably protected nickel afforded methyl 4,6-dideoxy-a-~-xylo-glucoside.Overendll has briefly mentioned the hexopyranoside (IV) and its di-0-benzoate respec- preparation of compound (IV) from methyl 4-deoxy- hexop yranoside by standard procedures. tively. Mild acid hydrolysis of the pyranoside (IV) CC-D-X~~O-(m.p. 137-138” ; We thank Drs. D. H. Ball J. G. Buchanan and gave 4,6-dideoxy-or-~-xylo-hexose (a] + 103” -+ 33”) a new dideoxy-sugar. L. D. Hall and Mr. A. W. Lewis for physical Kochetkov and Usovl0 have synthesised chalcose measurements. by (4,6-dideoxy-3-O-methyl-~-xylu-hexose) use of (Received August 17th 1963.) lo Kochetkov and Usov Tetrahedron Letters 1963 519. l1 Overend Chem. and Ind. 1963. 352. Reactions Involving the Addition or the Elimination of Metallic Compounds By A.J. BLOODWORTH and ALWYN G. DAVIES (WILLIAM RAMSAY LABORATORIES W.C.1) AND RALPH FORSTER UNIVERSITY COLLEGE LONDON WE wish to draw attention to the apparent generality alkyltin) oxides to give products such as of the reaction in which a group consisting of a metal Pr,Sn.NPhCO,.SnPr, Cl,C~CH(O.SnBu,), and bonded to a relatively electronegative atom adds Bu,Sn.N(l -C,,H,)C(O-SnBu,) N.l-C,@,. Some of across a polar multiple bond i.e. M-X + A=B these reactions are reversible and the reactants can 4M-A-B-X. then be recovered if the adducts are distilled. We have found that trialkyltin alkoxides react There is some evidence in the literature that similar rapidly and usually exothermically at room reactions will occur with dialkyltin oxides ; Lappert temperature with alkyl and aryl isocyanates? phenyl has demonstrated the addition of Sn-N bonds to the isothiocyanate,l carbon dioxide carbon disulphide same type of acceptor molecules,4 and the many re- sulphur dioxide trichloroacetaldehyde trichloro- actions which are known between tin hydrides and acetonitrile keten, and di-1-naphthylcarbodi-imide multiply bonded compounds are perhaps related.5 to give products which we believe to have structures Silicon amines add to sulphur trioxide? carbon such as Et,Sn.NBu-CO,Et Bu,Sn.NPhCS*OMe dioxide and carbon disulphide,’ and mercuric Bu3Sn.0.C0,Me Bu,Sn-S.CS*OMe alkoxides to keten? Bu Sn -0.S0 Me Bu Sn.0.C H( CC1 3) -0Me It seems likely that additions of this type and Bu,Sn-N C(CC13)-OMe Bu,SnCH,CO,Et and their retrogressions will be found to be common Bu,Sn.N( l-C1,H7)C(OMe) N.l-C10H7 respec-amongst the derivatives of many metals and metal- tively. Analogous reactions occur with bis(tri-loids. (Received September 17th 1963.) Bloodworth and Davies Proc. Chem. Suc. 1963 264. 1. F. Graham unpublished work. This reaction has previously been demonstrated by Lutsenko and Ponomarev J. Gen. Chem. U.S.S.R. 1961,31 1894. As far as we are aware all the other products represent new classes of organotin compounds. With aldehydes U.S.P. 2,591,675; 2,593,267. With esters B.P. 737,033. With carbon disulphide Reichle Inorg. Chem. 1962,1 650. Jones and Lappert Proc. Chem. SOC.,1962 358. e.g. Noltes and van der Kerk “Functionally Substituted Organotin Compounds,” Tin Research Institute Green- ford 1958.Schmidt and Schmidbauer Angew. Chem. 1958,70 657. Breederveld Rec. Trav. chim. 1962 81 276. * Lusenko Foss and Ivanova Proc. Acad. Sci. U.S.S.R.,1961 141 1270. ISOTOPES. A FIFTIETH ANNIVERSARY AN official meeting of the Chemical Society to commemorate the fiftieth anniversary of the first published use of the term “Isotopes,” will be held in the Chemistry Department University of Glasgow on Wednesday December 4th 1963. The programme will be as follows 3.00 p.m. Opening by the President 3.15 p.m. Dr. Andrew Kent M.A. “Frederick Soddy. A Historical Note.” 3.30 p.m. Lord Fleck K.B.E. F.R.S. “Early Work in the Radioactive Elements.” 4.20 p.m.Dr. John A. Cranston LL.D. F.R.I.C. “The Group Displacement Law.” 4.30 p.m. Tea Interval 4.45 p.m. Professor H. J. EmelCus C.B.E. F.R.S. “New Elements.” PROCEEDINGS NEWS AND ANNOUNCEMENTS Liaison Officers.-Dr. A. G. Davies has been appointed Liaison officer at University College London in succession to Dr. C.A. Bunton who has taken an appointment at the University of California. Dr. A. B. Meggy has been appointed Liaison Officer at the Plymouth College of Technology in succession to Dr. B. L. Tonge who has been appointed Research Manager of Pure Chemicals Limited Kirkby Liverpool. Local Representative for Brighton.-The Council has appointed Dr. R. A. Jackson of the University of Sussex as the first Local Representative of the Society in Brighton.Election of New FeUows.41 Candidates were elected to the Fellowship in September 1963. Deaths.-We regret to announce the deaths of the following Mr. N. flamer (25.8.63) Bury a FeIlow since 1925; Mr. K. M. Sastri (9.7.63) a student at the University of Wisconsin; and Mr. J. Walker (26.8.63) of the Clayton Aniline Company Limited Manches ter . Surplus Laboratory Apparatus.--The under-mentioned second-hand equipment is surplus to the Society’s requirements and will be made available as separate items free of charge to the first Fellow who in each case applies in writing on behalf of any School College or University Department The Fellows accepting the equipment will be required to make their own arrangements to remove it from Burlington House.Mullard Conductance Bridge (purchased 1950) Pye Scalamp Galvanometer (purchased 1955) Marconi Serum Electrode (purchased 1953) This apparatus was originally purchased through the Society’s Research Fund and subsequently returned to the Society. American Chemical Society Publications.-A long established reciprocal agreement allows Fellows of the Chemical Society not being Members of the American Chemical Society to subscribe to the publications of the latter Society at a discount of 10 per cent from the non-members’ rates. No discount is available on the Chemical Abstracts Service however. Fellows wishing to take advantage of this concession should apply to the American Chemical Society 1155 Sixteenth Street N.W.Washington 6 D.C. U.S.A. Fellows wishing to apply for membership of the American Chemical Society may obtain forms of application from the General Secretary. Meldola Medal.-This medal is the gift of the Society of Maccabaeans and is normally awarded annually. The next award will be made early in 1964 to the chemist who being a British subject and under thirty years of age at December 31st 1963 shows the most promise as indicated by his or her published chemical work brought to the notice of the Council of the Royal Institute of Chemistry before December 31st 1963. No restrictions are placed upon the kind of chemical work or the place in which it is conducted. The merits of the work may be brought to the notice of the Council either by persons who desire to recommend the candidate or by the candidate himself by letter addressed to The President The Royal Institute of Chemistry 30 Russell Square London W.C.1 the envelope being marked “Meldola Medal.” The letter should be accompanied by six copies of a short statement on the candidate’s career (date of birth education and experience degrees and other qualifications special awards etc.with dates) and of a list of titles with references of papers or other works published by the candidate inde- pendently or jointly. Candidates are also advised to forward one reprint of each published paper of which copies are available. The Beilby Medal and Prize 1964.-Awards from the Sir George Beilby Memorial Fund are made by the Administrators of the Fund representing the Royal Institute of Chemistry the Society of Chemical Industry and the Institute of Metals.Sir George Beilby had been President of each of these three bodies and they jointly sponsored the appeal for subscriptions whereby the Fund was raised as a memorial to him after his death in 1925. The Beilby Medal and Prize which consists of a gold medal and a substantial sum of money is specified as being “For Advancement in Science and Practice”. Such an award is now being offered annually but more than one may be made on the same occasion if there are several candidates of sufficiently outstanding merit. Thus two awards were made in 1963 each carrying a prize of 100 guineas.The awards are made to British investigators in science in recognition of independent original work of exceptional merit carried out continuously over a period of years and involving the development and application of scientific principles in any field related to the special interests of Sir George Beilby i.e. in chemical engineering fuel technology or metallurgy in their modern interpretations. The awards are intended as an encouragement to younger men and women (preferably under age 40) who have done distinguished work of practical signifi- cance in any of these fields. Consideration will be given in due course to the making of an award (or awards) from the Fund OCTOBER 1963 in 1964. Outstanding work of the nature indicated may be brought to the notice of the Administrators either by persons who desire to recommend the candidate or by the candidate himself not later than December 31st 1963 by letter addressed to The Convener of the Administrators Sir George Beilby Memorial Fund The Royal Institute of Chemistry 30 Russell Square London W.C.1. The letter should be accompanied by nine copies of a short statement on the candidate’s career (date of birth education and experience degrees and other qualifications special awards etc. with dates) and of a list of titles with references of papers or other works published by the candidate independently or jointly. Photographic copies of these documents are acceptable. Candidates are also advised to forward one reprint of each published paper of which copies are available.Ramsay Chemical Dinner 1963.-The Dinner is sponsored by the Glasgow Section of the Society of Chemical Industry in co-operation with the other Societies interested in Chemistry and is regarded as the premier social function of the chemical profession in Scotland. The Dinner will be held in the Central Hotel Glasgow at 6.30 for 7.00 p.m. on Thursday December 5th 1963. The Chair at the Ramsay Dinner is taken in rotation by the President or his Deputy of one of the Chartered Chemical Bodies and this year it is the turn of the Royal Institute of Chemistry whose President Professor H. J. Emelkus will be Chairman. The Principal Guest will be Sir Edmund Hudson F.R.S.E.After the dinner the toast to the memory of Sir William Ramsay is drunk in silence and then the main toast “The Profession of Chemistry” is proposed by the Principal Guest. The dinner will be followed by dancing until 1.00 a.m. Applications for tickets should be sent to the convener Mr. R. Douglas I.C.I. Ltd. 4 Blythswood Square Glasgow C.2. The cost is two guineas per person. Symposia etc.-The London Sections of the Institute of Biology the Institute of Physics and Physical Society and the Royal Institute of Chemistry will hold a one-day symposium on Modern Instrumentation in Science and Industry on Friday January 17th 1964 at the Institution of Electrical Engineers Savoy Place W.C.2. The Chairman for the symposium is Sir John Cock- croft O.M.Further details can be obtained from the Finance Officer Royal Institute of Chemistry 30 Russell Square London W.C. 1. The Eighteenth Annual Symposium on Funda- mental Cancer Research entitled “Cellular Radiation Biology” will be held in Houston Texas on March 2nd4th 1964 under the auspices of the University of Texas M.D. Anderson Hospital and Tumor Institute Houston 25 Texas from whom further details can be obtained. A Conference on Automatic Control in the Chemical Processes and Allied Industries will be held in Liverpool on April 14th-l6th 1964. Further enquiries should be addressed to the General Secretary Society of Chemical Industry 14 Belgrave Square London S.W.1. An International Symposium on Fundamental Phenomena in Hypersonic Flow will be held in Buffalo New York from June 25th-26th 1964.Further enquiries should be addressed to J. T. McCarthy Head of Public Relations of Cornell Aeronautical Laboratory Inc. P.O. Box 235 Buffalo New York. Personal.-Mr. C. D.Akon University College London has been awarded a Ramsay Memorial Fellowship in Chemistry for 1963-64. Dr. J. Carnduf formerly of the University of Glasgow has taken up a Research Fellowship at Havard University. Dr. R. D.G. Cooper is now with the Department of Organic Chemistry Quartermaster and Engineer- ing Research Division U.S. Army Natick Mass. U.S.A. Dr. W.L. Cunningham formerly Research Fellow at the R.C. University The Netherlands has been appointed Research Fellow in the Department of Biological Chemistry Marischal College University of Aberdeen.Dr. H. C. Dunn has been appointed U.K. Papers Secretary for the 3rd United Nations “Atoms for Peace” Conference to be held in Geneva in 1964. Mr. W. B. Emery formerly Factory Manager at the Glaxo Laboratories Limited Ulverston has been appointed Assistant to the Chairman and Managing Director. Dr. I. J. FauZkner has retired from Imperial Chemical Industries Limited Billingham Division. Mr. F. R. Graesser-Thomas,has retired from the Board of Graesser Salicylates Ltd. Mr. M. Green Junior Research Fellow of Merton College Oxford has taken up an Official Fellowship in Chemistry at Hertford College Oxford. Mr. J. A. Haines has been appointed to a Royal Society U.S.S.R.Exchange Research Fellowship at the Institute for the Chemistry of Natural Products in Moscow. Dr. D. Hamer Head of Department of Chemistry at Belfast College of Technology has been appointed first Principal of the new John Dalton College of Technology at Manchester. Mr. H. C. Hillman has been appointed to the Board of Cow and Gate Limited. The title of Reader in Chemical Endocrinology has been conferred on Dr. V. H. T.James in respect of his post at St. Mary’s Hospital Medical School. Dr. D. R. Jenkins formerly of the University of Cambridge has been appointed Senior Research Chemist at Thornton Research Centre Shell Research Limited. Professor Sir Hans Krebs has been appointed Official Visitor to the British Baking Industries Research Association for the next five years.Dr. T. F. Macrae who has been an Official Visitor for the past five years has accepted re-appointment for a further three years. Mr. G. F. Laws formerly of Chesterford Park Research Station has been appointed Senior Research Fellow at the Hydatid Research Unit New Zealand Medical Research Council Dunedin. Professor B. T. Newbold has been appointed Vice-Dean of the Faculty of Science in the Univer- sity of Moncton New Brunswick Canada. Professor Newbold will also continue as Professor of Chemis- try and Head of the Chemistry Department at the University. Dr. G. S. Park Lecturer in Chemistry Welsh College of Advanced Technology Cardiff has been appointed to the Readership in Polymer Chemistry at the College.Dr. F. H. Peakin has relinquished his post of Manager of Imperial Chemical Industries (Deutsch- land) GmbH of Frankfurt am Main and has joined the Board of Management Administration Limited as Chairman and also that of Unicost Limited. Dr. V.Petrow Head of the Research and Develop- ment Division of the British Drug Houses Limited has been appointed a Director of the Company. Dr. E. C. Potter is to tour Australia and New Zealand in November and December by invitation of the Royal Australian Chemical Institute giving lectures in the principal cities. PROCEEDINGS Dr. A. Raper formerly Departmental Head Sterile Process Glaxo Laboratories Limited Barnard Castle has been appointed Deputy Factory Manager.Mr. R. S. Robinson has been appointed Assistant Managing Director of Styrene Co-polymers Limited with a seat on the main Board. Dr. P. W. Sadler has resigned as Research Director of Benger Laboratories Limited and has left the Company. Dr. W. D. Scott has relinquished his Managing Directorship of B.T.R. Industries Limited but will remain on the Board as a non-executive Direc- tor. Dr. B. D. Sharma formerly Research Fellow in Chemistry at the California Institute of Chemistry Pasadena has joined the University of Nevada Reno as an Assistant Professor in Physical Chemistry. Dr. B. Shelton has completed his Research Fellow- ship at the University of New South Wales Sydney Australia and has rejoined the Research Staff of Cadbury Brothers Limited Bournville Birming- ham.Dr. P. Simpson has been appointed to a Research Associateship in the University of Sussex. Mr. E. J. Smith formerly of Fisons Fertilizers Limited has been appointed Development Manager (Textiles and Reinforcements) Fibreglass Limited St. Helens Lancs. Dr. M. E. U. Taylor has taken up a Thomas Cawthron Fellowship at the Cawthron Institute Nelson New Zealand. Mu. H. F. P. Webber has retired from the post of Group Scientific Adviser and Chief Chemist to the London Brewing Company of Courage Barclay and Simonds Limited. Dr. B. 0. West formerly Reader in Chemistry at the University of Adelaide has been appointed to the Chair of Inorganic Chemistry at Monash University Melbourne. FORTHCOMING SCIENTIFIC MEETINGS London Thursday November 21st 1963 at 6 p.m.Meeting for the Reading of Original Papers “The Kinetics and Mechanism Of Heteroaromatic Nitration. Part I. Quinoline,” by M. W. Austin and J. H. Ridd. “Part 11. Pyrazole and lrnidazole,” by M. W. Austin J. H. Ridd and B. V. Smith. “Mechanisms of Octahedral Substitutions in Non- aquems Solutions. Part 111. The Replacement of Co-ordinated Water in trans-Aquonitrobis(ethy1ene-diamine)cobalt(m) ions,” by -M. N. Hughes and .. . -M. L. Tobe. “Kinetics of the Pyrolysis of Neopentyl Chloride,” by A. Maccoll and E. S. Swinbourne. TObe held in the Rooms of the Society Burlington House w.1. (Abstracts of papers can be obtained from the General Secretary.) [British Railways are offering concessionary fares (single fare plus one half for the return journey) for London meetings until at least the end of 1963; a travel voucher for any meeting will be sent by the OCTOBER 1963 General Secretary on receipt of a stamped and addressed envelope.] Aberdeen Thursday December Sth 1963 at 8 p.m.Lecture “Some New Natural Products Structural and Biosynthetic Studies,” by Professor W. D. Ollis Ph.D. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Medical Physics Lecture Theatre Marischal College. Aberystwyth (Joint Meetings with the University College of Wales Chemical Society to be held in the Edward Davies Chemical Laboratory.) Thursday November 7th 1963 at 5 p.m.Lecture “Name and Number,” by Dr. R. B. Heslop M.Sc. F.R.I.C. Thursday November 21st at 5 p.m. Lecture “Optical Rotatory Power,” by Dr. S. F. Mason M.A. Thursday December 5th at 5 p.m. Lecture “Biosynthesis,” by Professor A. J. Birch D.Phil. F.R.S. Birmingham Friday November 15th 1963 at 4.30 p.m. Lecture “Some Unusual Electrophilic Aromatic Substitutions,” by Professor C. Eaborn D.Sc. F.R.I.C. Joint Meeting with the University Chemical Society to be held in the Chemistry Department The University. Bristol (Joint Meetings with the Society of Chemical Industry and the Royal Institute of Chemistry to be held in the Department of Chemistry The University.) Thursday November 7th 1963 at 6.30 p.m.Lecture “Taking a Look at Some Basic Concepts,” by Dr. H. J. T. Ellingham O.B.E. F.R.I.C. Thursday December 5th at 6.30 p.m. Lecture “Development of Severnside,” by Mr J. Davidson B.Sc. Cambridge Friday November 22nd 1963 at 8.30 p.m. Lecture “Transition-metal Hydrides and the Base Behaviour of Some Transition-metal Complexes,” by Professor G. Wilkinson Ph.D. F.R.I.C. Joint Meeting with the University Chemical Society to be held in the University Chemical Laboratory Lensfield Road. Cardiff Monday November llth 1963 at 5 p.m. Lecture “Chemical studies of Radiation Damage in Solids,” by Dr. A. G. Maddock D.I.C. to be held in the Chemistry Department University College Cathays Park. Dublin Friday November 22nd 1963 at 5.30 p.m.Lecture “Catalytic Reactions of Aromatic Mole- cules on Metals,” by Professor C. Kemball Sc.D. F.R.I.C. Joint Meeting with the Werner Society to be held in the Department of Chemistry Trinity College. Dundee (Meetings to be held in the Chemistry Department Queen’s College.) Tuesday November Sth 1963 at 5 p.m. Lecture “Structural Information from Electron-resonance Measurements,” by Dr. D. H. Whiffen M.A. Tuesday November 19th at 5 p.m. Lecture “Using Mutants to Elucidate Pathways of Biosynthesis,” by Professor C. H. Hassall Ph.D. F.R.I.C. Durham (Joint Meetings with the University Chemical Society to be held in the Science Laboratories South Road.) Monday November 4th 1963 at 5 p.m. Lecture “Some New Developments in the Chemistry of Diazonium Salts,’’ by Dr.J. M. Tedder M.A. Monday November 18th at 5 p.m. Lecture “Additions and Substitutions in Some Olefinic and Aromatic Systems,” by Professor P. B. D. de la Mare D.Sc. F.R.I.C. Monday November 25th at 5 p.m. Lecture “Some Aspects of the Chemistry of Flames,” by Dr. T. M. Sugden M.A. F.R.S. Edinburgh Tuesday November 19th 1963 at 4.30 p.m. Lecture “Kinetic Theory of Gases Old and New,” by Professor P. Gray M.A. Ph.D. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Thursday November 21st at 7.30 p.m. Lecture “Carbanions to Carbenes,” by Professor R. N. Haszeldine D.Sc. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College.Glasgow Thursday November 14th 1963 at 4 p.m. Lecture “The Chemistry of Bacterial Cell Walls,” by Professor J. Baddiley D.Sc. F.R.S. Joint Meeting with The Andersonian Chemical Society to be held in the Chemistry Department The Royal College of Science and Technology. Wednesday December 4th at 3 p.m. Official Meeting and Symposium “Isotopes.” (It should be noted that the time of this meeting has been advanced to 3 p.m. and that further details will be found on p. 135.) Hull (Joint Meetings with the University Students Chem- ical Society to be held at the Department of Chemistry The University.) Thursday November 21st 1963 at 4 p.m.Lecture “The Wittig Reaction,” by Dr. S. Trippett B.A. Thursday December 5th at 4 p.m. Lecture “Seeing Molecules with Microwaves,” by Dr. J. Sheridan M.A. Keele Friday November 29th 1963 at 5 p.m. Lecture “Chemical Production of High Tem-peratures,’’ by Professor P. Gray M.A. Ph.D. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Leicester (Joint Meetings with the University Chemical Society to be held in the Department of Chemistry The University.) Monday November 4th 1963 at 4.30 p.m. Lecture “Metal-to-Metal Bonds in Inorganic Chemistry,” by Professor R. S. Nyholm D.Sc. F.R.S. Monday November 18th at 4.30 p.m. Lecture “The Mode of Action of Tetraethyl-lead as an Anti-knock,” by Professor A.D. Walsh M.A. Ph.D. F.R.S.E. Liverpool Thursday November 28th 1963 at 5 p.m. Lecture “Living Polymers,” by Professor M. Szwarc Ph.D. D.Sc. Joint Meeting with the Univer- sity Chemical Society to be held in the Donnan Laboratories The Chemistry Department The University. Manchester Friday November lst 1963 at 10 a.m. Symposium “Silicones.” Joint Meeting with the Society of Chemical Industry and the Royal Institute of Chemistry to be held in the Manchester Literary and Philosophical Society 36 George Street. Thursday November 14th at 6.30 p.m. Lecture “The Synthesis of Peptides,” by Dr. G.T. PROCEEDINGS Young F.R.I.C. To be given in the Manchester College of Science and Technology. Newcastle-upon-Tyne (Meetings to be held in the Chemistry Department The University.) Friday November 15th 1963 at 5.30 p.m.Bedson Club Lecture “The Journal of the Chemical Society Present and Future,” by Dr. R. S. Cahn M.A. F.R.I.C. Tuesday November 19th at 5.30 p.m. Official Meeting and Lecture “n-Complexes of Transition Metals-Some Recent Studies,” by Professor P. L.Pauson Ph.D. F.R.I.C. Friday November 29th at 6.30 p.m. Lecture “Exploring Surface Reactions on an Atomic Scale,” by Professor J. S. Anderson Ph.D. F.R.S. Joint Meeting with the Royal Institute of Chemistry. North Wales Thursday November 7th 1963 at 5.45 p.m. Lecture “Hydrogen Bonding,” by Dr. L. J. Bellamy. Joint Meeting with the University College of North Wales Chemical Society to be held in the Chemistry Department University College Bangor.(Please note that the date of this meeting has been advanced from November 21st.) Nottingham (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University.) Tuesday November 5th 1963 at 5 p.m. Lecture “Magnetic Resonance and Degenerate Staes,” by Dr. L. E. Orgel M.A. F.R.S. Tuesday November 19th at 5 p.m. Lecture “Social Aspects of Pneumatic Chemistry,” by Dr. F. W. Gibbs. Thursday December 5th at 5 p.m. Lecture “Diffusion Incorporation and Trans-formation Processes during Chemisorption of Gases on Metabs,” by Professor F. C. Tompkins Ph.D. F.R.S. (Please note that the date of this meeting was originally December 3rd.) Oxford (Joint Meetings with the Alembic Club to be held in the Inorganic Chemistry Laboratory.) Monday November 4th 1963 at 3.30 p.m.Lecture “Miscibility and Immiscibility in Simple Fluids,” by Professor A. R. Rowlinson. Monday November 18th at 3.30 p.m. Lecture “Tracer Studies in Plants,” by Professor A. R. Battersby D.Sc. Ph.D. OCTOBER 1963 321 Monday November 25th at 3.30 p.m. Lecture “The Investigation of Surface Chemistry as an Atomic Scale of Resolution,” by Professor J. S. Anderson Ph.D. F.R.S. Reading Tuesday November 12th 1963 at 5.30 p.m. Lecture “Some Reactions of Substituted Cyclo- butadienes,” by Professor. R. C. Cookson M.A. Ph.D. F.R.I.C. Joint Meeting with the Royal Insti- tute of Chemistry and the University Chemical Society to be held in the Large Chemistry Theatre The University.St. Andrews (Joint Meetings with the University Chemical Society to be held in the Chemistry Department St. Salvator’s College.) Thursday November 14th 1963 at 5.15 p.m. Lecture “The Simplest Chemical Reaction,” by Professor G. Porter F.R.I.C. F.R.S. Thursday November 21st at 5.15 p.m. Lecture “A Beery Chemist’s Discourses,” by Dr. J. 0. Harris F.R.I.C. Sheffield Thursday November 14th 1963 at 4.30 p.m. Lecture “Boranes Manes and Gallanes,” by Professor N. N. Greenwood Ph.D. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry and the University Student Chemical Society to be held in the Department of Chemistry The University.Southampton (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University unless otherwise stated.) Friday November 8th 1963 at 5 p.m. Lecture “Some Aspects of Nuclear Magnetic Resonance,” by Professor R. E. Richards M.A. D.Phil. F.R.S. Friday November 15th at 7 p.m. Lecture “Overcrowded Molecules,” by Professor C. A. Coulson Ph.D. D.Sc. F.R.S. Joint Meeting with the Portsmouth and District Chemical Society to be held in the Lecture Theatre H.9 The College of Technology Anglesea Road Portsmouth. Friday December 6th at 5 p.m. Lecture “Co-ordination Complexes,” by Professor J. Lewis D.Sc. F.R.I.C. Swansea (Joint Meetings with the Student Chemical Society to be held in the Department of Chemistry Univer- sity College.) Monday November 1 lth 1963 at 4.30 p.m.Lecture “Branched-chain Sugars,” by Professor W. G. Overend D.Sc. F.R.I.C. Monday December 2nd at 4.30 p.m. Lecture “Some Problems of Photochemistry and Reaction Kinetics Exposed by Kinetic Spectro- scopy,” by Professor R. G. W. Norrish Sc.D. F.R.S. Tees-side Wednesday November 27th 1963 at 8 p.m. Lecture “Recent Trends in Chemical Education,” by Mr. D. G. Chisman B.Sc. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Constantine College of Technology Middlesbrough. OBITUARY NOTICES ANTONIO GIUSEPPE NASINI 1898-PROFESSOR GIUSEPPE ANTONIO NASINI Head of the Chemistry Department of the University of Turin died on January 21st 1963 in Turin after a short illness.Born in 1898 Nasini was an artillery officer during the First World War took his degree in Chemistry at the University of Pisa in 1921 and was then for a short time Assistant in the Istituto Superiore di Chimica Industriale of Bologna directed by Mario Giacomo Levi. In 1923 he was awarded a Ramsay Scholarship which he held for two years at Cam- bridge where he obtained the degree of D.Phi1. 1963 Returning to Italy Nasini was first the Assistant of Luigi Rolla at the University of Florence (1926- 27) then of Mario Giacomo Levi who became Director of the Istituto di Chimica Industriale of the Polytechnic of Milano and finally of Giulio Natta.In 1940 Nasini was appointed to the Chair of General Chemistry at the University of Pavia and in 1942 he moved to Torino to direct the Chemistry Department of that University. At the end of the war he did all he could to enlarge and modernise the Department to enable the in- creasing number of students to receive a more thorough and scientific education. In a few years Nasini succeeded in furnishing the Laboratories with equipment which allowed for research at the highest level for his purpose was to make scientific research the basis of experimental teaching. The research activity of Professor Nasini is col- lected in more than a hundred papers notes and reviews (some of them still in the press). His first investigations dealt with some problems of inorganic and applied chemistry (reactivity of boron azide with metallic oxides regeneration of barite from barium carbonate).He then became concerned with struc- tural problems through a series of investigations (commenced in Cambridge) on the isosterism in the Langmuir meaning of cyclic organic compounds and he succeeded in obtaining interesting results through the evaluation of the viscosity of the vapours of the critical constants and of the vapour pressures about the differences in the molecular properties of aromatic compounds as a consequence of the substi- tution of one or more carbon atoms in the ring. The direct consequence of this work was the investigation of the viscosity also at very high pres- sures (up to 1,OOO atrn.) of the vapours of associated molecules (chiefly hydrogen and nitrogen).This research requiring delicate work in setting up the apparatus allowed Nasini to obtain the first reliable data for the definitive planning of the industrial equipment for the synthesis of ammonia. Worthy of mention are the determination of the crystal lattices of some rare gases such as krypton and xenon through X-ray analysis; the establish- ment of some new analytical techniques the analysis of some Italian natural gases (continuing in this way the well known work of his father Raffaello Nasini) and a theoretical study of the origin and the distribu- tion of rare gases in the earth’s crust. Professor Nasini dwelt then on problems of colloidal chemistry.Immediately he proved himself a really good investigator in this field and we can today say that he was among the first to consider the stability of the dispersed systems as dependent upon the values of the interfacial tension and the de- pendence of this latter upon the chemical and physical parameters of the system. These studies carried out with refined techniques and keen intellect allowed Nasini to find new solutions for important technical problems such as those concerning the preparation and the stabilisation of concentrated bitumen emulsions. From knowledge of the factors involved in the stability of the colloidal systems he passed then to research on the kinetics of reactions involving oxidation of double bonds by oxygen ozone etc.on monomolecular layers. By refining those new and elegant techniques learned in Cam- bridge in the Laboratory of Sir E. Rideal he reached PROCEEDINGS basic conclusions concerning the phenomena of molecular adhesion and cohesion on monomolecular films succeeding in separating the effect of the structure of the molecules from that of position and arrangement of these in the case of polymerisation. It is surely this work begun in 1936 that caused Nasini to be steadily drawn to those spheres pro- viding opportunities for new research. His interest was drawn towards Macromolecular Chemistry in which field he was a pioneer in Italy building up a School in the Chemistry Department of the University of Turin which already in 1946 was able to take part in programmes of international col- laboration in the sphere of the Commission on Macromolecules of I.U.P.A .C. Among more than twenty papers dealing with the Chemistry and the Physical Chemistry of macro-molecules are to be remembered those concerned with the synthesis and the mechanism of formation of crystalline polyalkylidenes first discovered in the Chemistry Department of the University of Turin from the decomposition of diazoalkanes catalysed by metal surfaces such as colloidal metals or evaporated metal films. Another field of research in which the keen experimental technique and the new method of interpretation of experimental data allowed Nasini to obtain interesting results either from the theoreti- cal or the practical point of view is that of the study and the characterisation of the chemisorption of gases upon metals.In fact he immediately realised the necessity of using new techniques for the pro- duction of ultra-high vacua and for an efficient de- gassing of the metal surfaces as well as of using bulk materials thus avoiding all those troubles arising from materials such as films or powders whose structural and crystallographic characteristics are not easily controlled or whose complete degassing is practically impossible. By using new experimental techniques he produced data on the kinetics of chemisorption processes which agree favourably with the data recently obtained by other investigators using different techniques such as field emission microscopy ionic microscopy and electron diffrac- tion at low energies.Although the data so far ob- tained by Nasini are chiefly concerned with those metals displaying very low vapour pressure at very high temperatures the results so far obtained are of such a general kind that they can be easily extended to other metals and can also be used for the identifica- tion of different possible kinds of chemisorption of gases and for their characterisation. In particular the measurements of the successive adsorptions of different gases make it possible to re-examine all those factors related to the “topography” of an adsorbing surface and lead to a new and more OCTOBER 1963 quantitative interpretation of the surface hetero- geneity and of the active sites.Although the most important activity of Nasini was scientific research he was not averse to problems of practical application. In the field of paints and varnishes as already in that of bitumen emulsions he obtained important results in the study of the relations between the protective actions of the varnishing films and their adhesion to the support and permeability to aqueous solutions. In fact he first pointed out the ion-selective effect by experiments upon films obtained from a large number of sub-stances used as vehicles in paints and he succeeded in explaining the different influence of the cation- selective or anion-selective character on film de- gradation (blistering) as well as on their protective action by investigations upon ion-active model films prepared from inert substances and ion-exchange resins.Professor Nasini’s untimely death came just when work had begun on rebuilding his Department; work which he had so much at heart because of the increased opportunity it would provide for research. His open serene gentlemanly charming figure inspired confidence liking and benevolence. Very well known in international scientific circles im- mediately after the end of the war Prof. Nasini helped to reorganise the Union of Pure and Applied Chemistry of which for many years he was the Vice-President. In 1949 overcoming many difficulties Nasini organised an International Congress on Plastics in Turin and for the first time in Italy all the leading chemists in the field of macro-molecular chemistry were assembled.This one was the first of those International Congresses on Plastics which are now held every year in Turin in connection with the International Technical Exhibition. Eminent scientists from every part of the world partici-pated in high level discussions upon the most im-portant problems relating to the theory and the technology of high polymers. In the field of physical chemistry Antonio Giuseppe Nasini who though he passed away before his time had achieved recognition in Italy and throughout the world for himself and for the Chemical Institute of which he was Head. I am sure to obtain unanimous consent in asserting that his name has every right to appear in the history of Italian chemistry beside those of his father and uncle Raffaello Nasini and Giacomo Ciamician.MARIOMILONE. WILLIAM HENRY LEWIS 1869-1 963 WILLIAM HENRY LEWIS who died at Sidmouth on May 25th 1963 was born at the Mumbles near Swansea on May 17th 1869 and was educated at University College Aberystwyth and Jesus College Oxford. After seven years (1 894-1901) as science master at Exeter School he joined the staff of the embryonic University College Exeter where he held the Chair of Chemistry from 1901-1935; he was Vice-Principal of the College from 1925 to 1935. In the first few years of his tenure of the Exeter Chair Lewis carried out research in organic chem- istry in collaboration with the late Dr.F. D. Chattaway then at St. Bartholomew‘s Hospital Medical School; two papers (J. 1904,85 589 1663) deal with the migration under acidic conditions of a benzoyl group from nitrogen to nuclear carbon in substituted dibenzoylanilines and two (J. 1905 87 951 ;1906 89 155) with N-halogeno-compounds of piperazine and oxanilide respectively. However Lewis soon found himself fully occupied with the affairs of the struggling young college and during the last thirty years of his occupancy of the chair devoted himself entirely to promoting the in- terests of the College and of his Department. During the First World War Lewis together with his col- leagues the late Professor W. J. Harte and Professor A. E. Morgan was instrumental in the setting up of a Committee for the Furtherance of University Edu- cation in the South-west; there is no doubt that it was Lewis’s devoted work as a secretary of this Committee which sowed the first seeds of growth which led in due course to the foundation by Royal Charter in 1955 of the University of Exeter.Between the two World Wars much hard work was needed to get the University College fully accepted and once again Lewis was a leading member of a small group of devoted men without whose efforts nothing last- ing could have been achieved. The University Col- lege signalised its appreciation of his services by making Lewis professor emeritus on his retirement and the University by conferring on him in 1957 the honorary degree of LL.D. a distinction which he greatly prized.With all this Lewis in no way neglected his Department. Starting from almost nothing he built up a strong and active Department of Chemistry with a striking record of academic successes in the external degree examination of the University of London and a sound reputation for research which Lewis fostered by attracting good men to his staff and seeing to it that they had the facilities they needed for their work. He was responsible for the planning of new chemical laboratories in the Washington Singer Building opened in 1931; it would surely have pleased him to know that his old Department has now outgrown accommodation which must have seemed to many to be over-generous at the time. Although so much involved in College affairs Lewis found time to serve on the Council of the Royal Institute of Chemistry (1924-27) and on the External Council of the University of London (1930-35).Lewis has rightly been called one of the founding fathers of the University of Exeter; as such he has an assured and honoured place in the history of English universities. €3. N. RYDON. (Published with permission from ‘‘Nature.”) ADDITIONS TO THE LIBRARY Physical chemistry. W. J. Moore. 4th edn. Pp. 844. Longmans. London. 1963. Principles of catalysis. G. C. Bond. (Royal Institute of Chemistry Monographs for Teachers No. 7.) Pp. 51. Royal Institute of Chemistry. London. 1963. (Presented by the publisher.) Ion exchange separations in analytical chemistry.0. Samuelson. Pp. 474. Almqvist and Wiksell. Stockholm. 1963. Gmelins Handbuch der anorganischen Chemie. System-Nummer9 Teil B-Lieferung 3. Pp. 1131-1875. 8th edn. Verlag Chemie. Weinheim. 1963. Organic syntheses Coll. vol. 4. Edited by N. Rabjohn. Pp. 1036. John Wiley and Sons. New York. 1963. Advances in heterocyclic chemistry. Vol. 1. Edited by A. R.Katritzky. Pp. 476.Academic Press. New York. 1963. Enzymes. Edited by P. D. Boyer H. Lardy and K. Myrback. Vol. 7.2nd edn. Pp. 726. Academic Press. New York. 1963. Comparative biochemistry a comprehensive treatise. Edited by M. Florkin and H. S. Mason. Vol. 5. Pp. 637. Academic Press. New York. 1963. Progress in medicinal chemistry. Edited by G. P. Ellis and G. B. West. Vol.3. Pp. 407. Butterworths Scientific Publications Ltd. London. 1963. Ruthenium. Pp. 16. International Nickel Co. (Mond) Ltd. London. 1963. (Presented by the publisher.) Nickel plating a short account of technique and applications. Pp. 51. International Nickel Co. (Mond) Ltd. London. 1963. (Presented by the publisher.) British Chemical Plant 1963 edition. Pp. 444.British Chemical Plant Manufacturers. London. 1963. (Pre-sented by the publisher.) Report of the proceedings of the 13th session of the International Commission for Uniform Methods of Sugar Analysis held in Hamburg 1962. Pp. 125. I.C.U.M.S.A. London. 1963. (Presented by the pub- lisher.) CHRISTMAS COMPETITION MOSTreaders will recollect the exploits of Little Tommy the schoolboy who always managed to get his answers wrong by false association of ideas and syllables.A prize (book token for two guineas) is offered for the best set of four of Little Tommy’s answers to the following What are (a) Birch reduction (b) Bitter principles (c) Catalysis (d) Chemical shifts (e) Conformational analysis (f)Luciferin (g) Optical activity (h) Royal jelly Entries must reach the Editor (The Chemical Society 20-21 Cornwall Terrace Regent’s Park London N.W.1) not later than December 31st 1963 and may be accompanied by a pseudonym for publication. It is hoped to issue a report in the January 1964 issue of Proceedings. The Editor’s decision will be final.
ISSN:0369-8718
DOI:10.1039/PS9630000293
出版商:RSC
年代:1963
数据来源: RSC
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