|
1. |
Proceedings of the Chemical Society. November 1959 |
|
Proceedings of the Chemical Society ,
Volume 1,
Issue November,
1959,
Page 341-376
Preview
|
PDF (3706KB)
|
|
摘要:
PROCEEDINGS OF THE CHEMICAL SOCIETY NOVEMBER 1959 FARADAY LECTURE* History of the Isoprene Rule By L. RUZICKA IN1911 as co-worker of my teacher Staudinger I undertook a study of the insecticidal components of the flower heads of Chrysanthemum cinerariifolium Bocc. The most active substance pyrethrin I yielded chrysanthemic acid as acidic product on saponification. The structure1 (1) of this acid was established in 1913.t When Simonsen determined the formuls of the carenes in 1920-21 I was struck by the analogy in the structures of chrysan- themic acid and of car-4-ene (2). At the same time in 1920 Asahina and Tagaki published the formula of artemisia ketone (3) which if written as is shown here recalls structurally that of fenchone (4) pro-posed in 1905 by Sernmler.I mention these facts in detail because chrysan-themic acid fenchone and artemisia ketone do not comply with the definition of monoterpenes custom- .ary at the time according to which monoterpenes were compounds deducible from p-cymene. On the other hand the definition of monoterpenes as com-pounds with a carbon skeleton consisting oftwo iso-prene units attached either regularly “head to tail” or in an irregular sequence [e.g. (3) and (4) 1 ap-peared to be satisfactory for all known members of the monoterpene group. It was in 1920 that I became interested in the higher terpenes. In these studies the leading question was whether the carbon skeletons of the higher ter- penes were also composed of isoprene units.For all the compounds we examined the answer was posi- tive and thus the original working hypothesis gradually grew into the isoprene rule.Like other rules about the structure of large classes of natural organic compounds the isoprene rule has its antecedents. They go back to the dry * Delivered before the Chemical Society at the Imperial College of Science and TechnoIogy London on June 5th’ 1958. t The work on the pyrethrins was interrupted in 1916. For various reasons however the results could not be published until 1924. Staudinger and Ruzicka Helv. Chim.Ada 1924 7 201 390. 341 distillation of rubber. According to A. Bouchardat? Beale and Enderby in London carried out the dry distillation of rubber for industrial purposes.The volatile products were studied by Ure and by Faraday? who were the first* to examine the low- boiling fraction (b.p. cu. 35”) containing isoprene. This volatile product attracted the interest of various other chemists.? The results differed some analyses being close to the formula C,H8 and others to C,H1,. Only much later was it found that this crude isoprene fraction actually contains varying amounts of trime thy le thy lene (2-me thy1 bu t-2-ene)6 and other hydrocarbon^.^ The term isoprene is due to Gr. Williams.8 The structural determination of isoprene however pro- gressed very slowly. In 1884Tildeng discussed various hypothetical formula among others also the right one but it was Ipatiew and Wittorfs who in 1897 provided conclusive evidence in favour of the correct structure.An unambiguous synthesis was carried out in the same year by Euler.l0 ql/+y-In 1868 Hlasiwetz and Hinterberger,ll by passing the vapour of turpentine oil through a red-hot iron tube obtained a liquid C5H8. Tildens repeated this experiment in 1884 and extended it to other cyclic monoterpenes. He proved that in each case isoprene was obtained. The inverse observation that dipentene is produced by heating isoprene to 280” had already been made by G. Bouchardat12 in 1878. The solid dipentene dihydrochloride had also been prepared by PROCEEDINGS him and found to be identical with that derived from optically active limonene. For incomprehensible reasons the recognition that dipentene was nothing but optically inactive limonene took some time to be made.13 In fact it remained un- certain until 1891 whether limonene and p-cymene contain a propyl or an isopropyl group.l4 The correct structure of limonene and dipentene (5) was finally deduced from known facts by Wagnefi5 in 1894.Additional unambiguous proofs were published by Wallach and by Tiemann and Semmler one year later. The total synthesis of or-terpineol and of di- pentene carried out by W. H. Perkin jun. in 1904 may be considered as the conclusion of this chapter of organic chemistry. The painstaking and slow progress in this field is typical of the first half-century of structural organic chemistry. If one considers that the structure of indigo had been proved by A.von Baeyer as early as 1883 and that the same A. von Baeyer in 1894 still thought optically active limonene contained no asym- metric carbon atom16 (5a) one can realise the difficulties presented by the structural elucidation of unsaturated alicyclic compounds. A further impediment was the lack of a clear concept of the mechanism by which two molecules of isoprene can react to yield dipentene. Thus we find that in Wallach’s17 interpretation of the dimer- isation of isoprene a shift of three hydrogen atoms was supposedl to take place (5b). The first correct formulation of this reaction which is to be con- sidered as an early example of a Diels-Alder con-densation,was put forward7 by Ipatiew and Wittodg In the mechanisms proposed for the hypothetical formation of a sesquiterpene from three isoprene molecules Wallach17 assumed the shift of four hydrogen atoms5 (6).These formulations can however be considered as a presentiment of the isoprene rule. Of course Tilden9 should be mentioned as the first forerunner. In 1884 he stated “from the easy transformation of * Tn the thesis of Wohler’s pupil Himly,’ in 1835 the name “faradayin” was therefore proposed for this hydrocarbon. t BouchardaP mentions the names of Dumas,Liebig and Gregory as other earlier researchers in this subject. Robinson’ cites also John Dalton. $ “unter der unumganglich notwendigen Annahme dass die vorhandenen Wasserstoffatome teilweise einem Ortswechsel zughglich sind.” “keine Notwendigkeit besteht irgendwelche Umlagerungen anzunehrnen.” f Cf.also Semmler.18 * A. Bouchardat J. Pharm. 1837,23,454. Robinson Nature 1955 176 433. a Faraday Quart. J. Sci. 1826 21 19. Ipatiew and Wittorf J. prukt. Chern. 1897,55 1. 4 Reviewed in Ann. Pharm. 1838. 27,40. 7 Midgley jun. and Henne J. Amer. Chem. Sac. 1929,51 12. 0 Williams. Chem. News. 1860,2 206. * Tilden J. 1884,45,410. loEuler J. prukt. Chem. 1898.57. 13 1. 1% Hlasiwetz and Hinterberger 2.Chem. 1868 380 (mentioned in J. 1884 45 410). 1* 0.Bouchardat Compr. rend. 1878,86,654. g8 Wallach Anden 1888,246 225. l6Baeyer Ber. 1894,27 3485. 14 Widman Ber. 1891 24. 439 1362. l7 Wallach Annalen 1887 239 I. 16 Wagner Ber. 1894,27 1652. l8Semmler Ber. 1903 36 1038. NOVEMBER 1959 343 two C,H into C1,Hl and vice versa it appears probable that the molecule of terpilene is composed symmetrically of two halves (C,H,) = (CSH8).” We may now examine to what extent the idea that terpenes are composed of isoprene units was put to use in the study of sesqui- and poly-terpenes during the first two decades of this century.Semmlerl9 derived the first correct structural formula of a sesquiterpene a-santalene from its stepwise degradation to teresantalic acid. He could not decide which of the two formulae (7)and (7a) represents ol-santalene they are in fact two different projections of the spatial formula. In 19 13 Kerschbaurn2O established by degradation the structure of farnesol(8) the parent compound of the sesquiterpene group. The structures of both farnesol and or-santalene are in accordance with the isoprene rule.Neither Semmler nor Kerschbaum pointed out this interest- & cam,* ing fact. Semmler and MayerZ1 in their study of caryophyllene even proposed without forcible reason a carbon skeleton (9) that cannot be resolved into isoprene units of course on the basis of in-sufficient degradative results ; and Aschan and Virtanen22 in 1921 suggested without adequate evidence a formula (10) for abietic acid which did not comply with the isoprene rule. Likewise Willstiittee in 1911 put forward a formula (1 1) for phytol which does not correspond to the isoprene rule. This formula was based on unclear degradative results and was deduced from isoprene by an impossible rearrangement mechanism.It may thus be stated that up to 1921 the idea that the higher terpenes are structurally composed of iso-prene units was not used as an accepted working hypothesis. That a-santalene and farnesol have a structure which corresponds to this principle did not promote the study of its validity in the investigation of other sesquiterpenes and of diterpenes. SESQUKTERPENES The route by which we chose in 1921 to attack the sesquiterpene field on a broader front is best described by quoting from ow first paper on higher terpenexZ4 “Es scheint uns daher ein neuer Weg bei der Erforschung der Sesquiterpenverbindungen notig zu sein :die Anwendung der Dehydrierungsmethoden wobei dann in den Fallen geeigneter Anordnung der Kohlenstoffatome die aromatischen Grundkorper resultieren mussten.Diese fester gefiigt als die hydrierten Abkommlinge diirften dann eher charak- teristischc Abbauprodukte liefern und sich auch Ieichter synthetisieren lassen. Die sekundare Auf- gabe die Ermittlung der Lage der Kohlenstoffdoppel- bindungen lime sich dann an Hand des bekannten Ringsystems weit einfacher erledigen.” The first sulphur dehydrogenations* were carried out with sesquiterpene hydrocarbons and alcohols having a molecular refraction indicative of a bicyclic structure. SemmleP had divided the bicyclic ses- quiterpenes in two groups according to their specific weight to the group with higher specific weight he ascribed hypothetically a hydrogenated naphthalene * From 1925 onwards selenium (introduced by Diels) was used for dehydrogenation,as it generally gives better yields than sulphur.lo Semmler Ber. 1910 43 1893. 23 Willstatter Annalen 1911 378 81. 2o Kerschbaum Ber. 1913 46 1732 24 Ruzicka and Meyer Hefv. Chirn. Acta 1921 4 505. 21 Semmler and Mayer Ber. 1911,44 3657. 24 Sermder et al. Ber. 1913 46,1817; 1914 47 2557. 22 Aschan and Virtanen Annalen 1921 424 119 150. framework for the other he assumed a non-hydro- aromatic skeleton. This assumption for which Semmler supplied no experimental support proved to be right. Upon dehydrogenation only the ses- quiterpenes of the first group yielded homologous naphthalene hydrocarbons that is either cadalene (C15H1&) or eudalene (C,,Hl,).26As both dehydro- genation products were never obtained together from the same sesquiterpene it was possible to ascribe the elimination of a methyl group in the formation of eudalene to a particular structural feature of the cor- responding sesquiterpenes.It was indeed this very elimination of a methyl group which led to a con- siderable simplification in the structural determina- tion of both dehydrogenation products. Thus I did not reflect upon the various ways in which three molecules of isoprene could combine to yield a sesquiterpene that would lose a methyl group on dehydrogenation but I assumed tentatively that plants were able to cyclise an aliphatic chain such as the one present in farnesol (or nerolidol),* accord- ing to two schemes one (8a) leading after dehydro- genation of the bicyclic cyclisation product (12) to cadalene and the other (8b) yielding eudalene because of the attachment of a methyl group to a quaternary carbon atom as in (13).PROCEEDINGS recent review,30 to understand this interest “Within the field of sesquiterpenoid chemistry one finds a wide range of oxygenated function of ring size and of mechanistic change. If no other type of organic compound were known organic chemistry would still be a rich and varied field of investigation.” In choosing examples to illustrate this variety I have to limit myself to a few of the simplest repre- sentatives. The relative and the absolute configura- tion as established in recent times have been taken into account in drawing the formulae.In the course of time the isoprene rule as applied to the sesquiterpenes developed more and more into a farnesol rule because the carbon skeletons of the sesquiterpenes were found to be derivable schematic- ally from the farnesol chain. Various cyclisation modes must be assumed indeed the sesquiterpenes can be classified in sub-groups according to the hypothetical cyclisation scheme leading to their derivation from farnesol. A large number of sesquiterpenes belong to the eudesmol sub-group and for several of these e.g. santonin (17) proof has already been provided that they also possess the same configuration as eudesmol (16). Even Semmler’s a-santalene (7) belongs to the sesquiterpenes of the eudesmol type as does the The formulae of cadalene2s (14) (15) deduced on the basis of the above argument were proved by synthesis.Once the carbon skeleton of the sesquiterpenes had been established the posi- tions of the double bonds and of the substituents were determined but we cannot go into the experimental details here. Work in the sesquiterpene field is going on tq this day. More and more laboratories throughout the world have turned their attention to this class of compounds. It is enough to cite a remark from a and e~dalene~~ alcohol elem01~~2~~ (18) which though monocyclic also yields eudalene on dehydrogenation. It should also be stressed that the identity of the configuration of the angular methyl group in these sesquiterpenes and of the angular methyl group in position 10 of the steroids cannot be considered to have fundamental importance because the notation A and B for the two rings of the sesquiterpenes is purely conventional.With respect to the number of structural variations to which it gives rise the cadinene type [e.g. * The total syntheses of these two sesquiterpene alcohol^^^ which were carried out at the same time can be considered to have catalysed this useful working hypothesis. 26 Ruzicka Meyer and Mingazzini Helv. Chim. Acta 1922 5 345. 27 Ruzicka Helv. Chim.Acta 1923 6 492. f8 Ruzicka and Seidel Helv. Chim. Acra 1922 5 369. 30 Barton and de Mayo Quart. Rev. 1957 11 189. 2s Ruzicka and Stoll Helv. Chi?. Am 1922 5 923. 31 Ruzicka and van Veen Annulen 1929 476 70. 32 Sykora Herout cerny and Sorm Coll.Czech. Chem. Comm. 1954 19 566. NOVEMBER 1959 p-cadinene (19)] appears to be less prolific than the eudesmol type. I I The cyclisation of nerolidol or farnesol (8a) under the action of acids leads to the monocyclic bisabolene (20) and a mixture of non-identified bicyclic hydro- carbons (possibly of cadinene type) which on de- hydrogenation yields ~adalene.~~ On the other hand cyclisation to a compound of eudesmol type has never been achieved in the laboratory. A third sub-group of bicyclic sesquiterpenes yields azulenes on dehydrogenation. These blue hydro- carbons are isomers of cadalene and eudalene. Their structure was established by Pfau and Plattner.34 So far two azulenes CI5Hl8 both derivable from the farnesol chain have been obtained they are guai- azulene (21) and vetivazulene (22).Only two of the many bicyclic sesquiterpenes of the guaiazulene and vetivazulene type can find mention here guaiol(23) and vetivone (24). As an example of a tricyclic com- pound of this group patchouli alcohol (25) should be recalled; its carbon skeleton is derivable from that of guaiol. Greater difficulties were encountered in the structural elucidation of bi- and tri-cyclic sesquiter- penes which do not contain a hydroaromatic ring system and consequently do not yield aromatic deri- 33 Ruzicka and Capato Helv. Chim.Acta 1925 8 259. Pfau and Plattner Helv. Chim. Acta 1936 19 858. vatives on dehydrogenation. a-Santalene (7) is an exception because it was easily degraded to a known compound As an example of other tricyclic ses- quiterpenes I shall mention cedrol responsible for the odour of cedar wood.For the formula of cedrol two different projections (26 and 26a) are shown both corresponding to the same relative configura- tion (26b) based on degradati~n~~l~~ and ~ynthesis.~' In the projection (26) the formal derivation of the carbon skeleton of cedrol from a farnesol chain (8c) as well as the formal analogy to the cadinene type can easily be recognised. Of great interest is a group of sesquiterpenes also derivable from farnesol containing 9- lo- and 11- membered carbon rings. Cary~phyllene~~-~~ (27) (4-and 9-membered rings) (28) (1 1-membered ring) and pyrethr~sin~~ (29) (10-membered ring) belong to this group.Eremophilone was the first compound having the properties of a sesquiterpene but a carbon skeleton (30) that cannot be subdivided in isoprene units. The structure of eremophilone was proved by Simonsen and his colleagues44 in 1937. 35 Plattner Furst Eschenmoser Keller Klaui Meyer and Rosner Helv. Chim. Acta 1953 36 1845. 36 Stork and Breslow J. Amer. Chem. SOC. 1953 75 3291 3292. 37 S_tork and Clarke J. Amer. Chem. SOC.,1955 77 1072. 38 Sorm,DolejS and Pliva Coll. Czech. Chem. Comrn. 1950 15 186. 39 Barton and Lindsay Chem. and Ind. 1951 313; Barton Bruun and Lindsay J. 1952 2210. 40~awson, Ramage and Wilson Chem. and Ind. 1951,464. 41 Sorm Streibl Pliva and Herout Chem. Listy 1951 45 308 ; 1952 46,30.42 Clemo and Harris Chem. and Ind. 1951 799. 42a Hildebrand Sutherland and Waters Chem. and Ind. 1959 489. O3 Barton and de Mayo J. 1957 150. O4 Bradfield Pritchard and Simonsen J. 1937 760. Whereas fifteen years earlier such a formula would have been advanced without further comment in 1937 eremophilone caused a sensation. According to a proposal by Robinson this structure could originate for instance by dehydration accompanied by rearrangement of a hypothetical precursor (31) of the eudesmol type. Recently two sesquiterpenes of a new type-iresin and drimenol-have been isolated. The formula of drimen01,*~ the simpler of the two is shown here (32). This new type of structure is very seldom* encountered in the sesquiterpenes but is typical of the first two rings (A and B) of all known cyclic di- and tri-terpenes containing two or more rings.The configurations of the asymmetric carbon atoms of drimenol are the same as those of the cor- responding atoms of rings A and B of triterpenes steroids and most diterpenes. For the biogenesis of drimenol an enzymic cyclisation of a farnesol-type precursor may be postulated. Eschenmoser et al.46 have indeed carried out a total synthesis of racemic drimenol in vitro using the cyclisation product (34) of trans-farnesic acid (33). The biogenesis of sesquiterpenes derivable from a regular tri-isoprene chain can be assumed to consist in an enzymically catalysed cyclisation of an ali- phatic precursor such as farnesol nerolidol or farnesene.The synthesis of drimenol from trans-farnesic acid (33+34+32) as well as the cyclisation of farnesol to bisabolene (8a+20) can also be con- sidered as counterparts in vitro of the formation in vivo of these cyclic sesquiterpenes. In 1953 in a lecture‘’ entitled “The Isoprene Rule and the Bio- genesis of Terpenic Compounds” a hypo thetical formulation of the biogenesis of all classes of ter- PROCEEDINGS penes was proposed. For the sesquiterpenes a few examples taken from that lecture may be mentioned here. The bridged cation (20a) derived from bisabolene (20) can undergo cyclisation in two different direc- tions. The intermediate (35) leads to cc-santalene (7) after undergoing a Wagner-Meerwein rearrange-ment.The intermediate (36) gives rise to cedrol(26) by normal cyclisation. (381 + Farnesol (or farnesene or nerolidol) is the origin of the bridged cation (38) which may cyclise to an 1 1-membered ring (39) or to a 10-membered ring (4).The former intermediate yields humulene (28) or after a further cyclisation caryophyllene (27). From the intermediate (40) with the 10-membered ring it is possible to derive not only eudesmol (1 6) and elemol (18) but also the recently discovered pyrethrosin (29). DITERPENES The evolution of the isoprene rule to a generally accepted working hypothesis is in great part due to the simultaneous investigation of sesquiterpenes and of abietic acid. Crystalline abietic acid is isolated in good yield from the amorphous mixture of isomers present in rosin after isomerisation with boiling * A ring closure leading to the structure of ring A has long been known to occur in the cyclisation of pseudoionone to the ionones.45 Brooks and Overton Proc. Chen?.Soc. 1957 322. 46 Eschenmoser Felix Gut Meier and Stadler in “The Biosynthesis of Terpenes and Sterols,” Ciba Foundation Symposium 1959 p 217 J. & A. Churchill Ltd. London. 47 Ruzicka Eschenmoser and Heusser Experientia 1953 9 357. NOVEMBER 1959 acetic acid. It is therefore one of the most easily accessible terpene compounds but cannot be considered with absolute certainty as a natural product. The first attempts at a structural elucidation of abietic acid were undertaken in 1903 by Vesterberg,48 who dehydrogenated it to retene by heating it with sulphur.That the product of dehydrogenation of rosin is retene was first stated in 1887 in a German patent of the Aktiengesellschaft fur Chemische Industrie in Rheinau. The structural elucidation of retene was undertaken by Bamberger and H0oker-4~ in 1885 continued by Fortner and by Lux and concluded by BucheflO in 1910. I began work on abietic acid ten years later.51 The approach was the same as in the sesquiterpene field with the carbon skeleton of retene (42)as a co- ordinate grid the determination of the position of the two group bonds and of the methyl and tackled. boxyl double lost on dehydrogenation was the car-Though it was soon fairly obvious that abietic acid could be a terpene as defined by the isoprene rule a strict proof of the carbon structure was not obtained until 1933,52 and the position of the double bonds was definitely established in 194253(see 43).Seven years later the relative configurationM and there- after the absolute configuration were secured (43).55 The structural determination of la=vopimaric acid5s (44),one of the native acids from various pine resins was greatly facilitated by the extraordinary ease with 48 Vesterberg Ber. 1903 36 4200. 49 Baniberger and Hooker Annalen 1885 229 102. 51 Ruzicka and Meyer Helv. Chim.Acta 1922 5 315. 52 Ruzicka Waldmann Meier and Hosli Helv. Chim.Acta 1933 16 169. 63 Ruzicka and Sternbach Helv. Chim.Acta 1942 25,1036. M Barton Quart. Rev. 1949 3 36.65 Heusser Beriger Anliker Jeger and Ruzicka Helv. Chim. Ada 1953 36 1918. 66 Ruzicka and Kaufmann Helv. Chim. Acta 1940,23 1346; 1941,24 939. 67 Ruzicka and Sternbach Helv. Chim. Ada 1940 23,124. 6* Harris and Sanderson J. Arner. Chem. SOC.,1948 70 2081. Kg F. G. Fischer Annalen 1928 464,69. 6o Karrer Morf and Schopp Helv. Chim. Acta 1931 14 1036 1431. 347 which this acid is isomerised to abietic acid; it only remained to ascertain the position of the double bonds within the abietic acid framework. Dextropimaric acid represents another type of a native tricyclic diterpene. Its dehydrogenation leads to 1,7-dirnethylphenanthrene(pimanthrene) whereby three carbon atoms are lost in addition to the carboxyl group. The exact structure of this rosin acid (44) was established by appropriate degradative work.57s68 We shall now consider briefly the aliphatic mono- cyclic and bicyclic diterpenes.Their structural determination was relatively easy compared with the laborious and time-consuming efforts which were required for the elucidation of the tricyclic diterpenes. The history of polyterpenes shows that the difficulties of structural determination usually increase with the number of condensed rings present. In 1928 F. G. Fis~her,~~the basis of the on isoprene rule assumed that the ketone C,,W,,O pro-duced upon ozonisation of phytol is hexahydro- farnesylacetone and hence proposed for phytol the formula (46) a chain of four isoprene units joined regularly to each other.The correctness of this deduction was proved by synthesis. -~ 7-8& \’ -H02C (44) (45) The isoprene rule was useful also in the structural elucidation of vitamin A carried out by Karrer Morf and SchopfG0 in 193 1. The structural formula (47) was first confirmed by synthesis of the deca- hydro-derivative. 50 Bucher J. Arner. Chern. SOC.,1910 32,374. PROCEEDINGS ~ ~~~~ The structure (48) of a bicyclic diterpene agathene diacid (= agathic acid) could be established61 from the results of dehydrogenation and ozonisation. Sclareols2Sm(49) and manooP (51) have the same carbon skeleton as agathic acid. By converting the various di-and tri-cyclic diterpenes mentioned above into identical end- products still containing the respective asymmetric centres it could be shown that they all possess the same configuration at the A/B ring junction.Further- more the rings A and B of manool have been shown to possess the same configuration as the correspond- ing rings in lanosterol and hence in ~holesterol.~~ Diterpenes with an opposite configuration of rings A/B have been found only in recent years e.g. eperuic acid cafestol. In contrast with other diterpenes the resin acids of the abietic acid type are characterised by a carbon skeleton consisting of four isoprene units connected irregularly. Biogenetically this carbon skeleton may however be derived47 by cyclisation and rearrange- ment from an aliphatic precursor with a regular tetraisoprene chain such as geranylgeraniol (50) (or geranyl-linalool)* (cf.50 +51 -+45 -+44)(p. 347). In the last few years several tricyclic and especially tetracyclic diterpenes have been discovered e.g. vouacapenic acid and cafestol which can only be considered as members of the terpene family on the basis of the biogenetic isoprene rule. These com- pounds are not discussed here. It has also been considered best to disregard in this Lecture the terpenoids (i.e. compounds containing a number of carbon atoms non-divisible by 5) and the terpene-alkaloids. TRITERPENES The aliphatic triterpene squalene first isolated in 1916 by Ts~jimoto~~ from the liver oil of sharks has been the object of extensive investigations by Heilbron and his collaborators.68 Several structures were discussed among others the symrnetri~al~~ one (52) which in 1931 was proved synthetically by Karrer and his sch001~*~~~ by condensation of two mols.of farnesyl bromide. Of the reactions of squalene I shall only mention the acid-catalysed cyclisation,72 which starts simul- taneously from both ends and leads to what possibly represents a mixture of isomeric and stereoisomeric * Geranylgeraniol and geranyl-linalool have been prepared synthet~cally~~ and the latter has recently also been found in Nature.66 Ruzicka Bernold and Tallichet Helv. Chim.Acta 1941 24 223. 62 Ruzicka and Janot Helv. Chim.Acta 1931 14 645. 63 Ruzicka Seidel and Engel Helv. Chim. Acta 1942 25 621. 64 Hosking and Brandt Ber. 1935 68 1311. 65 Ruzicka and Firmenich Helv.Chim. Acta 1939 22 392. 66 Demole and Lederer Bull. SOC.chim. France .1958 1128. 67 Tsujimoto J. Znd. Eng. Chem. 1916 8 899. 6a Heilbron et al. J. 1926 1630 3131 3136; 1929 873 883; 1930 2546. 69 Kamm Dissertation Liverpool 1925; cf. Simonsen "The Terpenes," Cambridge Univ. Press 1957 Vol. IV p. 20. 70 Karrer Helfenstein Pieper and Wettstein Helv. Chim. Ada 1931 14 435. 71 Karrer and Helfenstein Helv. Chim.Acta 1931 14 75. 72 Harvey Heilbron and Kamm J. 1926 3136. NOVEMBER 1959 349 tetracyclosqualenes(53). The mechanism is the same explained by assuming that the triterpene molecule as that mentioned for the formation of drimenol(32). is partially split in two halves across ring c. The In squalene a novel structural pattern of the poly- three naphthalene compounds of formula (57) repre-terpenes is first encountered two regular tri-isoprene sent the rings A and B of the triterpene and sapotalene chains (farnesol chains) joined symmetrically tail to (58) represents the rings D and E.tail. An analogous pattern occurs in the aliphatic tetraterpene ly~opene~~ (54) and its bicyclic analogue carotene73 (55). In lycopene two regular four-isoprene chains (phytol chains) are arranged tail to tail. The structure of these two polyenes was pro- posed by Karrer. Here again the isoprene rule furnished a useful clue for the arrangement of the methyl groups along the polyene chain. That these carbon skeletons were indeed correct could then be proved by synthetical and degradative studies.The elucidation of the structure of pentacyclic triterpenes a group to which most of the triterpenes occurring in Nature belong was greatly facilitated by a systematic study of their dehydr~genation.~~ We shall limit ourselves here to a discussion of the results obtained with p-amyrin and oleanolic acid. Both compounds as well as the great majority of the other pentacyclic triterpenes yielded two groups of dehydrogenation prod~cts,'~ namely methyl-substi- tuted picene and naphthalene derivatives the struc- ture of which is given in formulae (56) (57) and (58). A hydrogenated picene framework (e.g. 59) could therefore be considered as the carbon skeleton of the pentacyclic triterpenes. The presence of naphthalene derivatives among the dehydrogenation products was cc R Me (56) LIe (57) R= H,Me,or OH HO Already in 1932 when the structure of some of the dehydrogenation products was not yet completely elucidated a triterpene carbon skeleton (59) was considered75 which differed from the final skelet on76177 (60)only in the position of two methyl groups.We were then somewhat worried by the great divergence in the evaluation of dehydrogenation results in the triterpene and in the steroid field. The carbon skeleton of cholesterol accepted at that time (61) could only be related to chrysene (62) one of the dehydrogenation products obtained by Diels in 1927 by assuming that a profound and inexplicable trans- formation of the original carbon skeleton had taken place during the dehydrogenation.The dramatic turn in the elucidation of the steroid structure during 1932 came just in due time. The well-known work of Bernal reminded Rosenheim and King of Diels's dehydrogenation results and so the correct skeleton (63) of cholesterol could readily be deduced. In Zurich this development was naturally wel- comed as a brilliant rehabilitation of the dehydro- genation method which played such a predominant part in the elucidation of sesquiterpene and polyterpene structure. 73 Karrer Helfenstein Wehrli and Wettstein Helv.Chim. Acta 1930 13 1084. 74 Ruzicka and van Veen Rec. Trav. chim.,1929,48 1018; 2.physiol. Chem. 1929 184 69. 75 Ruzicka Briingger Egli Ehmann Furter and Hosli Helv. Chim.Acta 1932 15 431. 76 Haworth Ann. Reports 1938 34 338. 77 Ruzicka Grob and van der Sluys-Veer Helv. Chim.Acta 1939 22 788. Dehydrogenation could have had a role of similar importance in steroid chemistry as early as 1927 if the steroid structures deduced by Wieland and Windaus from the manifold degradation results had not been so generally accepted as to mislead chemists into neglecting the study of Diels's second dehydro- genation product C,,H,,. In reversal of the route followed in the triterpene field the formula (64)of was successively added. Q-\M-fl && + 2c /\ \/ (!!,*",a) ' \ '\{ \ ',f HO 840 && (651 (661 &sH,61 (63) (W PROCEEDINGS tural elucidation of all these compounds was greatly facilitated by the successful interconversion of various representatives.The first step was the con- version of oleanolic acid into /?-am~rin.'~ There followed the analogous conversions of ursolic acid into a-amyrin and of betulin into lupeol. Thus three main sub-groups could be discerned the p-amyrin (or oleanolic acid) the a-amyrin (or ursolic acid) and the lupeol sub-group. A series of other sub-groups this hydrocarbon was deduced from the final formula of the steroids and then confmned by synthesis. It is of more than merely historical interest to demonstrate with this example how difficult it can be to co-ordinate* the multitude of degradation Of pO1ycyclic without having an independent indication of the carbon skeleton or at least of the ring system.Returning now to the structual elucidation of triterpenes 1 should like to stress the fact that the transition from the preliminary to the final formula (60)was not achieved in a single step mainly because of the difficulties encountered h establishing the exact Position of all of the eight methyl groups of P-amYrin. 'r'hus the Presence of the gem-dimethyl group at Position 4 of ring A (60)Was deduced from the isolation of picene and naphthalene derivatives carrying either a hYdroxYl Or a methyl GOUP at POSi- tion 2 (56 and 57). This result indicates that in the original triterpene the hydroxyl group at position 3 gives rise to the phenolic hydroxyl group or else indirectly through a Waaer-Meemein rearrange-merit to the methyl goup in position 2 of the aromatic compounds (56) and (57).The number of pentacyclic triterpenes isolated from natural sources rapidly increased. The struc- '4 \ '' '. . \ HO (67) (681 ourom laboratory in Ziirich thanks especially to Jeger's work as well as many other research teams particularly in Great Britain (B~~~~, Heilbron Jones Kon Spring and others) have taken part in the structural elucidation of the various triterpenes. 1949 the correct stmctural formula of E-amyrin (66) was established,79 whereas the structure of lupeol proposed in 194380 required a retouch in the position of a methyl group81 (67). me carbon skeletons of the three main sub-groups of the penta- cyclic triterpenes (65) (66) and (67)differ from one another and from the skeleton of pentacyclosqualene (68) only in ring E.An explanation why this should be so is given below in the discussion of the biogenesis of these pentacyclic triterpenes. Once the structural features had &en established attention was turned to the study of the stereochem- istry. A step of great importance was the correlation of the configuration at the A/B ring junction in different sub-groups of pentacyclic triterpenes di- terpenes and steroids by degradation to compounds of known relative and absolute configuration.82 * Confusion went so far that in the degradation of cholesterol and the bile acids products arising from the de- gradation of one ring were in some cases formulated as degradation products of another ring.Ruzicka and Schellenberg Helv. Chim. Acra 1937 20 1553. 70 Meisels Jeger and Ruzicka Helv. Chim. Acta 1949 32 1075. Ruzicka and Rey Helv. Chim. Acta 1943 26 2143. 81 Ames HalsaII and Jones J. 1951 450. 8z Cf. Simonsen "The Terpenes," Cambridge Univ. Press 1957 Vol. V pp. 428-508. NOVEMBER 1959 Later Barton’s method of conformational analysiss3 Klyne’s method of molecular rotation,84 and Prelog’s method of asymmetric synthesiss5 were decisive especially for the determination of the configuration at those asymmetric centres which were not easily amenable to the degradation method. A JJ... -n c It is now customary to illustrate the result of the correlation of different sub-groups of triterpenes with each other (65a) (66a) (67a) and with cholestanol (69) by the use of analogous configura- tional formula=.The present day notions of configuration and con- formation did not of course arise suddenly but evolved step by step at first in the steroid and then in the triterpene field. To illustrate the beginnings some examples may be recalled. In 1933 the anti-trans-configuration of the cholestane ring system was proposed.s6 In 1934 the configuration of the hydroxyl group in the four stereoisomeric saturated sterols cholestanol epicholestanol coprostanol and epi- coprostanol was po~tulated.~~ In 1938 the chair con- formation of ring A in these four stereoisomers was deduced from the relative ease of saponification of the corresponding acetates.ss If ring A were present in the boat conformation the relative steric hindrance in position 3 would be the opposite of the experi- mental results.The configurations and conformations so deduced have since been universally accepted on the basis of a larger body of chemical and physical evidence. The considerations which led to the above- mentioned configurational and conformational de- 351 tails may be regarded as the introduction into the steroid-triterpene field of what was later to be called conformational ana1y~is.s~ After the structure of the principal pentacyclic tri- terpenes had been elucidated the chemistry of the tetracyclic triterpenes assumed predominance. The most important and striking result was that practic- ally all the tetracyclic triterpenes (the exception was onocerin) present the cyclopentenophenanthrene ring system typical of the steroids.These triterpenes which may indeed be called the “steroidal triter- penes,” brought the triterpenes and the steroids into even closer relation than they were before. Three sub-groups of “steroidal triterpenes” are known all possessing the same carbon skeleton and differing only in the stereochemistry at particular centres. The typical representatives of these sub- groups are lanosterol euphol and tirucallol. The fundamentally important features of the molecular architecture of the steroidal triterpenes were first established in the case of their most easily accessible representative lanosterol. This steroidal triterpene which was encountered in sheep-wool fat and in yeast has the same configuration at its seven asymmetric centres as cholestanol.Originally this was of course not known just as nothing was known of the role of lanosterol in the biogenesis of chol- esterol. Even so lanosterol attracted the interest of various research teams who contributed to the elucidation of its struct~re.8~~~~ What I may call an exciting situation was reached at the “finish” in 1952 when it had to be decided which of the two formula (70) and (71) differing only in the position of the long side chain was right. The carbon skeleton of (71) with the side chain in position 15 is in accordance with the isoprene rule whereas the skeleton of the correct formula (70) which was independently proved* by degradationsg * The methods of conformational analysis and of molecular rotation did not permit an unequivocal decision.s2 R3 Barton Experientia 1950 6 316.84 Klyne J. 1952 2916; Klyne and Stokes J. 1954 1979. 85 Prelog et al. Helv. Chim.Acta 1953 36 308 320. Ruzicka Furter and Thomann Helv. Chim.Acta 1933 16 327. 87 Ruzicka Brungger Eichenberger and Meyer Helv. Chim.Acta 1934 17 1407. 88 Ruzicka Furter and Goldberg Helv. Chim.Acta 1938 21 498. 89 Voser MijoviC Heusser Jeger and Ruzicka Helv. Chim.Acta 1952 35 2414 and preceding papers. Barnes Barton Fawcett Knight McGhie Pradham,and Thomas Chem. andlnd. 1951,1067 and preceding papers and by X-ray analysis,91 cannot be completely dissected into isoprene units.A welcome confirmation of all configurational details (70a) was provided by the transformation of cholesterol into lanoster01.~~ Lanosterol may there- fore be called trimethylcholestadienol or trimethyl- zymosterol since the two double bonds in lanosterol and zymosterol occupy the same position in the respective carbon skeletons. U Me H HO (72) Eupholg4 (72) and tirucallols5 (73) both show the same configuration as cholestanol(69) at positions 3 5 and 10. The configuration of tirucallol at positions 13 14 17 and 20 is enantiomeric with those of cholestanol. Euphol and tirucallol differ from each other only in the configuration at position 20. The structure of lanosterol was of fundamental importance for two reasons first as a guiding principle in the elucidation of the biogenesis of cholesterol; and secondly as an initiator for the revision of the isoprene rule which led to the pro- posal of a plausible reaction mechanism for the biogenesis of the tetracyclic and pentacyclic triter- penes.BIOGENESIS OF TRITERPENES In his Harvey Lecture in 1952 Blochg6 discussed the state of the research on the biogenesis of cholesterol at that time. The vital questions were (a)whether squalene actually was an intermediate in the experimentally proved biosynthesis of cholesterol PROCEEDINGS from acetic acid and (b)what reaction mechanism governed the conversion of squalene into cholesterol. Since Channon’s biochemical investigations9’ in 1926 the possibility had been considered that squalene may be a biological precursor of cholesterol.After the formulae of the two compounds had been established Robinsong8 advanced a hypothetical scheme (74) for the conversion of squalene into cholesterol which required the loss of three methyl groups. a HO’ (76) An experimental test of this or any other scheme required the systematic degradation of cholesterol prepared by incubating 14CC-labelled acetic acid with rat-liver preparations in order to establish the origin of the 27 carbon atoms of cholesterol i.e. their derivation from the methyl group (marked 0)or from the carboxyl group (marked X) of acetic acid. The formation of an isoprene unit from acetic acid is represented by the simplified scheme 0‘x-0-x.0’ The results obtained in 1952 by stepwise degrada- tion of biosynthesised cholesterol in Bloch’s labora- tory provided unequivocal evidencesg that the carbon atoms in the side-chain of cholesterol are arranged in accordance with the isoprene rule (77). Cornforth Hunter and PopjaklOO simultaneously established also by stepwise degradation the origin of the carbon atoms in ring A and of C(19).All these results were compatible with Robinson’s cyclisation scheme (74). 91 Curtis Fridrichsons and Mathieson Nature 1952 170 321 ;Fridrichsons and Mathieson J. 1953 2159. 92 Barnes Barton Cole Fawcett and Thomas Chem. and Ind. 1952 426; Barnes Barton Fawcett and Thomas J. 1953 576. 93 Woodward Patchett Barton Ives and Kelly J.Amer. Chem. SOC.,1954 76,2852; J. 1957 1131. B4 Arigoni Viterbo Dunnenberger Jeger and Ruzicka Helv. Chim. Acta 1954,37 2306; Barton McGhie Pradhan and Knight J. 1955 876. 95 Arigoni Jeger and Ruzicka Helv. Chim. Acta 1955 38 222. 96 Bloch The Harvey Lectures 1952/3 Series 48,p. 68 Academic Press Inc. New York. B7 Channon Biochem. J. 1926 20 400. 98 Robinson Chem. and Ind. 1934 53 1062. B9 Wursch Huang and Bloch J. Biol. Chem. 1952 195 439. Iq0 Cornforth Hunter and Popjak Biochem. J. 1952 54 597. NOVEMBER 1959 However in the same year Bloch101*102 found that carbon atoms C(lj) and C,, did not originate from the carboxyl group of acetic acid-as required by (74)-but from the methyl group. Scheme (74) thus became untenable.* Woodward and Blochlo2 there- upon made a new proposal (75) which explained all available experimental results and was later found to indicate the correct origin of all the carbon atoms of cholesterol.103 This scheme was based on the structureoflanosterol (76) whichcouldthen be looked upon as an intermediate between squalene and cholesterol and it assumed two 1,2-methyl shifts or one 1,3-methyl shift.A further advantage of scheme (75) consists in the fact that it explains why lano- sterol is not constituted in accordance with the “classical” isoprene rule. Biogenetic Isoprene Rule.-This brilliant deduction encouraged us in Zurich to look for ascheme which could also explain the hypothetical cyclisation of squalene to pentacyclic triterpenes.4 Initially we proposed a scheme without stereochemical considerations.The biological cyclisation of squalene was considered to be initiated by the attack of a formal cation OH+. Thereupon cyclisation should proceed synchronously to completion. In this 1953 formulation the formal cation (78) which leads to lanosterol by hydrogen and methyl shifts could be converted by a rearrangement involving Cq16)to the formal cation (79). A further cyclisation of the latter to (80) and elimination of hydrogen would produce lupeol. The intermediate (80) could in turn rearrange to (81) and thus give rise to /I-amyrin. The migration of a methyl group in (81) would lead to the formation of a-amyrin. It should be emphasised that these biogenetic schemes are based on generally accepted reaction mechanisms.The proposed rearrangements and methyl shifts follow the rules of the Wagner-Meerwein re-arrangement. This also provides an explanation of the structural variations of ring E in the triterpenes (65),(66) (67) and (68) mentioned above. The fact that not only the structures of lanosterol and of the three types of pentacyclic triterpenes but also the structures of mono- sesqui- and di-terpenes can be derived in a similar manner from aliphatic precursors led us to propose a more general defini- tion for the isoprene rule.47 The revised version was called the “biogenetic” isoprene rule. In its terms terpenes are compounds formed by combination of isoprene units to aliphatic substances such as geraniol farnesol geranylgeraniol squalene and others of a similar kind and can be derived from these aliphatic precursors by accepted cyclisation and in certain cases by rearrangement mechanisms.t According to this definition compounds such as eremophilone and lanosterol that do not follow the classical isoprene rule are also to be considered terpenes. Since 1953 many compounds (e.g. euphol tirucallol friedelin and many others) have been added to those that do not follow the classical iso-prene rule but comply with the biogenetic one. The biogenetic isoprene rule can therefore also be con- sidered as a useful working hypothesis for elucidation of the structure and biogenesis of terpenic com- pounds. * It should be pointed out that the conversion of squalene into cholesterol according to scheme (74) cannot be formulated by a plausible reaction mechanism.t Changes in the oxidation degree (hydrogenation dehydrogenation oxidation) are of course permitted and do not affect the biogenetic isoprene rule. Io1 Bloch Helv. Chirn. Acta 1953 36,1611. lo3Cf. Popjak Ann. Rev. Biochern. 1958 27 533. Io2 Woodward and Bloch J. Amer. Chem. SOC.,1953 75 2023. PROCEEDINGS We next turned our attention to the search for a plausible a priori derivation not only of the struc- ture but also of the configuration of terpenes by the use of accepted reaction mechanisms and of the bio- genetic isoprene rule. Thanks to the studies of Eschenmoser and Arigoni this search was successful for all groups of triterpenes.lo4 In the light of our present knowledge it should be stressed however that a similarly straightforward deduction of con- figurational details is only exceptionally possible for mono- sesqui- and di-terpenes.It appears that the stereospecificity of terpene cyclisation diminishes in general with decreasing molecular weight. As yet it has not been possible to provide an exact explanation for this empirical statement. The tetra- and penta-cyclic triterpenes known to- day can be derived from 17 basic representatives,* which may differ from each other in the carbon skeleton in the position of a double bond or in con- figuration. The derivation from squalene of these basic representatives with all their structural and configurational details rests on the assumption of a few reasonable postulates (1) The cyclisation of squalene takes place in the all-trans-configuration and in a well-defined sequence of chair and boat conformations.(2) The transformation from squalene to the triterpenes proceeds according to the rules of anti-planar (= anti-parallel) cationic 1,2-addition 1 ,Zrearrangement (1 ,Zshift) and 1 ,Zelimination. (3) All steps on the route from squalene to the final product proceed in a non-stop reaction i.e. no intermediates produced by neutralisation of the formal cationic charge should occur. Natural squalene which was biologically trans- formed into lanosterol is indeed the all-trans-isomer.lo5 It is interesting that the same isomer allows the derivation also of all other basic triterpene repre- sentatives provided that the enzymes accomplish the important task of folding the squalene in the con- formation required for cyclisation so that the reaction can proceed rapidly and uniquely at physiological PH.To illustrate the efficacy of this biogenetic scheme it may be recalled that for instance 256 stereo-isomers are possible for the p-amyrin structure and as many as 1024 for a-amyrin. Of course the reaction mechanism can only account for the production of a racemate. In Nature it is the enzyme system that ~ ~ ~~~~~~ is responsible for the formation of one enantiomer of this racemate. In the following section the biogenetic derivation of the various triterpene representatives is discussed.The latter are grouped according to the sequence of chair and boat conformations of all-trans-squalene required for their formation. The intermediates pro- duced in the cyclisation lead either directly or in most cases after rearrangement to the individual triterpene representative. The biogenetic reactions are arranged in five charts (1-5). The numbering of the carbon atoms in the formulae in the charts corresponds to that of squalene (82) (89) (103) and differs therefore from the commonly used numbering of the polycyclic tri- terpenes (the latter has been used in the other parts of this Lecture). The large dots in the formulae represent methyl groups the smaller dots hydrogen atoms. The 1,Zshifts (and rearrangements) and the hydrogen eliminations are indicated in detail in order to permit the reader to follow easily the antiplanar mechanism.The ionic intermediates on this route are formu- lated as bridged (non-classical) cations but this is merely a graphic symbol for the stereospecificity of the cyclisation of squalene. Cyclisation of all-trans-Squalene in Chair-Boat-Chair-Boat Conformational Sequence (82).-The biogenesis of lanosterol (Chart 1) requires this con- formational sequence of all-trans-squalene. The boat conformation of ring B in contrast to its chair con- formation in squalene in Chart 2 (p. 356) is the condition for the formation of the configuration of the four asymmetric centres in ring D and the long side-chain of lanosterol.For the same reason the boat conformation of ring D in the intermediate (83) must change to a chair conformation (84) before the formation of the intermediate (85). Tsuda et d106 have recently reported on the constitution of a new sterol from algae sargasterol (88) which differs from the normal sterols in having the enantiomeric configuration in the long side-chain. The formula of the hypothetical triterpene 20-iso- lanosterol? (87 =87a) from which sargasterol is sup- posed to originate can be deduced from the inter- mediate (83) which cyclises to the intermediate (86). This final bridged cation leads to triterpene (87) by the same series of transformations as in the case of lanosterol. * The term “basic representative” is meant to indicate those triterpenes in which the sum of the number of carbon rings and of double bonds (actual and potential) is equal to six.In 1955 14 such basic representatives were known but 6-amyrin was overlooked in our paper.lo4 Since then three new representatives have been found (glutinone bauerenol and hydroxyhopanone) which all conform to the biogenetic isoprene rule. t Normal sterol numbering. This hypothetical triterpene if found in Nature would be the eighteenth basic triterpene representative. lo4Eschenmoser Ruzicka Jeger and Arigoni Helv. Chim. Acta 1955 38 1890. lo5Nicolaides and Laves J. Amer. Chem. Soc. 1954 76 2596. lo6Tsuda Hayatsu Kishida and Akagi J. Amer. Chem. Soc. 1958 80 921. NOVEMBER 1959 355 a 1 The cyclisation of squalene to lanosterol has been studied in great detail and the results provide an excellent proof of the postulates proposed in 1953 and 1955 in so far of course as they are amenable to experimental control.(a) Tchen and Blo~h~~~~~~~ furnished the proof that cyclisation of squalene to lanosterol requires aerobic conditions and is consequently triggered by some- R oammarenediot (971 PROCEEDINGS (c) Maudgal Tchen and Bloch,log as well as Cornforth Cornforth Pelter Horning and PopjakllO showed that displacement of the two central methyl groups actually takes place by two single 1,2-shifts and not by one 1,3-shift. Cyclisation of all-trans-Squalene in Chair-Chair-Chair-Boat Conformational Sequence (89) .-This second cyclisation mode which leads to 15 basic w Damrnarenedial I Euphd CHART2.thing like (OH)+. Only when the cyclisation is carried out in an atmosphere containing lS0,the IS0 appears in expected concentration in the hydroxyl of ring A. (b) Tchen and Blo~h~~~*~~~ were also successful in proving that conversion of squalene into lanosterol must be a non-stop reaction. When the experiment is carried out in the presence of D20no deuterium is detectable in the final product. tetracyclic and pentacyclic triterpEne representatives is subdivided into three Charts (2 3 and 4). It should be recalled that lanosterol and tirucallol are enantiomeric at the four asymmetric centres in ring D and the long side-chain. The reaction sequence (82) -+(83) -+ (84) -+(85) in Chart 1 can therefore be considered as a parallel to the sequence (89) + (90) +(91) -f (92) in Chart 2.The intermediate (90) 107 Tchen and Bloch J. Amer. Chem. SOC.,1956 78 1516. 108 Tchen and Bloch J. Biol. Chem. 1957 226 931. 109 Maudgal Tchen and Bloch J. Amer. Chem. SOC.,1958 80 2589. Cornforth Cornforth Pelter Horning and Popjak Proc. Chem. Soc. 1958 112. NOVEMBER 1959 undergoes a rearrangement to the bridged cation (93) from which euphol can be derived. The two dammarenediols differing from each other only in the configuration of the long side chain are produced directly from the intermediates (90) and (91) respec-tively by antiplanar addition of OH-. In their biogenesis euphol and sargasterol stand in the same relation to each other as tirucallol and lanosterol.lupeol r 1 exist in two structural types. One type is charac- terised by the presence of the gemdimethyl group in ring E (cf. Chart 4) whereas in the other type ring E carries two isolated methyl groups (Chart 3). In two representatives of the latter type (taraxasterol and $-taraxasterol) the methyl group at position 21 has a-configuration; in the other two representatives [a-amyrin and bauerenollll (loo)] its configuration \& HO Y -Taraxasterof Bauerenol a-Amyrin CHART 3. All the pentacyclic triterpenes are derived from the non-classical cation (91) by cyclisation of the long side-chain in its boat conformation (Chart 3). The intermediate (96) so produced gives rise to lupeol by elimination of hydrogen.On the other hand the formation of all the triter- penes with a six-membered ring E requires the re- arrangement of the same ring E in the intermediate (96) to a chair conformation (97). These triterpenes ll1 Lahey and Leeding Proc. Chem. SOC.,1958 342. is p. This difference in configuration requires two additional intermediates (98) and (99). Chart 4 contains the pentacyclic triterpenes with the gem-dimethyl group in ring E. Three basic repre-sentatives of this type are derived from the bridged cation (97) without rearrangement by hydrogen shifts and a final hydrogen elimination. Thus germanicol 8-arnyrin112 (101) and /3-amyrin are pro-duced. They all have the same carbon skeleton and 112 Musgrave Stark and Spring J.1952 4393. PROCEEDINGS Frieda1in Glut i none Taraxcrol Ccrmanicol -Amyrin p -Amyrin CHART4. (1051 Hyd foxyhoponone CHART5. NOVEMBER 1959 differ only in the position of the double bond in ring E D and c respectively. The formation of the other three basic representatives taraxerol glutin- one1l3(102) and friedelin requires shifts of methyl groups in addition to further hydrogen shifts. A simple general rule should be mentioned here. It states that the configuration at the D/E ring junction in pentacyclic triterpenes is trans (in fact anti-trans as all other ring junctions) if the double bond remains in ring E (lupeol and the taraxasterols); on the other hand if the double bond migrates from ring E to ring D c B or A (cf.Charts 3 and 4)the D/E ring junction is necessarily cis. Cyclisation of all-trans-Squalene in Chair-Chair- Chair-Chair-Boat Conformational Sequence (1 03).-As yet only one triterpene is known requiring this conformation of all-trans-squalene namely hydroxy- hopanone114 (1 09," whose formation proceeds with- out any rearrangement of the intermediate (104). Thus hydroxyhopanone and also the two dam-marenediols ambrein and onocerin contain in their carbon skeleton the unchanged squalene chain. Cyclisation of Squalene simultaneously from Both Ends.-Two natural triterpenes ambrein (106) and onocerin (107) are derivable from squalene by a Me Me mechanism which-allowance being made for stereo- chemical details-formally recalls the previously dis- cussed acid-catalysed cyclisation of squalene to the mixture of tetracyclosqualenes (53).Onocerin is a dihydroxytetracyclosqualene.It may be derived by a simultaneous double attack of OH+ at both ends of all-trans-squalene with these ends folded in the chair-chair conformation. If we disregard the nature of the cyclisation initiator (possibly H+) the last- mentioned mechanism applies also to the biogenesis of the bicyclic moiety of ambrein. Mevalonic Acid (108).-In this Lecture we cannot deal with the interesting details of the conversion of lanosterol into the terpenoid cholesterol. We should however consider the route leading from acetic acid to squalene which is of course more pertinent to our theme.Several research teams studied this problem intensively. It could be assumed that the first step is condensation of acetyl coenzyme A with acetoacetyl coenzyme A but the exact nature of the product remained unknown. Thanks mainly to Folkers's it has been recognised that this product is mevalonic acid. The biosynthesis of mevalonic acid follows the simplified reaction sequence presented in Chart 6. c,H3 + CH,-COSCoA co I \CH2-COSCoA CH CH2-C0,H \3p/ /"\ H0 CH,-CH;OH (108) CH\3/ CH,-CO,H -'c /\ HO CH2-COSCoA (IO8a) CHART 6. Mevalonic acid after an appropriate transforma- t i0n116J17 gives rise by self-condensation to terpens t e.g.,to squalene (108a -+109). In this transformation the carboxyl group is lost as carbon dioxide (p.360). In biological experiments with [2-14C]mevalonic acid119J20 and with 5,5-ditritiomevalonic acid,121 considerable information has been provided on the mechanism of its self-condensation to squalene (109) and cholesterol120 (110) both hydrogen atoms at position 5 are preserved in the process and in the four central isoprene units of the resulting squalene (109) and cholesterol (110) the radioactive label is rigorously localised. Thus the methylene group in position 5 of one molecule of mevalonic acid con- denses directly with the methylene group in position 2 of the next molecule. Whether the labelling at the * The configurations at positions 17 and 21 are probable but not proved. t Lynen117 has reported the isolation of farnesyl pyrophosphate.Earlier it had been found1ls that farnesic acid is a by-product of the biogenesis of lanosterol. 113Beaton Spring Stevenson and Stewart Tetrahedron 1958,2,246; Chapon and David BUN. SOC.chim. France 1953 333. 114 Schaffner Caglioti Arigoni Jeger Fazakerley Halsall and Jones Proc. Chem. SOC.,1957 353. 115 Wolf Hoffman Aldrich Skeggs Wright and Folkers J. Amer. Chem. SOC.,1956 78 4499. 116 Chaykin Law Phillips Tchen and Bloch Proc. Nut. Acad. Sci. U.S.A. 1958 44 998. 117 Lynen Henning Bublitz Sorbo and Kroplin-Rueff Biochem. Z. 1958 330 269. 118 Dituri Rabinowitz Hullin and Gurin J. Biol. Chem. 1958 229 825. Cornforth Cornforth Popjak and Gore Biochem. J. 1957 66 10 P; 1958 69 146. lZ0Isler Ruegg Wiirsch Gey and Pletscher Chimia (Swift.),1957 11 167.lZ1 Amdur Rilling and Bloch J. Amer. Chem. SOC.,1957 79 3646. two ends of squalene is specifically limited to the one methyl group only still remains to be established. A partial answer to this question has been pro- vided by the experiments on the biosynthesis of triterpenes in plants carried out recently for the first time by Arigoni.lZ2 From soya-beans grown on a culture medium containing [2-14C]mevalonic acid the radioactively labelled soyasapogenols were isolated. The degradation of soyasapogenol A (1 1 1) proved that the radioactive label is not distributed (108a) HO *’ CHiOH (I I I) over both gem-carbon atoms of ring A but is present in the methyl group only. A corresponding study of the distribution of the radioactive labelling at the PROCEEDINGS other end of the molecule will have to await the bio- synthesis of a triterpene with an oxygen function on one of the ring E methyl groups.The results obtained in the study of the biosyn- thesis of squalene cholesterol and soyasapogenol A starting from labelled mevalonic acid can be con- sidered as further support for the plausibility of the hypothetical mechanism advanced to explain the stereospecificity of the biogenesis of triterpenes. Among the biological syntheses of natural organic substances studied up to the present that of the tri- terpenes takes a special place. In no other group of natural compounds has it been possible to rationalise the seemingly confusing multiplicity of structural and configurational details by deducing them on the basis of reasonable postulates and of the principles of organic chemistry.That such a rationalisation is possible must be ascribed to the peculiarity of the carbon skeleton of the polycyclic triterpenes and to the fact that this skeleton is derived from a well- defined precursor with the same number of carbon atoms. In this historical review we have encountered biochemical formulations which violate the rules of organic chemistry. The biogenetic results of the last years-not only in the triterpene field-have shown that such formulations are not justified and must therefore be discarded. Further these results allow the statement that biological reaction mechanisms are governed by the same laws as our “unnatural” laboratory reactions or at any rate that proposals of “irregular” biochemical reaction mechanisms should be considered with great critical reserve.* * The fact that biological reactions can take place at non-activated carbon atoms does not contradict this statement.The strong link that connects the substrate to the enzyme may exercise the same activating effect as is responsible for instance for Prelog’s transannular reactions in medium-sized rings. 122 Arigoni Experientia 1958 14 153. COMMUNICATIONS Synergic Effects in the Solvent Extraction of Uranium By H. IRVING and D. N. EDGINGTON (INORGANIC LABORATORY, CHEMISTRY OXFORD) URANIUM(VI) nitrate can be readily extracted from nitric acid as a solvated complex U02(N0,),,2S (S = tri-n-butyl phosphate tri-n-butylphosphine oxide etc.).Its solvent extraction can also be effected after it has reacted with chelating agents (HX) such as 1,1,1 -trifluoro-3-2’-thenoylacetone (TTA) 8-hydroxyquinoline cupferron mono- and di-alkyl phosphoric esters which give formally uncharged complexes UO,X,. Blake er aZ.l have recently re- ported that when a dialkyl hydrogen phosphate (RO),PO.OH is used in conjunction with certain neutral organophosphorus reagents such as (RO),PO (RO),RPO (RO)R,PO and R,PO (R = n-butyl) the extracting power of the mixture exceeds the sum of the extracting powers of the components. The effect of the neutral reagent increased in the order Blake Baes Brown Coleman and White Second United Nations Conference on the Peaceful Uses of Atomic Energy Paper P/1550.NOVEMBER 1959 361 ~~~ ~ ~~ ~ shown. The authors state that “this synergistic en- results were obtained by equilibrating mixtures of hancement of the extraction coefficient seems limited 0.02hl-nA (HX) and 0.02hl-tri-n-butyl phosphate to dialkyl phosphoric acid-neutral reagent com- (TBP) or tri-n- butylphosphine oxide (TBPO) in binations” and referring to the elements V Th Al cyclohexane with 0.01 N-nitric acid containing rare earths Fe and U which they had studied 1.025 x 1O4wuraniumV1 as the tracer 233U.When “uranium is the only metal which extracts syner- 20% of the TTA had been replaced by tributyl phos- gistically.” phate there was a maximum synergic enhancement of is made only 0.003~ We feel that these statements are too sweeping for qJ1OOO-foId.If O-O~M-TTA in our consideration of the problem of synergic en- tributyl phoephate there is an enhancement of hancement of solvent extraction suggests that this %5000-fold. Similar experiments using tributylphos- phine oxide instead of the phosphate show an en- phenomenon may appear in a number of systems provided that (i) one of the active solvents is capable hancement of >10,000-fold when 10% of theTTA of neutralising the charge on the metal ion prefer- has been replaced by the oxide. ably by forming a chelated complex (ii) the second The composition of the extracted species has been active solvent is capable of displacing any residual co- shown to be UO,X,,TBP and U0,X2,(TBPO) ordinated water from this formally neutral metal respectively.complex and rendering it less hydrophilic (iii) the Values of the mixed equilibrium constant second active solvent is not in itself hydrophilic and K = [UO,X,(S),l,CH+I.2/[UO2++1. [HXIo2[SI,” is co-ordinated less strongly than the first (chelating) (where u and a refer to the organic and the aqueous solvent and (iv) the maximum co-ordination phases respectively for S = TBP x = 1 and for number of the metal and the geometry of the ligands S = TBPO x = 3) at room temperature are nulo ‘3 are favourable. for tributyl phosphate and for tributylphos- Such considerations explain inter alia the effect of phine oxide. Walton5 gives values of K = \lo- excess of 8-hydroxyquinoline (HOx) in promoting for the extraction of uranium by TTA alone (x = 0).the extraction of Sr++ into chloroform as Goble and Maddockc have also noticed a synergic Sr(0~),,2HOx,~the extraction of Mg++ from an effect in the solvent extraction of protoactinium from aqueous solution into a chloroform phase containing hydrochloric acid into mixtures of 2,4-dimethyl-and the pentan-3-01 and certain ketones ethers and nitriles. both 8-hydroxyquinoline and n-b~tylamine,~ observations made by Cunninghame et al. some The effect is comparatively small and must be years ago that the addition of tributyl phosphate had explained on entirely different premises. increased the extraction of praseodymium and neo- dymium by solutions of TTA in ben~ene.~ We are indebted to the U.K.A.E.A.for financial We have now obtained evidence of an exceptionally support. The results will form part of a Provisional large synergic effect for uranium in a system which Patent. does not involve a dialkyl hydrogen phosphate. Our (Received July 27th 1959.) Dyrssen J. Znorg. Nuclear Client. 1958 8 291. Umland and Hoffman Analyt. Chim. Ada 1957 17 241. Cunninghame Scargill and Willis A.E.R.E. C/M 215 (1954). Walton Barker and Byfleet A.E.R.E. C/R 768 (1951). ‘Goble and Maddock Trans. Faraday SOC., 1959 55 591. The Vapour Absorption Spectrum of Naphthalene at 3200 8 By D. P. CRAIG M. F. REDIES, J. M. HOLLAS and S. C. WAIT jun.* (DEPARTMENT OF CHEMISTRY UNIVERSITY COLLEGE LONDON and DEPARTMENT OF PHYSICAL CHEMISTRY SYDNEY UNIVERSITY) THEnaphthalene bands near 3200 8 have not been transition.We have measured the spectrum of comprehensively examined in the vapour since 1924l naphthalene vapour from room temperature to although particular spectral features have been 100°c using a Hilger large quartz spectrograph and st~died~9~ in connection with the assignment of the at high dispersion the 20-foot Ebert grating spectre-* Present address Carnegje Institute of Technology Pittsburgh Pennsylvania U.S.A. 1 Henri and de Laszlo Proc. Roy. SOC.,1924 A 105 662. Sponer and Nordheim Discuss. Fai-adaySoc. 1950 9 19. Knipe Sponer and Cooper J. Chern. Phys. 1953 21 376. graph previously described.* Octadeuteronaphtha- lene has also been photographed in the latter instru- ment.All the stronger bands in both spectrahavebeen accounted for and the electronic assignment deduced. The result is a confirmation of McClure’s5 assign- ment of the transition to the long-axis polarised species Bzu c A, which he based on studies of naphthalene imbedded in crystalline durene. The assignment of an electronic transition of a molecule as large as naphthalene solely from the vapour spectrum is we believe novel. We have found in the vapour spectrum just as McClure found5 in the durene solid solution that the system has interpenetrating sets of bands one set originating in a very weak electronically allowed 0-0 band now more precisely located at 32,020 cm.-l in the vapour another (the main set) in a ten times stronger 0-1 band induced by a non-totally sym- metrical vibration at 32,458 cm.-l and a third in a 0-1 band induced by another non-totally symmetrical vibration at 32,931 cm.-l.In the vapour spectrum these true and false origins are extended in sequences some of them long of 10 55 64 73 87 93 and 133 cm.-l and in short progressions of 501 702 987 and 1435 cm.-l. Photographs of the bands at low dispersion gave indications of a valuable diagnostic criterion. The bands that derived their intensity by vibrational perturbation showed doubled heads those that were electronically allowed had single heads. At high resolution the doubled heads proved to be separated by 2.4-3.0 cm.-l while the others remained unambiguously single. As is well known the rotational contour of a band depends on the direction of polarisation of the transi- tion so that in principle one can use the contour to identify the active axis.To do this it is necessary to know the expected contour types. Accordingly pure rotational contours have been computed (so far only on the basis of numbers of rotational transitions per unit of frequency i.e. without proper allowance for intensities) for long- and short-axis polarised transi- tions. The value of the asymmetry parameter in the ground state was found from the molecular dimen- sions determined by X-ray crystallography. For the upper state a value was used derived from the ground- state value by changes known to be reasonable from the study of other spectral features particularly the fact that there is no change of molecular symmetry and a small dimensional increase on electronic ex- citation.The calculations show that short-axis transi- tions give double-headed bands with separation of two or more wave numbers and long-axis transitions give bands showing either a single maximum or three PROCEEDINGS maxima depending on the as yet unknown intensity distribution. It is possible therefore to assign the allowed bands to the long-axis polarised species B, +-A andthe vibrationally induced bands to the short-axis vibronic species B, tA on the internal evidence of the vapour spectrum. McClure drew attention specifically to one principal feature of his analysis of the fluorescence spectrum of the mixed crystal naphthalene-durene which was in gross conflict with the rest of his inter- pretation.This was that the dominant apparently non-totally symmetrical ground-state frequency cor- responding to the perturbing 438 cm.-l frequency in the upper state was identified with a Raman-active frequency of about 512 cm.-l which gave a polarised Raman line. We now have several pieces of evidence that permit this difficulty to be disposed of by show- ing that the active frequency in the ultraviolet spectrum which appears as a “hot” band in absorp- tion is not the Raman active a 512 cm.-l but is another frequency of species b3,. For example the measured interval in the ultraviolet spectrum is close to 506-0 cm.-l which is sufficiently lower than any reported value of the Raman displacement (average reported value 512 cm.-l) to raise serious doubt that they refer to the same vibration.Again the high- resolution spectra displayed unambiguously that the 0-506 band is double-headed showing it to be short- axis polarised and establishing the b3s assignment for the 506 cm.-l vibration itself. Moreover the 0-506 band shows rotational perturbation; this we think might be expected if there is a second frequency of a symmetry near enough to be Coriolis coupled to it. The second frequency is of course the Raman active a 512 cm.-l. The upper state analogues of 512 and 506 cm.-l are 501 (a,) and 438 (b3,) respec-tively. Additional evidence for the existence of two ground-state vibrations in the region of 506-5 12 crn.-l in naphthalene and correspondingly near 49 1 cm.-l in octadeuteronaphthalene has been obtained and will be reported fully later together with full details of measured frequencies and assignments.The fluorescence of mixed crystals and of pure crystalline naphthalene can be satisfactorily inter- preted with these proposals. We are glad to thank Messrs. I.B.M. United Kingdom Ltd. for use of their 650 and 704 com- puters. One of us (J.M.H.) was supported by a British Celanese Research Studentship and one (S.C.W.) by a Fulbright Scholarship. (Received August 19th 1959.) King J. Sci. Instr. 1958 35 11 McClure J. Chem. Phys. 1954 1668. NOVEMBER 1959 363 Stretching Frequencies and Longitudinal Polarisabilities of Bonds By R.J. W. LEF~VRE (UNIVERSITY OF SYDNEY,N.S.W. AUSTRALIA) now available allow these properties to be connected empirically through a quantity Q = (1 /rz)(bLXY/M)~, in which r is the internuclear distance in A bLXythe longitudinal polarisability in units of lo-= c.c. and Xi the reduced mass of a bond X-Y. Straight-line relations exist between v (as cm.-l) and Q. Since both v and b vary somewhat with molecular environment many fairly similar equa- tions are possible one example being v = 9273Q -254. Insertion of appropriate values of bLXY enables v to be predicted as in Table 1. TABLE1. Bond C-H bLXY 0.064 v(cm.-l),calc. 2950 y(cm.-l) obs. 2962-285 3 c-c 0.10 745 See text C=C 0-28 1605 1616 in CH,:CCI,“ CrC 0.35 2240 2260-2 100 C=O 0.23 1750 1718 in Me,COb C-F 0.125 lo00 1048 in MeFC C-C1 0.32 710 732 in MeCIC C-Br 0.46 620 611 in MeBrC C-I 0.68 556 533 in MeTC a Corresponding Raman displacement at 1611 cm.-l (Thompson and Torkington4).1742 cm.-l in vapour (Hartwell Richards and Thomp- sod). Recorded by Randall et aL6 The ranges in v are quoted from bell am^;^ the single values of v are those reported for the specific molecules from which the b,=’s were extracted. Agreement appears SatiSfaCtOrY. Carbon monoxide with r = 1-14A and b = 0.26 fits the equation Pre- cisely v (calc.) and v (obs.) being 2143 cm.-l. Frequencies near 750 Cm.-’ are recorded for many polymethylene chains but are commonly ascribed to a rocking mode of the methylene groups; however Ramsay and Sutherland8 consider 802 cm.-l to be “probably the symmetrical C-C stretching fre- quency” in cyclohexane the compound from which Le F&vre and Le Fkvrel originally estimated b,c-c.The equation should also be usefuI in reverse for checking or forecasting the b values of bonds under examination by Ken effect-refractivity methods. As illustrations examples of cases where b,XY is already known and of others where it has yet to be deter- mined are given in Table 2. TABLE 2. Bond v(cm.-l) Y(& bLXY(calc.) bLxy (ex Kerr 0-H 3650-3590 0.97 0.06 effect) ? N-Hc-0 3400-3200 ca. 1100 1.01 1.43 O.OW.05 0.18 0.05 0.08 c=o 1720 1-22 0.22 0.23 C=N 1690-1 640 1.28 0.264l.24 ? CzN 2260-2240 1.15 0.30-0-29 ? c-c 802 1-54 0.12 0.10 c=c 1620 1 -34 0.29 0.28 N=N 1630-1 575 1.24 0.21“.195 ? NEN 2360 1 *09 0.26 0-24 C-F 1048 1.39 0.14 0.12 c-Cl 732 1.78 0.34 0.32 C-Br 61 1 1-94 0.45 0.46 c-I N-0 533 816751* 2.13 1-37 0.63 0*07,4.06 0.68 ? N=O 1681-1613* 1-22 0.22-0.20 ? N=O ca. 1400t 1.22 ca. 0.14 ? * In alkyl nitrites; 7 in nitrosamines The following comments on these results are made. A provisional value for bLO-H of 0.09 has recently been given9 on the assumption that b,o-H = b”0-H; howeverifb,o-H((whiChiStheexperimentallymeaSured and therefore definite semi-axis) is less than bTeH,then a value for bLo-Hof 0.054.06 is feasible; the relation given in ref. 11 produes a value for 6,O-H of 0.051-0.055. The value 0.18 forecast for the C-0 bond is quite incorrect; a value for b,cQ of 0.081 requires to be ca.780 cm.-lwhich is much below assignments usually made by infrared spectro~copists.~ Mafierbe and BermteinlO attribute several frequencies ob- served in the Raman spectrum of dioxan to ring Le Fevre and Le Fkvre Rev.Pure Appl. Chem Australia 1955 5 261. Le FCvre and Rao J. 1958 1465. Le Fevre and his co-workers J. 1958 1465; J. 1958 3002; 1959 1183 2340. Thompson and Torkington Proc. Roy. SOC.,1945 A 184 21. Hartwell Richards and Thompson J. 1948 1436. Randall Fowler Fuson and Dangl “Infra-red Determination of Organic Structures,” van Nostrand 1949. Bellamy “The Infra-red Spectra of Complex Molecules,” Methuen London 1954. Ramsay and Sutherland Proc. Ry Soc.1947 A 190 245. Le F&re Le Fkvre Rao and Williams J. submitted. lo Malherbe and Bernstein J. Amer. Chem. Suc. 1952 74 4408. l1 Le F&vre and his co-workers Proc. Chem. Suc. 1958 283. PROCEEDINGS stretching and among these is one at 834 cm.-l an-0-21,0-28,0-21,0.05,and 0.15 respectively. Le Fkvre notated as polarised and strong; this being used and Rao2 recorded the b value for the C-(CN) unit bLc-O emerges as 0.09. By the method described in = b,c-cby subtracting 0.35;in acetonitrile as 0.10 ref. 11 the b,’s of the bonds C-0 C=N CEN 0.25 is left as an estimate of hLEN. N=N N-0 and N=O are predicted to be 0.06 (Received 17th August 1959.) Metal Ketyls as Initiators of Polymerisation of Vinyl Monomers By ALBERT PEDATSUR ZILKHA NETA,and MAX FRANKEL OF ORGANIC THEHEBREW JERUSALEM, (DEPARTMENT CHEMISTRY UNIVERSITY ISRAEL) POLYMERISATION of vinyl monomers include electron- transfer catalysts’ and metal alkoxides,2 and metallic lithium acts as an electron-transfer catalyst.3 The reaction of electron-transfer catalysts such as naphthalene sodium with vinyl monomer gives an activated monomer which is an anion radical and propagates the polymerisation from both ends *CHR*CH,-+-+ -CHR-CH,*.According to their structural po~sibilities,~ the metal ketyls resemble the activated monomer ob-tained by electron-transfer catalysts in having a free radical and an anion in the same molecule the anionic part being an alkoxide. We investigated the polymerisation of vinyl mono- mers in tetrahydrofuran by metal ketyl catalysts in respect of monomer reactivities and dependence of yield and molecular weight on the concentrations of monomer and catalyst on the electropositivity of the metal attached on ketyls prepared from various ketones and on temperature of polymerisation.The vinyl monomers polymerised included acrylo- nitrile methyl methacrylate styrene methyl acrylate and vinyl acetate. The order of reactivity was found to be acrylonitrile>methyl methacrylate> styrene. Catalytic activity of the metal ketyls was propor- tional to the electropositivity of the attached metal the order of reactivity being potassium > sodium> lithium. Catalysts prepared from such aromatic ketones as benzophenone fluorenone benzoquinone Michler’s ketone and benzil were investigated.Differences in the reactivity of the various ketyls as catalysts in the polymerisation were found. The temperature of polymerisation was investigated between about -70” and 30”;the molecular weights of the polymers decreased considerably with increase in temperature. In a typical experiment sodium wire (0.144 g. 04063 g.-atom) was added to a solution of benzo-phenone (1.138 g. 0.0063 mole) in tetrahydrofuran (40 ml.) at room temperature and stirred at high speed. The blue colour of the metal ketyl appeared in a few minutes and the mixture was stirred for a further 15 min. and cooled to 0”. Acrylonitrile (10 ml.) in tetrahydrofuran (10 ml.) was added and polymerisation carried on for an hour at 0”.The polymer was filtered off and washed with light petroleum methanol and 15% hydrochloric acid. No residue of metallic sodium was found. The yield was 5 g. (62%),and the average molecular weight 2500. Using a greater amount of acrylonitrile(25 ml.) under the same experimental conditions caused explosive polymerisation. A copolymerisation experiment carried out under the conditions of the typical experiment with acrylonitrile (10 ml.) and styrene (10 ml.) was stopped after 3 min. and gave a copolymer whose nitrogen analysis showed it to be almost pure poly- acrylonitrile. This is compatible with the reactivities of both monomers in anionic cop~lymerisation.~ Infrared spectra of an acrylonitrile polymer prepared under the above conditions showed absorp- tion bands at 14 and 13-13.2 p (monosubstituted benzene) 9-9-3 p (dialkyl ether) 6-6-1 p (CH, double bonds).The infrared spectrum was identical in these features with that of acrylonitrile polymerised by sodium benzyl oxide.2 The above experimental evidence as regards reactivity of monomers copolymerisation of styrene and acrylonitrile explosive polymerisation (when 25 ml. of acrylonitrile were used) low-temperature polymerisation (-70”) and the infrared spectrum of this polyacrylonitrile tends strongly to show that polymerisation by metal ketyls is initiated mainly by the alkoxide part of the ketyl at least in polymerisa- tion of acrylonitrile. (Received September 1 1th 1959.) Szwarc Levy and Milkovich J.Anzer. Clzem. SOC.,1956 78 2656. Zilkha Feit and Frankel Proc. Chem. SOC.,1958 255; J. 1959 928. O’Dnscoll Boudreau and Tobolsky J. Polymer Sci. 1958 31 115; Overberger Pearce and Mayes ibid. p. 217; 1959 34 109. Wheland “Advanced Organic Chemistry,” 2ncl,edn. Wiley New York 1949 p. 719. Alfrey Bohrer and Mark “Copolymerisation Interscience New York 1952 pp. 231-232. NOVEMBER 1959 365 The Abnormal Hydrolysis of Certain Z-(Substituted ethy1)phosphines By ROYC. HINTON,FREDERICK TODD G. MANN,and DAVID (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) IT has been shown by Mann and Millarl that methyl acrylate always gave the phosphine (VIII) in diphenylphosphine (I) reacts with vinyl cyanide to addition to the methyl ester (VI).Consequently the form 2-cyanoethyldiphenylphosphine(II) which on required carboxylic acid has not yet been obtained. alkaline hydrolysis furnishes the crystalline stable The tertiary phosphine (VIII) has been identified 2-carboxyethyldiphenylphosphine(111). All attempts by (a) analysis (6) molecular-weight determinations and (c) its conversion into the stable highly crystalline Ph,PH -+ Ph,P[CH,],.CN -+ Ph,P.[CH,],.CO,H auric tribromide derivative (IX). m.p. 150° the infra- (1) (11) (111) red and nuclear magnetic resonance spectra of which show the presence of the SOMe and the -PMegroups. to cyclise this acid by condensation of the carboxyl Furthermore we have prepared authentic samples of group with an o-hydrogen of the phenyl groups the phosphine (VIIT) and of the ethyl homologue failed.Similar failures with comparable arsenic com- Ph(MeOC,H,)PEt by treating the sodio-derivative pounds were however overcome by utilising a rn-of the phosphine (IV) in liquid ammonia with methyl methoxyphenyl group the activation of which pro- and ethyl iodide respectively. The two phosphines moted ready cyclisation with the formation of a show some marked differences in properties but the 4-oxoar~ine.~ authentic P-methylphosphine is identical with the In an attempt to synthesise cyclic oxophosphines phosphine (VIII) prepared in our attempted hydro- on these lines we have prepared m-methoxyphenyl- lyses. These results remove all doubt that the phos- phenylphosphine (IV). This phosphine with vinyl phine could be the isomeric ethyl-nz-hydroxyphenyl- cyanide gives the corresponding 2-cyanoethylphos- phenylphosphine.phine (V). The 2-methoxycarbonylethylphosphine It is significant that the ethyl ester (VII) when (VI) was prepared (a) by direct union of the phos- phine (IV) and methyl acrylate and (6) by inter- oxidised by hydrogen peroxide in acetone to the action of the sodio-derivative of the phosphine (IV) phosphine oxide and then hydrolysed gives the in liquid ammonia with methyl /3-bromopropionate. stable crystalline acid (X). The 2-ethoxycarbonylethylphosphine(VII) was also The ethoxycarbonylmethylphosphine (XI) on prepared by both these methods. These derivatives hydrolysis also gave the phosphine (VIII) in this (V) (VT) and (VII) could be distilled under reduced case the phosphine (VIII) may have arisen by simple pressure in nitrogen without decomposition.decarboxyla tion of the corresponding acid. Ph( MeOC,H,)P.[CH,],-CN // (V) \ I -f Ph(MeOC,H,)PH/ Ph(MeO-C,H,)P~[CH,],.CO,Me -+ Ph(MeOC,H,)PMe (W \ (Vb 7 I (VIII) \i /+ Ph(MeO-C6H,)P.[CH,],.C0,Et Ph(Me0-C,H,)PMe i (VIO (IX) 4 i AuBr Fh(Me0.C H )P-[CH,],CO,H 4+ 0 (X) Ph(MeOC,H,)P.[CH,]CO,Et Ph(MeO-C,H,)P.[CH,],.CO,Me +-Ph(MeO.C,H,) P.[CH,],-CO,H (XI) (XI') (XIII) The 2-cyanoethylphosphine (V) on attempted However the 3-(methoxycarbonyl)propylphos-hydrolysis with hot aqueous-ethanolic sodium phine (XII) on hydrolysis gave the oily acid (XIII), hydroxide gave m-methoxyphenylmethylphenyl-identified as its crystalline benzylthiuronium salt.phosphine (VIII) in high yield. The methyl (VI) and The possible mechanism of the above reactions the ethyl esters (VII) when similarly treated or when will be discussed later. Our results indicate that the heated with 10% hydrochloric acid even under the phosphines (V) (VI) and (VII) must during the mildest conditions available also gave the phosphine general hydrolysis process undergo a splitting of (VIII); the interaction of the phosphine (IV) and the CH,CH bond of the 2-substituted ethyl group to Mann and Millar J. 1952 4453. Mann and Wilkinson J. 1957 3336. 366 PROCEEDINGS produce the phosphine (VIII) and that the mechan- ism must be fundamentally different from that sug- gested by Challenger et aL3 for the abnormal hydrolysis of methyl /3-methylthio- and /3-ethylthio- the sulphur atom.propionate in which the methyl portion of the methoxycarbonyl group is considered to migrate to (Received September 25th. 1959.) Challenger and Hollingworth Chem. andlnd. 1954,463;J. 1959,61; Challenger "Aspects of the Organic Chemistry of Sulphur Butterworths London 1959 p. 20. Two New Anodic Reactions By P. J. BUNYANand D. H. HEY (UNIVERSITY STRAND, OF LDNDON KING'SCOLLEGE W.C.2) RECENT work by Lippincott and Wilson1 has added considerably to the evidence that in non-aqueous media tlie Kolbe reaction involves the production of free radicals. However in the electrolysis of salts of aromatic carboxylic acids no dimeride is formed presumably because the aryl radicals are extremely reactive and attack the solvent.We have now in- vestigated the anodic oxidation of o-benzoylbenzoic acid and some of its para-substituted analogues which on electrolysis yield aryl radicals that might undergo internuclear cyclisation to give fluorenones. This possibility has now been realised and in addi- tion a new type of molecular rearrangement has been brought to light. In methanol containing sodium methoxide at 25-35 with identical smooth platinum electrodes O (4.2 x 1.4 cm.) 0.35 cm. apart and a current of one ampere o-benzoylbenzoic acid has been found to yield 3-phenylphthalide and methyl phenyl phthalate as the main identified products. In similar manner o-(p-chlorobenzoyl)benzoic acid gave 3-p-chloro-phenylphthalide and p-chlorophenyl methyl phthal- ate.The phthalates which are oils were identified by hydrolysis to phthalic acid and the phenol and by comparison of their infrared spectra with those of authentic specimens prepared by Dvornikoff's method.2 Further the p-bromophenyl methyl phthalate produced in the electrolysis of o-(p-bromo- benzoy1)benzoic acid had m.p. 71 " alone and mixed with an authentic specimen. Yields of the phthalates based on recovered starting acids are of the order of 25 %. The phthalides were identified by mixed melt- ing points and by elemental analysis. Electrolysis of o-benzoylbenzoic acid followed an entirely different course in pyridine containing sodium methoxide and 16% by volume of methanol at 90-95" with a constant potential drop of 120 v across the electrodes.Under these conditions the products isolated were fluorenone fluoren-9-01 and benzophenone. These compounds were chromato- graphically separated on alumina the benzophenone being eluted with light petroleum the fluorenone with benzene and the fluoren-9-01 with ethanol and identified by mixed melting points and by elemental analysis. o-(pChlorobenzoy1)benzoic acid in similar manner gave 3-chlorofluorenone 3-chlorofluoren-9- 01 and p-chlorobenzophenone. The combined yields of cyclised products in both cases were of the order of 10% based on recovered acid. It is concluded that on electrolysis of these acids in pyridine at 90-95" the carboxyl radical formed initially at the anode loses carbon dioxide and the resulting radical undergoes intramolecular cyclisa- tion to yield the ffuoroenone and by subsequent re- duction the fluorenol.It seems reasonable to postulate that on electrolysis in methanol at lower temperatures (25-35") the intermediate carboxyl radical is sufficiently stable to undergo the annexed novel rearrangement which leads to the formation of an aryl methyl phthalate. L"2 c- LU C02Me c0,m Formaldehyde has been detected among the reaction products which suggests that methoxyl radicals may also be produced at the anode and these could account for the final step although direct attack on the solvent may also be involved. Further work is in progress on internuclear cyclisation by means of electrolysis and on the eluci- dation and extension of the new rearrangement reported above.One of us (P.J.B.) gratefully acknowledges the award of a Research Studentship from the Depart- ment of Scientific and Industrial Research. (Received September 17th 1959.) Lippincott and Wilson J. Amer. Chem. SOC.,1956 78,4290. Dvornikoff U.S.P. 1 899 919. NOVEMBER 1959 367 Activation Energy and Entropy in the Racemisation of 2,2'-Dibromodiphenyl-4,4'dicarboxylic Acid in Ethanol By MARGARET M. HARRIS (BEDFORD LONDON) COLLEGE EXPERIMENTAL determination of the racemisation -20.9 e.u. (for N-benzoyl-2'-fluoro-6-methyldi-parameters for optically active 2,2'-dibromodiphenyl- phenylamine-2-carboxylic acid in chloroforni-4,4'-dicarboxylic acid has been desirable ever since ethanol) having been ob~erved.~ Westheimerl computed a value of 18 f2 kcal.mole-l Racemisation rate constants for 2,2'-dibromodi- for the energy of activation of its optical inversion phenyl-4,4,-dicarboxylic using as the geometrical basis for his calculation a been acid in ethanol have now with the results tabulated. Thence planar activated state. Previous experimental support Eracem = 19.0 f0.5 kcal. mole-' (graphical method; for this fiare rests upon and Adams's == -4.9 e.u. of kracem at a single temperature (k = 0.028 18.9 by least squares) and dSfrDCCm 0.034 min.-l in dioxan-methanol at 0");this has The direct observations of racemisation rates over been used to calculate a dF3 which is compatible this temperature range was accomplished by using with Westheimer's E if a "normal"l value for AS3 is a specially designed polarimeter tube round which a Temp.+!5.6" $1.0" -3.9" -9.25" -15.3" -20.7" l-5k (sec.-l) 157.5 85.9 51.2 21.1 10-3 4.46 assumed. Recent determinations of dStracIm for a thermostatically controlled coolant was pumped ;the variety of optically labile compounds show that this author is indebted to Mr. R. K. Mitchell for his factor can vary over an unexpectedly wide range assistance in the design and execution of this values of +9.2 e.u. (for 1 ,l'-dinaphthyL8,8'-dicar-apparatus. boxylic acid in 0.1waqueous sodium hydroxide) and (Received September 28th. 1959.) Westheimer J. Chem. Pliys. 1947,15,252;Rieger and Westheimer J. Amer. Chem. SOC.,1950,72 19. 7 Searle and Adams J. Amer Chem.S&. 1934,56,2112. Harris and Mellor Chem. and Ind. 1959,949;Brooks Harris and Howlett J. 1957 2380; Hall and Harris J., in the press. Fluoroalkyl Nitroso-compounds By J. M. BIRCHALL R. N. HASZELDINE, A. J. BLOOM and C. J. WILLIS (FACULTY UNIVERSITY OF TECHNOLOGY OF MANCHESTER) FLUOROALKYL nitroso-compounds,l available hither- could also be generated by further reaction of nitric to only from the relatively expensive fluoroalkyl oxide with the -CF,.NO group of any dinitroso- iodides have now been conveniently obtained by compound (CF,-NO) formed as intermediate in the reaction of nitric oxide with fluoro-olefins; in a early stages of the reaction in a manner similar to related reaction dinitrogen tetroxide and fluoro-that outlined for NO2CF2CF,.NO in the annexed olefins are known to give mainly nitro-compounds.2 3NO~CF~CF~NO Nitric oxide (2 mols.) and tetrafluoroethylene NO + CF, CF~ -NO~CF~CF~ (1 mol.) in the dark at 20" and atmospheric pressure give tetrafiuoro- 1-nitro-2-nitrosoethane (45 % yield ; 70 % based on C,F consumed) tetrafluoro- I ,2-di-nitroethane (10% yield; 15% based on C,F con-sumed) nitrogen and smaller amounts of perfluoro- 2-(tetrafluoro- 2-nitroethyl) -1,2-0xazetidine and NOiCFiCF~N:N-O-&" -NO&FiCF + N,t *O-NO2 probably difluoronitroacetyl fluoride.Radical chain '0-reactions are probably involved with initiation by NO1 IN0 Cycle -NO2+ N204 the NO radical-sufficient nitrogen dioxide is prob- ably present even in purified nitric oxide but it repeats Haszeldine J.1953 2075; Barr and Haszeldine J. 1955 1881 :1956 3416. Coffman Raasch Rigby. Barrick and Hanford J. Org. Chem. 1949 14 747; Haszeldine J. 1953 2075; Knunyants and Fokin Dokfady Akad. Nauk. S.S.S.R. 1956,111 1035. PROCEEDINGS scheme. This is related to Brown's proposals3 for The nitronitroso-compound like trifluoronitroso- reaction of nitric oxide with isobutene and accounts methane reacts smoothly with tetrafluoroethylene for the fact that the only nitroso-compound formed to give the oxazetidine (I) or the 1 :1 copolymer (II). ultimately is NO2-CF,-CF2*NO and that the com- pound NOCF,-CF,.NO is not a final product. The CFZNO,.CF*2N-0 NO,.CF,.CF,. radical acts as carrier for the conver- II (1) sion of nitric oxide into dinitrogen tetroxide and CF2 -CF2 nitrogen in the early stages of the reaction.Later it combines with nitric oxide to give NO,CF,CF,.NO or with nitrogen dioxide to give NO,CF,CF,.NO Conditions may be chosen for the synthesis of (I) or N0,CF,CF2.0.N0 (and thence the acyl fluoride or (II) directly from nitric oxide and tetrafluoro- NO,CF,COF via the radical N02-CF2CF,.0.4). ethylene. At 100" and 4 atmospheres an 80 % yield of In accord with this scheme the reaction between oxazetidine (I) is obtained in 2-3 hours. Reaction nitric oxide and tetrafluoroethylene is accelerated by at 0-20" gives the polymer (II) in 6045% yield. deliberate addition of small amounts of dinitrogen Like the polymers formed from perfluoroalkyl- the polymer tetroxide. Formation of dinitrogen tetroxide during nitroso-compounds and fluoro-olefin~,~ the reaction can be observed by the development of (11) ranges from a viscous oil to an elastomer which the brown colour which later changes as the blue is translucent tough and insoluble in common nitroso-compound (b.p.24.2") becomes the pre- organic solvents and has good low-temperature dominant product. Separate experiments show that characteristics. the compound N02CF2-CF2-N0 reacts rapidly with and excess of nitric oxide in the vapour phase to give The authors are indebted to Pennsalt Chemicals tetrafluorodinitroethane dinitrogen tetroxide and Corporation for a grant in support of this work. oxidative breakdown products. (Received,September 17th 1959.) Brown. J. Amer. Chem. Soc.. 1957. 79. 2480.Francis and Haszeldine J. 1955 2151; Haszeldine and Nyman J. 1959 387. Barr Haszeldine and Willis Proc. Chem. SOC.,1959 230. The Synthesis of Hydrazine by Glowdischarge Electrolysis of Liquid Ammonia" By A. HICKLING and G. R. NEWNS (UNIVERSITY OF LIVERPOOL) [It is regretted that this Communication was printed from a cylinder had m.p.s ranging from 1-0"to 1.5" without its diagram in Proceedings for September vapour pressure of 10.5 mm. at 20" and n22 1.4609. 1959 p. 272 It is reprinted here in full. ED.] These values of physical properties correspond to A SERIES of studies of glow-discharge electrolysis in > 97 % purity which agrees with chemical analysis. aqueous systems1 has shown that this form of ion In the cell used the anode was a platinum wire bombardment gives primarily the hydroxyl radical suspended in the gas phase above the solution in which subsequently undergoes reaction and under which a platinum cathode was immersed and a cur- some conditions can produce hydrogen peroxide.rent was passed by maintaining a discharge between This work has now been extended to systems in the anode and the solution surface. The cell was kept liquid ammonia and with an inert electrolyte it has at a reduced pressure and cooled by immersion in a been found that the chief product of glow-discharge bath of solid carbon dioxide in acetone. The experi- electrolysis is hydrazine. The conditions for its mental conditions usually employed were electro-formation are not critical and its purity seems solely lyte 20 ml.of 0-OlM-ammonium nitrate in liquid dependent upon that of the ammonia used from ammonia exposing a surface of 9 sq. cm.; anode to which it is readily separated by fractional distilla- surface distance 0.5 cm.; pressure 100 mm. mer-tion; this is in contrast to the usual methods of cury; current 0.025 amp.; voltage drop across the making hydrazine which result in a dilute aqueous discharge ca. 600 v. solution from which concentration to an anhydrous For studying the formation of hydrazine under product is difficult.2 Samples of hydrazine prepared various conditions the chosen current was passed for by the present method with liquid ammonia direct a measured time; the ammonia was then evaporated * This research provides the subject matter of Patent Appln.15,744159 filed by the National Research Development cow. Davies and Hickling J. 1952,3595;Hickling and Linacre J. 1954,71 1;Denaro and Hickling J. Electrochem. SOC. 1958. 105 265. NOVEMRER 1959 369 from the cell and the residue was acidified and In a number of experiments alternating (50 cycles) anaiysed volumetrically for hydrazine by the indirect was used instead of direct current; hydrazine was iodate method.2 In Fig. 1 are shown the results of a again found but the initial yield was decreased to 1.3 as against 2.5 moles per faraday suggesting that it is mainly during the anodic half cycle that hydrazine is formed. It has also been found that glow-discharge electrolysis can be carried out in liquid ammonia at atmospheric pressure with a small immersed anode if the current passing exceeds a critical value.This causes the anode to become surrounded by an en- velope of vapour through which a discharge at several hundred volts takes place and the process again leads to hydrazine as the main product. 111 It is probably premature to discuss the mechanism 012345 Quantityof e/ertrkity passed of hydrazine formation. Work in the aqueous systems faraday) (Denaro et aL1) has shown that in glow-discharge number of electrolyses under the above conditions gaseous ions with energies of about 100 ev enter the for different time intervals. It is seen that the initial liquid and bring about dissociation of solvent mole- yield is about 2-5 moles of hydrazine per faraday of cules and hydrogen peroxide probably arises by di-electricity passed and this falls only slightly with in- merisation of hydroxyl radicals.It is tempting by creasing quantities of electricity. The yield of analogy to suggest that hydrazine is produced in hydrazine was practically independent of the pres- liquid ammonia by a reaction of the type 2NH -+ sure in the gaseous phase (70-175 mm.). It tended N,H, but the results so far obtained favour rather a reaction of the form NH + NH -+ N,H,. It is to drop somewhat with increased current (0.0154.1 amp.) and with increase in the concentration of the hoped to discuss the mechanism fully in a later electrolyte used. Temperature-variation was limited communication. by the freezing point of the ammonia and the We thank the Department of Scientific and feasibility of maintaining glow-discharge at high Industrial Research for a maintenance grant to pressures but an increase of temperature of 16" G.R.N.resulted in a small increase of yield. (Received June 22nd 1959.) Audrieth and Ogg "The Chemistry of Hydrazine," Wiley New York 1951. Triiluoronitrosoethylene and its Polymers By C. E. GRIFFINand R. N. HASZELDINE (UNIVERSITY LABORATORY and CHEMICAL CAMBRIDGE FACULTY UNIVERSITY OF TECHNOLOGY OF MANCHESTER) TRIFLUORONITROSOETHYLENE has been synthesised by the photochemical reaction of trifluoroiodoethylene with nitric oxide in presence of mercury CF,:CFI Atr CF,:CF. CF,:CF-N:O When heated at 80" under a pressure of 40-60 atm. the intensely blue conjugated nitroso-compound 0 0' (b.p.-23.7") forms an unusual fused-ring dimer Cmns (I) cis (b.p. 45") by oxazetidine formation1 involving com- Poly(perfluoro-l,2-oxazetidin-2,3-ylidine), with the bination of the nitroso-group of one molecule with -N-C-N-C-N-C-backbone is a new type of the trifluorovinyl group of the second; cis-and trans-polymer structure and is elastomeric. When it is isomers are possible for perfluoro-4,8-dioxa-l,5-di-heated at 400" carbonyl fluoride splits off without azabicyclo [2,2,02y5]octane (I). appreciable degradation of the main chain to form Polymerisation of the trifluoronitrosoethylene -N=CF-N=CF-N=CF-units in the polymer also occurs by oxazetidine formation (cf. 11). which is then no longer an elastomer. Barr and Haszeldine J.1955 1881 ; 1956 3416 ;Barr Haszeldine and Willis Proc. Chem. Soc. 1959 230. II CF-N II CF-N ll CF-N II CF2 0 CF2 0 il iF2 0-C% 0-II I -CF-N -CF-N-CF-N-I II -CF2 ‘O-CF (I0 Copolymerisation of trifluoronitrosoethylenehas been achieved through its nitroso-group. Thus at PROCEEDINGS 0-20” tetrafluoroethylene or chlorotrifluoroethylene yield the 1 1 copolymers (111). in a manner similar to that observed earlier for trifluoroilitrosomethane and related compounds;l at higher temperatures the oxazetidines (IV) are formed. One of the authors (C.E.G.) is indebted to the U.S. National Institutes of Health for a Postdoctoral Research Fellowship (1955-57) during the tenure of which part of this research was carried out.(Received September 25th 1959.) ERRATUM Faith and Doubt The Theory of Structure in Organic Chemistry By W. V. FARRAR The formula on p. 285 and the illustration of p. 290 should be and K. R.FARRAR. interchanged (Proceedings October 19 59). NEWS AND ANNOUNCEMENTS Joint Library Committee.-The Council has appointed Dr. L. Crombie Dr. G. J. Minkoff and Dr. J. E. Salmon as representatives of the Society on the Joint Library Committee in succession to Pro- fessor R. M. Barrer Professor M. B. Donald and Dr. H. T. Openshaw who are due to retire at the end of this year. Local Representatives.-Additional Local Repre- sentatives have been appointed as follows Aberystwyth Dr. W. J. Orville-Thomas. Adelaide and Perth Australia Professor G.M. Badger. Brisbane Australia Professor F. N. Lahey. Mr. R. Towers one of the Local Representatives for Liverpool has resigned on leaving the area and Dr. B. G. Dutton has been appointed as his successor. Library.-The Library will close for the Christmas Holiday from 1 p.m. on Wednesday December 23rd until 9.30 a.m. on Tuesday December 29th 1959. Election of New Fellows.-20 Candidates whose names were published in Proceedings for September have been elected to the Fellowship. Reprinting Programme for the Journal.-An agree-ment between The Chemical Society and Butter- worths Scientific Publications provides for the re- printing of certain volumes of the Journal which are out of print. The volumes now available are 1848-1857 (Volumes 1-10) E7 per annum.1858-1 870 (Volumes 11-23) S5-5s. per set. 1848-1 870 (Volumes 1-23 complete set cloth bound) E138. 1941-1944 El0 per annum. The next volumes to be reprinted will be Volumes 24 and 25 (1871-1872) and copies are expected to be available early in 1960. The intention is to con- tinue future reprinting in sequence from Volume 26 (1873) onwards as the agreement is extended. Orders for the volumes now available may be addressed to The General Secretary The Chemical Society Burlington House London W. 1. Orders from the libraries of Universities and Technical Colleges placed directly with the Society are subject to a discount of 10 %. “The Presentation of Papers.”-A second edition of the brochure “The Presentation of Papers to the Chemical Society” is now available.Each Fellow of the Society is entitled to receive one copy gratis and non-Fellows may obtain copies at 2s. 6d. each post free on application to the General Secretary The Chemical Society Burlington House London W. 1. The first edition was exhausted so the opportunity has been taken to bring the material up-to-date. Some substantial changes are involved but the general plan of the contents remains the same. Notices to Authors.-The attention of authors for the Society’s publications is drawn to two changes of convention recently adopted by the Publication Committee. NOVEMBER 1959 (1) References. Idem will no longer be used in citing references; and Zoc. cit. will be used only in composite references not in references carrying a separate reference number (where the recognised abbreviation for the journal title should be repeated).(2) Formuke. In empirical and molecular formula elements will be cited in the order C H and all others thereafter in alphabetical order of symbols. Ex.,C19H18N20 C,,H,,C1,04Sb. All manuscripts submitted to the Society should in future conform to these new conventions. International Conference on Co-ordination Chem- istry.-The Report of the Conference held in London on April 6-1 1 th 1959 has now been published as No. 13 in the Society’s series of Special Publications. It contains the full text of the General Lectures delivered at the Conference together with abstracts of contributed papers.It is expected that copies already ordered will be distributed towards the end of November. Fellows who have not already ordered copies may still obtain them from the General Secretary at the special price of El 5s. The price for non-Fellows is E2 2s. (U.S.A. $6). The Nobel Prizes.-The Nobel Prize for Chemistry has been awarded to Professor Jaroslav Heyrovsky Director of the Polarographical Institute of Prague for his discovery and development of the polaro- graphic method of analysis. The Nobel prize for Medicine is to be shared by two American biochemists Professor Severo Ochoa of the New York College of Medicine and Professor Arthur Kornberg of Stanford University California. The Prize has been awarded for their discoveries made independently of the mechanisms in the biological synthesis of ribonucleic and deoxyribo- nucleic acid.The Office of the Lord Privy Seal.-With the appointment of Lord Hailsham as the Minister with general responsibility for science and technology in-cluding atomic energy the Atomic Energy Office and the Lord President’s Office will be combined. The new Office will be in the charge of Mr. F. F. Turnbull C.B. C.I.E. whose appointment as Deputy Secre- tary to succeed Sir Friston How in charge of the Atomic Energy Office was announced some months ago. It will be organised in two Divisions (1) a General Division under Mr. R. N. Quirk Under- Secretary corresponding to the previous Lord President’s Office and (2) an Atomic Energy Divi- sion under Mr.M. I. Michaels Under-Secretary corresponding to the previous Atomic Energy Office. World Directory of Crystallographers.-A second edition of the World Directory of Crystallographers is being prepared. The Editor of this edition is Dr. D. W. Smits of Groningen Netherlands but bio- 37 1 graphical information is being collected for each country by a sub-editor in the country. It is intended to include in the Directory all practising crystallo- graphers including advanced graduate students. Readers in the United Kingdom who consider their names should be included in the Directory but who have not received a questionnaire by November IOth 1959 are requested to write to Dr. P. T. Davies “Shell” Research Limited Thornton Research Centre P.O.Box 1 Chester. Meldola Award for 1959.-The Meldola Medal is the gift of the Society of Maccabaeans and is normal- ly awarded annually. The next award will be made early in 1960 to the chemist who being a British subject and under 30 years of age at December 31st 1959 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 1959. No restrictions are placed upon the kind of chem-ical 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 recom- mend the candidate or by the candidate himself by letter addressed to The President The Royal Insti- tute of Chemistry 30 Russell Square London W.C.l 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 a list of titles with references of papers or other works published by the candidate independently or jointly. Candidates are also advised to forward one reprint of each published paper of which copies are available. Congresses etc.-The Second European Sym- posium on Chemical Reaction Engineering Section on Non-conventional Reactors sponsored by the Royal Institute of Engineers and the Royal Dutch Chemical Association will be held in Amsterdam on April 27-29th 1960.Enquiries should be addressed to Mr. P. J. Hoftijzer Centraal Labor- atorium Staatsrnijnen Geleen (L.) Holland. The Second Conference on Reactions between Complex Nuclei organised by the American Physical Society will be held in Gatlinburg Tennessee on May 2-3rd 1960. Further details may be obtained from Dr. Robert S. Livingston Oak Ridge National Laboratory Oak Ridge Tenn. U.S.A. A Conference on the Mechanisms of Peroxide Reactions sponsored by the Office of Ordnance Research of the U.S. Army and Brown University will be held on June 15-17th 1960 at the Metcalf Chemical Laboratories of Brown University Pro- vidence 12 R.I.,U.S.A. Enquiries should beaddressed to Professor John 0. Edwards Director Peroxide Reaction Mechanisms Conference Metcalf Research Laboratory Brown University Providence 12 R.I.U.S.A. An International Conference on Semiconductor Physics sponsored by the Czechoslovak Academy of Sciences and the International Union of Pure and Applied Physics will be held in Prague on August 29-September 2nd 1960. Enquiries should be addressed to Dr. R. Fraser Administrative Secre- tariat International Council of Scientific Unions Paleis Noordeinde Van Trigtstraat 6 The Hague Holland. The Seventh Commonwealth Mining and Metal- lurgical Congress will be held in Southern Africa during the period April 10th-May 21st 1961 of which four weeks will be spent in the Union of South Africa and two weeks in Northern and Southern Rhodesia.Enquiries should be addressed to the Congress Manager Seventh Com- monwealth Mining and Metallurgical Congress P.O. Box 809 Johannesburg South Africa. Heavy Organic Chemicals.-A new Subject Group of the Society of Chemical Industry has been formed and was inaugurated at a meeting to be held in the rooms of the Society at 14 Belgrave Square S.W.l on Thursday November 12th. The new Group will be named “The Heavy Organic Chemicals Group,” and the first Officers are Dr. R. Holroyd (Chair- man) Dr. M. A. Matthews (Deputy Chairman) and Mr. H. P. Hodge (Honorary Secretary). Deaths of Fellows.-We regret to announce the deaths of the following Dr. Paul Laeuger (4.6.59) of Gentelino Switzerland ; Sir Henry Tizard G.C.B. A.F.C.F.R.S. (9.10.59) formerly Rector of the Imperial College of Science and Technology; and Dr. J. S. Watson (29.7.59) of the National Research Council 0t taw a. Personal.-Dr. C. J. Ballhairsen has been appoint- ed Professor of Chemistry in the University of Copenhagen from September lst 1959 and leader of the Physical-Chemical Institution of the Uni- versity in succession to Professor J. C. Christiansen who is retiring. Mr. M. J. S. Clapham has been appointed Chairman of I.C.I. Metals Division from January lst 1960 in succession to Dr. Maurice Cook C.B.E. who retires from the Company’s service on December 31st 1959. The title of Reader in Biochemistry in the Univer- sity of London has been conferred upon Mr. S. P. Datta in respect of his post at University College.Dr. D. I. Davies has been appointed a Lecturer in the Department of Organic Chemistry in the University of Leeds. Dr. D. S. Davies head of the Colours Experi- PROCEEDINGS mental Department at 1.C.I.k Grangemouth Works has been transferred to General Chemical Division as Deputy Research Manager. Dr. J. F. Duncan Reader in Chemistry at Mel- bourne University has been visiting the University institutions of New Zealand giving specialist lectures in Radiochemistry and taking part in laboratory classes in this subject. Dr. K. Grootheim has been appointed Professor of Inorganic Chemistry at the Technical College of Norway Trondheim. Dr. R. L. Guile (State University Michigan) has been appointed a Lecturer in Chemistry at Trinity College Dublin under the United States exchange programme.Professor Alexander Haddow of the Chester Beatty Research Institute London was awarded the Scheele Medal for eminent biochemical work during his visit to Stockholm on September 15th. Professor Haddow gave a lecture before The Physiological Society and the Stockholm Chemical Society on “The Mechanism of Chemical Carcinogenesis.” Dr. W. E. Harvey Senior Lecturer in Organic Chemistry at Victoria University of Wellington New Zealand has been awarded a Fulbright Travel Grant and proposes to spend some 12 months working with Dr. K. Bloch of Harvard University. Mr. F. Courtney Harwood has been elected a Governor of the Plymouth Colleges for Further Education.Mr. H. Holness has been appointed Assistant Director of the Laboratories in the Department of Chemical Engineering Fuel Technology and Metal- lurgy at the Manchester College of Science and Tech- nology. This is in addition to his appointment as Senior Lecturer in the Department. Dr. D. R. Jenkins has been appointed a University Demonstrator in Physical Chemistry at Cambridge University. Dr. R. B. Johns Lecturer in Chemistry at the Victoria University of Wellington New Zealand has been appointed to a Senior Lectureship in the Chemistry Department of Melbourne University. Mr. R. M. Johnson has been appointed Assistant Lecturer in Chemistry and Food Quality Control at the National College of Food Technology Wey- bridge. Dr. F.E. King has resigned from the Board of British Celanese. Mr. H. L. Long retired from his post of Head of the Science Department at the Slough College of Further Education on August 31st. Dr. D. H. Marrian Cambridge University Assist- ant Director of Research in Radiotherapeutics has been elected to a Staff Fellowship at Trinity College on his appointment as College Lecturer. Dr. M. Ottesen has been appointed Director of the NOVEMBER 1959 Chemical Department of the Carlsberg Laboratory Copenhagen Denmark in succession to the late Professor K. Linderstrom-Lang. Dr. S. E. Rasmussen has been appointed Professor of Inorganic Chemistry at the University of Aarhus Denmark from October lst 1959. Professor Erik Rudberg previously Head of The Metal Institute was appointed Permanent Secretary to the Swedish Royal Academy of Sciences from August lst 1959 in succession to Professor Arne Westgren.The title of Professor of Physical Chemistry in the University of London has been conferred upon Dr. F. C. Tompkins in respect of his post at the Imperial College of Science and Technology Dr. David Traill Director of Research Imperial Chemical Industries Limited (Nobel Division) re- tired on October 31st. FORTHCOMING SCIENTIFIC MEETINGS London Thursday December loth at 7.30 p.m. Centenary Lecture “Some Recent Advances in Fluorocarbon Chemistry,” by Professor G. H. Cady. To be given in the Rooms of the Society Burlington House W. 1. Aberdeen Thursday December loth at 8 p.m.Lecture “Chemical Kinetics in Relation to Large- scale Production,” by Professor K. G. Denbigh. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the University Union. Bristol Thursday December 3rd at 6 p.m. Lecture “Beryllium Production Properties Ap- plication~,’~ by Dr. G. A. Wolstenholme. Joint Meeting with the Chemical Engineering Group the Institute of Metals the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Department of Chemistry The University to be followed by Dinner at 8 p.m. Thursday December loth at 5.15 p.m. Lecture “Rockets,” by Dr. J. Black. Joint Meeting with the Student Chemical Society to be held in the Department of Chemistry The University.Friday January Sth 1960 at 6.30 p.m. Lecture “Radiochemical Analysis,” by Dr. J. N. Andrews A.R.I.C. Joint Meeting with the Royal Institute of Chemistry the Society for Analytical Chemistry and the Society of Chemical Industry to be held at the College of Technology Ashley Down Bristol 7. Cambridge Monday December 7th at 5 p.m. Lecture “Fluorescence of Organic Vapours,” by Dr. B. Stevens M.A. To be given in the University Chemical Laboratory Lensfield Road. Edinburgh Tuesday December Sth at 7.30 p.m. Lecture “The Biosynthesis of Porphyrins,” by Professor A. W. Johnson Ph.D. Sc.D. A.R.C.S. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at the North British Station Hotel.Friday January Sth 1960 at 7.30 p.m. Lecture “Chemistry Applied to Criminal Xnvestiga- tion,” by Detective Chief Inspector J. K. McLellan. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at the North British Station Hotel. Hull Tuesday December lst at 5 p.m. Lecture “Recent Studies in the Para-ortho-hydrogen Conversion,” by Professor D. D. Eley Sc.D. Ph.D. Joint Meeting with the University Student Chemical Society to be held in the Organic Lecture Theatre Chemistry Department The University. Irish Republic Wednesday January 6th 1960 at 5.30 p.m. Lecture “Aescigenin,” by Mr. J. B. Thomson. To be given in the Chemistry Department University College Upper Merrion Street Dublin.Newcastle upon Tyne Friday December 4th 1959 at 5.30 p.m. Lecture “Bridged Rings,” by Professor R. C. Cookson. To be given in the Chemistry Department King’s College. Northern Ireland Tuesday December lst at 7.45 p.m. Lecture “Oxidation of Organic Sdphides,” by Dr. L. Bateman. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Department of Chemistry Queens University Belfast. Nottingham Tuesday December 8th at 8 p.m. Lecture “The Study of Knock and Anti-Knock by the Method of Kinetic Spectroscopy,” by Professor R. G. W. Norrish Sc.D. Ph.D. F.R.I.C. F.R.S. Joint Meeting with the Society of Chemical Industry and the University of Nottingham Chemical Society to be held in the Chemistry Department The University.Thursday December loth at 7.30 p.m. Lecture “Infrared Spectroscopy,” by Dr. L. J. Bellamy. Joint Meeting with the Royal Institute of PROCEEDINGS Chemistry to be held at Nottingham and District Technical College. Swansea Friday December 4th at 3 p.m. Lecture “Fun with Free Radicals,” by Professor D. H. Hey D.Sc. Ph.D. F.R.I.C. F.R.S. Joint Meeting with the University College of Swansea Chemical Society to be held in the Department of Chemistry University College. Tees-side Wednesday December 9th at 8 p.m. Film Show. To be given at Spark‘s Cafe High Street Stock t on-on-Tees . APPLICATIONS FOR FELLOWSHIP (Fellows wishing to lodge objections to the election of these candidates should communicate with the Honorary Secretaries within ten days of the publication of this issue of Proceedings.Such objections will be treated as confidential. The forms of application are available in the Rooms of the Society for inspection by Fellows.) Bedford Geoffrey Robert B.Sc. 67 Cole Lane Ockbrook Derby. Bee John Arthur B.Sc. 1 Bentley Avenue Thornham Castleton Nr. Rochdale Lancs. Beltrame Paolo. Laboratorio di Chimica Fisica Via Saldini 50 Milano Italy. Bethell Donald B.Sc. Ph.D. Department of Organic Chemistry The University Liverpool. Bevan William Idris. 8 Compton Drive Sea Mills Bristol. Beyler Roger Eldon M.A. Ph.D. Department of Chemistry Southern Illinois University Carbondale Illinois U.S.A.Black Donald Kirkbright. 12B Parade Lane Ely Cambs. Brocklehurst Keith B.Sc. 27 Park Road Audenshaw nr. Manchester. Burton Raymond B.Sc. 41 Clanricarde Gardens London W.2. Carol Geoffrey Victor. 89 Hopewell Road Hull East Yorks. Chignell Colin Francis B.Pharm. 24 Buxton Road London E.6. Clark Stanley Frederick B.Sc. 18 Wharf Road Stanford- le-Hope Essex. Colebrook Lawrence David M.Sc. Chemistry Depart- ment The University of Auckland Box 2553 Auck-land New Zealand. Conn John B.Sc. 36 Maple Terrace Shiney Row Houghton-le-Spring Co. Durham. Cunningham John George M.A. 121 Alexandra Avenue Luton Beds. Dale Johannes Dr. Philos. European Research Associ- ates 95 rue Gatti de Gamond Bruxelles 18 Belgium. Daniels Peter.Ferens Hall Cottingham Yorks. Darlow Rex Leslie Richard. 53Hillcroft Crescent Oxney Watford. Davies Donald Harry. 566 Bay Street Ottawa 4 Ontario Canada. Games David Edgar BSc. 47 Thurleigh Road London s.w.12. Gee Wilfred B.Sc. A.R.C.S. 5 Carmel Court Gloucester Gardens London N.W.11. Glover Richard Brian B.Sc. Spring Hill House Spring Hill Somerset Street Bristol 2. Gravenor Ronald Brynley B.Sc. 60 Woodville Road Mumbles Swansea. Hall Richard John. 2 East View Framwellgate Moor Durham City. Hawthorne David Geoffrey B.Sc. 112 Leopold Street South Yarra Victoria Australia. Hill Laurence Albert B.R. 64 20th Avenue Mossel Bay Cape Province South Africa. Hudson Keith Samuel. 90 Potters Green Road Wals- grave Coventry. Hughes Martin Neville B.Sc.125 Crockett Road, Swansea Glam. Husain David B.Sc. Pembroke College Cambridge. Jorgenson Margaret Jefraim M.A. Ph.D. 9 Panoramic Way Berkeley 4 Calif. U.S.A. Kakabadse George Juri Dr. ing. 14 Hargreaves Road Timperley Altrincham Cheshire. Kennard Colin Harold Leslie B.Sc. 10 Wolseley Road Point Piper New South Wales Australia. Lapidus Jules B. M.S. Ph.D. 1865 North Starr Road Columbus 12 Ohio USA. Leonard John Alex BSc. 214 Ermin Street Stratton St. Margaret nr. Swindon Wilts. Lethbridge James William B.A. 1 Burton Avenue Withington Manchester 20. Low Thin-Fook BSc. St. John’s College St. Lucia Brisbane Australia. Luckhurst Geoffrey Roger. Ferens Hall Northgate Cottingham East Yorks. McKenzie Elwyn Donald M.Sc.School of Chemistry, University of New South Wales Broadway Sydney New South Wales Australia. McMorris Ian B.Sc. 19 Brentvale Avenue Wembley Middlesex. Marsh John Frederick B.Sc. Hill Top Windy Harbour Lane Bromley Cross Bolton Lancs. Mellor John Macrae B.A. 59 Victoria Road Oxford. Newall Christopher Earle. 7 Coney Hill Road West Wickham Kent. NOVEMBER 1959 Nicholls John Francis Charles. 12 St. Mary’s Crescent Osterley Middlesex. Oliver Peter Michael B.Sc. 274 Northwich Road, Northwich Cheshire. Pauwels Peter Jean Stephen B.Sc. 16 Woodwarde Road London S.E.22. Petronici Clara. Piazza Marina 29 Palermo Italy. Polson Janet Elizabeth B.Sc. 17 Lynmouth Avenue Flixton nr. Manchester. Prince Alan Keith B.Sc.7 Merwood Grove Victoria Park Manchester 14. Read James Franklin. 29 Stratheden Road London S.E.3. Reeder Alan James Leonard B.A. 62 Stratton Drive Barking Essex. Reesor John William Brian M.A. Ph.D. Defence Research Board of Canada 66 Ennismore Gardens London S.W.7. Richardson Anthony Charles B.Sc. Ph.D. Department of Biochemistry University of California Berkeley 4, California U.S.A. Robson Norman Clifford. 44 Alwhton Terrace Gos- forth Newcastle-on-Tyne 3. Rowland Peter B.Sc. Department of Chemistry The University Manchester 13. Siddons Phillip Thomas B.Sc. A.R.C.S. 37 Kitchener Road Thornton Heath Surrey. Simpson Peter Laurence B.Sc. 31 Broom Crescent Rotherham Yorks. Skapski Andrzej Czeslaw. 212 Southfield Road London w.4.Smith Henry Gordon M.Sc. Department of Chemistry The University Manchester 13. Soldano Benedetto A. Ph.D. Oak Ridge National Laboratory Post Office Box X Oak Ridge Tennessee U.S.A. SoIleveld Eric. 50 Manton Road Hitchin Herts. Steele Maxwell Campbell M.Sc. Metal Manufactures Ltd. P.O. Box No. 21 Port Kembla New South Wales Australia. Sye George Robinson B.Sc. 97 Gregagh Road Belfast 6. Taylor Brian. 42 Frinton Road London E.6. Tittle Barry B.Sc. University Chemical Laboratory Lensfield Road Cambridge. Usher Gerald Edward. 577 Basingstoke Road Reading Berks. Vargas Jose Israel Ph.D. University Chemical Labora- tories Cambridge. Walker Alan B.Sc. 75 Radcliffe Road West Bridgford Nottingham. Walters Raymond. 19 Claude Avenue Linthorpe, Middlesbrough.Ward John William B.Sc. 66 St. James’s Road Orrell Wigan Lancs. Wareing Robert George. 104 Bedford Road Walton Liverpool 4. Waring Anthony John B.A. 27 Curzon Road Offerton Stockport Cheshe. Warrell David Charles. 54 Culver Lane Earley Reading Berks. Yorke Brian Alan. 1 Chapel Place Ramsgate Kent. OBITUARY NOTICES EDMUND MILTON RICH 1876-1959 MEMBERS of the Society will have learnt with regret of the death on April 14th 1959 at the age of 83 years of Mr. E. M. Rich C.B.E. B.Sc. F.C.G.I. who from 1933 to 1940 was Chief Education Officer of the London County Council. It is a common-place that anyone is at a great dis- advantage in administering a social service unless he has experienced either in his person or his profes- sional life how the other man lives; that is by having himself climbed the ladder from humble beginnings or having accumulated experience by a period of social work.From this point of view Rich’s qualifica- tions for the post he eventually achieved were out- standing. For after his school days at Aske’s School Hatcham during which on occasions he suffered real hardship he passed to the Central Technical College South Kensington where he obtained his Bachelor of Science Degree and then had nine years’ ex- perience as a teacher and organiser ofscience classes and as inspector in the Irish Department of Agricul-ture and Technical Instruction before returning to London in 1905 to be a Senior Officer in the newly formed L.C.C.Education Department. From this point his career ran straight to the top head of the elementary education branch 1910-1928; head of the technological branch 1907-1910 and 1928-1933; senior assistant education officer 1928 ; education officer 1933-1 940. Many of the most prominent features of to-day’s London education service still bear the stamp of Rich’s enthusiasm and imaginative insight ;the even- ing institute system the co-ordination of the work of the polytechnics and technical institutes the open air schools the out-county playing fields and school journeys to mention a few only. Others such as the re-organisation of the old style elementary schools to allow for a break at llf and the formation of Central Schools became the launching platform for London’s progress with “secondary education for all” under the 1944 Education Act.It is nevertheless for his personal qualities especially those he displayed in his later years that those who were privileged to work closely with him will chiefly remember him. Ehund Rich belonged to that class of educational administrator perhaps too rare to-day who always put first the “pastoral” aspect of the contribution he could make towards the building of a better nation through its educational services. His whoIe career was indeed irradiated by the belief that the sole certainty to which a man can hold steadfast in this life is the certainty that the Kingdom of Heaven will some day cover the earth as the waters cover the sea; and that this millenium must be achieved through a broadening and expand- ing process of national enlightenment through public education.In this impelling faith and indeed in all his endeavours he was wonderfully supported by Mrs. Rich. It is significant that they both never failed even in his retirement to attend the annual service of rededication of teachers held in one or other of London’s national sanctuaries. In certain quarters it is fashionable to-day to hold that the social scientist or social administrator should never permit himself to become emotionally involved in his work This was a test which Edmund Rich would not have passed. Indeed he would have scorned to do so. The welfare of the individual child or teacher the particular school occupied the whole of his waking thoughts sometimes his sleeping thoughts too for one of the smallest but most appreciated gifts he received from a colleague was a pencil with an electric torch inside it which enabled him to write down ideas which occurred to him during the night without having to turn on his bed- side lamp! This profound preoccupation with the welfare of others was probably the characteristic which principally endeared him to his colleagues and to the London teaching service.Nevertheless it took a toll of his nervousenergy so seriousthat during the first bleak war-time winter of evacuation even his iron constitution began to show unmistakable signs of strain under his pre-occupation with the lot of the evacuated London child.After his retirement Rich continued to take a wide interest in a multiplicity of activities educational and personaI. His large garden at Beckenham was a delight but its cultivation did not prevent him from serving for a number of years as Secretary of the Chadwick Trust and as a Governor of the Covenanters Trust becoming a regular attendant at meetings of the Royal Society of Arts,and a keen follower of scientific developments. He remained Chairman of the London Schools Swimming Association until the day of his death. In the various stages of his career in the Education Department a number of eager young men passed through his secretariat. It was a valuable and most appreciated experience. Rich never forgot them.With him it was “once a member of the secretariat always a member of the secretariat”. They and indeed many of his former colleagues looking back over his long life of service to his fellow men will be irresistibly reminded of the words used of another such spirit “one who has lived well loved much and laughed often who has earned the respect of intel- ligent men and the love of little children whose life was an inspiration and his memory a benediction”. ANON. 14N MORRISON AITKEN 1931-1958 IANMORRISON AITKENwas born in Glasgow on November 11th 193 1 and died suddenly in London on December 14th 1958. He attended Loretto School Edinburgh before beginning in 1949 his higher education at the Uni- versity of St. Andrews where he graduated with honours in chemistry in 1954.He elected to work for the doctorate degree at his Alma Mater and was duly awarded the Ph.D. degree in October 1958 for a thesis entitled “Aromatic Systems containing the Perinaphthene Nucleus.” He joined the research group at Imperial College of Science and Technology London under the direction of Professor D. H. R. Barton and was enthusiastically engaged in his post- doctoral problems at the time of his death. Aitken became a Fellow of the Chemical Society as an undergraduate student. Aside from chemistry he had many and varied interests among them travel in which he indulged his strong curiosity. He was a perfectionist and impressed those who knew him by his inquiring and analytical mind his loyalty and sense of duty and his unusual sense of humour.D.H. REID.
ISSN:0369-8718
DOI:10.1039/PS9590000341
出版商:RSC
年代:1959
数据来源: RSC
|
|