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Proceedings of the Chemical Society. October 1961 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue October,
1961,
Page 357-396
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PROCEEDINGS OF THE CHEMICAL SOCIETY OCTOBER 1961 CENTENARY LECTURE* 1,3-Dipolar Cycloadditions By ROLFHUISGEN (UNIVERSITY OF MUNICH,GERMANY) THEdevelopment of a new research field may be [2,2,1 Ihept-Zene and its derivatives described by likened to the industrialisation of an underdeveloped Alder and Stein in 1931. In the reaction1 with di- country of which we read so much in the newspapers cyclopentadiene (I) addition occurs only to the these days. It begins very slowly and seems to pro- double bond in the bicyclic system forming a tri- ceed at a snail's pace until a phase of exponential azoline ring. The heat of hydrogenation2 of bicyclo- growth is reached. In our work on 1,3-dipolar addi- heptene exceeds that of common cycloalkenes by tions in the first year one co-worker was engaged in 6-7 kcal.mole-1 (cf. ref. 2 and Table 1) and discloses preliminary exploration. At the beginning of the an angle strain. So capacity to add phenyl azide is second year two more people joined the effort. Now regarded as diagnostic of angular strain in double in the third year seventeen co-workers reap the bonds. harvest and contribute to further expansion of this reaction. Are ring closures by way of 1,3-dipolar addition really new? If one regards reactions as new only if N they have no forerunners not even singular examples (1) buried in the literature then 1,3-dipolar additions TABLE1. Heats of hydrogenation (kcal. mob-l) in cannot claim novelty. But if one defines reactions as acetic acid at 25". novel which are for the first time recognised for their 27.1 generality scope and mechanism the judgment Cyclohexene must be different.Cycloheptene 25.9 Some sixty years ago 0. Dimroth discovered the Bicyclo [2,2,1 Ihept-2-ene 33.1 formation of triazoles by addition of organic azides Phenyl azide has two major mesomeric structures to acetylenes. Of greater mechanistic interest is the with electron octets on all atoms and both are di- closely related reaction of phenylazide with bicyclo- polar in character Three more canonical forms each * Given before the Society at the Royal Institution Albemarle Street London W.1 on December 8th 1960. Alder Stein and Finzenhagen Annalen 1931 485 21 1. Turner Meador and Winkler J. Amer. Chern. Suc. 1957 79 4116. 357 having one electron sextet contribute somewhat less.On the basis of the all-octet structures phenyl azide is a linear tripole the middle nitrogen holds the formal positive charge while the negative charge is shared between the end nitrogen atoms. In addition of phenyl aide to a double bond three mechanisms are conceivable (see chart 1) (A) the positive end of the dipole may initiate attack and the negative pole then complete the addition; or (B) the negative centre may be attached first and then the positive end; or (C) both charge centres may add at the same time. AI Chart I. Doubts concerning mechanisms A and B are immediately raised because the sluggish organic azide displays neither strong electrophilic nor strong nucleophilic character.The concerted process C is immune to such objections. Here a synchronous shift of electrons results in the formation of two new a-bonds and allows all three nitrogen atoms to achieve stable octets without having to bear a formal charge. Kinetic solvent effects offer a means of distinguish-ing the synchronous from the two-step mechanism. The rate-determining first steps of paths A and B form zwitterions the charges of which are isolated by a tetrahedral carbon atom. Good solvents for ions should facilitate such processes. On the other hand mechanism C is attended by some loss of di- polar character and should be slightly retarded by increased solvent polarity. We have measured the rate of addition of phenyl azide to a strained double bond in several solvents.8 I refer here as in most of this lecture to unpublished work from our laboratory.The results (see Table 2) show no dramatic rise with increasing polarity of the solvent. The rate constants differ by less than a factor of two. The modest trend is even slightly opposed to the dielectric constants of the solvents. Huisgen Stangl and Wagenhofer unpublished work. Roberts Chem. Ber. 1961 94 273. PROCEEDINGS Ali of this is however consistent with the polycentre mechanism which calls for some decrease in polarity in the activation process. TABLE 2. Kinetics of the addition of phenyl azide to the strained double bond of diethyl tetrahyctro-3,6- methylenepyridazine- lY2-dicarboxylate (11). 104k2 Dielectric Solvent Acetonitrile (1.mole-l sec.-l) 1-50 constant 36.7 Ethanol 1-67 24.3 Methylcellosolve Benzene 1 -89 1*90 -2.3 Dioxan 2.10 2.2 PyridineCyclohexane 2.24 275 12.3 2.0 The organic wide is represented in the reaction scheme with a sextet formula one of many resonance structures. The arrows show a conceivable pattern of electron shift during the reaction. These are of course only a kind of electron book-keeping since it is meaningless to define the direction of electron movement in a cyclic process. FIG.1. Configurationof azides. .. + -,-=N=N -,:N-&EN R 114' .' R Molecular-orbital calculation (LCAO). (J. D. Roberts 1959). Em = 6~ + 4.838 4u + 243B + Q 2a + 043p < Q < 2u + 2g u = Coulomb integral of nitrogen./3 = Resonance integral of nitrogen. 0, Q = Energy gain for -Qg -N OU 0 Result The bending of the nitrogen chain of an organic aide does not require much energy. However the rod-like organic azide with its linear three-nitrogen chain must bend in the activation process in order to make contact with the n-bond of the alkene. I am highly indebted to Professor J. D. Roberts for a LCAO calculation on the azide system the clear result of which is that relatively little energy is required to distort the linear structure as shown in Fig. 1. OCTOBER 1961 Now let us generalise this train of thought in order to define the broad phenomenon of 1,3-dipolar addition. 1,3-Dipolar addition is the union of a 1,3-dipole a-b-c with a multiple bond system d-e the so-called dipolarophile to form a five-membered ring.A 1,3-system with an electron sextet at a with attendant positive charge and an unshared electron pair at the anionic centre c constitutes a 1,3-dipole in the sense we intend. In the addition the two reactants “collapse” to a five-membered ring with loss of the formal charges. This principle of ring closure fits in a regular sequence between olefin di-merisation to cyclobutane derivatives and the Diels-Alder synthesis (see Chart 2). Cycloadditions. a c a-c Thermal and photo- b-d” induced dimerimtion :+a -I of alkenes. aT +kt -gay lY3-Dipolar addition. \c e a -Be I Diels-Alder reaction. +II -C f ci \d ‘d’ a+ :c -:c -With double bond.Without double bond. b=N b=NorO Chart 2. 1,3-Dipoles with the positive centre an electron- deficient carbon nitrogen or oxygen atom are not capable of existence as stable substances. The symbol used in the formula refers to a resonance structure in which atom b holds a lone pair of electrons. This pair can fill the electron gap at atom a by forming an additional bond thus shifting the formal charge to b. If the “unmasked” 1,3-dipole con- tains a double bond as shown on the left in Chart 2 the middle atom b must be nitrogen. The first row of the Periodic Table does not offer another element which can accommodate a lone pair in the neutral tervalent state. On the other hand we can imagine an unmasked 1,3-dipole without a central double bond.Again a lone pair of atom b must through resonance effect stabilisation of the electrophilic centre. Within the first period atom b may now be nitrogen or oxygen. TABLE 3. 1,3-Dipolar systems with double bonds. Nitrilium betaines. -Ct=fj-s-< -CZN?C-<.. Nitrile ylides. + ..--CLE-O--C=N-0 Nitrile oxides. Diaz0niu.mbetaines. N+=N-c-< -N+-c-< Diazoalkanes. N+=N-OY -REN+-O! Nitrous oxide. Six 1,3-systems with a double bond are conceiv- able. These are classified as nitrilium and diazonium betaines (see Table 3). Within each group the anionic centre is varied from C through N to 0,that is from the ylide through the imine to the oxide. For each type the all-octet formula is given at the right of the Table while the resonance structure symbolising its 1,3-dipolar character is shown on the left.H... Ph<pq H.. 2 isomers R-Ph 63% Reagents 1 CH,:CH.CN. 2 RCHO. 3 Chloranil. The first of these systems the nitrile ylide was not to be found in the literature. In our laboratories Dr. H. Stangl discovered that benzimidoyl chloride with a p-nitrobenzyl group on the nitrogen atom eliminates hydrogen chloride on treatment with tri- ethylamine in benzene at room temperature. The labile nitrile ylide (three resonance structures of which are shown) cannot be isolated but is easily intercepted by dipolarophiles. In the presence of acrylonitrile 1,3-addition yields two diastereomeric 1-pyrrolines which can be dehydrogenated to an aromatic pyrrole derivative; the position of the cyano- group is still uncertain.The aldehyde group was also a suitable dipolarophile. Crystalline adducts were obtained with benzaldehyde and acetaldehyde the oxazoles resulting from dehydrogenation were identical with products of independent syntheses. If we change the carbanion to a nitrogen anion we get the nitrilimines. Thorough investigation of this class served as a touchstone for the usefulness of the synthetic principle. The "isodiazomethane" of E. Muller is the parent substance of this class and was its only representative in the literature. Cycloaddi- tions of isodiazomethane are not known. Thermal breakdbwn of 2,5-d@henyltetrazole. 1,3-Dipolar addition of diphenylnitrilimine to multiple CO and CN bonds bN-NPh PhC I N=N Ph 4"NPh PhqNhPh 04Ph -N 1 150-170° NT,Hic[-p (52%) J \ (Ph*C+=N-N'Ph ..Ph QN'N Ph PhFN 'NFh PhN-fPh PhN-$ (48'10) (73'10) Reactants 1 PhCHO. 2 p-C,H*Cl.CN. 3 Ph.CH:NPh. 4 PheNCO. M. Seidel discovered a general route to nitrilimines in the thermal breakdown of 2,5-disubstituted tetrazoles. At 150" a nitrogen molecule is expelled from the aromatic nucleus of 2,5-diphenyltetrazole. The diphenylnitrilimine so formed undergoes an unusual variety of addition^.^ Combination with the carbonyl group of benzaldehyde gives a derivative of 1,3,4-oxadiazoline a new heterocycle. When it is generated in solutions of nitriles diphenylnitrilimine adds to the CrN triple bond producing 1,2,4-tri- azoles.The C=N double bonds of benzylidene- aniline and of phenyl isocyanate have also proved to be good dipolarophiles. PROCEEDINGS Thermolysis of 2,5-diphenyltetrazole at 150-1 70". Additions of diphenylnitrilimine to alkenes and alkynes. J 88% 'I Reactants 1 Dicyclopentadiene. 2 Et fumarate. 3 1,4-Naphthaquinone. 4 1,2-Dihydronaphthalene. 5 Et phenylpropiolate. Alkenes and alkynes may also function as acceptors for diphenylnitrilimine. When diphenyl- tetrazole is thermally decomposed in diethyl fumarate diphenylpyrazoline-4,5-dicarboxylicester is formed in 88% yield. The quinonoid system the strained double bond of dicyclopentadiene and the phenyl-conjugated double bond of 1,2-dihydro-naphthalene afford further typical examples chosen from a large body of experiments.The dipolaro- philic triple bond is represented in the reaction scheme only by ethyl phenylpropiolate :the structure of the pyrazole derivative formed in 84% yield has been firmly established and the same is true for all the other adducts shown. I should like to mention in passing that nitrilimines with alkyl groups on the carbon or nitrogen atom are also available from analogous syntheses and are reactive in dipolar additions. This decomposition of tetrazoles leads to a number of interesting heterocyclic systems. However we were worried by having to use temperatures above 150" to open the tetrazole nucleus. We should have preferred reactions which ran smoothly at room temperature without the need for catalysis and in quantitative yield.Huisgen Seidel Sauer McFarland and Wallbillich J. Org. Chem. 1959,24 892; Huisgen Seidel Wallbillich and Knupfer Tetrahedron 1961 in the press. OCTOBER 1961 Preparation of diphenylnitrilimine from N1-a-chloro-benzy lidene-N2-phenyIhydrazine. 1,3-Dipolar additions to multiple carbon-carbon bonds. N-NHPh EtSNH' C1-PhC< + NEt 7+ + Ph- CEN-N-Ph CI P A /Lornone Ph 9470 Norbornadiene (10equiv.) Cyclopentene Styrene Acrylonitrile Phenylacetylene &Ph &CN Ph 8070 Ph 85qo Ph 72% A synthesis carried out by G. Wallbillich5 approxi- mates to this ideal. In W-a-chlorobenzylidene-W-phenylhydrazine we have a derivative of benzoyf chloride in which the carbonyl-oxygen atom is re- placed by the phenylhydrazone group.Treatment Further additions of nitrilimines. dN-NHPh I 2 WC -Ph<N\Nph 'Cl CH N+N-CH 'kN,N>Ph6 I' 46% Ph<&h PhN >Ph 63% 'N .. Me.CO*C JN-NHPh hkOC<aPh 'CI 84% Reactants 1 C(=N-C,H,,),-NEt,. 2 CS,. 3 Nor-bornene-NEt,. 4 NEta in norbornene. with a tertiary amine sets free the diphenylnitrilimine even at 20".In the presence of norbornene 94% of the exo-adduct was formed. Some further pyrazolines and pyrazoles are listed in the scheme with yields. The adducts are all of confirmed structure except that the relative orientation in the bisadduct of norbornadiene is uncertain. Cumulated systems such as carbon disulphide and carbodi-imides react twice-of course one double bond after the other-with diphenylnitrilimine to produce heterocyclic spiro-compounds (see reaction scheme).This second path to nitrilimines is also open to variation. The hydrazide chloride of pyruvic acid is converted into the nitrilimine which adds smoothly to norbornene. The nucleophilicity of the nitrogen of this nitrilimine is so diminished by a p-nitro-group that the compounds fail to react with norbornene head-to-tail dimerisation of the 1,3-dipole to a di- hydrotetrazine derivative then takes place as a competing reaction. Diphenylnitrilimine as a 1,3-dipole. Stereoselective cis-addition to cis-trans-isomeric alkenes. H Ph M.p.167-168' Ph /NxNPh PhLPh Ph QPh f NEt PhoPhe MeO,.J-.-Me Me C0,Me Me-Me02C C02Me M.p 107-108' Mp 144-145" By analogy with the related Diels-Alder reaction 1,3-dipolar addition would be expected to take a stereoselective cis-course. The reactions of diphenyl- nitrilimine with cis- and trans-stilbene do produce diastereomeric pyrazolines which give the same tetraphenylpyrazole on dehydr~genation.~ Diastereo-meric products are likewise formed by cis-addition to dimethyl fumarate and ~naleate.~ Continuing down our list of 1,3-dipolar systems we come next to nitrile oxides. These veterans amongst the 173-systems became known through early investigations of A. Werner and of H. Wieland. 1,3-Dipolar additions of nitrile oxides. Dimerisation. Ph *C= N+-,d + i Ph(:O ,I' Ph .&N+-0-Ph Nb-Addition to alkenes and alkynes.HC~N+-O--co +H& HCZH H0.N Their smooth dimerisation to furoxans6 is now recognised as 173-additionof one molecule to a second acting as a dipolarophile. A. Quilico has studied within the last twenty years many additions of nitrile oxides to alkenes' and alkynes? forming isoxazolines and isoxazoles. 1,3-Additionsof benzonitrile oxide to nitriles aldehydes and ketones. 4 NOH Ph-C 'CI 0-f Ph 5570 H Reactants 1 PhCN. 2 (MeCO),. 3 NCC0,Et. 4 OHCCOzEt. 5 PhCHO. Under conditions of high dilution nitrile oxides can be caused to undergo 173-additions with a multitude of nitriles aldehydes and ketones at the expense of the dimerisation. By slowly adding tri- ethylamine to a solution of benzhydroxamoyl chloride and benzonitrile in ether at -lo" Dr.W. * Wieland and Semper Ber. 1906 39. 2522. Quilico and Grunanger Gazzetta 1952 82 140. Quilico and Panizzi Gunettu 1942 72 458. PROCEEDINGS Mack obtained diphenyl-l,2,4-oxadiazolein 70 % yield. Benzonitrile oxide combines with sufficiently active carbonyl compounds-only a few examples are illustrated-to form 1,3,4-dioxazoles which represent a new heterocyclic system. Next on our list of 1,3-dipoles comes the second sub-group comprising betaines of molecular nitro- gen. The ylides of this sub-group are the diazo-alkanes. Their readiness to form pyrazolines with a@-unsaturated carbonyl compounds has been known for seventy years. A kinetic investigation carried out by Drs.H. Stangl and H. Wagenhofer revealed only a minute and irregular dependence of the rate of addition on the solvent. This is evidence for a synchronous 1,3-dipolar addition contrary to earlier assumptions. Though we have also worked on the additions of diazoalkanes and azides I shall pass on to the 173-dipoles which lack a double bond in the "un-masked" resonance structure. As already mentioned TABLE 4. 1,3-Dipolar systems without a double bond. (1) Nitrogen as the centre atom. \ + '* -/ \ ,C -y-C . -,C=N+-g-< Azomethine ylides. I \ + .. ... ,C-F;I-N ->c=$l'-N\ Azomethine imines. ,C-N-G: ,.+ .. .._ -,C=\ N+-0 Nitrones. I I -N=y+-N-, -Nt-N-N- Azonium imines. *-I *-+ .. ..--N -NI -0 -N=~,J+-@ Azoxy-compounds... .. I :o+-N-G.. -:p~+-~yNitro-cornpounds. .. I I (2) Oxygen as the centre atom. /c .. \ +-Q-G-< -xq+-S-<Carbonyl ylides. ,+ .. ..-\ /c-o-N\ -,C=O+-N-\ Carbonyl imines. ,c,+ ** -9-0; ->c=O+-O' Carbonyl oxides. .. ..-t ,N-O-p!\ -N=~+-~;Nitroso-imines. -&+-O-OT -N=O+-OT Nitroso-oxides. ..+ .. ..-9-0-9 -:O=O+-Oi Ozone. either nitrogen or oxygen can act here as the middle atom. Table 4 shows the succession from azomethine ylides to ozone. Several of these 173-dipoles are still unknown and I shall here discuss only two of the series. OCTOBER 1961 The all-octet formulae with C=N double bonds mark the first three systems as azomethonium betaines derivativesof Schiff's bases.The ylides and imines of this series were prepared in our laboratory for the first time. A fortuitous observation by Dr. R. Azomethine imines from aryl diazocyanides and diazoalkanes. N-CN c,mrJ/ Ac1 \==/+ 20° -Diaziridine formda 3.0-\ 33 2-5220 300 O 400 500 220 300 400 500 Wavelenqth (ny) Fleischmann opened the door to a series of stable crystalline azomethine imines. Aromatic diazo-cyanides react with diazoalkanes at room tempera-ture. Electrophilic attack on the central carbon of diazofluorene for example is quickly followed by elimination of a nitrogen The electronic and vibrational spectra of the resulting orange-red crystals are clear evidence for the open-chain zwitterion rather than the cyclic diaziridine.Azomethine imines of this type neither dimerise nor react with alcohols or amines. However their readiness to undergo 1,3-dipolar additions is dis-closed when they are gently warmed with nor-bornene or styrene whereby crystalline 1:1 adducts are formed in yields of 96% or 92% respectively.1° The CIC triple bond also serves as an acceptor for the azomethine imine. Additions to acetylenedi-carboxylic ester phenyl isothiocyanate and phenyl isocyanate studied by A. Eckell occur smoothly at 2Oo.l0The orientation in these additions is yet to be elucidated. 1,3-Dipolar additions of the azomethine irnine from p-chlorobenzene diazocyanide and diazofluorene. Reactants 1 Norbornene at 90". 2 Styrene at 70". 3 Acetylene in acetone at 40".4 Phenyl isothiocyanate at 20".5 Phenyl isocyanate at 20". An even more reactive class of azomethine imines is available by proton abstraction from the hydro-zonium salts of the 3,4dihydroisoquinoline series described in 1958 by E. Schmitz. These salts can be regarded as intramolecularalkylation products of an aldehyde arylhydrazone. Treatment with a tertiary amine liberates the dark red azomethine imine which adds smoothly to a variety of unsaturated com-pounds as Dr. R. Grashey has observedJl Dicyclo-pentadiene yields quantitatively a pure crystalline adduct though structural isomers and diastereomers might be expected. I am aware that claims of 100% yield are tolerated only in patent applications but I do not hesitate to risk my reputation here.Maleic and fumaric esters give isomeric products showing that original steric relationships are maintahed. What happens to these azomethine imines in the absence of dipolarophiles? Dimerisation occurs precipitating the hexahydrotetrazine as yellow crystals. The existence of a reversible thermochrom-ism indicates a mobile equilibrium. Significant amounts of the monomeric zwitterion are present at temperatures as low as 50-80". The hexahydro-tetrazine is stable and offers a convenient source for such azomethine imines. Aryl-conjugated olefins exhibit good dipolaro-philic activity as the pleasing yields of adducts from styrene and acenaphthylene testify. The red azomethine imine combines with alcohols to form yellow 1,3-adducts which in turn begin to dissociate at 100"into the components.This thermal cleavage provides a small equilibrium concentration * Huisgen Fleischmann and Eckell Tetrahedron Letters 1960 No. 12 1. lo Huisgen and Eckell Tetrahedron Letters 1960 No. 12 5. l1 Huisgen Grashey bur and Leitermann Angew. Chem. 1960 72 416 and unpublished work. PROCEEDINGS Azomethine imines of the 3,4-dihydroisoquinoline series. t c- Reagents 1 NEt in H.C0.NMe2. 2 HBr. Reactants 3 Me maleate at 20”(Mez fumarate gives an isomeric product.) 4 Dicyclopentadiene at 20”. Azomethine imines of the 3,4-dihydroisoquinoline 1,3-Dipolar additions of azomethine imines from the series. 3,4-dihydroisoquinoIine series. Phenyl-conjugated alkenes. Cumulated systems. Styrene.Acenaphthylene. 1-Alkoxy-2-arylamino-1,2,3,4-tetrahydroisoquinolines as generator. Non-conjugated alkenes. Allylbenzene at 80O . Cyclopentene at 75”. Ph*CH2 74% 60% Reactants 1 Ph,C:CO. 2 C(=NPri) at 90”. 3 PhNCO Reactant 1 CHiC.CO,Me. 2 PhCH:NMe. at 20”. OCTOBER 1961 365 of the 1,3-dipole and makes the 1-alkoxy-2-aryl- aminotetrahydroisoquinolines excellent sources of azomethine imines. The additions to methyl pro- piolate and benzylidenemethylamine exemplify this procedure. Cumulated systems such as ketens carbodi-imides isocyanates and even carbon disulphide are excellent dipolarophiles giving fast additions and very good yields. Though non-conjugated alkenes are relatively inert allylbenzene and cyclopentene react reasonably well.The azomethine imines so far mentioned are not simple types but are rare structures more or less curiosities. In the beginning we were anxious to obtain quickly representative 1,3-dipoles and to determine their capability for 1,3-addition. But now we are engaged in the elaboration of general syn- thetic pathways. Incidentally the arylated hexa- hydrotetrazines which dissociate to azomethine imines are conveniently and cheaply available by other methods of synthesis. How strong is the driving force of 1,3-dipolar addition? The behaviour of azomethine imines with a C=N double bond built into an aromatic nucleus is instructive. One of the numerous resonance struc- tures of the blue-violet pyridine imine has in its +C-N-Nf group the characteristic structural ele- Azomethine imines with aromatic C=N bond.Pyridine imine. Quinoline imine. pale yellow . MJH 39% N-Ph 7 9 qm*R 81°/0 N=C-S-Reagent 1 K,CO in H-CO.NMe,. Reactants 2 (MeO,C.Ci),. 3 PhCiCC0,Et. 4 CS2. ment of azomethine imines. That 1,3-addition occurs even though the aromatic pyridine resonance must be sacrificed shows that the driving force is strong indeed. R. Krischke studied the reaction with di- methyl acetylenedicarboxylate at room temperature. The primary adduct undergoes a redox reaction with a second molecule of the acetylene derivative pro- ducing a pyrazolopyridinedicarboxylicester and di- methyl fumarate. In the analogous reaction of iso-quinoline imine with acetylenedicarboxylic ester the primary adduct was isolated as yellow crystals in 75% yield.Quinoline imine and isoquinoline imine occur in dimeric form as hexahydrotetrazines with non-aromatic hetero-rings. Their readiness to undergo 1,3-addition is explicable in terms of a small equi- librium concentration of the monomeric imine. 2-Methylindazole as masked azomethine imine. Reaction with maleic anhydride. H 20% 270 0 I Maleic anhydride in boiling AcOH (4 hrs.). It is surprising that 2-methylindazole shows 1,3-reactivity inasmuch as the 1,3-dipole is com-pletely incorporated in an aromatic ring. The reaction with maleic anhydride indicates the reality of the azomethine imine grouping in this molecule. Admittedly if we consider the structure lacking formal charges the difference between 1,3-dipolar addition and the DieIs-Alder reaction becomes to some extent a question of semantics.By a series of changes this reaction gives quinoline its 3-carboxylic acid and the 2,3-dicarboxymethylimide.The 1,3- addition is followed we think by opening of the anhydride ring and elimination of methylamine and carbon dioxide.la Azomethine oxides (nitrones) have been known for eighty years and are thoroughly investigated. Their only reported cyclo-addition is that with phenyl iso- cyanate described by E. Beckmann in 1890. In our hand almost all kinds of olefinic double bonds com- bined readily with the 1,3-system of nitrones.13 This 1,3- Dipolar additions of nitrones. Phenyl isocyanate.AlCH,Ph $H,Ph Alkenes. 1Hydrogcnoiy.lr reaction was also explored recently by M. A. T. Rogers in England. Diphenylnitrone and styrene react quantitatively at 90"to give triphenylisoxazoli- dine the structure of which was elucidated by hydrogenolysis. The addition of a dialkylnitrone to methyl methacrylate is a second example. 3,4-Dihydroisoquinole N-oxide a mixed aro-matic-aliphatic nitrone unites smoothly with the strained double bond of norbornene. Diastereomerk adducts are obtained with dimethyl fumarate and maleate in noteworthy yields. The clean additions suggest analytical application in the characterisation of liquid olefins. Dr. R. Grashey prepared in less than four months more than 5 dozen nitrone-adducts. It is not even necessary to prepare the nitrones in advance:interaction of butyraldehyde with phenyl- PROCEEDINGS 1,3-Dipolar adaitions of nitrones.3,4-Dihydroisoquinolhe N-oxide. H-H % Me02C C02Me too 70 95yo 0 M~o~c-~-H 100% H C0,Me Reaction with nitrones in sifu. Yh MeCH2*CH2.CH0 + Ph.NHOH65"-"=32)QH + Ph.CH=CH H2 Ph Reactants 1 Norbornene. 2 Me2 fumarate. 3 Me, maleate. hydroxylamine in an excess of styrene gives a sub-stantial yield of the isoxazolidine. Our discyssion has been limited so far to 1,3- dipoles which can be written with all-octet structures. Even within this group many important lY3-dipoles are not isolable. Abandoning our emphasis on octet stabilisation let us proceed to further classes of 1,3-systems which now possess carbon as the central TABLE 5.1,3-DipoZar systems without octet stabilisation. Systems with double bond. +--c=c-c/ +-.+ -c.-c=c< Vinylcarbenes. LJ ItY' Ir + ..-.. .. -c=c-N--c-c=N-Iminocarbenes. I -. I -c+=c-o -?-C=O Ketocarbenes. I *-I. N+=c-G-< -N-c=c< Vinylazenes. *-1 Systems without double bond. ,+ I .._ ,+ I ..- .. \ c+-6-c-y\ ,C-?-!-,c-c-0 l2 F. Wimmer Ph.D. Thesis Munich 1959. l3 Grashey Huisgen and Leitermann TetrahedronLetters 1960 No. 12 9. OCTOBER 1961 367 atom as listed in Table 5. Every resonance structure of every 1,3-dipole in this class bears the blemish of an electron sextet and so we do not hope to isolate these dipoles. The first sub-class comprises un- saturated carbenes and azenes.The dipoles with a tetrahedral carbon in the middle constituting the second sub-class are still nameless but not unknown. Our hope of carrying out cyclo-additions with such highly labile 1,3-systems has been realised in several cases. I shall single out the ketocarbenes which are hypothetical intermediates in the Wolf€ rearrange-ment of diazo-ketones. Thermal or photolytic Ketocarbenes. Thermolysis of diazo-ketones. {O) &{P h ?-;-+ 6-1-Ph ph,C=CO Ph \ 60% PhC=C-Ph Photolysis of diazo-oxides. 1,3-Dipolar additions. Reactants 1 Me maleate. 2 PhCN. 3 Ph-C=CH. 4 PhNCO. elimination of nitrogen convepts benzoylphenyl-diazomethane (a-diazodeoxybenzoin) into diphenyl- ketocarbene which rearranges to diphenylketen so fast that all attempts to intercept it with trapping reagents have failed>* Diazo-oxides which have the diazoketone struc- ture in an aromatic ring undergo a similar rearrange- ment after the expulsionof nitrogen.15 Our speculation that the aromaticity of the intermediate would retard ring contraction and increase the life of the aromatic ketocarbene turned out to be correct.Dr. H. Konig isolated crystalline ketocarbene adducts on thermal l4 Schroeter Ber. 1909 42 2336. l6 Siis Annalen 1944 556 65 85. cleavage of tetrachlorobenzene-o-diazo-oxide in maleic ester phenylacetylene benzonitrile and many other dipolarophiles. Thus the intermediate has not only been proved to exist but put to work. Our researches to date which have produced more than 500 analysed adducts constitute a first survey of the scope of 1,3-dipolar addition.The hetero- cycles thus available are reviewed in Tables 6-8.. TABLE 6. Heterocyclic systems available by I ,3-dipolar additions (I). Pyrrolines and pyrrolidines. Imidazolidines. Pyrazoles pyrazolines and pyrazolidines. lY2,3-Triazoles and triazolines. The ring systems in boxes had not been prepared by this principle before our work. A complete theoretical account concerning mole- cular structure and reactivity in lY3-dipolar addition is beyond the scope of this Lecture. However allow me to pull a few threads out of the fabric of governing factors. The problem of the activity sequence of dipolaro- philes is of major importance for preparative application.Dipolarophilic reactivities do not match dienophilic character in the Diels-Alder reaction. The excellence of phenyl isocyanate and carbon disulphide as dipolarophiles are cases in point. The strength of the new a-bonds formed is another decisive factor. Ozone for instance reacts exclusively with the C=C double bond. Addition to the C=O or C=N double bond fails because the energy of the new 0-0 or N-0 bond is too low. This factor alone TABLE 7. Heterocyclic systems available by 1,3-dipolm addition (11). 1,2,CTriazoles -triazolines and -triazolidines. I"-% I Tetrazoles and pentazoles. Furans and dihydro- and tetrahydro-furans. 1,3-Dioxolans and 1,2,3- and 1,2,4-trioxolans.demonstrates that there canbe no universal dipolaro- phile scale. Every 1,3-systern requires experimental study of its own dipolarophile sequence. The high activity of bicycloheptene derivatives is easily accounted for by relief of angle strain. Any kind of conjugation increases the activity of an ole- finic dipolarophile even though loss of conjugation energy during the addition diminishes the reaction enthalpy. In the rates of addition of diphenyldiazo- methane to alkenes we see (Table 9) that a neighbour- ing cyano- or carboxylic ester group is more helpful than phenyl.16 The great influence of steric effects is consistent with the high negative entropy of activation of poly- centre addition. The rate constant for acrylic ester is reduced 14-fold by an a-methyl group while a p-methyl group causes a remarkable 280-fold re- tardation.Of cis-trans-isomeric alkenes the trans- compound always reacts the faster. The van der PROCEEDINGS TABLE 8 Heterocyclic systems avaitable by 1,3-d@olar addition (111). Oxazoles oxazolines and oxazolidines. Tsoxazoles isoxazolines. and isoxazolidines. 1,lf.l 1,2,4-Oxadiazoles and -0xadiazolidines. )L---. Furoxans 1,3 ,Coxadiazolines and -oxadiazolidines and 1,3,4-dioxazoles. 1,3,4-Thiadiazolines and -thiadiazolidines 1,3-oxathioles and 1,4,2-0xathiazoles. Waal's compression of the cis-substituents is in- creased when during the activation process the bond angles of 120' shrink to tetrahedral ones. This adds to the activation energy and makes the TABLE 9.Electronic and steric efects on the rates of 1,3-dipolar additions of diphenyldiazomethane. Rate constants (105k in 1. mole-I sec.-l) are for solutions in dimethylformamide at 40". H2C= CHBU v. slow H2C=CHPh 1-40 H2C= CHCN 434 H2C- CH.CO,Et 707 H,C=CMe.CO,Et 51 MeCH= CHC0,Et 2-5 Ph CH = CH.CO2Et 1.3 Me maleate 69 Me fumarate 2450 Me methylmaleate 1-6 Me methylfumarate 13-9 l6 Huisgen Stangl Sturm and Wagenhofer Angew. Chern. 1961,73 170. OCTOBER 1961 trans cis rate ratio a valuable argument for con-certed additions. Directive effects in the 1,3-addition drive home the Additions of dip hen y Initrilimine . Subtle structural changes can reverse the orientation in addition.Ethyl acrylate. Acrylonitrile. 85% H Methyl propiolate. Propynal di-n-propyl acetal. Ethyl phenylpropiolate. Ph &iPh Et0,C Ph 84% Ethyl cinnamate (88%). PhN'"NPh + H"rr/Ph Et02C H H CO,Et Major Minor important role of steric factors. The sense of di-phenylnitrilimine addition changes with the steric requirements of the unsaturated ester.17 Apparently the beneficial influence of conjugation on addition rate is not due only to the resonance effect of the carboxy-function. We are inclined to believe that higher polarisability of conjugated systems is responsible for the rate enhancement. The well-known exaltations in molecular refractions of conjugated systems testify to their greater electron mobility. To conclude I express my warmest thanks to my able co-workers to whose enthusiasm skill and diligence I owe so much.Albrecht Eckell Dr. Rudolf Fleischmann Dr. Rudolf Grashey Hans Knupfer Dr. Horst Konig Roland Krischke Peter Laur Herta Leitermann Dr. Wilhelm Mack Michael Seidel Dr. Heinz Stangl and Gunther Wallbillich participated in the work which I have presented in this Lecture. The achievements of other co-workers could not be discussed in the limited time available but are no less worthy of acknow- ledgement Klaus Bast Rudolf Bermes Dr. James M. Craven Hans Hauck Dr. Robert M. Moriarty Gerhart Miiller Elmar Steingruber Dr. Hans-Jurgen Sturm Edmund Stelter and Volkmar Weberndorfer. Above all I appreciate the especial contributions of my associate Dr.Grashey. l7 Huisgen Seidel Wallbillich and Knupfer Tetrahedron 1961 in the press. COMMUNICATIONS Acetoxylation accompanying Nitration with Nitric Acid-Acetic Anhydride Mixtures By A. FISCHER J. VAUGHAN, J. PACKER and G. J. WRIGHT (UNIVERSITY CHRISTCHURCH, OF CANTERBURY NEWZEALAND) O-XYLENE (2 mol.) was nitrated at 0" with nitric acid (1 mol.) in acetic anhydride (4 mol.) under condi- tions designed to minimise polynitration. The aro- matic fraction of the final mixture was isolated with- out using alkali and its components were separated on commercial large-scale gas chromatogram. Apart from the excess of xylene the fractions yielded 3-nitroxylene (16 %) 4-nitroxylene (33 %) and 3,4- dimethylphenyl acetate (51 %); the retention time of the acetate was closely similar to that of 3-nitro-xylene.Product compositim was reproduced to f1% in three runs and neither the isomeric acetate nor any acetoxynitroxylene appeared to be present. The nitro-group of nitroxylene was shown to resist replacement under the conditions of the reaction. In similar conditions only 2% of acetoxylation occurred with toluene a result which indicated an electrophilic acetoxylating species. Hemimellitene was also of interest because the failure of o-xylene to yield any 3-acetoxy-product had led us to suspect that the acetoxylating species might be relatively large. Hemimellitene has its more activated ring- carbon in the hindered 4-position but activation at this point is greater than at either of the two available positions of o-xylene.From hemimellitene were ob- taincd the 4-nitro-(55 %) 5-nitro-(9 %) 4-acetoxy-(9 %) and 5-acetoxy-derivatives (27 %). Acetoxyla-tion in the hindered position is here appreciable even after allowance for the identity of the 4-and the 6-pssition of hemimellitene. In further experiments the hydrocarbon used was o-xylene. Variation in the amount of nitric acid used (between 1 and 0.006 mol.) did not affect product composition. nor did addition of acetic acid (1 mol.). PROCEEDINGS Addition of sulphuric acid which has a marked acetoxylating species is protonated acetyl nitrate and accelerating effect on nitration in acetic anhydride that nucleophilic attack by an activated ring- appeared to have an even greater effect on acetoxyla- carbon takes place on the oxonium oxygen of the tion.The proportion of acetoxy-product rose to 54 % Ac~H-NO ion. We consider that involvement of with 0.01 mol. of sulphuric acid and to 58% with this ion is more likely than that of an alternative 0.02 mol. while the ratio of nitro-isomers remained species in which a terminal oxygen is protonated and unchanged. Xylene was not acetoxylated when nitric which would react to release a nitrous acid molecule. acid was replaced by an equivalent amount of sulphuric acid. Application of a modified Griess-Ilosvay reagent Financial support from the New Zealand Univer- indicated that acetoxylation is accompanied by sity Research Committee and the award of an I.C.I. release of an approximately equivalent amount of (N.Z.) Research Fellowship (to G.J.W.) are grate- nitrite.fully acknowledged. On the basis of these results we suggest that the (Received August 21st 1961.) Reaction of Olefin-Palladium(~~) Chloride Complexes with Nucleophiles :a New Vinylation By E. W.STERNand M. L. SPECTOR (THEM. W.KELLOGG Co.,JERSEYCITY N.J. U.S.A.) IT has been reported recently1 that good yields of octane at room temperature for 118 hours 36.6 vinyl acetate were obtained by reaction of the com- mole% (calc. on PdCld of isopropenyl acetate was plex (C2H,PdCIa2 or of ethylene and palladium(@ produced. chloride with acetic acid containing sodium acetate All of the above reactions were accompanied by that this reaction was accompanied by reduction of the precipitation of palladium.No precipitation was the chloride to the metal and that a similar reaction observed when butadiene was shaken with acetic occurred between ethylene and ethanol to yield acid palladium(@ chloride and the phosphate for acetaldehyde diethyl acetal presumably by the acid- 168 hours at room temperature however precipita- catalysed addition of ethanol to the vinyl ether tion occurred when the reaction mixture was heated formed initially. to 65O butadienyl monoacetate being produced. We have found that the complex,2 (C,H,PdCla, Reaction of propene with n-butylamine and with reacts with acetic acid in iso-octane in the presence acetamide in tetrahydrofuran in the presence of the of disodium hydrogen phosphate to yield 3-2mole % metal chloride and phosphate was indicated by the (calc.on the complex) of vinyl acetate in 16 hours at precipitation of palladium. Isolation and analysis of room temperature. Similarly the complex reacted products in these cases were complicated by the fact with isopropyl alcohol to yield 1.6 mole% of vinyl that both the nucleophiles and the products apparent- isopropyl ether and 15.8% of acetaldehyde di-iso- ly formed stable complexes with palladium(n) propyl acetal in 4 hours at 5". Extension of the chloride. Destruction of these complexes by hydro- reaction time to 16 hours at room temperature in- genation yielded butylisopropylamine and N-iso- creased the acetal yield to 21*0%,while the yield of propylacetamide respectively indicating that vinyl ether remained unchanged.vinylation had taken place. In a similar manner Ethylene when shaken with palladium(1r) chloride N-ethylacetamide was obtained on reaction of and disodium hydrogen phosphate in iso-octane (C2H4PdC1,)2 with acetamide. containing acetic acid was converted into 22.2 mole% (calc. on PdCl,) of vinyl acetate after 120 On the basis of these findings it appears that a hours at room temperature. Under similar condi- new vinylation reaction has been found. A detailed tions ethylene reacted with isopropyl alcohol to discussion is deferred but we suggest now that the yield 1-5 mole % of isopropyl vinyl ether and 20.2% symmetrical complex formed initially from the olefin of the isopropyl acetal after 16 hours. Again extend- and palladium(@ chloride3s4 is converted into an ing the reaction time to 288 hours under these con- unsymmetrical charged species by solvolysis of a ditions did not affect the ether yield but the yield of chloride from the complex followed by a nucleo-philic attack on a positively charged carbon as acetal was increased to 35.6%.When propene was shaken with acetic acid illustrated here for the reaction of ethylene with palladium(u) chloride and the phosphate in iso- acetic acid. (Received,Jury 3rd 1961 .) Moiseev Vargaftik and Syrkin Doklady Akad. Nauk. S.S.S.R. 1960 133 377. Kharasch Seyler and Mayo J. Amer. Chem. SOC.,1938 60 882. Chatt and Duncanson J. 1953 2939. Reeves Canad.J. Chem. 1960,38 736. OCTOBER 1961 371 Carbon-basicity of Halide and Halogenoid Ions in Nitrobenzene By A.J. PARKER* (WILLIAM LABORATORIES COLLEGE W.C. 1) RAMSAYAND RALPHFORSTJZR UNIVERSITY LONDON ATTEMPTShave been made1s2 to compare the nucleophilic tendencies [i.e. the relative rates at which different Y-displace a standard group X in reaction (i)] of a series of anions Y- with their basicities towards hydrogen. The conclusion is that there is little correlation between the two properties when the nucleophilic atom of Y-is changed. Thus although the nucleophilic tendencies of a series of oxygen anions can be correlated closely with their basicity,’ iodide ion in water is a stronger nucleo- phile3 but a weaker base than chloride ion in water and sulphur-containing anions are much stronger nucelophiles but much weaker bases than the corresponding oxygen anions.2 It is not reasonable to compare a kinetic property such as nucleophilic tendency with a thermo-dynamic property such as basicity.The displacing tendencies of Y-at carbon and hydrogen are best compared through the equilibrium constants of re- actions (i) and (ii) i.e. by the basicity of Y-towards carbon and hydrogen respectively. R,C-X + Y-+ R,C-Y + X-0) H-X + Y-+ H-Y + X-(ii) It is convenient to use terms such as hydrogen- basicity carbon-basicity and sulphur-basicityt for equilibria involving displacements at hydrogen carbon and sulphur respectively. Just as one can draw up a series of pKzL values for anions with hydrogen with a standard displaced group (e.g. water) as reference it is possible to obtain an equi- valent series of carbon-basicities with a suitably labile group as reference.Equilibrium constants for a variety of displacements at carbon can then be predicted. Many measurements of nucleophilic tenden~y,~ hydrogen-basicity,6 and sulphur-basicity4 have been made but there has been little discussion or measure- ment of carbon-basicity.’ Carbon-basicity measure- ments in nitrobenzene have many advantages over measurements in other solvents. Reactants and pro- ducts are soluble but not solvolysed ionic species are dissociated at < 0.02~,* and equilibrium is reached much more rapidly than in protic solvents? A com-parison between hydrogen- and carbon-basicity in protic solvents is misleading because the contribution made by hydrogen bonding to the solvation of X-and Y-in protic solvents superimposes a hydrogen- basicity effect on the carbon-basicity.This problem is avoided in the dipolar aprotic ~olvent,~~~ nitro-benzene in which anions are similarly solvated. The equilibrium mixture in nitrobenzene can be effectively “frozen” (by pouring it into a protic solvent at a lower temperature) and then analysed3 without disturbance from equilibrium. Equilibrium constants for the reaction of n-butyl bromide with tetraethylammonium halides and halo- genoids in nitrobenzene at 80” are in the Table. Equilibrium constants for the other butyl halide- halide or -halogenoid ion reactions’O agree closely with the values reported here. Carbon-basicity“ Anion BuBr in MeBr in MeBr in Ph.NOzb H2O acetoneC N3-4 x 105 -c1-1-5 x lo2 10 1.7 x lo2 Br-1 1 1 SCN-1 -I-2 x 13 8 x a Equilibrium constants for reactions of anions with the substrate in the solvent indicated.At 80”. At 25”; cf. ref. 3. It has been shown that protic solvents differentiate and dipolar aprotic solvents level the nucleophilic tendencies of halide and halogenoid ions.3 However protic solvents level and dipolar aprotic solvents differentiate carbon-basicity as illustrated in the * I.C.I. Research Fellow 1961. t In our previous papers on displacement at bivalent su1phury4 the term “sulphur-basicity” would now be preferred in place of “sulphur nucleophilicity.” Leahy Liveris Miller and Parker Austral. J. Chem.1956 9 382. a Hine “Physical Organic Chemistry,” McGraw-Hill New York 1956 p. 138; Streitweiser Chem. Rev. 1956 56 581. Parker J. 1961 1328. Parker and Kharasch Chem. Rev. 1959,59 583; J. Amer. Chem. SOC.,1960 82 3071. Swain and Scott J. Amer. Chem. SOC.,1953 75 141. Bell “The Proton in Chemistry,” Methuen London 1959. Fahat-Aziz and Moelwyn-Hughes J. 1959,2636; de la Mare Hughes Ingold et al.,J. 1955,3169-3200; Bunnett, Hauser and Nahabedian Proc. Chem. SOC.,1961 305. Walden “Salts Acids and Bases,” McGraw-Hill New York 1929. Miller and Parker J. Amer. Chem. SOC.,1961,83 117. lo Parker unpublished work. Table and as is also the case with hydrogen basicity.ll Chloride and azide ions which are the strongest hydrogen bases in dipolar aprotic solvents,ll are also the strongest carbon bases.Iodide ion in nitrobenzene l1 Janz and Danyluck Chem. Rev. 1960,60,209. PROCEEDINGS is a weak base towards carbon and hydrogen and although in water it has a much greater nucleophilic tendency than chloride ion in water towards methyl br~mide,~ it is only a very slightly stronger carbon- base in water than chloride ion in water. (Received August 30th 1961.) Tetrahedral and Bridged Octahedral Complexes of CobaIt(I1) By S. M. NELSON (QUEEN'S BELFAST, UNIVERSITY N. IRELAND) A CONFIGURATIONAL change from octahedral to tetrahedral in the solid state in complexes Co py2L2 (where py = pyridine and L = SeCN- SCN- or OCN-) which is not readily explained in terms either of steric considerations or of ligand polarisa- bility has been observed in this laboratory.The compounds were prepared from complexes contain- ing more pyridine (see Table) by controlled revers- ible removal of two molecules of pyridine [four in the case of Copy,(NCO),] in vacuo at 70". The structural assignments were made on the basis of the magnetic moments and of colour. Compound Colour Co pys(NCO) Pink Co py4(NCS) Pink Co pya(NCSe) Pink Co py2(NC0) Blue Co py2(NCS) Violet Magnetic moment (B.M. at 18") Confign. 5-1 Octahedral 5-1 Octahedral 5.1 Octahedral 4.5 5.1* Tetrahedral Octahedral Co py2(NCSe) Green-brown 5.1 Octahedral * In agreement with the value of Gill and Nyho1m.l The first three compounds are clear cases of octahedral co-ordination and call for no comment here.In the bispyridine complexes on the other hand the metal can achieve six-co-ordination only by bridging of the anion between cobalt atoms. This has previously been demonstrated for the dithio- cyanatel and on the basis of the magnetic data presented above must be assumed for the diseleno- cyanate also. The intensely blue colour of Co py (NCO), however suggested a tetrahedral structure and this was confirmed by the lower moment of 4.5 B.M. a value in accordance with the lower orbital contribution expected for cobalt(@ in this environment. The usual steric factors cannot be responsible for this structural change and it seems unlikely also that packing conditions in the crystal should be significantly different in the three cases.Nor applying Pauling's electroneutrality principle would one expect OCN- to be more polarised than SCN-or SeCN-. Possibly there is more double bonding in the Co-NCS and Co-NCSe bonds whereby some negative charge is returned from the metal to the ligand which should be reflected in the positions of the three ligands in the spectrochemical series. All three complexes are soluble in polar organic solvents giving intensely blue or blue-green non-conducting solutions. The high extinction coefficients (500- loob) in nitromethane for example indicate that like the dithiocyanate,l Co PY,(NCO)~ and Co py2 (NCSe) also are tetrahedral in solution. The posi- tions of the bands in the 500-700 mp region are close in all three cases pointing to much the same degree of perturbation of the metal d-orbitals and suggesting that OCN- is similarly bonded to the metal through the nitrogen atom.It follows that a tetrahedral configuration is imposed on Co py (NCO) in the solid state not because the metal cannot easily accommodate more ligands but because the bridging capability of OCN- is smaller than that of SCN- or SeCN-. This may well be due to the absence of d-orbitals on the oxygen atom i.e. there may be a significant d,,-d, contribution to the Co-S and Co-Se bonds. This is certainly true in SCN- and SeCN- complexes of class (b) metals in which very stable metal-sulphur and metal-selenium bonds OCCUT,~ a consequence being that SCN- and SeCN-can act as strong bridges between two different metal atoms one of class (a) and the other of class (b) character as suggested4 recently for Hg(SeCN),Co.The selenocyanate complex described here which to the author's knowledge has not been reported before provides an example of bridg-ing by the SeCN- ion of metal atoms of the same kind [Found Co 13.8; SeCN 47.9. Co (C,H,N) (NCSe) requires Co 13.8; SeCN 49-2%]. (Received August 14th 1961.) Gill and Nyholm,J. Inorg. Nuclear Chem. 1961 18 88. a Holm and Cotton,J. Chem. Phys. 1960 32 1168. Toropova Zhur. neorg. Khim. 1956,1 243. Turco Pecile and Niccolini Proc. Chem. Soc. 1961 213. OCTOBER 1961 373 Hydrogen Bonding in the Acid Malonate Ion By S. N. DAS (CHEMISTRY UNIVERSITY DEPARTMENT OF PATNA BIHAR INDIA) and D.J. G. IVES DEPARTMENT COLLEGE W.C. 1) (CHEMISTRY BIRKBECK MALETST.,LONDON RECENT evidence that the hydrogen maleate ion in aqueous solution is internally hydrogen-bonded1 lends interest to a similar conclusion regarding the hydrogen malonate ion reached in the course of a preliminary study of the thermodynamics of the dis- sociation of malonic acid. This forms part of a pro- jected investigation of a series of dibasic acids to be carried out with use of the improved hydrogen- calomel cell3 for which revised E" data covering a range of temperatures have recently been proposed.* The results here (Table 1) have now been obtained by methods to be described elsewhere. TABLE1. Temp. 5" 1@K 1-3162 106K 2.1696 10 1-3580 2.1559 15 1-3948 2.1241 20 1.4144 2.0761 25 1 ~4236 2.01 30 30 1-4162 1 -9472 35 1-3973 1.8630 40 1 -3729 1-7691 45 1.3348 1.6801 The results for 25"c are in good agreement with earlier determinations by the same meth~d,~ and all of the K values compare favourably with those of Hamer Burton and Acreq6 as do the following Some confidence may therefore be placed in the functions now obtained for the first dissociation which are particularly interesting when considered comparatively.Malonic acid may be regarded as a member of a sequence of substituted acetic acids differing little in acid strength; in Table 2 they are arranged in order of decreasing positive values of the standard free energy of ionisation.In terms of Bell's suggestiong that AGO serves best for an ad hoc comparison of molecular models it may be inferred that the polar effect of the carboxyl group in promoting dissociation lies between those of the chloro- and the cyano-group. The other functions may be credibly used in discussing solva- tion effects; it is seen that for the first dissociation of malonic acid they present three outstanding features namely a AH"some lo00 cal. more positive than the others a negative AS" even lower than that for cyanoacetic acid and an inordinately large negative dCpo. The following is a possible interpretation of these facts. The AH" value suggests that the formation of ions from malonic acid involves some additional bond- breaking so that the hydrogen malonate ion has relatively a greater structure-breaking effect than the other anions.This is consistent with the lower than normal entropy loss on ionisation although the TABLE 2. Acid CH2CC02H7 CH,RrC0,H7 CH2CIC02H7 CH,(CO,H) CH2CN-C02H8 AC" (cal.) 4330 3958 391 1 3883 3368 AH" Aso Ac; (cal.) (cal. deg.-') (cal. deg.-l) -1416 -19.3 -32.9 -1239 -17.4 -38.1 -1123 -16.9 -46.4 +17 -13.0 -61.0 -888 -14.3 -35.6 hydration of the undissociated malonic acid mole- cules (no doubt enhanced by hydrogen-bonding of water molecules to the additional carboxyl group) must play its part in limiting this loss and there is no decisive way of assessing how AS = S -S1,the derived thermodynamic functions for the second dissociation AGO AH0 Aso Ac; (cal.) (cal.) (cal.deg.-l) (cal. deg.-l) 7770 -1139 -29.9 -58.1 Dodd Miller and Wynne-Jones J. 1961 2790. Das Thesis London 1961. Hills and Ives J. 1951 311. * HiIls and Ives "Reference Electrodes," ed. Ives and Janz Academic Press New York and London 1961 p. 137. Hills Thesis London 1950; Gupta Thesis London 1957. Hamer Burton and Acree J. Res. Nat. Bur. Stand. 1940 24 290. Ives and Pryor J. 1955,2109. Feates and Ives J. 1956 2802. Bell "The Proton in Chemistry," Methuen London 1959 p. 69. entropy change as a function of final and initial states arises. The abnormally large heat-capacity loss helps however to resolve this uncertainty. In general heat-capacity data in isolation are difficult to interpret because they may incorporate two effects the capacity of a system in a particular state at a given temperature to absorb heat and the manner in which the state of the system may at that temperature change as a function of temperature.The two contributions are akin to specific heat and latent heat. In the present case the abnormally low heat capacity of the ionised system may be assigned to an extensively broken water structure less com- pensated than usual by the establishment of a hydra- tion zone capable of absorbing heat by "melting." In 0 other words relative to the other anions in this sequence of acids (which as far as is known have net structure-making effects) the acid malonate ion PROCEEDINGS is less hydrated and less structure-making (or more structure-breaking).This conclusion is consistent with the observed values of AH" and AS" for the first ionisation and requires some special feature to be present in this ion which is not present in the others. It is suggested that this is the internally hydrogen-bonded structure (A) which seems likely to involve a symmetrical hydrogen bond other examples of which are known.l0 If this is so the residual charge will be spread over two oxygen atoms which are already engaged in interaction and this might reduce primary hydration to zero and reduce secondary hydration* because of delocalisation of charge and reduction of field strength. It is note- worthy that such a structure is less sterically favoured in the case of the hydrogen succinate ion and that for the first ionisation of succinic acid AS" and ACpO tend to resume 4'normal" values (-16.7 and -35.4 cal.deg.-l respectively).ll It is hoped to explore certain obvious ways of checking this conclusion but the interesting study of how ACpOmay vary with temperature must await the provision of more extensive and accurate primary data. One of us (S.N.D.) records thanks to the authorities of the University of Patna for study leave. (Received September 6th 1961.) lo Pauling "The Nature of the Chemical Bond," Cornell Univ. Press 1960 pp. 484 485. l1 Parsons "Handbook of Electrochemical Constants," Butterworths London 1959. A Synthesis of Calythrone By M. ELLIOTT and K.A. JEFFS OF INSECTICIDES ROTHAMSTED (DEPARTMENT AND FUNGICIDES EXPERIMENTAL STATION HARPENDEN, HERTS.) CALYTHRONE, isolated by Penfold and Simonsenl from Calythrix tetragonn Lab. was formulated as (I) by Bir~h.~,~ Attempts by Birch and Murray3 to synthesise this and related structures by condensa- tion of dimethyl maleic anhydride or esters with ketones in the presence of sodium ethoxide sodium amide or boron trifluoride failed. We found that isobutyl methyl ketone reacts with dimethyl maleate in the presence of sodium hydride to give calythrone and as the major product the ester (11) b.p. l5Oo/0.1 mm. TZ;O 1.4840 Amax. 285 mp (E 7410) (copper derivative m.p. 155"). Calythrone b.p. 148"/12 mm. nLo 1.5216 Amax. 240, 265 mp (E 21,500 19,500) was isolated by fractiona- tion and purified as the copper derivative m.p.Penfold and Sirnonsen J. 1940 412. Birch J. 1951 3026. Quoted by Birch and English J. 1957 3805. Elliott Pruc. Chem. Soc. 1960 406. 21 2-216" (reported1 208-210"). The infrared (sharp band at 1703 cm.-l shown by other cyclopentenedi- ones4) and ultraviolet spectra dioxime (m.p. 131") and hydrated sodium salt (m.p. 115") agree with reported data.1-3 Like the related aromatic compound 2-isovaleryl- indane-l,3-dione (~alone),~ calythrone has insecti- cidal activity.6 Me -C-CO 11 )U-I-C0.CH2*CHMe2 (I) MQvC-CO MeO,C.CMe A CMe CO.CH,.CO.CH,.CH Me (a) (Received August 9th 1961 .) Kilgore Ford and Wolfe Ind. Eng. Chem. 1942 34 494.Needham unpublished results. OCTOBER 1961 375 ~ ~ ___~ a-Amino-acids and or-Keto-acid OximeS from a-Hydroxylamino-acids A New Disproportionation Reaction By IAN D. SPENSER and A. AHMAD (DEPARTMENT MCMASTER HAMILTON CANADA) OF CHEMISTRY UNIVERSITY ONTARIO a-HYDROXYAMINO-ACIDS (I) have been described as weak acids without marked basic properties,l and as yielding distinctly acidic solutions,2 but also as amphoteric compounds with isoelectric points be- tween pH 6 and 7.3 They are reported not to yield a purple colour when treated with ninh~drin,~ but have also been alleged to give a positive ninhydrin re- a~tion.~ They may be prepared from a-hydroxy- amino-nitriles i.e. from the adducts of oximes and hydrogen cyanide by hydrolysis with concentrated hydro~hloric~~~~~ acid.Sulphuric acid or sulph~ric~~~ hydrolysis has been reported to be accompanied by oxidation yielding amides of a-hydroxyimino-acid^.^^^ a-Hydroxyamino-acids can also be obtained from a-halogeno-acids by treatment with stoicheio- metric amounts of hydroxy1amine;l reaction of a-halogeno-acids with an excess of hydroxylamine however leads to a-hydroxyimino-acids (III).' These discrepancies have now been resolved Established proced~res~.~ for the preparation of a-hydroxyamino-acids yield mixtures which in addi- tion to the desired products contain the correspond- ing a-amino-acids and also in most instances either the corresponding a-keto-acid oxime or the lower homologous nitrile.Fractionation was achieved by extraction of ether-soluble products followed by separation of a-amino-acids from a-hydroxyamino- acids by ion exchange on Dowex 50. Potentiometric titration showed a-hydroxyamino- acids to be amphoteric electrolytes with isoelectric points pH 3.9-4.1. Values of their pKl (2.1-2.3) (titration with 0.~N-HCI)were unaffected by form- aldehyde whereas values of their pK2 (5-7-5-9) (titration with 0.1N-NaOH) were lowered by 3-4 pK units in the presence of formaldehyde. This estab- lishes that the dissociation pK, is associated with the hydroxyamino-group and demonstrates the zwitterionic nature of the compounds which must be formulated as -02CCHR.NH2+-OH. Spots of six analytically pure a-hydroxyamino- acids could be made visible on paper before chroma- tographic development with silver nitrate.After development with butan-1-01-acetic acid-water Cook and Slater. J.. 1956. 4130. (4:1:5) only a-hydroxyaminopropionic and a-hydroxyaminoisobutyric acid yielded silver nitrate- positive spots. In every case however a ninhydrin positive spot with distinct tailing was obtained whose R value was identical with that of an authentic sample of the corresponding a-amino- acid. a-Hydroxyamino-acids had been reduced to a-amino-acids in the course of chromatography. The formation of the a-amino-acids can be explained by a disproportionation. The second pro- duct would be an a-nitroso-acid (II) from which the corresponding a-hydroxyimino-acid (111) would be formed by tautomeric shift.g In the preparation of a-hydroxyamino-p-phenylpropionicacid we did indeed isolate phenylpyruvic acid oxime.In all other cases only traces of the a-hydroxyimino-acid were obtained presumably because of their rapid conver- sion into nitriles.1° In the preparation of a-hydroxy-aminoisobutyric acid which has no proton on the a-carbon atom a transient but intense blue colour indicative of a nitroso-compound was observed. The reaction sequence may be formulated as annexed. The reaction requires the formation of R-7H-CO2-RCH-C02-+NH,.OH +NH, I R *CH-C02-R-FH+CO,H R-$-CO2H N=O (a) HO-N 'AH2-OH (I) R*CN + CO + H,O // equimolar quantities of a-amino-acid and a-hydroxyimino-acid or since below pH 7 the latter decomposes rapidly to give the nitrile and carbon dioxide,1° of carbon dioxide.An aqueous solution of a-hydroxyamino-acid was refluxed for 24 hours under nitrogen. Carbon dioxide was determined gravimetrically and a-amino-acid and unchanged a-hydroxyamino-acid were estimated in each other's presence by potentiometric titration utilising the differences in pK2. The results are summarised in the Table. von Miller and Plochl Ber. 1893 26,1545. Neelakantan and Hartung J. Org. Chem. 1958 23,964. Snow J. 1954 2588. Hurd and Longfellow J. Org. Chem. 1951 16 761. Munch Ber. 1896 29 62. Hantzsch and Wild Annalen 1896 289 285. * Traube Ber. 1895,28 2297. Cf. Miiller Fries and Metzger Chem. Ber. 1955 88 1891. lo Ahmad and Spenser Canad.J. Chern. 1961,39 1340. Stoicheiometry of the disproportionation of acids H0.NH2+*CHR*C02-. a-NH2-acid R formed (%)* Me 100 Et 91 Prn 73 Pri 96 BaCO formed (%)* 101 85 98 100 A possible mechanism of the disproportionation involves a hydride shift either from NH or from OH. * % of theory and not % of yield. l1 Kjellin Svensk Kem. Xdskr. 1921 33 213. l2 Bamberger Ber. 1894 27,1548. PROCEEDINGS Such a disproportionation may be a general reaction of hydroxylamine and its N-substituted derivatives :the decomposition products of hydroxyl-amine,ll N-methylhydroxylamine,ll and N-phenyl- hydroxylamine12 are certainly compatible with this interpretation. The formation of whydroxyimino- acids on treatment of a-halogeno-acids with an excess of hydroxylamine7 may be explained by an analogous oxidation-reduction between the primary product of the reaction cc-hydroxyamino-acid and hydrox- y lamine.(Received Julv 7th 1961.) Coloured Bipyridyl Complexes of Beryllium By G. E. COATES and S. I. E. GREEN (UNIVERSITY SCIENCE LABORATORIES, SOU.! H ROAD DURHAM) SEVERAL derivatives of decaborane are coloured; the bispyridine compound B1,Hl,py,,a for example being yellow. A recent study with substituted pyridines has shown that the colours deepen with the electronegativity of the substituents. The colours are attributed to electron transitions from three-centre bonds in the decaborane group to the n-electron system of the pyridine rings.l We now report evidence for similar transitions in a much simpler system namely the o-phenanthroline and bipyridyl complexes of beryllium alkyls aryls and halides.The colours of the bipyridyl complexes BipyBeX, listed in the Table vary markedly with the electronegativity of X. X in Colour BipyBeXZa c1 White Br Pale cream I Yellow Ph Yellow Me Yellow Et Red Amaxb Molar extinction (mp) coefficient x 352 infl. 1.2 364 2.4 368 7.0 353 infl. 0.5 395 2.7 46 1 3.7 a Satisfactory analyses have been obtained for all these compounds. b All the complexes also have high-intensity bands in the 220-300 mp region similar to those of free bi- pyridyl. We suggest that the transition causing these colours is an electron transfer from one of the Be-X bonds to the lowest unoccupied orbital of bipyridql.The Be-X bonds would thus be acting as electron donors in the excited state of the complex and their donor character would clearly be greater if the electrons in the bonds were relitivelv loosely bound (as is probable in the Be-alkyl bond) than if the bonding were strong as it probably is in the Be-CI bond. Measuremmts of the ionization potentials of beryllium alkyls would be therefore of interest. A decrease in the elzctronegativity of X should increase the extinction coefficient as observed since it would increase the size of the beryllium orbitals and hence their overlap with the n-orbitals of the bipyridyl. Most of the complexes listed are very sparingly soluble in organic solvents with the exception of the bright red diethyl complex (Found Be 4.0 4.25%; M cryoscopic in benzene 233 220.Cl,H18BeN2 requires Be 4.0 %;M 223). Diethylberyllium forms an orange-yellow monomeric complex with pyridine Et2BePY2' Yellow bipyridyl complexes of methyl-zinc -cadmium -aluminium and -gallium have also been prepared. The cadmium complex (BipyCdMed is relatively unstable since it slowly decomposes into its components in vacuo at room temperature. Dimethyl- diphenyl- and di(pheny1ethyny 1)-mercury do not form bipyridyl complexes. The authors are indebted to Dr. L. E. Orgel and Professor D. A. Walsh for helpful discussion. (Received JuZy 25th 1961.) Graybill and Hawthorne J. Arner. Gem. SOC.,1961,83,2673.OCTOBER 1961 377 Electron-spin Resonance Spectra of Sulphur Nitride Ions By D. CHAPMAN A. G. MASSEY, R. M. GOLDING and J. T. MOELWYN-HUGHES (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) ELECTRON-SPIN RESONANCE^,^ of aromatic ions in solution provides hyperfine structure that has been valuable for studying the delocalisation of the un- paired electron in a molecular orbital over the ring. However little work has hitherto been recorded of studies of pseudo-aromatic systems or of inorganic systems where considerable delocalisation is thought to occur. Tetrasulphur tetranitride S4N4 has now been examined. X-Ray3 and electron diffraction4 studies show a puckered ring structure with the four nitrogen atoms lying in one plane.The S-N bond exhibits consider- able double-bond character. These studies as well as chemical investigations have shown that all the sulphur atoms present must be in the same valency state5 and suggest that electron delocalisation occurs in the ring. A number of resonance formula can be written to describe the molecule and the observed sulphur-sulphu? distance suggests that structures of the type shown have a certain weight. :*N-$ :S-ES-?: 'I :A'+ :N-N: ;hg$ Ill :O-NX :SIN+ :s-N -s When tetrasulphur tetranitride is treated with vacuum-distilled potassium in scrupulously dry di- methoxyethane a claret-red diamagnetic solution is first obtained. Shaking causes the colour to change I.66gauss FIG.1. Electron-spin resonance derivative spectrum of S,N negative ion.gradually to green and an electron-spin resonance spectrum is observed (Fig. 1) containing nine lines of intensity 1 4 10 16 19 16 10 4 1 consistent with delocalisation involving four equivalent nitrogen atoms. The splitting constant is 3.22 f0.04 gauss. Further shaking with potassium causes the spectrum to increase in intensity up to a maximum. On further reaction the intensity of the spectrum first decreases to almost zero and then increases again a nine-line spectrum again being produced of the same splitting and intensity ratio as before. The solution becomes yellow on further reaction and no signal is observed. This is consistent with the formation of more highly charged negative ions some of which are diamagnetic and others paramagnetic i.e.S4N4-+ S,N,--f S4N42-3S4N4&+ S,N:-. Considerable discussion has centred on hetero- morphic aromatic structures in large ring systemss-" and delocalisation has been predicted to be possible even in puckered rings. It is of interest that S4N4F4 the analogue of the phosphonitrilic compounds is said to have little if any delocalisation over the ring9 whilst the present evidence shows that it does occur with S4N4. Sublimation of the compound immediately before reaction with potassium gives rise to both a three- line and a five-line spectrum superposed on the nine- line spectrum. Such treatment is known to produce I I f I I 10 I I I I I I FIG.2. Electron-spin resonance derivative spectrum of S,N4 dissolved in concentrated sirlphuric acid.ring cleavage,1° and the spectra probably arise from fragments containing one nitrogen and two equi- valent nitrogen atoms respectively. Ward and Weissman J. Amer. Chem. SOC.,1954,76 3612. Carrington Dravnicks and Syrnons J. 1959 947. Clark J. 1952 1615. Chia-Si Lu and Donohue J. Amer. Chem. Soc. 1944,66 818. Goehring and Ebert 2.Naturforsch. 1955 lob 241. Craig J. 1951 997. Dewar Lucken and Whitehead J. 1960 2423. a Craig Chem. Soc. Special Publ. 1958 No. 12 p. 343. von Wiegers and Voss Acta Cryst. 1961 14 562. lo Goehring and Voigt Naturwiss. 1953 40 482; Z. anorg. Chem. 1956 285 181. PROCEEDINGS Reaction of tetrasulphur tetranitride with con- centrated sulphuric acid in air or in a vacuum also causes ring cleavage with precipitation of sulphur.The resultant solution gives rise to an intense spec- trum having five lines of splitting constant 3-32 f 0.04gauss (Fig. 2). This type of spectrum arise from the presence of sulphur-nitrogen radicals contained two equivalent nitrogen atoms. After some weeks a three-line spectrum is observed suggestive of further formation of a sulphur-nitrogen radical containing a single nitrogen atom. The stability of these sulphur-nitrogen radicals is of particular interest and points to the use of electron-spin resonance spectra as a powerful method for studying their reactions. The spectra were obtained by using a Varian 100 kc. spectrometer. (Received August 4th 1961 .) An Unusual Protonation Reaction of Some a-Bonded Ally1 Complexes By M.L. H. GREEN and P. NAGY (THEUNNERSITY, CAMBRIDGE) IN a study of some 0-and n-bonded allyl complexes of irony1 where the bonding of the allyl group is analogous to that in known allyl complexes of Pt,2 Pd,3 Ni,4 CO,~ and Mn,6 we have found that the 0-ally1 complexes n-C,H5Fe(CO),o-C,H,R (where R = H or Me) (I) are readily protonated on treat- ment with gaseous hydrogen chloride or dilute hydrochloric acid. One proton is added to the a-ally1 group resulting in an unique rearrangement to a cation containing a vbonded propene group (see II). The diamagnetic red-brown aqueous solutions of the cation are com- paratively stable. There is no evidence for exchange of protons in D20 solution and the reaction does not appear to be reversible.Precipitates are obtained r l+ as yellow powders with suitable anions e.g. [PtC16l2- or PF6- (Found c,30-2;H 3.0; Fey12.8; Cl 24.4. [C5H5Fe(CO)2C,Hs]:+ [PtCl6I2- requires C 30.3; H 3.3; Fey12.9; Cl 24.1. Found C 54.9; H 4-6. [C,H,Fe(CO),C,H,]+PF,-requires C 54.8 ; H 4.6%). Analogous cations containing iron molybdenum or tungsten to which ethylene is co-ordinated have been prepared from ethylene.’ The analytical and proton magnetic resonance data of our complexes are wholly compatible with the suggested configura- tion. The infrared spectra in mulls and in D20solu-tion show bands which may be assigned to the C=O groups ( R = H 2082 and 2057 cm.-l) the n-cyclo- pentadienyl group the =CH vinyl group and in the region 1200-1500 cm.-l to the methyl group.A weak band at 1527 cm.-l may be assigned to the C=C stretching frequency of the co-ordinated ethylenic group (see also ref. 7). The 3000 cm.-’ region is unusual in that when R = H there is only one strong sharp peak namely at 3138 cm.-l. Absorption bands characteristic of the C-H stretches of a methyl group are absent. In the light of the analytical proton magnetic resonance and chemical evidence this anomaly may be understood as a rare example of reduction by an order of magnitude of the intensity of the methyl C-H stretch absorption bands. Other examples of this phenomenon are re- ported for inter alia methoxyl and acetyl groups? In the case of the propene cation the reduction of in- tensity must be associated with some property of the CH =CH- co-ordinated system.The infrared spectra of the but-1-ene complex (R = Me) shows bands of medium intensity which may be assigned to the C-H stretches of the CH or of both the CH and the CH group. We thank International Nickel Company (Mond) Ltd. for a gift of iron carbonyl the Hungarian Relief Fund for financial support (to P.N.) and Dr. L. Pratt and Dr. N. Sheppard for assistance with the spectra. (Received August 16th 1961 .) Nagy and Green unpublished work. Shaw and Sheppard Chem. and Ind. 1961 517 and references therein. McClellan Hoehn Cripps Muertterties and Howk J. Amer. Chem. Soc. 1961 83 1601 and references therein.Heck,Chien and Breslow Chem. and Ind. 1961 986 and references therein. Heck and Breslow J. Amer. Chem. SOC.,1960 82 750 and references therein. Kaesz King and Stone 2.Naturfosch. 1960 15b 682. Fischer and Fichtel Chem. Ber. 1961 1200. Jones and Sandorphy Weissburger “Techniques of Organic Chemistry,” Interscience Publ. Inc. New York 1956 Vol. IX 341 ; Francis,J. Chem.Phys. 1951,19,942. OCTOBER 1961 379 The Preparation and Identification of Volatile Germanes By J. E. DRAKE and W. L. JOLLY OF CHEMISTRY RADIATION (DEPARTMENT AND LAWRENCE LABORATORY UNIVERSITY BERKELEY U.S.A.) OF CALIFORNIA 4 CALIFORNIA WE report a convenient electric-discharge procedure for the preparation of germanium hydrides as high as the octagermanes. Previously germanium hydrides up to pentagermanes have been prepared in low yield by the hydrolysis of magnesium germanide.lS2 Monogermane may be efficiently prepared by reduc- tion of germanic acid by aqueous hydr~borate,~ and we have converted monogermane into higher ger- manes by circulating it through an ozonizer-type silent electric discharge at a pressure of about 0.5 atm.The discharge tube was maintained at -78" so as to collect the products. When practically all the monogermane was decomposed the discharge was turned off and the hydrogen was separated. Digermane and trigermane were separated by dis- tillation under a vacuum and the other hydrides by gas-liquid chromatography on a column containing 10% of Silicone fluid on Celite separation of the two isomeric tetragermanes being good at 90".At 135-195" eleven additional peaks were clearly de- fined corresponding to species up to heptagermane. A further unresolved band undoubtedly corre-sponded to the octagermanes. Digermane was identified by its infrared spectrum and vapour pressure. The infrared spectra of triger-mane the tetragermanes and the pentagermanes are very similar in the sodium chloride region and hence may be used only to identify these compounds as germanium hydrides. Trigermane was principally identified by its mass spectrum and its proton mag- netic resonance spectrum. The latter spectrum was almost the exact mirror-image of that of pr~pane,~ being characterised by a small ratio of chemical shift to spin-spin coupling constant for the protons in -GeH2- and -GeH3.A similarly low ratio of chem- ical shift to coupling constant was reported for the silanes by Borer and Phillips.2 The tetragermanes were identified as such prin- cipally by mass spectroscopy. We assumed on the basis of the expected relative volatilities that the normal isomer was that which was held longest on the chromatographic column. The mass spectrum of this fraction had a fragmentation pattern similar to that of n-butane in that the relative amounts of the fragments were in the order M,+ > M2+ > M4+> M1+(M = Ge or C). The other isomer presumed to be isotetragermane had a fragmentation pattern similar to that of isobutane the order being M3+ > M2+ > Mlf > M4+.The amount of the second fraction (presumed to be n-tetragermane) was about nine times that of the first fraction. Qualita- tively these are the relative yields to be expected on the basis of statistics if in the discharge tube tetra- germane is built up from Ge units plus Ge units and pairs of Ge units. The germanes higher than tetragermane have been identified on the basis of their chromatographic re- tention times. For the normal series of hydrocarbons a plot of the logarithm of the retention time against the number of carbon atoms per molecule gives a straight line.5 This is also true for the silanes,2 and the Figure shows that it is also true for the germanes. No of Ge atoms The relative yields of the isomers varied slightly for each preparation but for hexa- and hepta- germanes the supposed normal species was never the Dennis Corey and Moore J.Amer. Chem. SOC.,1924 46 657; Amberger Angew. Chern. 1959 71 372. Borer and Phillips Proc. Chem. SOC.,1959 189. Jolly and Drake unpublished war! Pople Schneider and Bernstein High-Resolution Nuclear Magnetic Resonance," McGraw-Hill New York, 1959 p. 235. Desty and Whyman Anah?. Chem. 1957 29 320. PROCEEDINGS -~-~ ~ ~~~ most abundant (again predictably from statistical considerations). The yields of each species also varied according to conditions but typical yields based on the amount of germanium in monogermane that was converted were as follows digermane 20% triger-mane 30 % tetragermanes 6 % pentagermanes 0.4 % hexagermanes 0.12 % heptagermanes 0.1 % and octagermanes 0.04 %.We thank Dr. Newton and Mr. Sciamanna for obtaining the mass spectra. This work was spon- sored by the U.S. Atomic Energy Commission. (Received September 5th 1961.) TheRates of Association of Thiocyanate Ions with Nickel(I1) and Cobalt(@ Ions By ANTHONY G. DAVIESand W. MAcF. SMITH OF CHEMISTRY UNWERSITY ONTARIO) (DEPARTMENT QUEEN’S KINGSTON THE DRIES^ about crystal field stabilisation of the initid and transition states for corresponding reactions involving nickel(r1) and cobalt(I1) in solution suggest that reactions of nickel(r1) should be slower than those for cobalt(I1). Measurements2 by relaxation techniques on the reactions of nickel(1r) and cobdt(I1) with sulphate in aqueous solution support this prediction.We are using spectrophoto- mstric methods and flow and stopped-flow tech- niques to investigate the reactions of the ions of nick-lfIr) and cobalt(I1) with various ligands in aqueous solution and find direct evidence that with thiocyanate as the associ iting entity the reaction with nickel(r1) is substantially less than that for the reaction with co balt(I1). Our stopped-flow equipment resembles that A described by Chan~e.~ dual-beam oscilloscope fitted with camera records simultaneously the optical transmission of the reacting solution and the speed of the plungers which force the reactant solutions through a mixer and down the quartz observation tube. Data applying to conditions of flow as well as the conditions of “stopped-flow” could therefore be obtained.Light of wavelength 270 and 280 mp was used to follow the reactions of nickel(1x) and cobalt(I1) respectively and we have assumed that the concentration of complex formed is proportional to the change of optical density. Association constants for the monothiocyanato- complexes required in the interpretation of the kinetic data were based on spectrophotometric measurements carried out at 242-5-252.5 mp for nickel(@ and 265-285 mp for cobalt(rr) with the concentration of metal ions in five- to twenty-fold excess over that of the thiocyanate. Values for the association constants for the nickel(n) complex were determined at 1-445” the data being in- terpreted as outlined by McConnell and Davidson? Pearson.J. Phvs. Chem.. 1959. 63 321. The values at 5-2” and 9.3” included in the Table were interpolated. The constant for the mono-thiocyanato-complex for cobalt(n) at 1 -5” was about 16 mole-l 1. for an ionic strength of 0.5. Equilibrium constants and second-order rate constants for the association of nickel(I1) and thiocyanate at ionic strength 0.5. Temp. (“c). Assoc. Constant Rate Constant 1.4 24 (mole-I I.) 1-5 (lo3mole-I 1. sec.-l) 5.2 22 1.9 9.3 19 2-52 The time for flow between the points of mixing and observation was 5-7 msec. and we have been unable to discriminate the order of magnitude of rate constants for reactions which are more than 95% complete in less than 5 msec.The reaction of cobalt(11) with thiocyanate was “instantaneous” by the standards set by our equipment. With the concen- trations of reactants used this implies a rate constant greater than 7 x lo3 mole-I 1. sec-I at 1.5”. The reaction of nickel(I1) with thiocyanate yielded the rate constants listed in the Table. These were calculated on the assumption that the rate of formation of the complex from the free ions is of second order and that the reverse reaction is of first order and the fact implied by the association constant that the concentration of complex at equilibrium is sub-stantially less than that of metal ions. Data applying to both “flow” and “stopped-flow” conditions were obtained from each run at 1-5” and plots of logarithm of the fraction of uncompleted reaction against time showed considerable scatter but no significant deviation from linearity.For the measure- ments at 1.5” the concentration of metal ion was varied between 4 x lod2 and 7 x M that of thiocyanate between 0.75 x and 1.5 x M. zigen 2.Eleckochem. 1960,64 115. Technique of Organic Chemistry Vol. 8 Investigation of the Rates and Mechanisms of Reactions ”,Interscience Publishers Inc. New York 1953 Ch. X Part 2. McConnell and Davidson J. Amer. Chem. Soc. 1950 72 3164. OCTOBER1961 Variation of pH between 2 and 3 produced no observable effect on the rate. The standard deviation for the nine rate constants obtained at 1.5" was 0.18 x lo3 and there was no significant dependance of rate constant on concentration of reactants.The constants applying to temperatures higher than 1-5O were calculated from data obtained solely under flow conditions and involve six runs at 5-2" and four runs at 9.3". Eigen2 estimates that the first-order rate constant for the formation of the monosulphato-complex of nickel(r1) from an ion pair (two ions separated by a water molecule) is about 1 x lo4 sec.-l at 20" and he suggests that the rate is independent of the nature of the ligand. Extrapolation of our results by a log k against 1/T plot indicates a second-order rate constznt for the formation of the monothiocyanato- nickel(@ complex of 4.3 x 103 mole-l 1. sec.-l at 20"and ionic strength 0-5. This constant is different 381 in nature and dimensions from Eigen's.Eigen assumes the presence of two types of ion pairs; ion IIa in which the two ions are separated by two water molxules ion IIb in which they are separated by one. His rate constant (kb& applies to the first- order transformation of ion IIb into compIex in which the metal and ligand are directly adjacent. If it is assumed that the concentrations of the two types of ion pairs are small relative to the conccntrations of the free ions and do not differ much from the values for equilibrium then the rate constants k of the Table will be approximately equal to Kkb where K is the effective association constant for ion pairs of type IXb from nickel(@ and thiocyanate ions. If Eigen's value for kbg applies to the ion pair between nickel(r1) and thiocyanate at an ionic strength of 0.5 and the value for k of 4.3 x lo3 being used a value of 0.43mole 1.-l for K at 20" and ionic strength 0.5 is implied.(Received July loth 1961.) A Synthesis of 5-Amino-l-~-~-ribofuranosylimidazole-4-~rboxylic Acid 5'-0-Phosphate By G. SHAWand D. V. WILSON (CHEMISTRYDEPARTMENT OF TECHNOLOGY 7) INSTITUTE BRADFORD THEphosphorylated amino-acid (I) is an intennedi- ate in the biosynthesis of purine nucleotides and has been prepared enzymically in an impure state from the mine (11) and hydrogen carbonate in the presence of a carboxylase from pigeon or chicken liver.' The assigned p-and D-configuration and the position of the phosphate group were assumed from (I) Hb OH solution with those for 5-aminoimidazole4car-boxylic acid itself.We now record a synthesis of the amino-acid (I) by an unambiguous method (an extension of our earlier imidazole nucleoside synthesis3) which con- firms the structure. The formimidate (111) from methyl a-amino- a-HO OH ( Et 0CH :NCH (CN) C0,Me '2 the fact that the substance may be converted cyanoacetate and ethyl formimidate hydrochloride enzymically into inosinic acid. The structure of the with 2,3,5-tri-O-benzoylribofuranosylamine gave the substance was confirmed by comparison of its ultra- tribenzoate (IV; R = Bz R = Me) m.p. 223-225" violet absorption spectra the absorption spectra of (decomp.) which with methanolic sodium methoxide a coloured derivative produced in the Bratton- gave the nucleoside (IV; R = H R = Me) m.p.Marshall test,2 and its rate of decarboxylation in acid 148-150". This with acetone and p-toluenesulphonic Lukens and Buchanan J. Biol. Chem. 1959 234 1799. Bratton and Marshall J. Biol. Chem. 1939 128 537. a Shaw Warrener Butler and Ralph J. 1959 1648; Shaw and Warrener Proc. Chem. SOC.,1958 193. acid gave the isopropylidene derivative (V) m.p. 161-162" Amax 268 mp (E 9600) in ethanol. This compound was phosphorylated by reaction with 2-cyanoethyl phosphate4 and dicyclohexylcarbodi- imide in pyridine and then treated successively with aqueous acetic acid and hot O*S~-barium hydroxide to give the barium salt of acid (I) which was purified by precipitation from water by ethanol. In this way the crude material was freed from absorbing im- purities analogous to those present in the natural material.The properties of the final product agreed with those recorded for the natural material having A,, 249 rnp in alkaline solution changing to two- peaked absorption in acid with loss of absorption on Tener J. Arner. Chem. Soc. 1961 83 159. PROCEEDINGS storage. However the absorption maximum of the coloured derivative produced in the Bratton-Marshall test by our synthetic material while show- ing a peak at ca. 525 m,u similar to that recorded for the natural material has in addition a charac- teristic but less intense peak at 565-570 mp. The spectral properties also agree with those of analogues prepared by reaction of the imidate (111) with prim- ary amines and hydrolysis of the resulting ester.Microanalyses of the synthetic product suggested that it is a pentahydrate. We thank the Medical Research Council for a maintenance grant (to D.V.W.). (Received August 24th 1961.) Hofmann versus Saytzeff Elimination in the Interaction of t-Pentyl Chloride and Acetyl Chloride By G. BADDELEY and M. A. R. KHAYAT (THE MANCHESTER OF SCIENCE MANCHESTER) COLLEGE AND TECHNOLOGY THE interaction of acid chlorides and ethylene through the agency of aluminium chloride is a well- known route to 2-chloroethyl and vinylketones R*COCI+ C2H -+ R*C0.CH2.CH2CI -+ R*CO*CH:CH2; other alkenes usually behave less straightforwardly and are under further investigation in these labora- Me Me tories.When a 1,l-dialkyl- or a trialkyl-ethylene is used polymerisation of the olefin can account for much of the product and is readily avoided as shown by usY1 by preparing the olefin in situ from the t-alkyl halide e.g. see (I1 +V +I11 -+IX). For preparative purposes it is necessary to know whether the olefin is afforded by Hofmann or Saytzeff elimination. Using our procedure Balaban and NenitzescuZ Me Me Baddeley Quart. Rev. 1954 8. * Balaban and Nenitzescu Annalen 1959,625 74. OCTOBER 1961 showed that t-pentyl chloride (11) with two molecular proportions of Friedel-Crafts acetylating agent gives the pyrylium ion (X) and recognised that the interaction involves Hofmann elimination on two separate occasions (I1 -+ I) and (IV + VII) or (VIII -+ XI).They concluded that the expected Saytzeff elimination (I1 -+ 111) may occur preferen- tially but that trimethylethylene being sterically prevented from combining with the acetylating agent rearranged to 2-methylbut-1-ene (I) from which the cation (X) is obtained. This conclusion did not satisfy us since we already knew the main product from these reactants in molecular propor- tion to be the chloro-ketone (IX); it readily loses hydrogen chloride when heated with tertiary amine and the resulting unsaturated ketone (XIV) gives acetone by ozonolysis and reacts with acetyl chloride in the presence of aluminium chloride or zinc chloride to give the pyrylium ion (XV) which is obtained again when the chloro-ketone (IX) reacts with acetyl chloride in the presence of zinc chloride.Clearly our reaction unlike Nenitzescu’s involves the Saytzeff elimination (I1 -+ 111). The cause of this difference is easily revealed when the chloro-ketone (IX) is added to a mixture of Barltrop and Rogers J. 1958 2566. acetyl and aluminium chloride the pyrylium ion (X) is obtained the acetyl group of (IX) having moved from the 3-to the 1-position of the isopentane system. Knowing that deacylation followed by re- acylation at another position is one way of isomerie- ing aromatic ketones through the agency of hydrogen chloride-aluminium chloride) e.g. see (XVIII -f XIX) we envisaged the mechanism (IX -f VI 3I11 -+ I -f X) but having no previous example of a deacylation of the type (VI -+ 111) we were fortunate to have the opportunity to discuss our work with Dr.N. A. J. Rogers who provided us with helpful comment and the unambiguous example (XX -+ xx11.3 Since the unsaturated ketone (XIV) gives the pyrylium ion (XV) and not (X) the mechanism is presumably (XIV -f XVII -f XVI -+ XV) and not (XIV -+VI -+XI1 -+XV). Further since aluminium chloride causes the change (IX -+ X) whereas zinc chloride causes the change (IX -+ XV) we suggest that the former catalyst can effect the change (IX -+ VI) the latter a much weaker Lewis acid providing only the route (IX -+ XI1 -+ XIV +XV). For convenience the metal halides are not shown in the formula. (Received August 16th 1961.) Dimerisation by Co-ordination of Distannoxanes* By R.OKAWARA (OSAKAUNIVERSITY, OSAKA,JAPAN) THEstable product obtained from the cohydrolysis of a dialkyltin dichloride R,SnCl (R = Me Et Prn or Bun) and chlorotrimethylsilane is in all cases the tetra-alkyl-1,3-bistrimethylsiloxydistannoxane Me,Si-O.[SnR,-O],.SiMe,. Bistrimethylsiloxystan-nanes Me,Si.O.SnR,.O.SiMe, can be isolated but are unstable and gradually change into the distan- noxanes evolving hexamethy1disiloxane.l Tetra-alkyl- 1,3 -bistrimethylsiloxydistannanes are dimeric in benzene and in cyclohexane. Molecular- weight determinations on the monostannanes were not possible owing to their instability but we find that trialkyltrimethylsiloxystannanes,Me,Si.O*SnR (R = Prn or Bun) are monomeric in benzene and that tetra -alkyl -1,3 -dichlorodistannoxanes [ClR,Sn],O (R = Et Prn or Bun) are dimeric in moderate concentration in benzene solution.An X-ray analysis of tetramethyl-l,3-bistrimethyl-siloxydistannoxane shows the molecules to be paired with co-ordination from the oxygen atom between two tin atoms of one chain and a tin atom of the other chain. The resulting Sn-0-Sn-0 skeleton is nearly square as shown in the Figure. The four Sn-0 bonds forming the dimer are approximately equal in length (for those shown as co-ordinated bonds 2.3 A; for the others 2.2 A). ,Sn a =Sn-0 t1 O-Sn= ES/n This type of coupling readily explains the stability and the dimeric character of the distannoxanes (con- taining the Sn-0-Sn unit) and the monomeric character of the siloxystannanes.An oxygen atom between two tin atoms is clearly more basic than an oxygen atom between a tin atom and a silicon atom. This type of dimerisation readily explains certain unexplained results in the literature2 and is thought to be of great importance in the chemistry of the distannoxanes. (Received August 8th 1961.) * The contents of this communication were presented at the Chemical Society Symposium on Inorganic Polymers at Nottingham University July 1961. Okawara White Fujitani and Sato J. Amer. Chem. SOC.,1961 83 1342. See Ingham Rosenberg and Gilman Chem. Rev. 1960,60 508. PROCEEDINGS Hyperfine Interactions from Methyl Groups in Aromatic Positive Ions By J. A. BRIVATI and M. C. R.SYMONS R. HULME (DEPARTMENT THEUNIVERSITY, OF CHEMISTRY LEICESTER) OXIDATION of solutions of various alkyl-substituted benzenes in sulphuric acid by persulphuric acid results in the formation of radicals.lt2 It has been postulated by analogy with the behaviour of various polynuclear hydrocarbon^^,^ that these and in particular the one derived from p-xylene are cations formed by loss of one 7-electron from the benzene ring.l However quantitatively it seemed to us that the hyperfine splitting constant associated with the methyl groups (aMJ was surprisingly small Applica- tion of the empirical relationships and parameters derived from spectra of various aliphatic radicals and the approximation that the unpaired electron density is equally distributed around the ring,5 lead to a predicted value for aMeof about 6 gauss for p-xylene whereas the measured value is only 3-89 gauss.' Similarly the splitting of 3-0gauss which was postulated to arise from the ring protons,' is small compared with the value of 3.75 gauss expected for an even distribution of electron spin.Positive ion derived from An thracene aMe - a,,,,6-65 3.11 a2,3 1.40 9,lO-Dimethylanthracene 7-95 - 2.4 1.2 9 -Methylanthracene 7.8 7.1 2-83 2.83 It therefore seemed possible that more deep-seated oxidation had occurred giving a compound in which two equivalent methyl groups were retained and four other protons had fortuitously equivalent coupling constants.* Since the identification of radicals formed from polynuclear hydrocarbons in sulphuric acid as the corresponding positive ions seems fairly well establi~hed,~?~ it was decided to measure the splitting from methyl groups substituted appropri- ately in such compounds.We chose 9-methyl- and 9,lO-dimethy I-anthracene since we were already partially familiar with the behaviour of the former in sulphuric acid' and since the symmetry of the latter should facilitate interpretation. As expected a very complex spectrum consisting of over 150 lines was obtained from solutions of 9-methy lanthracene whereas 9,1 O-dimethylan thra- cene in sulphuric acid gave a radical with a far simpler pattern dominated by a major heptet having accurately the relative intensities 1 :6 :15:20 :15:6 :1. The hyperfine coupling constants for these main groups of lines identified as aMe are tabulated together with values for the outer ring protons (al and a& for 9,lO-dimethylanthracene.The larger splitting (a,) is assigned to the a-protons (positions 1 4 5 and 8) by analogy with our results for the anthracene positive ion,4 which are listed for comparison. Derivation of the electron-spin resonance absorption of the positive ion from 9 I0-dimethylanthracene. In contrast with the results from the radical formed from p-xylene the splitting constant for the methyl protons is rather larger than would be pre- dicted from simple theory if the electron distribution found for the anthracene cation were used. In order to compare the results quantitatively with those expected for the unsubstituted positive ions we have used the relation aN = QpN for the ring protons using Q 5 31,4 together with the constants for the methyl group given earlier,5 and hence calculate a * It has now been showne that the correspondingp-semiquinonecation (A) gives a spectrum identical with that shown in ref.1. Bolton and Carrington Proc. Chem. SOC.,1961 174. a Brivati Hulme and Symons unpublished results. a Weissman de Boer and Conradi J. Chem. Phys. 1957 26 963. Carrington Dravnieks and Symons J. 1959,947. Symons J. 1959 277. * 'Carrington personal communication. Grace and Symons J. 1959 953. OCTOBER 1961 splitting of 8-5 gauss for the methyl groups in 9,lO-dimethylanthracene. We conclude that the radicals formed from 9-methyl-and 9,1 O-dimethyI-anthracene are the corresponding cations whilst those formed by oxidation of p-xylene and related compounds with persulphuric acid are not.We thank Imperial Chemical Industries Limited Dyestuffs Division for a gift of 9,10-dimethyl-anthracene the Department of Scientific and In- dustrial Research and Imperial Chemical Industries Limited for financial assistance and “Shell” R~~xx~ Limited for a grant (to R.H.). (Received August 4th 196 1 .) The Electron-spin Resonance Spectra of Semiquinones in Sulphuric Acid A Reassignment of Spectra previously attributed to the pXylene Positive Ion By 3. R. BOLTON and A. CARRINGTON OF THEORETICAL UNIVERSITY (DEPARTMENT CHEMISTRY OF CAMBRIDGE) IN a recent Communication1 we described the electron-spin resonance spectrum of the free radical obtained by treating p-xylene with a solution of potassium persulphate in concentrated sulphuric acid.The spectrum consists of thirty-five lines the spacings and relative intensities being consistent with hyperfine contributions from four ring protons and six methyl protons. We interpreted the spectrum as arising from the positive ion of p-xylene but we now know that this interpretation is incorrect. The free radical present is in fact 2,5-dimethyl-p-benzo- semiquinone and we will now describe the evidence in support of this conclusion. We have found that oxidation of anisole phenol and quinol with persulphate in concentrated sul- phuric acid gives solutions which exhibit the same electron-spin resonance pattern shown in the Figure.This spectrum consists of five lines arising from four ring protons each of which is split into a triplet. The separation between the members of the quintet is 2-36gauss the same as in the p-benzosemiquinone ion in alkaline solution.2 There is little doubt that the spectrum arises from the semiquinone [p-C6H,(OH),]+(p-benzoquinol positive ion) with an additional hyperfine splitting of 3.44 gauss from the hydroxyl-protons since the same spectrum can be produced in concentrated sulphuric acid by reduc- tion of p-benzoquinone with sodium dithionite and by oxidation of quinol with potassium persulphate. Semiquinones of this type in strong acid solution have not previously been reported in the litera- t~re.~ We further discovered that the electron-spin resonance spectrum obtained by treating durene with persulphate in concentrated sulphuric acid was identical with that obtained by reducing duroquinone with dithionite or oxidising duroquinol in sulphuric acid.The spectrum consists of thirteen lines arising from the twelve methyl protons each split into a triplet by the hydroxyl-protons. Finally the spectrum obtained in concentrated sulphuric acid by treatment of p-xylene with per- sulphate is identical with that obtained by reduction of 2,5-dimethyl-p-benzoquinoneor oxidation of the corresponding quinol. An additional complica- tion is that the hydroxyl-proton splitting is virtually Electron-spin resonance spectrum of the p-benzo-seniiquinone ion in concentrated sulphuric acid.identical with the ring proton splitting. Further the experiments in concentrated dideuterosulphuric acid described in our previous Communication,l confirm the assignment of the methyl proton hyper- fine constant but cannot distinguish between hydroxyl-and ring-protons since both undergo exchange readily with deuterium under these con- ditions. We have now obtained better resolution of the spectrum in dideuterosulphuric acid and each Bolton and Carrington. Proc. Chem. Soc.. 1961. 174. Venkataraman Segal and Fraenkel J. Chem. khys. 1959,30 1006. Fraenkel has observed similar spectra (personal communication). methyl hyperfine line is split into the expected nine components by the four equivalent deuterons.We have made a study of a number of semi- quinones in alkaline and acid solution and the results will be described in detail later. In concen- trated sulphwic acid there is always a triplet splitting from the hydroxyl-protons and the ring- proton splittings vary only slightly in changing from alkaline to acid solution. The spectra are usually well mations a parallel similarity should obtain between the spectra of the anion and the cation of an odd dtemant sy~tem,~~~ and for the particular case of arylmethyl ions the Huckel theory indicates addi- tional req~irements.~ In an arylmethyl ion the bonding and the anti- bonding n-orbitals are paired as in all alternant systems but with an odd number of conjugated atoms one orbital is left over after the pairing and remains a non-bonding level bisecting the array of paired levels at the centre of gravity of their energid (see Figure).The highest bonding and the lowest antibonding levels of a symmetrical di- or tri-aryl- methyl ion have the same energies in the Huckel PFLOCEEDMGS resolved but that of p-benzosemiquinone displayed in the Figure shows considerable line broadening which we have not been able to reduce. J. R. B. thanks the Shell International Petroleum Company for the award of a Post-Graduate Re- search Studentship. We are indebted to the D.S.I.R. and to General Electric U.S.A. for generous financial assistance towards the cost of apparatus.(Received August 9th 1961.) -. . . . ...-Non-bonding orbitals ~netgy 0 -. --.-. . -. -.-Highest bonding orbitals ArSCH Arsc The relative energies of the lowest antibonding non- bonding and highest bonding n-orbitals of an aromatic hydrocarbon (ArH) and of the corresponding sym- metrical diarylmethyl (Ar,CH) and triarylmethyl (Ar3C) systems. The long wavelength absorption band maxima in the spectra of di- and tri-arylmethyl ions. Methyl ion Cation Anion Tris-p-bipheny1y 1 Tr is-&- bip hen y1y 1 SO00 Bis-p- bip hen y1y 1 5550 Bis-p-biphenylylmethyl 5150 approximation as the corresponding levels of the aromatic hydrocarbon from which the ion is schematically derived by the substitution of the appropriately charged methyl group4 (see Figure).Thus corresponding symmetrical di- and tri-aryl- methyl ions independently of the position of substi- tution of the methyl group in the aromatic nuclei 10,100 4850 45,500 71,400 5450 156,000 64,OOO 5900 145,000 corresponding absorption of the aromatic hydro- carbon from which the ion is derived. In order to examine these requirements the electronic spectra of a number of arylmethyl ions have been obtained (see Table) the light absorption of the cations being measured in concentrated sul- phuric acid solution and that of the anion potassium Aalbersberg Hoijtink Mackor and Weijland J. 1959 3049. a Dewar and Longuet-Higgins Proc. Phys. SOC.,1954,67 A 795. Lmguet-Higgins and Pople Proc. Phys. SOC.,1955 68 A 591.Grinter and Mason “Steric Effects in Conjugated Systems,” ed. Gray Butterworths London 1958 p. 52. Longuet-Higgins J. Chem. Phys. 1950 18 275. OCTOBER 1961 salts in diethyl ether under a vacuum. The spectrum of the tris-p-biphenylylcarbonium ion has been measured previously in different media.6 The bipheny lylcarbonium ions conform moderate ly well to theoretical expectations giving low- frequency absorption bands at similar wavelengths (Table) which are approximately twice that of the longest-wavelength singlet band of biphenyl' (2500 A). The absorption wavelengths of the biphenylyl- methyl anions however deviate more widely from the theoretical value (Table). The deviations cannot be ascribed to steric hindrance between aromatic nuclei attached to a common carbon atom or to the neglect of electron repulsion in the Huckel approxi- mation since these factors affect equally the energy levels of an arylmethyl anion and those of the corresponding cation.A change from sulphuric to other strong mineral acids does not alter the spectra of arylcarbonium ions but the absorption wavelengths of conjugated anions vary with the particular alkali-metal gegenion and with the particular ether used as solvent the varia- tions being the greater the more localised is the nega- tive charge in the anion.8 In even alternant ions the charge in general is delocalised over all of the con- jugated atoms but in the ground state of odd alternant ions the charge is confined to the starred atoms the exocyclic carbon atom in the arylmethyl ions always carrying the largest fraction of the charge? Thus the influence of ion-pairing and solva- tion forces upon the transition energies is more marked in the arylmethyl anions than in the aro- matic hydrocarbon negative radical ions accounting for the poorer resemblance between the spectra of corresponding anions and cations in the odd alternant series (Table) than for the even alternant syskmS.1 (Received August 14th 1961 .) Burawoy Ber.1931,64 1635; Chu and Weissman J. Chem. Phys. 1954.22 21. Clar "Aromatische Kohlenwasserstoffe," Sprrnger Verlag Berlin 1952. Carter McClelland and Warhurst Trans. Furaduy SOC.,1960,56,455. The Reactionof p-Keto-esters with Hydroxyiamine By A.R. KATRITZKY and S. 0-(THEUNIWRSITY LABORATORY, CHEMICAL CAMBRIDGE) IN 1891 Claisen and Zedell obtained a phenyliso- xazolone by reaction of benzoylacetic ester with hydroxylamine and formulated the product as a 5-0x0-compound (I -+XI; R = H R' = Ph) by analogy with the formation of pyrazolones. The reaction was extended to acetoacetic ester,2 methyl- and ethyl-acetoacetic ester and other p-keto-ester^;^ in all cases the products were formulated as isoxazol-$ones (11 or a tautomeric form thereof) (although the product from acetoacetic ester was later found to be a bimolecular condensation product).K In many cases f!-keto-esters and hydroxyl- arnifle do give isoxazol-5-ones as has been shown by spectroscopy,6 isolation of the intermediate oxime,' and comparison with compounds synthesised by unambiguous methods such as the hydrolysis of S,5-dialkoxy-2-isoxa~olines~ or 5-alko~yisoxazoles.~ Claisen and Zedel Ber.1891 24 140. Hantzsch Ber 1891,24,495. However we have now shown that isoxazol-3-ones may be produced in such reactions the product3 from methylacetoacetic ester is 4,5-dimethylisoxazol- 3-one 011; R =R' = Me) which rapidly absorbs 1 mol. of hydrogen (Pt-EtOH 20'/760 mm.) to yield a-methylacetoacetamide (V; R = R = Me) m.p. 77-78' (Iit.,lo m.p. 73") identified by mixed m.p. and infrared comparison with an authentic sample,1° m.p. 76-77". The product m.p. 118-120" from ethyl 2-oxocycloheptanecarboxylate is also an isoxazol-3-one as shown by its hydrogena- tion to 2-oxocycloheptanecarboxamide,m.p.118" and spectra indicate that the same holds for the product m.p. 49-50" (lit. m.p. 50') from ethyl- acetoacetic ester. Isoxazol-5-ones (11) yield ketones (IV) on reduction,ll and in this way we showed that the product m.p. 107-108" (1it.,l2 106-107") from * Uhlenhuth Annalen 1897 296 33. 'See Barnes in Elderfield " Heterocyclic Compounds " Vol. V Wiley New York 1957 p. 474 et seq; Loudon in Rodd's " Chemistry of the Carbon Compounds ",Vol. IVA Elsevier 1957 p. 346 et seq. ti Donleavy and Gilbert J. Arner. Chem. SOC.,1937,59 1072. Boulton and Katritzky Tetrahedron 1961 12 41. 'Billon Ann. Chim. (France) 1927 7 356. * Scarpati and Speroni Gazzetta 1959 89 1511. Griinanger and Langella Gazzetta 1959 89 1784.loPeters Annalen 1890 257 339. l1 Panizzi Gazzettu 1946,76 44. laWahlberg Ber. 1932 65 1857. ethyl 3,3'-dimethyl-2-oxopentanecarboxylicacid was 3-t-butylisoxazol-5-one. The product m.p. 170-171O (lit.,13 166") from diethyl acetylmalonate we hydrogenated to ethyl #%aminocrotanate; it was thus 4-ethoxycarbonyl-3-methyl-isoxazol-5-one. The fact- ors that decide the direction of ring closure are under R CH-C-R' NH -OH I6 A co Et investigation. In some cases both products may have been formed although we have isolated only one. PROCEEDINGS Italian workers1* recently reported the preparation of 5-phenylisoxazol-3-one and described it as the first isoxazol-3-one not realising that such com- pounds had unwittingly been prepared 64 years earlier.3 Isoxazol-3-ones exist predominantly in the 3-hydroxyisoxazole form (cf.ref. 14); a study of their tautomerism will be reported later. The above results modify our previous conclusion6 as to the tautomerism of isoxazol-5-ones alkyl derivatives such as 3-meth~l-l~ and 3-t-butyl-isoxazol-5-one resemble their 3-aryl-analogues existing as mixtures of the CH and NH forms in proportions which depend on the medium.16 One of us (S. 0.)thanks the Royal Norwegian Council for Scientific and Industrial Research for a grant and the Royal Norwegian Defence Research Establishment (Kjeller) for leave of absence. (Received August 1Sth 1961.) l3 Palazzo and Salvo. Gazzetta. 1906 36 I. 612. l4 Bravo Gaudiano Quilico and Ri&a,-Ghzzetta 1961,91 47.l6 Details of the preparation of this compound were supplied by Dr. J. W. Cornforth to whom we are greatly indebted. l6 Unpublished work. Stereospecificity of Lithium Aluminium Hydride Reductions :Reduction of Podophyllotoxin By D. C. AYRES and P. J. S. PAUWELS (SIRJOHNCASSCOLLEGE E.C.3) LONDON LITHIUMALUMlNIUM HYDRIDE is regarded1 as stereospecific in its action next to a racemisable asymmetric centre and its application to controlled reduction in the lignan field was recently discussed by Gensler,2 who had observed base-catalysed epi- merisation of podophyllotoxone during reduction by sodium borohydride. This epimerisation was con- sistent with the known3 lability of compounds of the class on treatment with bases picropodophyllin (I) [a]* +9.4" being so derived from podophyllotoxin (IJ) [aID -132" whose reduction by lithium aluminium hydride afforded a product described4 as podophyllyl alcohol m.p.198.5-200-5° [a]i50". It seemed possible that this optically inactive product was a mixture of triols derived from a mixture of the epimeric lactones particularly as base-catalysed changes have been observed5 during reductions by lithium aluminium hydride. By reduction in tetrahydrofuran we obtained a product havingm.p. 179-181 O [a]1,8'5-179" (~0.27 in CHCI,) which we prefer to describe as podo- phyllol (111) following Hartwell [Found C 63.0; H 6.1 %; active H 3.2 atoms (mean of 3 Zere- witinoff determinations with lithium aluminium hydride).C22H26OS requires C 63-2; H 6-3X.1 Podophyllol is readily dehydrated in hot xylene with the formation of anhydropodophyllol (Found C 66.5; H 6.2%; active H 1.3 atoms. Calc. for OH OH Ar = 3,4,5-trimethoxyphenyl C2,H,,0, C 66.0 H 6.0%) by 2,3- or more prob- ably 1,3-closure of a tetrahydrofuran ring; the alter- native dehydration to form a conjugated double bond in ring B is excluded by the ultraviolet absorption spectrum. The optical inactivity of the anhydride at Noyce and Denney J. Amer. Chem. SOC.,1950,72 5743. Gender Johnson and Sloan J. Amer. Chem. SOC.,1960 82 6074. Hartwell and Schrecker J. Amer. Chem. SOC.,1950 72 3320. Drake and Price J. Amer Chem. SOC.,1951 73 201. See,e.g. Gaylord "Reduction with Complex Metal Hydrides," Interscience Pub].Inc. New York 1956 p. 92. OCTOBER 1961 the sodium D line (c 0.30 in CHCla suggests that it was the product described earlie+ as podophyllyl alcohol and its dextrorotation at shorter wavelengths compared with the lzevorotation of podophyllol and picropodophyllol obtained by reduction of picro- podophyllin excludes the possibility of external compensation. Details of optical rotations measured in methanol solution are as tabulated. changed after being refluxed in xylene (Found C 63.7; H 6.5%; active H 2-9 atoms. Calc. for C22H2608 C 63.2; H 6.3 %). Thus the reduction appears to be stereospecific but confirmation of this awaits a determination of the mode of dehydration of podophyllol; this will also indicate whether or not 2,3-closure of a lactone ring is a feasible route to podophyllotoxin.Compound [+]at Podophy 1101 Picropodophy1101 -310 Anhy dropodophy 1101 0 0 These differences between the reduction products of the epimeric lactones suggest that the podophyllo- toxin configuration is retained in podophyllol. Further support for this is afforded by differences in infrared spectra and by the observation that picro- podophyllol unlike podophyllol crystallised un-600 500 400 350 330 320 310mp -660 -1080 -2100 -3270 -4170 -6100 -945 -1050 -1070 -840 $292 +800 +1190 +2160 We thank Professor W. Klyne for the measurement of the optical rotary dispersions and acknowledge the award by the Department of Scientific and In- dustrial Research of a Research Grant and a Research Studentship (to P.J.S.P.).(Received August 14th 1961 .) The Transition-state Volume Change in a Reverse Menschutkin Reaction By J. M. STEWART and K. E. WEALE (IMPERIAL OF SCIENCE LONDON,S.W.7) COLLEGE AND TECHNOLOGY THEvolume change dV* which accompanies the formation of the transition state in a liquid-phase reaction at 1 atm. is related to the change of the rate constant with pressure by the equation a log k/aP= -A Y*/RT. In Menschutkin reactions d Y* is nega- tive (reactions accelerated by pressure) and is chiefly attributable to solvation of the incipient ionic charges which appear in the transition state? R,N + RHal = R,Na+. -R -* -Hala-+R,N+ + Hal--d V* is however considerably less than -d V, the overall decrease in volume for the same reaction in the same solvent.2 Thus for ethyl iodide and tri-n- propylamine in methanol3 d V* at 1 atm.is -24 c.c./mole and dYsis -56.6 c.c./mole. This does not accord with the view that the transition states of Menschutkin reactions closely resemble the solvated product ions. It is also difficult to reconcile with the only published study of a reverse Menschutkin re- action under pressure (the decomposition of allyl- benzylmethylanilinium bromide in chloroform*) which yields the low value of +3.3 c.c./moIe for d V*. As this is a mean figure for the large pressure range 1-3000 atm. we have examined another reverse reaction in an attempt to remove the discrepancy. The decomposition of ethyldimethylanilinium iodide in nitrobenzene yields about 95 % of N-ethyl-N-methylaniline (vapour-phase chromatography).First-order rate constants from electrical-conduc- I I I I 0 1000 2000 P(atm> The efect of pressure on the rate constants of the forward reaction (A) and the reverse reaction (B). (The broken line corresponds to A V* = +45 c.c. fmole at 1 atm.). Hamann “Physico-Chemical Effects of Pressure,” Butterworths London 1957. Gonikberg and Zhulin Austral. J. Chern. 1958 11 285. Harris and Weale J. 1961 146. Williams Perrin and Gibson Proc. Roy. SOC.,1936 A 154,684. tivity determinations depended somewhat on con- centration and were usually determined at about 0-05 mole/l. Second-order rate constants for the forward reaction (methyl iodide with ethylmethyl- aniline) were obtained by a titration method and the overall volume change was observed in a dilato-meter.Relative rate constants are tabulated and shown in the Figure. PROCEEDINGS 2000 atm. taken alone would give a mean d V* of +10-6 over this pressure range. d V for the forma- tion of the quaternary salt is -55.8 c.c./mole at 25" which is similar in magnitude to the combined values of d V* for the two reactions (exact comparison re- quires corrections for temperature-dependence and allowance for incomplete dissociation of the salt). dV* for the reverse reaction is considered to arise Relative rate constants in nitrobenzene. P (atm.) 1 Forward reaction at 50" kJk 1 Reverse reaction at 65" kJk 1 From the initial slope of the curve for the forward reaction dV* is -20 c.c./mole at 50".d V* for the reverse reaction is less easily estimated but is about -45 c.c./mole at 65". The great difference between this value and the earlier result seems due to the pronounced curvature shown e.g. our point at 200 500 lo00 1500 2000 -1-44 2.03 2.68 -0.756 0.638 0.525 -0.466 mainly from release of solvating molecules by the reacting ions. This finding that it is much larger than had been supposed appears to resolve a major difficulty in the interpretation of earlier results for Menschutkin reactions. (Received August 16th 1961 .) NEWS AND ANNOUNCEMENTS International Symposia etc.-A Symposium on the Physics of Graphite Moderated Reactors arranged by the Institute of Physics and the Physical Society in collaboration with the British Nuclear Energy Conference will be held in Bournemouth April Mth 1962.Enquiries should be addressed to the Secretary Institute of Physics and the Physical Society 47 Belgrave Square London S.W.l. An International Symposium on Analytical Chem- istry to commemorate the 70th birthday of Professor F. Feigl (Brazil) is to be held at the University Edgbaston Birmingham on April 9-13th 1962. Enquiries should be addressed to the Honorary Symposium Secretary M. L. Richardson A.R.I.C. c/o John & E. Sturge Ltd. Lifford Chemical Works Lifford Lane Kings Norton Birmingham 30 England. The Second Conference on Kinetics Equilibria and Performance of High Temperature Systems sponsored by the Western States Section of the Combustion Institute is to be held at the University of California at Los Angeles on April 14-16th 1962.Enquiries should be addressed to Mr. Gilbert S. Bahn 16902 Bollinger Drive Pacific Palisades California U.S.A. A European Corrosion Conference is to be held in Paris on May 2nd-3rd 1962. The meeting is spon- sored by the European Federation of Corrmion and the French Corrosion Centre and is being held on the occasion of the Sixth Exhibition of Chemistry and International Conference of Chemical Arts. Enquiries should be addressed to SociktC de Chimie Industrielle 28 rue St. Dominique Paris 7e France. The Fourth International Symposium on Gas Chromatography will be held in Hamburg on June 13-16th 1962.Enquiries should be addressed to Fachgruppe Analytische Chernie Gesellschaft Deutscher Chemiker Postfach 9075 Frankfurt am Main Germany. Election of New Fellows.-77 Candidates whose names were published in Proceedings for August have been elected to the Fellowship. Deaths.-We regret to announce the deaths of the following Professor H. V. A. Briscoe (24.9.61) Emeritus Professor of Inorganic Chemistry at the Imperial College of Science and Technology London; Dr. Ernest Chapman (22.2.61) formerly of I.C.I. Ltd. Dyestuffs Division Blackley; Mr. C. E. Ramsden (April 1961) formerly of C. E. Ramsden & Co. Ltd. Fenton Stokeon-Trent; Mi-. W. A. Voss (4.7.61) Station Chemist North Thames Gas Board; and Mr.E. Walls (May 1961) a Fellow of the Society since 1919. It is much regretted that the late Professor M. W. Travers Professor Emeritus of Chemistry University of Bristol was incorrectly described as Professor Emeritus of Physics in the Proceedings for September 1961. D.S.I.R. Headquarters.-The Headquarters of the D.S.I.R. has moved from Regent Street London S.W.1 to State House High Holborn London w.c.1. Visitors to Australia.-The Western Australian OCTOBER 1961 Branch of the Royal Australian Chemical Institute and the Staff of the Chemistry Department of the University of Western Australia are anxious to receive visits from any chemists who may come to or pass through Australia.They point out that several through air-journeys can be broken suitably at no extra fare. Dr. A. R. H. Cole (Department of Chem- istry The University of Western Australia Ned- lands) would be glad to help potential visitors. Institution of Chemical Engineers.-In recognition of their long and distinguished service to the Institu- tion Sir Harold Hartley Mr. H. W. Cremer and Professor M. B. Donald have been elected to Honorary Membership of the Institution in the class of Corporate Members. Personal.-Mr. K. W. Allen of the Northampton College of Advanced Technology is visiting research associate and instructor at the Crystallography Laboratory of the University of Pennsylvania on a Fulbright Scholarship for 12 months from September 1st last.Dr. B. E. Betts has been given a year’s leave of absence from the Polytechnic Regent Street London to take a postdoctorial research associate- ship at the University of Illinois. Dr. K. E. Bharucha has returned from India and has joined the staff of Imperial Chemical Industries Ltd. Paints Division. Professor L. H. Briggs Auckland University New Zealand has accepted a Commonwealth Visiting Fellowship for the academic year 1961-2 attached to the University of Aberdeen. Dr. B. E. Conway Professor of Chemistry at the University of Ottawa has been awarded the degree of D.Sc. by the University of London. Mr. S. Dfxon has retired as public analyst and official agricultural analyst for the City of Cardiff and the County Borough of Swansea.He had held the appointment since 1929. Dr. C. Eizborn Reader in Physical-organic Chemistry at Leicester University has been ap-pointed to the Chair of Chemistry at the new University of Sussex. Dr. P. N. Edwards formerly of the University of Minnesota has taken up a N.A.T.O. Fellowship at the University of Manchester. Mr. J. P. Elder formerly of the British Non- Ferrous Metals Research Association has taken up a research appointment in the division of applied electrochemistry and corrosion Royal Institute of Technology Stockholm Sweden. Dr. I. J. Faulkner formerly ammonia works manager Imperial Chemical Industries Ltd. Billing- ham Division has been appointed products works manager. Mr. E. B. Fielding formerly of J.Wattie Can- 391 neries Ltd. Hastings New Zealand has taken up an appointment as chief chemist and bacteriologist Robert Wilson Food Industries Ltd. Skelmorlie Castle Ayrshire. Dr. R. Gurran staff manager of the Alkali Group I.C.I.A.N.Z. Ltd. Melbourne has been elected President of the Royal Society of Victoria. Dr. B. M. K. Gatehouse formerly of the Division of Chemical Physics of the C.S.I.R.O. has been appointed Lecturer in the Faculty of Applied Science of the University of Melbourne. Dr. M. S. Habib has been appointed Chief Analyst Burroughs Wellcome & Co. (Pakistan) Ltd. Karachi. Dr. D. A. Hall divisional chief scientist National Coal Board Durham Division has been awarded the degree of D.Sc. by the University of Bristol.Dr. A. K. Holliday Senior Lecturer in the Depart- ment of Inorganic and Physical Chemistry of the University of Liverpool has been awarded the degree of D.Sc. by the University of Leeds. Dr. T. P. Hughes formerly of Tube Investments Limited has been appointed assistant managing director of The B.B. Chemical Co. Ltd. Leicester. Dr. D. W.Hutchinson,formerly of the Department of Chemistry Massachusetts Institute of Technology has taken up an I.C.I. Fellowship at the University of Cambridge. Mr. A. W. Jubb formerly of the Associated Chemical Companies Central Research Laboratories has taken up an appointmcnt as Chief Chemist with Bardens (Bury) Ltd. Dr. D. F. Larder formerly of the University of Alberta has been appointed Professor of Chemistry of Notre Dame University College Nelson B.C.Canada. Dr. H. A. E. Muckenzie has been appointed Assistant Factory Manager African Explosives and Chemical Industries Modderfontein Dynamite Factory. Dr. G. E. Mapstone formerly of Dermacult S.A. Pty. Ltd. Johannesburgh has joined the develop- ment department of African Explosives and Chem- ical Industries Ltd. Dr. J. Nunn has been appointed to the new Chair of Organic Chemistry at Rhodes University Grahamstown Cape Province. Dr. C. N. R. Rao has recently received the degree of D.Sc. of the University of Mysore. Mr. H. N. Read Superintendent R.N. Propellent Factory Caenvent Monmouthshire has retired after 38 years in Admiralty service. Dr. G. F. Reynolds has resigned his post as Principal Scientific Officer in the Chemical Inspec- torate War Office and has been appointed Reader in Analytical Chemistry at Loughborough College Leicestershire.Dr. B. Roberts has been awarded a post-doctoral Fellowship in the Division of Pure Chemistry National Research Council of Canada Ottawa. Mr. R. S. Ruche formerly of the Dounreay Experimental Reactor Establishment is now a B.X. Plastics Research Scholar at the University of Glasgow. Mr. R. A. Rothenbury has been awarded a post-doctorate research fellowship under Professor R. J. Gillespie at McMaster University Hamilton Ontario Canada. Mr. C. A. Russell has been appointed senior lecturer in organic chemistry at the Harris College Preston. Professor F.Sebba Professor of Physical Chem- istry at the University of Witwatersrand is spending a year’s study leave in the Royal School of Mines London as a guest of the School and assisted by a grant from the Ernest Oppenheimer Memorial Fund. Mr. J. D. Shapland has been appointed managing director of Foamite Limited Feltham Middlesex. PROCEEDINGS Dr. Herchel Smith has been appointed manager of the Steroids and Natural Products Section of the Wyeth Laboratories Incorporated Radnor Penn- sylvania. Dr. M. E. U.Taylor formerly with Fisons Ltd. has taken up a Norwegian Government post-doctorate fellowship at the Fiskeridirektoratets Havforskningsinstitutt Bergen. Dr. D. W. Theobald,formerly of the University of Strasbourg has taken up an appointment at the Manchester College of Science and Technology.Dr. J. Thomson has been appointed lecturer in chemistry Queen’s University Kingston Ontario for the session 1961-62. Mr. H. Warson formerly of Vinyl Products Ltd. has been appointed development manager (Polymers) of the Dunlop Chemical Products Division. Dr. H. H. Zeiss formerly of Monsanto Chemical Company’s Research and Engineering Division has been elected president and director of Monsanto Research S.A. of Zurich Switzerland. FORTHCOMING SCIENTIFIC MEETINGS London Thursday November 2nd at 2 p.m. Symposium on “Electron Spin Resonance”. To be held at Queen Mary College. (A full programme has been circulated.) Thursday November 16th at 7.30 p.m. Centenary Lecture “Some Reactions of Free Radicals,” by Professor G.B. Kistiakowski. To be given in the Rooms of the Society Burlington House w.l. Aberdeen (Joint Meetings with the Royal Institute of Chem- istry and the Society of Chemical Industry to be held at Marischal College.) Thursday November 9th at 8 p.m. Lecture “The Discovery of New Drugs,” by Dr. A. F. Crowther M.A. Friday December 8th at 8 p.m. Lecture “Inorganic Heterocycles,” by Dr. N. L. Paddock B.A. Aberystwyth (Joint Meetings with the University College of Wales Chemical Society unless otherwise stated to be held in the Edward Davies Chemical Labora- t ories .) Thursday November 9th at 5 p.m. Lecture “The Anatomy of the Chemist,” by Dr. T. S. Stevens A.R.I.C. Tuesday November 14th at 5 p.m.Lecture “Nuclear Magnetic Resonance Spectro- scopy,” by Dr. R. E. Richards M.A. F.R.S. Joint Meeting with the Royal Institute of Chemistry. Thursday December 7th at 5 p.m. Lecture “Microcalorimetry and the Thermogenesis of Living Species,” by Dr. H. A. Skinner B.A. Birmingham (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University.) Friday November loth at 4.30 p.m. Lecture “The Active Centres of Enzymes,” by Professor H. N. Rydon D.Sc. F.R.I.C. Friday December lst at 4.30 p.m. Lecture “New Reactions in Dinitrogen Tetroxide,” by Professor C. C. Addison D.Sc. F.R.I.C. Bristoi Thursday November 2nd at 6.30 p.m. Lecture “Some Studies in the Porphyrin Field,” by Professor G.W. Kenner Ph.D. Sc.D. Joint Meeting with the Royal Institute of chemistry and the Society of Chemical Industry to be held in the Department of Chemistry The University. Friday November 24th. Annual Dinner and Dance. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at Long Ashton Research Station. OCTOBER 1961 Thursday December 7th at 6.30 p.m. Lecture “Mining Smelting and Refining of Nickel,” by Dr. G. L. J. Bailey. Joint Meeting with the Royal Institute of Chemistry the Society of Chemical Industry and the Institute of Metals to be held in the Department of Chemistry The University. Cambridge (Meetings will be held in the University Chemical Laboratory .) Friday November 3rd7 at 8.30 p.m.Lecture “Dielectric Absorption and Aspects of Molecular Behaviour,” by Dr. M. M. Davies M.Sc. Joint Meeting with the University Chemical Society. Tuesday November 7th at 4.30 p.m. Lecture “Unimolecular Decomposition of Excited Molecules Formed by Methylene Addition Re-actions,” by Dr. H. M. Frey M.A. Monday November 13th at 5 p.m. Lecture “The Physical Chemistry of Ion-exchange Polymers,” by Dr. E. Glueckauf. Friday November 17th at 8.30 p.m. Official Meeting and Centenary Lecture “Some Reactions of Free Radicals,” by Professor G. B. Kistiakowski. Joint Meeting with the University Chemical Society. Monday November 20th at 5 p.m. Lecture “Persulphate Oxidation of Carboxylic Acids,” by Dr.R. H. Thomson F.R.I.C. * Friday December lst at 8.30 p.m. Lecture “Biphenylene and Related Compounds,” by Professor W. Baker D.Sc. F.R.S. Joint Meeting with the University Chemical Society. Monday December 4th at 5 p.m. Lecture “Some Hydrogen Transfer Reactions,” by Professor H. B. Henbest Ph.D. F.R.I.C. Cardiff Monday December 4th at 5 p.m. Lecture “Transfer Reactions of Oxygenated Radi- cals,” by Professor A. F. Trotman-Dickenson Ph.D. to be given in the Department of Chemistry Univ- ersity College Cathays Park. Dublin (Meetings to be held in the Department of Chemistry Trinity College.) Wednesday November 22nd at 5.30 p.m. Lecture “The Stereochemistry of Flavan-4-ols,” by Professor Eva M. Philbin D.Sc. Friday November 24th at 5.30 p.m.Lecture “Some New Photochemical Reactions,” by Professor D. H. R. Barton D.Sc. F.R.S. Joint Meeting with the Werner Society. Durham (Joint Meetings with the Durham Colleges Chemical Society to be held in the Science Laboratories The University.) Monday November 13th at 5 p.m. Lecture “Surface Radiochemistry,” by Dr. S. J. Thompson B.Sc. Monday November 27th at 5 p.m. Lecture “Metals and /3-DiketonesyY’ by Dr. M.R. Truter B.Sc. Edinburgh Wednesday November 8th at 7.30 p.m. Lecture “Some Principles and Practices in Corrosion Protection,” by Dr. T. P Hoar M.A. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at the Heriot-Watt College. Tuesday November 28th at 4.30 p.m.Lecture “Hydrogen Bonding from a Crystallo-grapher’s Viewpoint,” by Dr. J. C. Speakman M.Sc. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Exeter Friday November 17th at 5 p.m. Lecture “Recent Developments in Acetylene-Allene Chemistry,” by Professor E. R. H. Jones D.Sc. F.R.S.Joint Meeting with the University Chemical Society to be held in the Washington Singer Laboratories. Glasgow Friday November 17th at 4 p.m. Lecture “Some Aspects of Cholesterol Biosyn- thesis,” by Dr. G. J. Popjak F.R.S. Joint Meeting with the Alchemists Club to be held in the Chem- istry Department The University. Friday December 8th at 7.15 p.m. Lecture “The Structure of Natural Products by Direct X-Ray Analysis,” by Professor J.Monteath Robertson D.Sc. F.R.I.C. F.R.S. Joint Meeting with the Royal Institute of Chemistry the Society of Chemical Industry and the Society for Analytical Chemistry to be held in the Royal College of Science and Technology. Hull (Meetings will be held in the Department of Chem- istry The University.) Thursday November 2nd at 5 p.m. Lecture “Molecular Addition Compounds,” by Professor N. N. Greenwood Ph.D. Sc.D. Joint Meeting with University Students Chemical Society. Thursday November 16th at 5 p.m. Lecture “Some Studies in the Porphyrin Field,” by Professor G. W.Kenner Ph.D. Sc.D. KeeIe (Joint Meetings with the University College Science Society to be held in the Department of Chemistry University College of North Staf€ordshire.) Tuesday November 7th at 8.30 p.m.Lecture by Dr. J. S. Anderson F.R.S. Tuesday November 21st at 8.30 p.m. Lecture “The Anatomy of the Chemist,” by Dr. T. S. Stevens A.R.I.C. Leeds Thursday November 30th at 6.30 p.m. Lecture “Aspects of the Biosynthesis of Phenolic Compounds,” by Professor C. H. Hassall M.Sc. To be given in the Chemistry Lecture Theatre The University. Leicester (Joint Meetings with the University Chemical Society to be held in the University.) Monday November 2Oth at 4.30 p.m. Lecture “Some Applications of Electron-spin Resonance Spectroscopy,” by Professor H. C. Longuet-Higgins M.A. D.Phil. F.R.S. Tuesday December Sth at 4.30 p.m.Lecture “Some Recent Observations on the Activity of Metal Catalysts,” by Professor C. Kernball M.A. Ph.D. F.R.I.C. Liverpool Thursday November 23rd at 5 p.m. Lecture “Some Aspects of Structure and Reactivity in Ionic Solutions,” by Professor K. W. Sykes MA D.Phi1. Joint Meeting with the Student Chemical Society to be held in the Department of Inorganic and Physical Chemistry The University. Manchester Tuesday November 14th at 6.30 p.m. Centenary Lecture “Some Reactions of Free Radicals,” by Professor G. B. Kistiakowski. To be given in Room FlyManchester College of Science and Technology. Thursday November 16th at 5 p.m. Lecture “The Biogenesis of Alkaloids,” by Sir Robert Robinson O.M. D.Sc. F.R.S. Joint Meet- ing with the Students Union Chemical Society of the Royal College of Advanced Technology Salford to be held in the Conference Hall (Room 327) of the College.PROCEEDINGS Thursday December 7th at 6.30 p.m. Official Meeting and Lecture “The Structure of Proteins,” by Dr. M. F. Perutz F.R.S. To be held in Room Fly Manchester College of Science and Technology. Newcastle upon Tyne (Meetings will be held in the Chemistry Department King’s College.) Monday November ZOth at 5.30 p.m. Lecture “Free Radicals in Irradiated Crystals,” by Dr. D. H. Whiffen M.A. Friday December lst at 5.30 p.m. Bedson Club Lecture “The Gibberellins a New Group of Plant Hormones,” by Dr. P. W.Brian F.R.S. Northern Ireland Thursday November 23rd at 7.45 p.m.Lecture “Some Aspects of Tannin Chemistry,” by Professor R. D. Haworth D.Sc. F.R.S. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Chemistry Department David Keir Building Queen’s University Belfast. Nottingham (Joint Meetings with the University Chemical Society to be held in the Department of Chemistry The University.) Tuesday November 14th at 5 p.m. Lecture “Experimental Methods in the Study of Chemical Kinetics,” by Professor J. C. Robb Ph.D. F.R.I.C. Tuesday November 28th at 5 p.m. Lecture “Some Chemical Applications of Electron Resonance Spectroscopy,” by Professor H. C. Longuet-Hies M.A. D.Phil. F.R.S. Oxford (Joint Meetings with the Alembic Club to be held in the Inorganic Chemistry Lecture Theatre.) Monday November 13th at 8.15 p.m.Lecture “Some Aspects of the Chemical Structure of Proteins,” by Professor H. D. Springall M.A. D.Phil. F.R.I.C. Monday November 27th at 8.15 p.m. Lecture “Some Hydrido-complexes of Transition Metals,” by Dr. J. Chatt F.R.S. St. Andrews and Dundee (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University St. Andrews.) OCTOBER 1961 Friday November loth at 5.15 p.m. Lecture “Chemical Relationships between Brewing Beer and Baking Bread,” by Dr. M. A. Pyke. Friday November 24th at 5.15 p.m. Lecture “New Reactions in Dinitrogen Tetroxide,” by Professor C. C. Addison Ph.D. F.R.I.C. Sheffield (Joint Meetings with the Royal Institute of Chem-istry and the University Chemical Society to be held in the Department of Chemistry The University.) Thursday November 16th at 4.30 p.m.Lecture “Polynuclear Complex Formation in Solution,” by Dr. F. J. C. Rossotti M.A. Thursday November 30th at 4.30 p.m. Lecture “The Electronic Structures of Some Molecules and Radicals,” by Dr. J. W. Linnett MA. F.R.S. Southampton Friday November 3rd at 5 p.m. Lecture “Addition Accompanying Substitution in the Halogenation of Aromatic Compounds,” by Professor P. B. D. de la Mare Ph.D. Joint Meeting with the University Chemical Society to be held in the Chemistry Department The University. Friday November 17th at 5 p.m. Lecture “The Rapid Reactions of Some Complex Ions,” by Dr.R. G. Wilkins. Joint Meeting with the University Chemical Society to be held in the Chemistry Department The University. Swansea Monday November 13th at 4.30 p.m. Lecture “Recent Advances in Nuclear Resonance,” by Dr. R. E. Richards M.A. F.R.S.Joint Meeting with the University College Chemical Society to be held in the Department of Chemistry University College. Tees-side Friday November loth at 8 p.m. Lecture “Aspects of Chemistry of Olefin Complexes of Transitional Metals,” by Professor G. Wilkinson Ph.D. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at the William Newton School Norton. Tuesday November 28th at 8 p.m. Official Meeting and Lecture “Means to Some Ends,’’ by Professor C.L. Wilson D.Sc. F.R.I.C. To be held at the Constantine Technical College Middlesbrough. 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.) Merman-Faber Alida Cornelia. De Leew van Vlaan- derenstraat 8-1 11 Amsterdam,The Netherlands. Armstrong William Lawrence A.B. Chemistry Depart- ment University of Rochester Rochester 20 New York U.S.A. Baig Stephen Robert. 96 Peter Street Moncton New Brunswick Canada.Beaven Michael Anthony B.Pharm. M.P.S. School of Pharmacy Chelsea College of Science and Technology Manresa Road S.W.3. Blomquist Alfred Theodore M.S. Ph.D. Baker Labora- tory of Chemistry Cornell University Ithaca N.Y., U.S.A. Bloom Murray Ph.D. 1836 Colby Avenue Apt. 3 Los Angeles 25 California U.S.A. Bloomfield Peter Richard B.Sc. A.R.I.C. 28 Cedar Close Bagshot Surrey. Bouffard Roland A. B.S. Chemistry Department Box 29 University of Connecticut Storrs Connecticut U.S.A. Bray Roger Garth B.k. Rossall School Fleetwood Lancashire. Brock William Hodson M.Sc. Department of History of Science The University Leicester. Campion Alexander David B.Sc. 22 Tylehurst Gardens Ilford Essex. Cooley George M.Sc. A.R.P.S.96 Church Road Richmond Surrey. Cowley Alan Herbert M.Sc. Ph.D. 16 Fife Road Norton Stockton-on-Tees Co. Durham. Dann Anthony Edward. 44 Gladstone Road Acton Green Chiswick W.4. Davy Richard B.Sc. C/o Mrs. D. Moffat Outrigg House St. Bees Cumberland. Deshpande Shrinivas Manohar M.Sc. Ph.D. College of Science Banaras Hindu University Varanasi-5 India. Ellis Gwynn Pennant Ph.D. F.R.I.C. 10 Offley Avenue Sandbach Cheshire. Evans Jeffrey Cut hbert B.Sc. Chemistry Department , University College Cathays Park Cardiff. Forsyth Ronald Stewart B.Sc. A.R.I.C. Chemistry Division Aktiebolaget Atomenergi Studsvik Tyst- berga Sweden. Fox John Richard B.Sc. 8 Eardulph Avenue Chester- le-Street Co. Durham. Gardner Ralph Alexander M.S. Ph.D.16312 Throckley Road Cleveland 28 Ohio U.S.A. Goodman Barry John Anthony. 41 The Uplands, Loughton Essex. Gordon Myra A.B. Chemistry Department University of Pittsburgh Pittsburgh 13 Pennsylvania U.S.A. Grudniewicz Jerzy Andrzej B.Sc. 74 Babington Road London S.W.16. Haworth Susan B.Sc. British Cotton Silk and Man- Made Fibres Research Association Shirley Institute Didsbury Manchester 20. Hepworth Walter M.Sc. 16 Syddall Avenue Cheadle Cheshire. Herries David Gordon B.Sc. Department of Biochem- istry Yale University School of Medicine 333 Cedar Street New Haven Connecticut U.S.A. Howard John Charles Ph.D. Medical College of Georgia Department of Biochemistry Augusta, Georgia U.S.A. Jennings Raymond B.Sc. 36 Bedford Square Aspatria Carlisle Cumberland.Jones Edward Barry B.Sc. 8 Ruthin Gardens Cathays Cardiff. Joshi Arvind Purushottam M.Sc. Ph.D. Research Divi- sion L. Light & Co. Ltd. Poyle Estate Colnbrook Bucks. Kaelin Alfred Charles. Llandaff House Earl Road Penarth Glamorganshire. Kerigan Ann Kathleen B.Sc. Chemistry Department University of British Columbia Vancouver 8 Canada. Kirsten Gottfried Oskar M.Sc. Bartholomaeusstrasse 57 Hamburg 22 Germany. LeMahieu Ronald Andrew B.A. 1103 H University Village East Lansing Michigan U.S.A. Metzger Robert Philip Paul B.Sc. 13906 Van Nuys Boulevard Pacoima California U.S.A. Murphy David B.Sc. 133 Knighton Road Leicester. Narayanan Mundoli Neelakandha B.Sc. M. Pharm. Pharmacy Department Andhra University Waltair Visakhapatnam-3 India.Neuff Alan Trevor B.Sc. “Nimrod,” Thorngrove, Bishop’s Stortford Herts. ADDITIONS TO A cross referenced index of radiochemical teaching experiments applicable to chemistry. G. R. Choppin. Nuclear Science Series Report No. 36. Pp. 50. United States National Research Council. Subcommittee on Radiochemistry. Washington. 1961. (Presented by the publisher.) Separations by solvent extraction with tri-n-octyl-phosphine oxide. J. C. White and W. J. Ross. Issued by the United States Atomic Energy Commission. Nuclear Science Series NAS-NS 3102. Pp. 56.. United States. National Research Council. Subcommittee on Radio-chemistry. Washington. 1961. (Presented by the publisher.) Low-level radiochemical separations.T. T. Sugihara. Pp. 34. Issued by the United States Atomic Energy Com-mission. Nuclear Science Series NAS-NS 3103. United States. National Research Council. Subcommittee on Radiochemistry. Washington. 1961. (Presented by the publisher.) Trattato di chimica industriale. Edited by Michcle Giua. Vol. 4. Pp. 1141. Unione Tipografico-Editrice Torinese. Turin. 1961. Nicholson Geoffrey Charles B.Sc. A.R.C.S. Chemistry Department Royal College of Science Imperial Institute Road S.W.7. Petrucci Ralph H. Ph.D. Morley Chemical Laboratory Western Reserve University Cleveland 6,Ohio U.S.A. Phillips Brian Desmond B.Sc. Chemistry Department University College Cathays Park Cardiff. Pocock Herbert. 3 The Ramblers South Strand, Angmering-on-Sea Sussex.Ponnamperuma Cyril Andrew B.A. B.Sc. Lawrence Radiation Laboratory University of California, Berkeley 4 California U.S.A. Pringle Geoffrey Eric Ph.D. A.Inst.P. Department of Inorganic and Structural Chemistry University of Leeds Leeds 2 Yorks. Randall Alan Arthur Ph.D. A.R.I.C. Courtaulds Limited Research Laboratory Lower Cookham Road Maidenhead Berks. Richards Martin B.Sc. 29 Gilkes Crescent Dulwich Village S.E.21. Ross Norman Cruickshank Ph.D. 26 Cranes Drive Surbiton Surrey. Savory Maurice John B.Sc. 349 Manor Avenue Sale Cheshire. Slade John Anthony B.A. 10 Lyndhurst Road London N.W.3. Smalley Henry Marshall B.Sc. Chemistry Department University of Manchester Oxford Road Manchester 13. Waite James Arthur Ph.D.Chemistry Department Kings College Strand London W.C.2. Wallis Anthony Kenneth B.Sc. Courtauld Institute of Biochemistry Middlesex Hospital Medical School London W.l. Walton David Edwin. 187 Lathom Road East Ham London E.6. Whelan Daniel James B.Sc. Chemistry Department University of Melbourne Parkville Victoria Australia. Whittle Eric M.Sc. Ph.D. Chemistry Department University College Cathays Park Cardiff. THE LIBRARY High temperature resistance and thermal degradation of polymers papers (with discussions) read at a sym-posium organised by the Plastics and Polymer Group held 1960 at the University of London. Pp. 500. Society of Chemical Industry Plastics and Polymer Group. London. 1960. (Presented by the publisher,) Combustion flames and explosions of gases.Bernard Lewis. Pp. 731. Academic Press. New York. 1961. Fatty acids. Edited by Klare S. Markley. Part 2. Pp. 1485. Interscience Publishers Inc. New York. 1961. Heterocyclic systems with bridgehead nitrogen atoms. William L. Mosby. Part 2. Pp. 1466. Interscience Publishers Inc. New York. 1961. pH Measurement and titration. G. Mattock. Pp. 406. Heywood. London. 1961. (Presented by the author.) Treatise on Analytical Chemistry. Edited by I. M. Kolthoff P. J. Elving and B. Sandell. Vol. 3 part 1. Pp. 1750. Interscience Publishers Inc. New York. 1961. Hormones in blood. Edited by C. H. Gray and A. L. Bacharach. Pp. 655. Academic Press. New York. 1961. (Presented by the editors.)
ISSN:0369-8718
DOI:10.1039/PS9610000357
出版商:RSC
年代:1961
数据来源: RSC
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