1048
NOTES
VOl. 77
TABLE I DATAO N COPOLYMERIZATIONS BY DIFFERENT CATALYSTS OF 0.02 MOLEOF STYRENE A N D 0.02MOLEMETHYL METHACRYLATE Catalyst
Mole % catalyst
Sa
( C6H5)3CINa
1 .0 0.5 (Ce.H5)3CNa (CJLCOO), 0.1 (p-ClCIHIC00)z 0.1 (t-CaHsO)z 0.1 a On shaking machine.
Time, Temp.,
'C.
Room Room Room 60 60 100
hr.
Yield, % b y wt. of monomers used
65 24.5 65 7.7 16 2.5
11 18 4 11.8 12.3 21.3 17.5
because its solubility in ether ensured separation from excess sodium) \vas prepared from triphenylmethyl chloride and sodium in ether solution.* Procedure.-Techniques previously reported were used for the preparation8 and purificationlo of the polymers. In the reaction with triphenylmethylsodium, an ether solution of the catalyst was added to the monomer mixture. The degassing process was carried out with a conventional high vacuum system and a pressure of 2.5 X mm. was ohtained at least three times before the sample was allowed to polymerize for the indicated time. Repetition of polymerizations previously reporteda was undertaken t o determine the accuracy in duplication of the previous work, and good agreement was obtained. The results are given in Table I. (8) Org. Syntheses, 19, 83 (1939). (9) F. R. M a y o and F. M. Lewis, THISJ O U R N A L , 66, 1594 (1944). (IO) F.M. Lewis and F.R. Mayo, Ind. Eng. Chem., Anal. E d . , 17, 134 (1945).
MORLEYCHEMICAL LAB. WESTERNRESERVEUNIVERSITY CLEVELAND, OHIO
1,3,5-Trichloro-2,4,6-tribromocyclohexane BY H R. FRISCH RECEIVED M A Y 13, 1954
Benzene reacts with chlorine to form a mixture of isomers of benzene hexachloride and with bromine to yield a mixture of the hexabromides, but chlorine does not react with benzene hexabromide with the replacement of any bromine atoms. Under the conditions described below the reaction of benzene with a mixture of chlorine and bromine yields a product which is probably a mixture of isomers of 1,3,5-trichloro-2,4,6-tribrornocyclohexane, eight of which are theoretically possible with a cyclohexane of planar configuration. On alkaline hydrolysis 3 moles of the alkali bromide and 1,3,5-trichlorobenzene were obtained. The formation of 1,3,5-trichloro-2,4,6-tribromocyclohexaneis best explained if a chemical combination of chlorine and bromine is assumed; the existence of chlorine bromide has been suggested, but not conclusively demonstrated. The insecticidal potency of the mixture against roaches and mites is about the same as that of crude benzene hexachloride. Experimental Under actinic irradiation and a t temperatures below l o " , benzene reacted quantitatively 1% ith stoichiometric amounts of chlorine and bromine to yield a solid product which was recrystallized from hot glacial acetic acid as colorless plate: of 1,3,5-trichloro-2,4,6-tribromocyclohexane, m.p. 171 with slight decomposition.' Anal. Calcd. for CsHeClaBra: C, 16.99; H , 1.43; C1, 25.07; Br, 58.51; mol. wt., 424.24. Found: C, 16.3; H, 1.47; C1, 22.38; Br, 56.42;mol. wt., 427. ( I ) Tests were carried out by courtesy of Niagara Chemical Division of Food Machinery and Chemical Corporation, Middleport, N.Y.
Mole c; styrene in polymer
c. % 60.17& 0.04 60.27& .24 60.88 76.18 75,70 75.81& .5s
0 . i j f 0.1
8.16f 0.01 8.12f .23 6.11 7.99 8.31
0.80=t0 . M 2.70 50.19 48.70
8 , 1 5 & .15
4 9 . 0 1 1 1.80
The coinpound is soluble in most organic solvents with the exception of carbon tetrachloride. On alkaline hydrolysis it yielded 3 moles of alkali bromide and a waterinsoluble oil, 1,3,5-triclilorobeiizene; b.p. 208' (760 mm. ), C158%. INSTITUTE OF ORGANIC CHEMISTRY UNIVERSITY OF DELFT(NETHERLANDS)
Pyrosynthesis of Aspartic Acid and Alanine from Citric Acid Cycle Intermediates' BY SIDSEYItT.FOX,JOSEPH E. JOHNSON MIDDLEBROOK JUNE 21, 1954 RECEIVED
AND
XfAVIS
Experiments directed toward synthesis of true protein, and elucidation of its primordial origin2 and subsequent evolution3 have been performed. In the course of these experiments, almost all chromatographic evaluations of pyropolymerization of various pairs of DL-amino acids revealed, following hydrolysis, a number of ninhydrin-reactive spots which exceeded the number of reactants. These results indicate that the conditions which produce polymer^^.^ from unsubstituted amino acids lead also to the formation of additional amino acids (and in part possibly to amines). Attention was diverted to a possible thermal origin of aspartic acid from the citric acid cycle by the postulate that those features of current biochemistry which are biologically relatively ubiquitous were also part of a primordial bioche~nistry.~ Over a century ago, aspartic acid had been prepared by heating ammonium fumarate or amnionium malate6q7although of course not with reference to the now recognized citric acid cycle. In the present experiments, ammonium salts of two additional acids from the citric acid cycle were each heated for up to three hours a t 200") chromatographed, and also hydrolyzed and chromatographed. Faint ninhydrin spots were obtained from heated ammonium fumarate and ammonium malate, although there were none from ammonium citrate or ammonium succinate either before or (1) Journal paper N o . J-234G of t h e Iowa iZgricultural Experiment Station, Ames, Iowa. Project 1 111, supported by t h e Rockefeller Foundation. ( 2 ) S. W. Fox and R1. AIiddlebrook, Fede?,oliov I'roc., 13, 211 (19.54). (3) S . W. Fox, A m . 5 u f i L r n i i s t , 87, 233 (19.53). (4) H. Schiff, Ann., SOT, 231 (1899). ( 5 ) Additional reasons for this particular study were t h e facts t h a t aspartic acid is a n early or t h e earliest amino acid in biosynthesis and t h a t its metabolic origin is from t h e citric acid cycle (see E. Baldwin, "Dynamic Aspects of Biochemistry," the TJniversity Press, Cambridge, 19.52). ( 6 ) J. Wolff, A n n . , 76, 4 Y 1 (18,iO). ( 7 ) Descaigneq, Cowpt. ? , ? ? t L , 30, 324 (1S;Oi
Feh. 20, 1955
NOTES
after hydrolysis. The fumarate and malate products however yielded greatly increased ninhydrin reactions after hydrolysis (Fig. 1). The low intensities prior to hydrolysis are explainable on the basis that the conditions employed for synthesis of aspartic acid are identical to those which cause rapid pyrohomopolymerization of aspartic acid to an acidhydrolyzable p r o d ~ c t . ~The , ~ conversion of malate to aspartate was visibly greater than that of fumarate at 120, 160 and 200". .............. .. .....
1049
.............
c-..-*--.'.
.
........ ..-
3 4 5 6 7 8 Fig. 2.-1. 10 X of aspartic acid; 2, 10 X of a-alaniac; 3, 10 A of @-alanine; 4, 10 h each of aspartic acid and aalanine; 5, 10 X each of aspartic acid and p-alanine; 6. 10 X each of aspartic acid, a-alanine, and @-alanine; 7, 20 X of product from ammonium malate heated a t 160'; 8, 20 A of product from ammonium malate heated a t 200'. Chromatographic solvent was 7 pyridine:3 water. 1
1 2 3 4 5 6
7 8 9 1 0 1 1
1213
Fig. 1.-1, 10 X of aspartic acid standard; 2, 10 A of alanine standard; 3, 10 X of leucine standard. to permit comparisons of R F ;4, 10 X of unheated monoammonium fumarate; 5, 10 A of unheated monoammonium malate; 6, 10 X of heated monoammonium fumarate; 7. 2 X of hydrolyzed heated monoammonium fumarate (2 A); 8, 10 A of heated monoammonium malate; 9, 1X of hydrolyzed heated monoammonium malate showing faint spot with RF of alanine; 10, 10 X of hydrolyzed heated monoammonium succinate; 11. 10 X of hydrolyzed heated ammonium citrate showing non-ninhydrin spot at origin; 12. 10 A of hydrolyzed heated monoammonium fumarate (this amount shows alanine spot better than does spot 7 ) ; 13. same as 12 for monoammonium malate instead of spot 9. Heating was fw 3 hours at 200' in tubes of 16 X 150 mm. size in oil-bath. Hydrolyses were performed with concd. hydrochloric acid a t 15 Ib. steam pressure for 12 hours. The dried products from 1.0 g. of reactant were dissolved in 15.0 ml. of water. Standards were from solutions containing 1.0 mg. of amino acid per ml. Chromatographic solvent was 4 butanol:l acetic acid: 1 water.
2
concepts of prebiological chemistry must necessarily be highly speculative. If origins of biochemistry are to be con~idered,~ however, the experiments reported here indicate that thought must be accorded to a thermal origin of biochemistry. In this connection, it is of interest that, on the basis of taxonomic studies, CopelandLosuggested the origin of biology in thermal waters. (9) S. 1.Miller, Scicnrr, 117, 528 (1953). (10) I. 1. Copeland. Ann. N. Y. Acod. Sri.. 111). 1 (10301.
DEPARTMEW OF CHEMISTRY IOWA STATE COLLEGE AMES,IOWA
Conjugate Addition of t-Butylmagnesium Chloride to Cinnamaldehyde and Ethyl Cinnamate BY REYNOLD C . ~ AND N LEWISI. N K S RECEIVEDOCTOBER15, 1954
The only report of the conjugate addition of a Grignard reagent to an a,p-unsaturated aldehyde In all chromatograms showing additional ninhy- was made by Stevens, who succeeded in condensing drin spots following pyropolymerizations of amino t-butyl- and t-amylmagnesium chloride with croacids and hydrolysis, spots with the RF of alanine tonaldehyde in the 1,4-manner.' By the use of the were observed. Inasmuch as the RF values of a- t-butyl reagent we have been able to achieve a simialanine and of &alanine, in the butanolacetic lar result with cinnamaldehyde. The 1,Caddition acid solvent used, are the same: new chromato- product, 8-t-butylhydrocinnamaldehyde (I), isograms were run in pyridine-water (7:3), in which lated by way of the sodium bisulfite addition the RF values differ. The results from the hydroly- compound, underwent oxidation when exposed zate of heated ammonium malate (Fig. 2) confirm to the air to give the corresponding acid. We were able to synthesize 8-t-butylhydrocinin the second solvent system that the spot is alanamic acid (II), which had been described earlier nine and that this is partly or entirely a-alanine. In this latter system, p-alanine has the same RF as as- by Koelsch,2 from ethyl cinnamate and t-butylmagnesium chloride. These compounds had been partic acid. The same conditions can thus yield aspartic acid shown by others not to combine in the 1,4-manner from a citric cycle acid, can lead to the formation under the conditions ordinarily employed for such of one or more additional amino acids, and can re- condensations. (1) P. G. Stevens. Tars louamr., VI, 112 (1935) sult in a proteinoid polymer from which these am(2) C. F. Koelsech, {bid., 65, 1640 11943). ino acids are recovered following hydrolysis. Any (31 C. R. Hauser, R. S . Yort and B. I . R i n ~ l e r .J . O r p Chmr., (8) H. K. Berry. H. E. Sultun. L. Cain and Teras Piibli~ntiooNo. 51U9, 1951. p. 22.
I. S.
Berry, Univ. of
14, 26 11949): A. D. Pelrovand P. S. Eatacv.J. Grn. Chcm. 1U.S.S.R.). PO. 2236 (1950).
