June, 1947
COMMUNICATIONS T O T H E EDITOR
1551
FISSION OF BETA-OXYGENATED dl - Hexahydro - 2 - oxo - 4 - (4 - hydroxybutyl)ORGANOSILICON COMPOUNDS l-furo-(3,4)-imidazole (V), m. p. 154-155' (Anal. Sir : Calcd. for CgH1603N2: C, 53.98; H, 8.05; N, Gilman and Clark in THISJOURNAL, 69, 967 13.99. Found: C, 54.12; H, 7.81; N, 13.80) was obtained from 2-furanbutano12 (cr-naphthyl- (1947)) quite naturally assume that the formation urethan, m. p. 72-73'; Anal. Calcd. for ClgH1g- of acetone from the reaction product of triethyl0 3 N : C, 73.76; H, 6.19; N, 4.53. Found: C, chlorosilane and sodioacetoacetic ester proves the '73.82; H, 6.17; N, 4.71) by the procedures de- absence of EtaSiCH(COCH3)COzEt. While that veloped in these laboratories for the synthesis of substance is likely absent, many studies in progsimilar corn pound^.^^^ Treatment of (V) with ress in this Laboratory on related /?-oxygenated thionyl chloride gave dl-hexahydro-2-oxo-4-(4-silicon compounds convince us that their reaschlorobutyl)-l-furo-(3,4)-imidazole (VI), m. p. oning is unsafe. Thus, we find that reactions 124-126' (Anal. Calcd. for CgHljOzN2C1: C, expected to form R3SiCH2COCH3and R3SiCH249.38; H, 6.90; N, 12.80; C1, 16.22. Found: C02H actually give acetone and acetic acid, reC, 49.16; €I, 6.84; N, 12.54; C1, 16.27), which on spectively. Moreover, R3SiCH2CHOHCH3 is reaction with sodiobenzyl mercaptide was con- sensitive to acid, giving propylene readily. In verted into the corresponding benzyl thioether each case most of the silicon appears as (R3Si)ZO. (VII), m. I). 76-79' (Anal. Calcd. for C16HZ2O2- Acetyl chloride and the Grignard reagent (I) N2S: C, (52.73; H, 7.24; N, 9.14; S, 10.46. from chloromethyltrimethylsilanelgave a yellow Found: C, 62.54; H, 6.96; N, 9.31; S, 10.32). solid which, on decomposition with water, formed Reductive cleavage of (VII) yielded dl-hexahydro- a variety of products including acetone. The latter was identified by conversion to dibenzal2 - oxo - 4 - (4 - mercaptobutyl) - 1 - furo - (3,4)- acetone, m. p. and mixed m. p. 111-113'. imidazole (VIII), which on oxidation with barium Addition of carbon dioxide to (I) formed a colpermanganate was converted into the crystalline orless gel which, on steam distillation, gave hexabarium salt. of oxybiotin sulfonic acid (I). (Anal. methyldisiloxane. The residue was acidified with Calcd. for C9H1505N2SBa/2: C, 32.53; H, 4.55; dilute sulfuric acid and steam distilled. The disN, 8.44; S, 9.66; Ba, 20.69. Found: C, 32.58; tillate smelled strongly of acetic acid. This was H, 4.74; N,8.18; S, 9.43; Ba, 20.33.) The con- identified as the p-phenylphenacyl derivative, m. figuration of (I) must be identical with that of dl- p. 110-11l0. oxybiotin (111), since (VI) upon reaction with Acetaldehyde and (I) gave P-hydroxypropyltripotassium cyanide followed by hydrolysis gave methylsilane, b. p. 48' a t 10 mm., nZoD 1.4281. (111). Anal. Calcd. for C6Hl6SiO: Si, 21.2. Found: Similarly, dl-homooxybiotin sulfonic acid (11) Si, 2.4. Warming with a few drops of 10% sulwas prepared from dl-hexahydro-2-oxo-4-(5- furic acid gave a stream of gas which was conchloropentyl) -1-furo-(3,4)-imidazole' through the verted to propylene dibromide, b. p. 139' a t 728 corresponding benzyl thioether (IX), m. p. 66-68' D mm., ~ z ~ O 1.5196. Other studies point to similar conclusions on the (Anal. Calcd. for C17H2402N2S: C, 63.73; H, sensitivity to hydrolytic agents of the grouping i . m ; N, 8.74; S, 10.00. Found: C, 63.24; H, in which the last two atoms may be 7.36; N, 8.89; S, 10.30), and the mercapto- Si-C-C-0 pentanol (X). .is in the case of the lower singly or doubly bound in alcohols, ketones, acids, homolog (11) was also isolated in the form of esters and the like. The resulting fissions are not its crystalline barium salt. (Anal. Calcd. for surprising in view of the ease with which silicon CI0H17O5N2SBa/2: C, 34.70; H, 3.95; N , can give an electron pair to an electronically de1.10; S, 9%; I3a, 19.86. Found: C, 34.37; ficient carbon atom in the position beta to it.* (1) Whitmore and Sommer, THISJOURNAL, 68, 481 (1D4G). H, 5.20; N, S.14; S, 9.30; Ba, 19.60.) Com(2) Cf.Whitmore, rbrd , 64, 3277 (1932); 55, 4153 (1933), Sompounds (I), (VII), (VIII), (IX), and (X) were mer, et aE , ibid., 68, 1083 (1946). found to have pronounced antibiotin and antiSCHOOL OF CHEMISTRY F. C. \I"ITMORE oxybiotin activity for a number of microorganA N D PHYSICS L. H. SOMMER isms, in contrast to substance (11)) which had PENNSYLVANIA STATECOLLEGE JACKGOLD PA. R. E. \-AN STRIEN a slight stimulatory effect. A detailed descrip- STATECOLLEGE, RECEIVED MAY13, 1947 tion of the synthesis and microbiological activity of these coinpounds will be presented in the near future. SYNTHESIS OF PROTEIN ANALOGS r
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Sir: I~EPARTMENT OF CHEMISTRY KLAUSHOFMANN We wish to record what we believe to be the UNIVERSITY OF PITTSBURGH, ASD ANNABRIDGWATER THE INSTITUTE O F PATHOLOGY WESTERN PENXSYI,V.4SIA HOSPITAL A. E. AXELROD first successful synthesis of molecules having, like fibrous proteins, the structure PITTSBURGIT, PA. RECEIVED MAY9, 1947 HOOC-CH(RI)-SH-(COCH(R,) NH),,-COCH (Rs,+ 1 ) KHz I 12) Hofmann, Bridgwater a n d Axelrod, unpublished resiilts. (3) Hofmann, TIXIS JOIJRNAL: 67, 1459 (1945).
with very large values of n.
