COMMUNICATIONS T O T H E EDITOR STEROLS. CLVIII. SAPOGENINS. LXX. THE STRUCTURE OF LILAGENIN
Sir:
genin (I) like yuccagenin (11) absorbs bromine in acetic acid more slowly than the other unsaturated sapogenins, such as diosgenin and yamogenin. This accounts for our previously reported negative bromine test. We propose structure I for lilagenin.
Previously [THIS JOURNAL, 62, 2620 (!940)] we reported the isolation in small amounts from Liiium rubrum magni$cum of a new steroidal sapogenin, lilagenin, m. p. 2455246'. Eoiling c I 0-C acetic anhydride formed a diacetate, m. p. 156". c-c( >-c Lack of material prevented further characterizac 1 /'c--c tion of this substance. In our more recent plant A P \ { O studies, however, we have found a better source HCl-EtOH in Lilium humboldtii. The identity was estabv 20 hr. lished by the melting points, mixed melting points and analyses of the genin and its acetate as HO follows: geniii, ni. p. and mixed m. p., 242-246'. I. Lilagenin Anal. Calccl. for C2,H& C, i 5 . 3 ; H, 9.9. C i ~ o u i i d . C,'73.4, H, 9.9, cliacetate, m. p. and I /c-c- )c-c c-c, mixed in. p., 133-135c. Anal. Calcd. for O C'31H4606:C, '72.3; H, 9.0. Found: C, 72.4; H, 9.0. Treatment of lilagenin with 2 N ethanolic hydrochloric acid for twenty hours gave yuccagenin (11) [THISJOURNAL,65, 1199 (1943)], m. p. and mixed In. p., 244-246'. Anal. Calcd. HO for C2,H4204: C, 75.3; H,9.9. Found: C, 75.2; 11. Yuccagenin H, 10.0. The identity was further established We thank Parke, Davis and Company for their by means of the diacetates, m. p. and mixed m. p., 1i6-178'. Anal. Calcd. for C&4&: C, 72.3; assistance. RUSSELLE. MARKER H, 9.0. Found. C, 2 . 4 , 13, 9.2. Thus, lilaR. B. WAGNER SCHOOL OF CHEMISTRY AND PHYSICS genin is not only isomeric with yuccagenin (11) THE PENNSYLVANIA STATE COLLEGECLARENCE H. RUOF PENNA. DALEP. J. GOLDSMITH but differs from the latter only in the configuru- STATECOLLEGE, PAULR. ULSHAFER tzon of the side-chain. Other pairs of isomeric RECEIVED JUNE12,1943 sapogenins are similarly related [THIS JOURNAL, 65, 1199 (1943)], namely, sarsasapogenin and THE STRUCTURES OF OSAJIN AND POMIFERIN srnilagenin ; texogenin and samogenin ; yamogenin and diosgenin ; neotigogenin and tigogenin. Sir: 'i he first of each pair is converted to the other by We have obtained evidence which in conjunctreatment with ethanolic hydrochloric acid. tion with that previously reported, establishes We reported enoneously [THISJOURNAL, 62, the formulas of osajin, pomiferin, iso-osajin and '2020 (1940)] on the basis of the analyses and an isopomiferin. apparently negative bromine test, that lilagenin The alkaline fusion of iso-osajin and isopomiwas isomeric with gitogenin (C27H4404) and its ferin yielded acetone and 2,2-dimethyl-5,7-chroacetate with gitogenin diacetate (C31H4806). 1t mandiol, identical with an authentic synthetic so happens that the earlier analytical figures, sample prepared from phloroglucinol according to iiainely, C, 75.1; H, 10.1 and C, 72.3; H, 9.% the directions of Robertson and co-workers.? for the first specimens of lilagenin and its acetate, (1) M. L. Wolfrom and S . M. Moffett, THISJOURNAL, 64, 311 respectively, agree equally well with the calcu- (1942), and preceding communications. (2) W. Bridge, R. G. Heyes and A. Robertson, J . Chcm. Soc., lated values for the compositions &,Ha04 and 279 (1937); W. Bridge, A. J. Crocker, T . Cubin aod A. Robertson, CoH4R06, respectively. We I I O W find that Ma- i h i d . . 1530 119:17!
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