COMMUNICATIOXS TO THE EDITOR
Aiug.20, 19p3fj
THE REMAINING STEREOISOMERS OF THE SPARTEINE GROUP
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picrates of authentic synthetic dl-bases,& using infrared spectra and melting points where applicable.
Sir: (5) Kindly supplied by Professor N . J. Leonard; cf. N. J . Leonard ii7e have found that the alkaloid I-spartalupine, C1&t26N2,which we have isolated for the first time and R . E. Beyler, THIS JOURNAL,74, 1316 (1950). MARVINCARMACK from specimens of Lupinus sericeus Pursh collected DEPARTMEXT BRYCEDOUGLAS in Utah, is one of the enantiomorphs of the third CHEMISTRY INDIANAUNIVERSITY ERICW. MARTIN and remaining racemic pair stereoisomeric with BLOOMINGTOK, INDIAKA HANNA SUSS (id-sparteine and df-a-isosparteine. Our structure RECEIVED JULY 5 , 1955 proof consists of epimerization to d-sparteine and to d-a-isosparteine and the direct cornparison of the natural base with d2-spartalupine, which we have MERCAPTAN CATALYSIS IN THERMONEUTRAL synthesized along with its diastereoisomers. The FREE RADICAL EXCHANGE : only other naturally occurring alkaloid thus far R. + R*H R H + R*. isolated having the same stereochemical configura- Sir : tion as spartalupine is lupanoline, C 1 6 H ~ N 2 0 2 ,a It has been proposed that when a free radical is hydroxy-lactam. generated in a solvent from which it may be Isolation.-Alcoholic extraction of the dried thought of as being derived by removal of one atom, plant yielded l-2yGof total alkaloid, which gave the radical will be continually regenerated in type directly upon distillation mostly 1-spartalupine base, by exchange with the solvent.' However, the b.p. 110" (0.03 mm.), m.p. 32.2-32.4' (calcd. for formation of acetate radical CH3CO0. in solvent CIBH2&J2:C, 76.86; H, 11.18; h', 11.96. Found: CI4H3COOHby decomposition of acetyl peroxide C , 76.99; H , 11.18; N, 12.02; [a]*'D -15.4' led to CH4containing about 1% of the radioactivity (abs. alc.)) Jlonoperchlorate, m.p. 211.5-212' of the solvent,2 indicating that the postulated (calcd. for CljH2&2.HC104: c , 53.80; H, 8.13; exchange reaction N,8.37; C1, 10.59. Found: C, 53.82; H, 8.20; CH3COO. f C"H3COOH If CHaCOOH + C"H3C00. N, 8.06; C1, 10.33). Dipicrate, m.p. 133-133.5' (calcd. for C15H?6Sz.L'C6Hz(h-02)30H : c, 46.82; was slow compared to loss of C01 by the unstable H, 4.AG; K, 16.18. Found: C, 47.03; H, 4.43; acetate radical. N, 16.40). The infrared spectrum of the base was We have formed a more stable radical, (CSHS)?very similar to that of the base obtained from lup- CHS3(I), in (CeHs)2C14Hz (11) by decomposition of anoline with LiX1H4.? (C6H5)aCH-N=N-CH(CeH6)23 in 0.017 m sohStructure Proof.-I-Spartalupine was treated with tion in 3:1 ( C ~ H E , ) C ~ ~ Ha~t :64" C ~under H ~ co?. mercuric acetate by the method of Winterfeld 1,1,2,2-Tetraphenylethane(111) was obtained in and R a ~ c h . Under ~ mild conditions, a dehydro 95% yield, and its radioactivity was only 1.1% base was formed which was hydrogenated over of that of the solvent. The exchange was far platinum to d-sparteine, [ a ] % 19.5" (ethanol). Under more drastic conditions, a didehydro base (C8Ha)zCH. f (CeHs)C14H2 (CsHsICHz f (CsHs)C14H. (1) was obtained which was rehydrogenated to d-aisosparteine monohydrate, m.p. 110-116', [ a I z 8 ~slower than the dimerization reaction +48.4' (methanol). The infrared spectra of the Z(COHa)?CH.+( C ~ H ~ ) ~ C H C H ( C E , H (~2))~ products were identical with those of their respective authentic I-isomers. However, in the presence of 0.035 m C 6 H 5 S H (IV) Synthesis.-The synthesis of Sorm and Ked4 the yield of nitrogen remained nearly quantitative, was repeated, except for reduction of the dioxo and the yield of 111fell to 59%, but its radioactivity compound with LiXIH4. Three dioxo compounds was 17% of that of the solvent, the exchange rem.p. l7+173.5" (calcd. for action (1) having effectively occurred to this extent were isolated : CI5HZ?N?O2: C , 68.67; H, S.45: K j 10.68. Found: in the presence of the mercaptan. C, 68.53; H , 8.39; S,10.63). Reduction of -1 This may be accounted for by a sequence of two yielded dl-spartalupine (and not dI-a-isosparteine4). of lower activation energy than re The infrared spectra of the natural l- and syn- action (1) which tend to equilibrate diphenylthetic d l bases were superimposable. d!-Spartalu- methyl, diphenylmethane, thiophenol and phenylpine dipicrate, m.p. 220.5-El O dec. (calcd. for thio radical. CijH26Nz.?.CsH?(NOp'iaOH: C , 46.S2; H, 4.6G; N, (C6H,)2CH2f CsHsS, (3a) 16.18. Found: C, 46.64; H, 3.61; N, 16.19). (C6H5)?CH.+ CtiHsSH The dioxo compound B, n1.p. 132-133.5', reduced CsITS. (CsH;)?C14HzJ_ C6HsSH + ( C ~ H S ) ~ C ' " C H(3bl . to db-sparteine, and a third dioxo compound C, isolated as a monohydrate, m.p. 150-160', reduced to dd-a-isosparteine monohydrate. The two latter Reaction (3a) leads to diminished yield of 111 since (1) W. A. Waters, "The Chemistry of Free Radicals," Oxford bases were identified by direct comparison of the University Press, Xew York. N. Y., second edition, 1948, p. 19, 139, bases with their optically active forms and with the 231.
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+
(1) L. Marion, N. J. Leonard, and B. P. Moore, Can. J . Chrm., 31, 181 (1953); cf. J. F. Couch, THISJOURNAL, 62, 554 (1940). 2 ) B. P. Moore and L. RIarion, C a n . J . Chem., 31, 187 (1953). (3) K. Winterfeld and C . Rauch, Arch. Pharm., 272, 273 (1934). (4) F. Sorm and B. Keil, Coil. Czech. Chem. Comm., 13, 544 (1948).
(2) A. J. Fry, B. &I.Tolbert and M. Calvin, Trans. Faraday Soc., 49, 1444 (1963).
77,2457 (1955). (3) S. G. Cohen and C. H. Wang, THISJOURNAL, (4) A. F. Bickel and E. C. Kooyman, Nature, 170,211 (1952). (5) K. E. J. Barrett and W. A . Waters, Disc.Faraday Sac., 14, 221 (1953).
