ALKALOIDS FROM DISCARIA SERE4 TIFOLIA RES^ TORRES,'F R ~ S CDELLE O ~ I O K . ~and CH GIOTXNSI E BATTIST.% hl.iRIsI BETroLo Centro CNR, Chaniica dei Recettori e delle Jfolecole Bzologicanzente A t f i f e , I s t z f z ~ fdz o Chimzca, L-mLersztiz Cnttolrca del Sacro Cuore, Ronia Via Piiiefa Sacdietti 644, 00168 Roma
Some South American Discarias (Rhamnaceae) u-ere investigated for their secondary metabolites, and the presence of alkaloids, triterpenes, flavonoids, fatty alcohols and organic acids was established (1-5). In the course of our research on Chilean plants, we examined the aerial parts of Discaria serratijfolia, a shrub gron-ing in the surroundings of Catillo (provincia de Conceptih, VI1 R e g i h , Chile). I n this communication, we report the isolation and structure determination of four benzylisoquinoline bases. Two of these alkaloids are rather unusual as natural products, and this is the first time their isolation from this family has been reported. The first, R(-)-0-methylarmepavine (l), had previously been obtained by synthesis (6) and as one of the components of bisbenzylisoquinoline alkaloids cleavage products (7). Moreover, only recently, it has been isolated as a secondary metabolite from Xylopia panclzeri (Annonaceae) (8). The dextrotoratory isomer has been isolated from Magnolia acz~minata(Magnoliaceae) (9). The second, R ( -)-S-demethylcollettine (2), was also isolated from Xylopia pa??cheri, although its quatern a F derivative, colletine, n-as reported in 1967 from an Argentine Rhamnaceae, Colleiia spiiiosissima (10). The other tu-o alkaloids, R(-)armepavine (3) and R ( -)-S-methyl-
coclaurine (4) are common bases described in many species. including Chilean Discarias ( 3 ) .
EXPER11\IESTAL2 MATERIAL.-DiscarZa serrafzfoha (Vent.) Benth et Hook. v a r . discolor (Hook.) Escalante was collected in December (summ e r ) , 19i4, near Catillo (provincia de Conc e p c i h , vii R e g i h , Chile). A voucher specimen was deposited in the herbarium of t h e hluseo Nacional de Historia S a t u r a l , Santiago de Chile. PLkST
EXTR~CTIOS A K D IsoLkmos.-Air-dried leaves and stems (4 kgj finely ground were extracted successively with petroleum ether and 95Go ethanol. Upon concentration t o dryness under vacuum, the ethanol extract yielded a brownish residue, which was suspended in 2N HC!. The acidic extract 2Elemental analyses are consistent with the empirical formulas. Melting points were performed in a Kofler apparatus and are uncorrected, uv spectra were recorded on a Beckman model ;icta I11 spectrophotometer, ir spectra were determined on a Perkin Elmer model 247 spectrophotometer; pmr spectra %-ere determined on a Varian model EA1 360 instrument, with TMS as internal standard: mass spectra were run on a LKH-9000 S mass spectrometer; optical rotations were measured on a Perkin-Elmer 141 automatic polarimeter.
'Fellowship from IIL.i/CNR on leave from Facnltad de Ciencia, Universidad Tecnica del Estado, Santiago de Chile. 430
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19791
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ALKALOIDS O F DISCARIA SERRATIFOLIA
was basified with ammonium hydroxide (255) and extracted xvith chloroform. T h e chloroform solution afforded 2.8 g of alkaloidal mixture after concentration in '~'uczto. T h a t mixture was separated through a column cif silica gel (400 g) prepared in chloroform and eluted with chloroform and then chloroform-methanol (methanol, 0.5 t o 5%). Four fractions, A, B, C and D n-ere collected on t h e basis of tlc.
R (- )-O-niethj-larmepavine (1) .-Fraction A (250 mg) -ins rechromatographed over a small colirnin of silica gel (10 g ) . T h e chloroform eluates yielded an oil n-hich crystallized from petroleum e t h e r m p 65' [lit. (8) mu G5':: .a-,?OD-81" i c 1.2. CHC1-1: hmas (log e ) ' ( E t O H ) , 227 and 282 nm (4.14 and 3.76). ir, Y ma\ (CHCl,), 2850 cni-'. pmr ICDCI,), 6 2.53 is, 3H, S C H s ) . 3 55 (s,311, OCH,), 3 . X (s, 3H, OCHs), 3 83 (s, 3 H , OCH,j, 0.00 (s, l H , aromatic), 6.56 is, l H , aromatic , 6 70-7.13 (m, -4?B2 system, AH, aromatic>): ms, 712 e 327 [W-,C?,H?S O 3 , 207 i5S), 206 ( l O O ) , 191 (29,, 190 (3S), 162 (131, 132 ( 2 1 , 121 ( 7 ) . This compound shon-ed uhrsical and suectral d a t a identical t o t h e product obtaineh from 0-methylation of authentic R-(-)-armepavine Tvith ethereal diazomethane, and t h e pnir spectrum agreed x i t h t h a t reported b y Tomita (11). R-(-)-Demethylcolletine (2j.-Fraction B (125 mg) was purified through a column of silica gel (15 g j . Pure alkaloid was obtained as an oil (26 m g ) : [aj20D-740 (e 0.7, 11eOHj: Xmas (log E) ( E t O H ) , 226 and 283 nm (4.03 and 3.743, bathochromic shift in basic solution t o 299 nm: Y max (CHCI,), 3550 and 2850 em-1: p m r ICDC13): 6 2.43 ( s , 3H, S C H 3 ) , 3.74 (s, 3H, OCHsj, 3.80 ( s , 3H, OCH,), 8.30 (s, lH, aromatic), 6.50 (s, lH, aromatic), 6.52-7.30 im, AZBZ system, 4H, aromatics). Pnir d a t a agreed Kith published d a t a (8, 11): ms, w e 313: (M-, C i 9 H 2 3 S 0 35), , 193 (25), 192 (loo), 177 (18), 176 (5), 148 (3), 121 (SI. Reaction with ethereal diazomethane gave a compound identical with E-(-- )-0-methj-larmepavine (tlc, uv, ir, pmr and specific rotation). R-(-)-;lrmepavine (3) .-Reextraction of fraction C (850 mg) yielded 550 nig of a white product which was recrystallized from ethyl acetate. mD 145-146' l i t 1.7) mo 136'1: [cujLDD-105C(c' 0.9, MeO-H/: ima; (log e ) ( E ~ O H I229 , and 284 n m (4.18 and 3.741, bathochromic shift t o 290 nni in basic solution: Y m a s (CHCIa))3600 and 2850 em-': p m r (CDCl,,, 6 2.53 i s , 3H, N C H s ) , 3.56 is, 3 H , OCH,), 3.80 ( s ) 3 H , OCH;), 5.93 is! lH, aromatie), 6.59 i s , IH, aromatic), G.60-6.97 (m, A,B, system, 4H, aromatics), ms, 171 e 313 (W, CIPH2iS0,, 0.2), 207 (12), 206 (1001, 191 iG), 190 191, 162 i5), 132 ( 2 ) , 10T
43 1
(2). Comparison o f 3 with authentic R-(-)armepavine (tlc, uv, ir,, p m r and specific rotation) established i t s identity.
R-i-)-~l--~Iethylcnclaurine(4) .-Fraction D (380 mg) crystallized from chloroform yielded 200 m g of white needles, m p 181-182' [lit (4) mp 181-183";: [n]2@D-920 ( e 0.5, 3IeOH): h m a s (log e ) E t O H ) , 227 and 284 nm (4.21 and 3.80), hathochromic shift in basic solution t o 299 nni: Y m a s (CHCI:), 3600 and 2850 em-': pmr (CDClS), 6 2.46 ( s , 3H, S C I I ) , 3.80 (s, 3H, OCHs), 5.90 (broad s , 2H, 2 O H ) , G.50 (s! l H , aromatic), 6.607.00 (m, A2B?,4H, aromatics): ms, ni e 299 (ll-, CisH2iS03, 0.21, 193 (41, 192 (loo), 178 (4)! 177 (G), 176 (0.4), 148 (21,. 107 J2). Physical and spectral d a t a n-ere identical with those of authentic R-i-)-Al~-metliylcoclanrine. dCKSOJYLEDGlIEXTS T h e authors wish t o espress their thanks t o D r . C. Galeffi, I s t i t u t o Superiore d i Sanita, Roma, for providing facilities for t h e determination of mass spectra and optical rotation measurements, and t o Drs. MClica lluiioz, Museo de Historia Katural, Santiago, Chile, for t h e classification of t h e plant material. ReceiL'ed IS Febritarj 1979.
LITERATURE CITED 1. T-. 31. Merkuza, 0. d. E i s c a r e t t i , R . Crohare and E. -4. Rfiveda, Phytochenii s f r y , 10, 908 (1971): 2 . 0. A . Mascaretti, T . M Merkuza, . G. E. Ferraro, E. -4.RGveda, Ch-,J. Chang and E. Wenkert, P h y i o c h m i s t r y , 11, 1133 (1972). 3. P . Pacheco, S. 11. Alb6nico and 11. Silva, P hytochem istry, 12, 954 (1973). 4. 31. Silva, D. S. Bhakuni, P. G . Sammes, 31. P a i s and F. S.Jarreau? P hytochem i s t r y , 13, 861 11974). a . I-. M. Merkuza, 11. Gonzilez, 0. Mascaretti, E. RGveda, Ch-J. Chang and E. K e n k e r t , PhIfocheniisfrj, 13, 1279 11974). 6. L . Marion, L. Lemay and I-. Portelance, J . O r g . C hem ., 15>218 (1950). I . AI. R.Falcn, J . S.de 1-ries, A . G . d e Brovetto, Z . 11acci6, S. Rebuffo and I . R . C. Bick, Tetrahedroi2 Lctt., 1953 (1988). 8. 11. S i e t o , T . Sevenet, 11.Loboeuf and -4.Cave, P/!!?7ta.Urd., 30, 48 (197Gi. 9. G. J . Kapadia, S . .J. Shah and R . J . Highet, -7. Piiarm. Sci., 53, 1140 (1964:). 10. E. Sinchez and J . Coniin, Terruhedron, 23, 1139 (1967). 11. 11.Toniita, T . Shingu, K. Fnjitani and H. Furukan-a, C17e777. Phiirn7. Bit//., 13, 921 (1966).
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