Cis-trans-isomere 2-äxthyliden-3-methylsuccinimide aus phycoerythrin

Synthesis of bile pigments. 9. Chemical total synthesis of (+)-(2R,16R)- and (+)-(2S,16R)-phycoerythrobilin dimethyl ester

“…Anal. (C29H40N2O6) C, , N. a-Methylfenchyl (2R)-and (2S)-3,3'-Dimethyl-4-(2-hydroxyethyl)-4'-(2-methoxycarbonylethyl)-5(2//)-2,2'-dipyrrylmethanone-5'-carboxylate (11). The foregoing 5(1 Ff)-pyrromethenone (800 mg) was hydrogenated on 10% palladized charcoal according to the method described previously15 for the corresponding 5'-rerr-butyl ester, yielding 750 mg (93%) of levorotatory 11 as a mixture of epimers at C-2: IR (KBr) 3230, 2890, 1720, 1650, 1440, 1280 cm"1; NMR (90 MHz) 0.94 (3 ), 1.07 (6 H) (each s, 1"and 3"-CH3), 1.4-2.1 (m, 7 H, fenchyl-CH2 and 4"-H), 1.49 (s, 2"-CH3), 1.96 and 2.00 (each s, 3-and 3'-CH3), 2.3-2.9 (m, 4 H, a-CH2 of propionic ester and C//2CH2OH), 2.9-3.3 (m, 4 H, (3-CH2 of propionic ester and CH2 bridge), 3.6-3.9 (m, 3 H, C//2OH and OH), 3.64 (s, OCH3), 4.11 (m, 2-H), 6.91 and 7.08 (each br s, corresponding to two diastereomeric lactam NH), 9.33 (br s, pyrrole NH); MS m/e 514 (M+), 374 (azafulvenium ion -methylfenchyl ester35), 364 (M+ -1methylcamphene), 320 (364 -C02), 224 (azafulvenium ion36), 180 (224 -C02).…”

“…The organic phase was filtered through methylene chloride soaked filter paper and the solvent was removed on a rotary evaporator to yield 33 mg (83%) of crystalline 19. Recrystallization from methylene chloride/zz-hexane provided analytically pure aldehyde 19: mp 138-139 °C; [a]25o +291.4°( 73 mg/L in methanol); ORD (73 mg/L in methanol) [M] 600 (+1220), 400 (+2790), 325 (+11 260), 306 (0), 280 (-10 350), 270 (-11 260), 257 (0), 240 nm (+8100); IR (KBr) 3200, 2880, 1730, 1680, 1630, 1450, 1170 cm"1; >H NMR (90 MHz) 1.98 (s, 3'-CH3), 2.09 (s, 3-CH3), 2.55 (t, J = 7 Hz, a-CH2 of propionic ester), 2.7-3.3 (m, 4 H, /3-CH2 of propionic ester and CH2 bridge), 3.64 (s, OCH3), 4.22 (m, 2-H), 5.38 (dd, JAX=U, JBX = 3 Hz, 37), 6.21 (dd, JAB = 17, = 3 Hz, HB37), 6.41 (dd, JAB = 17, _/AX = 11 Hz, Ha37), 7.30 (br s, lactam NH), 9.40 (s, formyl ), 11.00 (br s, pyrrole NH); MS m/e (rel intensity) 330 (100) M+, 301 (17) M+ -CHO, 299 (14) M+ -OCH3, 208 (26) 5-formyl-3methyl-2-methylene-2/f-pyrrolium-4-propionic acid methyl ester.…”