Reaction Steps
Preparative TLC of fraction CC on silica gel with 10% methanol in chloroform as eluent gave some baccharinol (B4) (Fraction DD) which was combined with Fraction BB as above, and a residue (Fraction EE) which was crystallized from methanol-chloroform-ether. Recrystallization from acetone-hexane gave isobaccharinol (B6, 0.20 g, 0.00037%): mp 249°-251° C.; [α]D24 +149° (c 0.66, MeOH); uv max (EtOH) λ (ε) 260 nm (20,400); ir (KBr) 3420, 1750, 1720, 1650, 1605 cm-1 ; NMR (CDCl3) ε 0.83 (3H, s, 14-H), 1.16 (3H, d, J=6 Hz, 14'-H), 1.65 (3H, s, 12'-H), 1.83 (3H, s, 16-H), 2.84, 3.13 (each 1H, d, J=4 Hz, 13-H), 3.38 (1H, s, 2'-H), 4.24, 4.46 (2H, ABq, J=12 Hz, 15-H), 5.52 (1H, d, J=5 Hz, 10-H), 5.8 (1H, m, 4-H), 5.81 (1H, d, J=11 Hz, 10'-H), 5.92 (1H, dd, J=15 and 3 Hz, 7'-H), 6.59 (1H, dd, J=11 and 11 Hz, 9'-H), 7.40 (1H, dd, J=15 and 11 Hz, 8'-H); mass spectrum (chemical ionization: methane reagent gas) m/e 563.2493 (M+ +H, calcd, for C29H39O11, 563.2492). Anal. Calcd for C29H38O11 :C, 61.91; H, 6.81. Found: C, 61.86; H, 6.85.
