White prisms (MeUH); mp 233-235 "C; [a): -125' (C = 0.2, CHC13); UV h max/nm 216; iR v (KBr) cm-' 3 120, 1760, 1745, 1220, 890; '1-1 NMR (200 MHz, CDC13) S/ppm 1.02 (3H, s, H-14), 1.63 (IW, m, H-34, 2.03 (3H, s, 2.64(1H,ddd,~=14.1;9.0; 1.3Hz,H-4a),2.88(1H,ddd,J COCHs),2.10 (3H, d , J = 1.2 Ih.Il-13), 2.31 (IH,m, H-3h), = 14.0; 9.0; 9.0 Hz, H-4b). 3.39 (lH, dd, J = 12.0; 1.9 Hz, H-2), 5.86 (174, br.S, N-7),6.01 (113, S, H-10),7.05 (1H, d, J = 1.3 WZ, H-fi), 7.23 (lH, d, J = 1.2 Hz, H-12); I3C NMR (SO MHz, CDC13) 6/ppin59.94