TMS as internal standard. 1H–1H COSY, HSQC,
HMBC and NOESY (500 ms mixing time) were
obtained using the standard pulse sequences. ESITOFMS
and ESI-MS/MS were recorded in positive
mode on a API Q-STAR PULSA of Applied Bio-system.
CC was carried out on silica gel (Acme) finer than
200 mesh (0.08 mm)