“…The crude crystalline material was purified by recrystallization from ether, dichloromethane and acetone, and by preparative TLC and/or HPLC (silica gel SH-043, 20 x 250 mm, Yamamura Chemical Lab. (2). Thirty mg of 1 was dissolved in acetic anhydride (3 ml) and heated at 110°C for I hr.…”