“…The residue was purified by recrystallization (hexane/EtOAc, 8:2), giving 0.44 g (63%) of 14a as a white solid. Mp 172-1741C (mp 176-1781C [Tyler and Whittaker, 1959]); R f 0.46 (hexane/EtOAc/AcOH, 1:1:0.1); IR (CH 2 Cl 2 ) 3700-2280, 1758, 1610, 1583, 1483, 1456, 1422, 1295, 1253, 1232, 1158, 1092, …”