反应详情

Crude acid from example 84 (25 g, 118 mmol) was dissolved in ether and treated with excess diazomethane (generated by adding 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) to a mixture of 40% KOH (aq) and ether at 0° C.). Excess diazomethane was quenched with acetic acid after 30 m. Vacuum distillation gave 18.8 g (70%): [α]25D -100°; bp 100°-109° C. (0.5 mmHg); 1H NMR (300 MHz, CDCl3) δ 7.40 (1H, dd, J=1 Hz), 6.34 (1H, dd, J=1 Hz), 6.29 (1H, dd, J=1 Hz), 4.43 (1H, t, J=7 Hz), 4.00 (2H, q, J=16 Hz), 3.72 (3H, s), 1.92 (2H, m), 1.33 (4H, m), 0.89 (3H, t, J=7 Hz); mass spectrum (FAB): 244 (M+NH4).

1. customExcess diazomethane was quenched with acetic acid after 30 m
2. distillationVacuum distillation
3. customgave 18.8 g (70%)