反应详情

A mixture of 0.57 g (1.43 mmol) of the starting material XVIII, 6 ml of triethyl orthoformate and a catalytic amount of hydrochloric acid was stirred at 80° C. for 1 h. After cooling the precipitated crystals were filtered off, washed with ethanol and dried to yield 0.45 g (77%) of the title compound; Mp.: 212-213° C.

1. temperatureAfter cooling the precipitated crystals
2. filtrationwere filtered off
3. washwashed with ethanol
4. customdried