反应详情

Prepared in the manner described in Example 25, Stage A, from 37.6 g. (0.14 mol) of 6-methoxy-4-hydroxy-3-phenyl-coumarin, 375 ml. of glacial acetic acid, 750 ml. of 62% hydrobromic acid and 375 ml. of acetic anhydride. Weight 12.2 g.; yield 33.7% (theoretical yield 35.6 g.); M.P. 261°-263° C. (dioxane-diisopropyl ether: 50-50).

1. customPrepared in the manner