Hydrogen Bromide → 3-Phenyl-4,8-dihydroxy-coumarin

반응식

C[O:2][C:3]1[CH:4]=[CH:5][CH:6]=[C:7]2[C:12]=1[O:11][C:10](=[O:13])[C:9]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[C:8]2[OH:20].Br.C(OC(=O)C)(=O)C>C(O)(=O)C>[OH:20][C:8]1[C:7]2[C:12](=[C:3]([OH:2])[CH:4]=[CH:5][CH:6]=2)[O:11][C:10](=[O:13])[C:9]=1[C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1

참가 물질

실험 절차

37.6 g. (0.14 mol) of 8-methoxy-4-hydroxy-3-phenylcoumarin are brought to reflux for 1 hour in a mixture of 750 ml. of 62% hydrobromic acid, 375 ml. of glacial acetic acid and 375 ml. of acetic anhydride. The mixture is poured on to 5.3 kg. of ice, filtered and dried. 25.3 g. of a solid are obtained, which is recrystallised from a mixture of dioxane and diisopropyl ether (50:50). Weight 13 g., yield 38.1% (theoretical yield 34.2 g.); M.P. 220° C.