C[O:2][C:3]1[CH:8]=[C:7]([C:9]2[NH:13][N:12]=[N:11][N:10]=2)[CH:6]=[C:5]([N+:14]([O-:16])=[O:15])[C:4]=1[OH:17]>Br>[N+:14]([C:5]1[CH:6]=[C:7]([C:9]2[NH:13][N:12]=[N:11][N:10]=2)[CH:8]=[C:3]([OH:2])[C:4]=1[OH:17])([O-:16])=[O:15]4.0 g of 2-methoxy-6-nitro-4-(1H-tetrazol-5-yl)phenol are treated with 40 ml of constant-boiling hydrobromic acid, whereupon the mixture is stirred at 140° for 8 hours under a nitrogen atmosphere. After cooling, the mixture is poured on to ice. The separated precipitate is filtered under suction and recrystallized from ether. There is obtained 3-nitro-5-(1H-tetrazol-5-yl)-pyrocatechol in the form of orange crystals of m.p.>240° (dec.).
Wird geladen…