反应详情

A mixture of 8.7 g of 2-(2-amino-5-bromobenzoyl)-pyridine, 5.7 g of ortho-methyl-acetate, 2.8 ml. of acetic acid and 100 ml. of benzene is refluxed, while removing alcohol formed by azeotropic distillation, for 1.5 hours and then cooled. The resultant is washed with saturated aqueous sodium hydrogen carbonate, then with water, and dried over sodium sulfate. Evaporation of the solvent under reduced pressure gives 2-[2-(1-methoxyethylideneamino)-5-bromobenzoyl]-pyridine as oily product. This product is dissolved in 60 ml. methanolic solution and 44 ml. of hydrazine hydrate (100%) and 1.9 ml. of acetic acid are added to the solution. The mixture is stirred at room temperature for 3 hours and the precipitate formed is collected by filtration, washed with methanol and dried to give 3-amino-6-bromo-3,4-dihydro-4-hydroxy-2-methyl-4-(2-pyridyl)quinazoline as crystals. Recrystallization from a mixture of methanol and chloroform gives colorless crystals, melting at 208° to 210° C (decomposition).

1. customwhile removing alcohol
2. customformed by azeotropic distillation, for 1.5 hours
3. temperaturecooled
4. washThe resultant is washed with saturated aqueous sodium hydrogen carbonate
5. dry with materialwith water, and dried over sodium sulfate
6. customEvaporation of the solvent under reduced pressure