Acetic Acid → 2-[2-(1-Methoxyethylideneamino)-5-bromobenzoyl]pyridine

참여 물질

반응 단계

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 produced by azeotropic distillation, for 1.5 hours and then cooled. The resultant mixture is washed with saturated aqueous sodium hydrogen carbonate solution, then with water, and dried over sodium sulfate. Evaporation of the solvent under reduced pressure gives 2-[2-(1-methoxyethylideneamino)-5-bromobenzoyl]pyridine as an oily product. This product is dissolved in 60 ml. of methanol, and to the solution are added 44 ml. of hydrazine hydrate (100 %) and 1.9 ml. of acetic acid. After stirring at room temperature for 3 hours, the resulting precipitate 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).

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