Hydrochloric Acid → 6-benzyl-3-methyl-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione

참여 물질

반응 조건

반응 단계

3.2 1 of 30% hydrogen peroxide were added dropwise at 0° C. over a period of 51/2 h, with stirring, to a suspension of 210 g of 6-benzyl-3-methyl-2-thioxo-2,3,5,6,7,8-hexahydro-1H-pyrido[4,3-d]pyrimidin-4-one from b) in a solution of 78 g of NaOH in 4 1 of water. After subsequent stirring for 1/2 hour at 0° C., the pH of 9.7 was adjusted to 7.4 with conc. hydrochloric acid and the precipitate was filtered off, washed with water and dried. The above preparation was repeated and the precipitates were combined (396 g). These were purified by suspension in I 1 of water and dissolution with 33% sodium hydroxide solution (pH 13.5). Activated charcoal was added, with stirring, the mixture was filtered and the filtrate was adjusted to pH 10. The precipitate formed was filtered off with suction, washed with water and dried under reduced pressure to give 192 g of 6-benzyl-3-methyl-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione, which was debenzylated by hydrogenolysis in d).

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