CH 150 → 2,6-dimethyl-3-ethyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido(1,2-a)pyrimidine

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Reaction Steps

4.04 g. of 2,6-dimethyl-3-ethyl-4-oxo-4H-pyrido(1,2-a)pyrimidine are dissolved in 50 ml. of ethanol and the solution is hydrogenated in the presence of 2 g. of Raney-nickel catalyst, previously washed to anhydrous with ethanol. Hydrogenation is performed under atmospheric pressure. In about seven hours the calculated amount of hydrogen is used up and the hydrogen consumption drops rapidly to zero. The catalyst is filtered off and the ethanol solution is evaporated. 4.10 g. (99.5%) of 2,6-dimethyl-3-ethyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido(1,2-a)pyrimidine are obtained as a pale-yellow non-crystallizing oil, which can be distilled under a pressure of 25 mmHg of 190° C.

Provenance & Evidence