Hydrochloric Acid → ethyl 6-methyl-4-(3-nitrophenyl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

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Reaction Steps

A solution containing m-nitrobenzaldehyde (7.55 g., 50.0 mmole), ethylacetoacetate (6.5 g., 50.0 mmole), and thiourea (3.8 g., 50.0 mmole) in absolute ethanol (30 ml.) is treated with concentrated hydrochloric acid (0.2 ml.). The resulting reaction mixture is heated at reflux for 6 hours. It is then cooled to room temperature and triturated. A small amount of a white solid precipitates out. The reaction flask is then allowed to cool in the refrigerator overnight. The precipitate that forms is filtered off and washed with additional absolute ethanol to provide 2.5 g. of colorless solid product. Recrystallization from absolute ethanol gives an analytically pure sample of 1,2,3,4-tetrahydro-6-methyl-4-(3-nitrophenyl)-2-thioxo-5-pyrimidine-carboxylic acid, ethyl ester; m.p. 208°-209°. TLC (silica gel; ethyl acetate:hexanes, 1:1) Rf =0.45.

Provenance & Evidence