2-Propenoic acid, 2-cyano-3-ethoxy-, ethyl ester → HCID 19089095, compound

Participants

Reaction Steps

To a solution of 2-(ethoxymethylene)-2-cyanoacetic acid ethyl ester (56.3 g) in ethanol (200 ml) was added dropwise 2-hydrazinopropionaldehyde diethyl acetal (54 g) in ethanol (80 ml) at room temperature. The mixture was refluxed for 4 hours. The reaction mixture was cooled at room temperature and the solvent was distilled off in vacuo to give the crude. 1-(1-methyl-2,2-diethoxyethyl)-4-ethoxycarbonyl-5-aminopyrazole (100 g). The crude product (100 g) was dissolved in aqueous 4N-sodium hydroxide (170 ml) and the mixture was refluxed for 1 hour. The reaction mixture was cooled at room temperature and washed with ethyl acetate (100 ml×2). The aqueous solution was adjusted to pH 3.5 with 6N-hydrochloric acid and stirred for 1 hour. The precipitate was collected by filtration, washed with water and dried over phosphorus pentoxide to give 1-(1-methyl-2,2-diethoxyethyl)-4-carboxy-5-aminopyrazole (9.93 g).

Provenance & Evidence