Acetic Anhydride → 8-Ethyl-4-methyl-2-(methylthio)-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidine-6-carbonitrile

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (10.0 mL) was added to a flask charged with 8-ethyl-7-imino-4-methyl-2-(methylthio)-7,8-dihydropyrido[2,3-d]pyrimidine-6-carbonitrile (0.506 g, 1.95 mmol) and heated to 100° C. After one h, the reaction was allowed to cool to room temperature and concentrated in vacuo. The acetylated residue was then treated with 6 N HCl (40 mL) and heated to 95° C. for one hour then transferred to a large flask. A saturated solution of NaHCO3 (500 mL) was added slowly at 0° C. until a pH 8.0 was achieved. The aqueous phase was washed thrice with ethyl acetate (100 mL) and the organic layers combined, then washed with brine and dried over Na2SO4. The drying agent was filtered and concentrated in vacuo to afford crude 8-ethyl-4-methyl-2-(methylthio)-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidine-6-carbonitrile which was used in the subsequent step without further purification.

Provenance & Evidence