Sulfuric Acid → HCID 10812046, compound

Participants

Reaction Steps

A mixture of 2-amino-3-(3,4-dimethoxybenzoyl)-4,5-dimethylthiophene (3.6 g), ethyl 4-chloroacetoacetate (2.1 g), concentrated sulfuric acid (0.5 ml) and acetic acid (50 ml) was stirred for two hours at temperature ranging from 90° to 100° C. The reaction mixture was concentrated under reduced pressure. The concentrate was poured into water, which was neutralized with potassium carbonate, followed by extraction with chloroform. The chloroform layer was washed with water and dried (MgSO4), then the solvent was distilled off under reduced pressure. The residue was subjected to column chromatography on silica gel. From the fractions eluted with chloroform-hexane (4:1, v/v), ethyl 6-chloromethyl-4-(3,4-dimethoxyphenyl)-2,3-dimethylthieno[2,3-b]pyridine-5-carboxylate (3.5 g, 67%) was obtained. Recrystallization from ethyl acetate-hexane gave colorless prisms, m.p.162°-163° C.

Provenance & Evidence