Triethylamine → N-(3-cyanophenyl)-6-methyl-2,3-dihydro-1,4-oxathiine-5-carboxamide

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Reaction Steps

5,6-Dihydro-2-methyl-1,4-oxathiin-3-carboxylic acid (5.0 g, 0.031 mole) and thionyl chloride (4.1 g, 0.034 mole) were heated under reflux in methylene chloride for about 2 hours, then evaporated under reduced pressure. The solid residue, crude 5,6-dihydro-2-methyl-1,4-oxathiin-3-carbonyl chloride, was dissolved in methylene chloride and the chilled solution treated dropwise with a solution of 3-aminobenzonitrile (3.7 g, 0.031 mole) and triethylamine (3.2 g, 0.032 mole) in methylene chloride. The reaction mixture was stirred at room temperature for a further 3 hours and then worked up by washing with dilute hydrochloric acid and dilute sodium hydroxide. Evaporation of the solvent gave a solid residue, which was recrystallized from methanol to give a white solid, m.p. 119°-121° C. (5.5 g, 67% yield).

Provenance & Evidence