Triethylamine → Isopropyl 2-chloro-4-fluoro-5-[(6-methyl-2,3-dihydro-1,4-oxathiine-5-carbonyl)amino]benzoate

Participants

Reaction Conditions

Reaction Steps

Thionyl chloride (4.2 g, 0.035 mole) was added to a stirring slurry of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxylic acid 4.8 g, 0.030 mole) in methylene chloride (40 ml). The mixture was warmed to 35° C. for 3 hours, then left stirring overnight at room temperature. The solution was then evaporated under reduced pressure at about 35° C. The solid residue, crude 5,6-dihydro-2-methyl-1,4-oxathiin-3-carbonyl chloride, was dissolved in methylene chloride (50 ml) and the solution chilled in ice and treated dropwise with a solution of 1-methylethyl 5-amino-2-chloro-4-fluorobenzoate (7.0 g, 0.030 mole) and triethylamine (3.5 g, 0.035 mole) in methylene chloride (50 ml). The addition was carried out over 2 hours, after which the reaction mixture was stirred at 20°-35° C. for 3 hours.

Provenance & Evidence