反应详情

温度

35 °C

Thionyl chloride (4.0 g, 0.034 mole) was added to a stirred mixture of 2-ethyl-5,6-dihydro-1,4-oxathiin-3-carboxylic acid (5.9 g, 0.034 mole) and methylene chloride (100 ml). The mixture was warmed to about 35° C. for 3 hours, then evaporated under reduced pressure. The residue, crude 2-ethyl-5,6-dihydro-1,4-oxathiin-3-carbonyl chloride, was dissolved in methylene chloride (100 ml), and the ice-chilled solution treated dropwise with a solution of ethyl 5-amino-2-chlorobenzoate (6.8 g, 0.034 mole) and triethylamine (3.7 g, 0.037 mole) in methylene chloride (100 ml). The reaction mixture was stirred overnight at room temperature and then worked up by washing in sequence with water, dilute hydrochloric acid, water, 2% sodium hydroxide and water. Evaporation of the solvent left an oil, which solidified. After recrystallization from ethanol (30 ml) the product (7.0 g, 58% yield) melted at 86°-88° C.

1. customevaporated under reduced pressure
2. dissolutionThe residue, crude 2-ethyl-5,6-dihydro-1,4-oxathiin-3-carbonyl chloride, was dissolved in methylene chloride (100 ml)
3. temperaturethe ice-chilled solution
4. washby washing in sequence with water, dilute hydrochloric acid, water, 2% sodium hydroxide and water
5. customEvaporation of the solvent
6. waitleft an oil, which