反应详情

Cesium carbonate (4.7 g, 14.4 mmol) was added to a stirred solution of 2,5-thiophenedicarboxylic acid in dimethylformamide (35 mL) under an inert atmosphere at room temperature. After 5 minutes, a solution of 3,4-methylenedioxybenzyl chloride in dichloromethane (3.7 mL, 14.3 mmol) was added. After 24 hours the mixture was stirred into water (150 mL) and acidified with dilute aqueous HCl. After several hours, the precipitate was filtered off, rinsed with water, and dried to afford 0.6 g of thiophene-2,5-dicarboxylic acid di-1,3-benzodioxol-5-ylmethyl ester. Recrystallization of a sample from ethanol gave product with a mp 141-148° C.

1. waitAfter several hours
2. filtrationthe precipitate was filtered off
3. washrinsed with water
4. customdried