反应详情

A mixture of thieno[3,2-b]thiophene-2-carboxaldehyde (8) (23.30 g., 138.5 mmole); ethylene glycol (31 mL., 34.39 g., 554.0 mmole); pyridinium tosylate (2.5 g., 10 mmole); and benzene (200 mL) was stirred and refluxed and the water (3.2 mL) was removed by a Dean-Stark trap (~4 hours). The reaction was cooled to room temperature, extracted with water three times and then with a saturated solution of sodium bicarbonate. The organic layer was dried (MgSO4), filtered, and the solvent was evaporated to leave a crystalline mass. Trituration with a small amount of ether removed the color to give 24.72 g of a white crystalline product, mp. 88°-90° C. An additional 1.43 g of product was collected from the ether washing, mp 88°-89° C., yielding a total of 26.15 g of 2-(2-dioxolanyl)thieno[3,2-b]thiophene (9). This product was used in the next step without further purification.

1. temperaturerefluxed
2. customthe water (3.2 mL) was removed by a Dean-Stark trap (~4 hours)
3. extractionextracted with water three times
4. dry with materialThe organic layer was dried (MgSO4)
5. filtrationfiltered
6. customthe solvent was evaporated
7. customto leave a crystalline mass
8. customTrituration with a small amount of ether removed the color