Hydrochloric Acid → 2-(4,5-dihydro-1H-thieno[2,3-g]indazol-1-yl)ethanol

Participants

Reaction Steps

To a tetrahydrofuran (20 ml) solution containing 2.95 g of potassium tert-butoxy was added dropwise a tetrahydrofuran (10 ml) solution containing 2.00 g of 4-oxo-4,5,6,7-tetrahydrobenzo[b]thiophene and 3.89 g of ethyl formate under ice-cooling, and the mixture was stirred at room temperature for 30 minutes. After addition of 26 ml of 1 N hydrochloric acid to the reaction solution, 3.16 g of hydrazinoethanol was added under ice-cooling, and then the mixture was stirred at room temperature for 2 hours. The reaction solution was extracted with methylene chloride, and the organic layers were combined, washed with brine and then dried with anhydrous magnesium sulfate. After removal of the drying agent by filtration, the resulting filtrate was concentrated under a reduced pressure to give 1.56 g of 2-(4,5-dihydro-1H-thieno[2,3-g]indazol-1-yl)ethanol as a pale yellow solid.

Provenance & Evidence