Water → 5,6-Dihydro-4-oxo-5-(2-ethoxycarbonylethyl)thieno[2,3-b]thiopyran

Participants

Reaction Steps

Under N2, thionyl chloride (5.5 g, 0.043 mol) was added dropwise to a solution of 1 (11.5 g, 0.04 mol) in DMF (4 drops) and methylene chloride (100 ml). After the addition, the solution was stirred at room temperature for 4.5 hours. The mixture was then cooled to -10° and SnCl4 (5.3 g, 0.02 mol) was added dropwise. After the addition the reaction was allowed to stir at room temperature for 28 hours. The mixture was then added to H2O and the aqueous layer extracted with EtOAc (3×). The organic extracts were backwashed with saturated NaHCO3, dried, filtered and concentrated to dryness to yield 10.5 g (97%) of 2 wherein R1, R2, R3 and R4 are each H.

Provenance & Evidence