Methyl propiolate → methyl 4,5-dihydro-7-oxo-8-phenyl-7H-thieno[2,3-a]quinolizine-10-carboxylate

Participants

Reaction Steps

(ba) A suspension of 31.65 g of 5,6-dihydro-3-hydroxy-2-phenylthiazolo[3,2-a]thieno[2,3-c]pyridinium hydroxide (internal salt) in 770 ml of toluene was treated with 10.94 g of methyl propiolate, the mixture was heated under reflux until the reaction has finished, the reaction mixture was evaporated in vacuo and the residue was chromatographed on silica gel with toluene/ethyl acetate (9:1). There was obtained methyl 4,5-dihydro-7-oxo-8-phenyl-7H-thieno[2,3-a]quinolizine-10-carboxylate as yellow crystals of m.p. 116° (from ethyl acetate).

Provenance & Evidence