Dimethylformamide dimethyl acetal → Methyl alpha-[(Z)-methoxy methylene]-4-[(E)-styryl]-5-thiazolacetate

Participants

Reaction Conditions

Reaction Steps

A mixture of 2.5 g of the product of Step A and 25 ml of dimethylformamide dimethyl acetal was heated to 50° C. and after 4 hours at this temperature, the mixture was allowed to return to 25° C. The reaction mixture was evaporated to dryness and the residue was dissolved in 30 ml of tetrahydrofuran and 5 ml of an aqueous solution of 2N hydrochloric acid. After standing for 2 hours at 25° C., the mixture was decanted followed by extraction with methylene chloride. The organic phase was dried over magnesium sulfate, filtered and evaporated to dryness. The residue was dissolved in 30 ml of acetone and 4 g of potassium carbonate and 6 ml of methyl iodide were added. The mixture was stirred for 16 hours at 20° to 25° C. and after filtering and evaporating to dryness, the residue was chromatographed on silica, eluting with a hexane--ethyl acetate mixture (7-3) to obtain 1.1 g of the desired product. Thin layer chromatography; Rf=0.17 [eluant: hexane--acetate of ethyl (7-3)].

Provenance & Evidence