Ethyl Acetate → 2-Amino-4-ethoxycarbonyl-5-ethynylthiazole

Participants

Reaction Steps

2-Amino-4-ethoxycarbonyl-5-iodothiazole (1.40 g) prepared in step a) in Example 1 was dissolved in 20 ml of N-methyl-2-pyrrolidinone. tri-n-butylethynyltin (1.63 ml), 127 mg of tri(2-furyl)phosphine, 127 mg of tris(dibenzylideneacetone)dipalladium(0), and 1.27 g of zinc chloride were added to the solution under an argon atmosphere, and the mixture was stirred at room temperature for 2.5 hr. Brine and ethyl acetate were added to the reaction solution. The insolubles were removed by filtration through Celite, and the filtrate was extracted twice with ethyl acetate. The organic layers were combined, were washed with brine, were dried over anhydrous magnesium sulfate, were filtered, and were concentrated under the reduced pressure. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate=3:1) to give 597 mg of 2-amino-4-ethoxycarbonyl-5-ethynylthiazole.

Provenance & Evidence