Acetyl chloride → 7-(acetylamino-methyl)-2-amino-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester

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Reaction Steps

To a ice water cooled solution of the above 2-amino-7-aminomethyl-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester (1.5 g, 5.27 mmol) and triethylamine (1.5 ml) in dichloromethane (50 ml) was added dropwise acetylchloride (0.46 g, 5.80 mmol). The reaction mixture was allowed to reach room temperature and stirred for an additional 0.5 h. The reaction mixture was washed with water (2×25 ml), dried (Na2SO4), filtered and the solvent evaporated in vacuo. The residue was purified by column chromatography on silicagel (1 L) using first ethyl acetate and later on a mixture of ethyl acetate and ethanol (20:1) as eluents. Pure fractions were collected and the solvent evaporated in vacuo affording 0.3 g (17%) of 7-(acetylamino-methyl)-2-amino-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester as a solid.

Provenance & Evidence