Triethylamine → 2-amino-7-(4-methoxymethoxy-1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester

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Reaction Steps

A mixture of 2-amino-7-aminomethyl-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester (0.15 g, 0.53 mmol) and 4-methoxymethoxy-isobenzofuran-1,3-dione (135 mg, 0.64 mmol) was dissolved in distilled acetonitrile (7 ml) under nitrogen. The flask was cooled in an ice bath with stirring and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.12 g, 0.64 mmol), and triethylamine (0.22 ml, 1.59 mmol) were added. The reaction was warmed to ambient temperature and stirred for 18 h. The solution was concentrated in vacuo and the residue dissolved in ethyl acetate (40 ml). The organic layer was washed with 1% hydrochloric acid (2×10 ml), saturated sodium bicarbonate (10 ml), and brine (10 ml). The resulting solution was dried (Na2SO4), filtered, and the solvent evaporated in vacuo which afforded 0.18 g of a crude 2-amino-7-(4-methoxymethoxy-1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carboxylic acid tert-butyl ester which was used without further purification.

Provenance & Evidence