反应详情

To a stirred solution of 2-Amino-5-(4-methoxy-phenyl)-thiophene-3-carboxylic acid methyl ester (7.15 g, 27.2 mmol) in anhydrous THF (150 mL) was added trichloroacetyl isocyanate (6.4 mL, 54 mmol) slowly over a period of 5 min. After the addition was complete, a precipitate formed and the reaction stirred for an additional 1 h. The desired product was obtained by filtration to give 6.9 g (56%) an off-white solid. The product was used in the next step without purification 1H NMR (d6-DMSO δ 12.3, br s, 1H; δ 12.2, s, 1H; δ 7.46, d, 2H; δ 7.32, s, 1H; δ 6.85, d, 2H; δ 3.75, s, 3H; δ 3.66, s, 3H), LC/MS (APCI, ES, M+H=451).

1. additionAfter the addition
2. customa precipitate formed