反应详情

A solution of 100 mg of 3-(2'-acetamidoethylthio)-7-oxobicyclo[3.2.0]hept-2-en-2-carboxylic acid in 5 mL of a mixture of ethylacetate and methanol was treated with a slight excess of α-naphthyldiazomethane. After the solution was stirred for 1 hr and then concentrated on a rotary evaporator, the crude product was purified by preparative thin layer chromatography on a 20×20×0.2 cm silica gel plate eluted with 5% methanol in methylene chloride affording 130 mg (85.5%) of 3-(2'-acetamidoethylthio)7-oxobicyclo[3.2.0]hept-2-en-2-carboxylic acid, 1-naphthylmethyl ester, as a glass. IR (neat): 3200, 1780, 1690, 1660 cm-1 ; NMR (220 MHz; CDCl3): δ 1.86 (3H, s), 2.6-3.0 (5H, m), 3.0-3.5 (4H, m), 4.43 (1H, m), 5.61 (1H, d, J=18), 5.64 (1H, d, J=18 ), 6.30 (1H, m), and 7.3-8.2 (7H, m); MS (chemical ionization) confirmed molecular weight of 409.

1. concentrationconcentrated on a rotary evaporator
2. customthe crude product was purified by preparative thin layer chromatography on a 20×20×0.2 cm silica gel plate
3. washeluted with 5% methanol in methylene chloride affording 130 mg (85.5%) of 3-(2'-acetamidoethylthio)7-oxobicyclo[3.2.0]hept-2-en-2-carboxylic acid, 1-naphthylmethyl ester, as a glass