反应详情

There was reacted 1.7 g (8.25 mmole) of 2-methoxycarbonyl-7-methoxybenzofuran with chlorosulfonic acid as in Example 1, yielding 2 g of 2-methoxycarbonyl-4-chlorosulfonyl-7-methoxybenzofuran (yield: 80%, MS (m/z): 304 (M+), 269, 238 and 210). The obtained chlorosulfonyl compound was reacted wit glycine ethyl ester hydrochloride as in Example 1 to give an ester compound (yield: 88%, MS (m/z): 371 (M+), 340, 298 and 269), which was then hydrolyzed to give 2-carboxy-4-(N-carboxymethylsulfamoyl)-7-methoxybenzofuran (colorless needles, yield: 86%). The physical constants are shown in Table 4.