NITRATION OF DIMETHYL 1-SUBSTITUTED INDOLE-2,3-DICARBOXYLATES:SYNTHESIS OFNITRO-AND AMINOINDOLE DERIVATIVES

摘要

The treatment of dimethyl indole-2,3-dicarboxylate with nitronium tetrafluoroborate in the presence of tin (IV) chloride produced dimethyl 5-nitroindole-2,3-dicarboxylate as the major product.In a similar manner,the dimethyl 1-benzyl-and l-benzenesulfonylindole-2,3-dicarboxylates provided a mixture of the corresponding 4-nitro-,5-nitro-,6-nitro-and 7-nitroindole derivatives.However,dimethyl 5-bromoindole-2,3-dicarboxylate gave dimethyl 5-bromo-4-nitroindole-2,3-dicarboxylate as the sole product,which was converted to dimethyl 4-aminoindole-2,3-dicarboxylate.