An improved procedure for the regiospecific synthesis of electron deficient 4- and 6-substituted isatins

Article abstract of DOI:10.1016/S0040-4039(98)01719-5

The regiospecific synthesis of 4- and 6-substituted isatins 5a-g in four steps from halonitrobenzenes 1a-g has been investigated for a variety of substrates (Scheme 1). The procedure makes use of readily available, easily handled materials and in most cases purification of neither intermediates nor final products is required. Yields of isatins are between 26 and 75% (Table 1). Improved yields of known isatins are reported as well as the syntheses of previously unreported isatins. This method, taken together with known procedures, provides for the synthesis of the full complement of isatin regioisomers.