Sodium dithionite in the regioselective reduction of the ortho-positioned nitro group in 1-R-2,4-dinitrobenzenes

1-R-2,4-Dinitrobenzenes are regioselectively reduced with sodium dithionite at near-neutral pH into the product having amino group ortho to the substituent R. Although the yields of products varied from moderate to good, the procedure does not involve the use of transition metals.