Synthesis, analysis and reduction of 2-nitropropyl starch

Granular 3-nitropropyl potato starch was synthesized by reaction with 3-nit ropropyl acetate in an aqueous suspension. Nitroalkylation occurs preferent ially with the amylose fraction of potato starch, as was confirmed by leach ing experiments and digestion of the modified starch with alpha -amylase. T he 2-nitropropyl substituent is a mixture of the nitroalkane and nitronic a cid tautomer. Some grafting occurs and to a lesser extent additional reacti ons (formation of carbonyls and oximes) of the nitro group take place. Afte r catalytic hydrogenation of water soluble 2-nitropropyl starch only a smal l amount of the nitro functionality was reduced to the corresponding amine. Reduction of granular 7-nitropropyl starch with sodium dithionite did not go to completion and led to a complex mixture of starting material, several intermediates and side products (for example sulfamates). (C) 2001 Elsevie r Science Ltd. All rights reserved.