Process for the preparation of 2-nitro-3-aminopyridine, and the intermediates which are formed in the reaction

摘要

2-Nitro-3-aminopyridine is prepared by (a) reacting 3-aminopyridine with phosgen COCl2 or urea H2NCONH2 to give N,N'-di-(3-pyridyl)-urea, (b) nitrating and N,N'-di-(3-pyridyl)-urea with nitric acid or with a mixture of nitric acid and sulfuric acid to give N,N'-di-(2-nitor-3-pyridyl)-urea, and (c) hydrolyzing said N,N'-di-(2-nitro-3-pyridyl)-urea to give 2-nitro-3-amino-pyridine. N,N'-di-(3-pyridyl)-urea and N,N'-di-(2-nitro-3-pyridyl)-urea, which are formed in the course of the reaction as intermediates are new compounds. The end product of the process, 2-nitro-3-aminonpyridine, is an intermediate in various specialized fields.