azathioprine analogs- 2-subsituted derivatives of 7-methyl-6-(l-methyl-4-nitroimidazol-5-ylthio)purines 5 has been achieved by the reaction of 2-subsituted 6-purinethiones 4 with 5-chloro-1-methyl-4-nitroimidazole in ethanol. In the case of 7-methyl-2,6-dithioxanthine 4j, reaction in DMF gave di(imidazolyl) product 51. The key step in this synthesis was preparation of the appropriate 2-substituted 6-purinones