3-Deazaneplanocin A （3-DNPA, 2）, an antiviral and antitumor agent, has been synthesized in an optimized procedure in 10 steps, with an increased overall yield of 11.2%. Started from 2,4-dihyroxyl-3-nitropyridine, reduction of nitro group and ring closure of imidazole were carried out in one pot, without the separation of diaminopyridine （10）, to give 3-deazapurine （11）. Moreover, the conversion of 6-chloro-3-deazapurine （12） to 6-amino-3-deazapurine （13） and the synthesis of N^6,N^6,N9-tris-Boc-3- deazadenine （16） was promoted by microwave-aid method. Compound 16 benefited the formation of N9 isomer of 3-DNPA in Mitsunobu reaction.
