Two synthetic approaches to 9-deaza analogues of 9-(2,3-dihydroxypropyl)adenine (DHPA)

Two approaches to prepare 7-(2,3-dihydroxypropyl)-2,4-dimethoxy-5H-pyrrolo[3,2-d]pyrimidine are described. The first approach starts from 6-cyanomethyl-2,4-dimethoxy-5-nitropyrimidine which is substituted on its active methylene with 2,3-dihydroxypropyl group; the hydrogenation of this compound results in simultaneous reduction of the nitro group and condensed pyrrole ring-closure. The second approach to this DHPA analogue consists in addition of alkaline salt of 2,4-dimethoxy-5H-pyrrolo[3,2-d]pyrimidine on (RS)-2,3-O-isopropylideneglyceraldehyde followed by reductive removal of the hydroxy group.