Diazido-pyrimidines

Scheme 9 shows an example of selective electrophilic substitution at N-3 of [l,2,3]triazolo[4,5- pyrimidin-7-one reported by Ding et al., who showed that glycosylation can occur at the 4-position of diazido-2-deoxystreptamine derivative, if the alkyl halide is appropriately substituted at this position <2003AGE3409>. 

Triazolopyrimidine 313 was synthesized by the diazotization of diamine 312 (95JMC587). The triazolo[4,5-d]pyrimidine 315 was prepared by heating the diazo derivatives 314. The latter were obtained from the reaction of l,3-dimethyluracil-6-arylhydrazones with 2,4-diazido-6-(cyanomethoxy)-l,3,5-triazine (94MC208) (Scheme 63). 

Benzol 3,6-Diacetoxy-4,5-diazido-1,2-dimethyl- VI/lc, 565 Pyrimido[4,5-d]pyrimidin 4-(2-Methoxy-ethylamino)-2-(4-nitro-2-furyl)- E9c, 384 (Cl - NHR)... 

Stirring 2 with sodium azide in acetone for 30 minutes gives 4,8-diazido-2,6-dichloropyrimi-do[5,4-c/]pyrimidine in 86% yield. 

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