A SHORT SYNTHESIS OF 4-SUBSTITUTED 1-(HYDROXYALKYL)-1H-PYRAZOLO[3,4-D]PYRIMIDINES

A simple and practical procedure was developed for the preparation of ted-1-(hydroxyalkyl)1H-pyrazolo[3,4-d]pyrimidines. This was achieved b y reacting nucleobase 3a or 3b with cesium carbonate or DBU in the pre sence of various alkyl iodides at 0 degrees C in DMF. This procedure a ppears to be of general general utility, proceeds in reasonable yield, and is applicable to different alkyl chain lengths including protecte d and unprotected alcohols. The synthetic utility of this approach is demonstrated by the facile synthesis of ST 689, a potent immunostimula tory drug.