Synthesis and hydrolytic stability of 4-substituted pyrazolo[3,4-d]pyrimidine 2′-deoxyribofuranosides

Abstract

Phase-transfer glycosylation of 4-chloro-1H-pyrazolo[3,4-d]pyrimidine (1) with 2-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride (2) yielded the N-1 glycosylation product (3) in 42%. The protected intermediate (3) was converted into pyrazolo[3,4-d]pyrimidine 2′-deoxyribofuranosides with amino, oxo, and thioxo substituents at C-4. Kinetic data of proton-catalysed hydrolysis showed that pyrazolo[3,4-d]pyrimidine 2′-deoxyribofuranosides are more stable at the N-glycosylic bond than are the parent purine nucleosides.