Synthesis and evaluation of pyrazolo[3,4-b]quinoline ribofuranosides and their derivatives as inhibitors of oncogenic Ras

A series of pyrazolo[3,4-b]quinoline ribofuranosides were prepared using the glycosylation methodology of Vorbruggen. Oxidative cleavage of the ribose moiety in 6 furnished the dialdehyde intermediate 36, which cyclizes upon reductive amination providing the morpholino compound 37. Derivatives from both the ribose and morpholino series were evaluated for their ability to inhibit the nucleotide exchange process of oncogenic Ras. 1a