Potential inhibitors of nucleotide biosynthesis. 1. Nitrosoureidonucleosides. 2

Several nitrosoureidonucleosides (9a, 9b, 11a, 11b, 18 and 20) designed as inhibitors of enzymes that metabolize purine and pyrimidine nucleotides have been prepared and their chemical and biological properties studied. The low level of biological activity observed may be due to the unexpected stability of these nitrosoureas compared to biologically active compounds such as N-methyl-N-nitrosourea (MNU), N,N'-bis(2-chloroethyl)-N'-nitrosourea (BCNU), and N,N'-dicyclohexyl-N-nitrosourea (DCyNU).