The chlorination of N-alkoxy-N-alkylureas (1) by the action of t-BuOCl proceeds regiospecifically to give stable N-chloro-N-alkoxy-N'-alkylureas (2). The alcoholysis of 2 leads to N,N-dialkoxy-N'-alkylureas (3). The alkaline hydrolysis of 3 is a new, convenient method for the preparation of dialkoxyamines.
A series of 9-(2'-beta-C-methyl-p-D-ribofuranosyl)-6-substituted purine derivatives were synthesized as potential inhibitors of HCV RNA replication. Their inhibitory activities in a cell based HCV replicon assay were reported. A prodrug approach was used to further improve the potency of these compounds by increasing the intracellular levels of 5'-monophosphate metabolites. These nucleotide prodrugs showed much improved inhibitory activities of HCV RNA replication. (C) 2004 Elsevier Ltd. All rights reserved.