Non-nucleoside inhibitors of the hepatitis C virus NS5B polymerase: discovery of benzimidazole 5-carboxylic amide derivatives with low-nanomolar potency
摘要:
Optimization of benzimidazole 5-carboxamide derivatives previously identified as specific inhibitors of the NS5B polymerase of the hepatitis C virus (HCV) has led to the discovery of potent analogues that inhibit the enzyme at low-nanomolar concentrations. Greater than 800-fold improvement in potency from the original lead structure was achieved through the combined effects of conformational rigidification, molecular size extension and the identification of previously unexploited interactions. Furthermore, these inhibitors retain specificity for HCV polymerase relative to other viral and mammalian RNA polymerases. (C) 2003 Elsevier Ltd. All rights reserved.
The 5-bromo derivative 2 of the cyclic tautomer of N(b)-methoxycarbonyl-L-tryptophan methyl ester 1 undergoes reaction with CuCN in refluxing N-methylpyrrolidone (NMP) to give 5-cyano derivative 3a with some ring opened 5-cyano product 3b. Both 3a and 3b can be converted, in high yield, into free 5-cyano-L-tryptophan 4 with BBr3 under mild conditions.