The reactivity of carboxy-terminated poly(1-vinylpyrrolidin-2-one) (PVP-COOH) 40-mers 1 with various small bi-functionalized molecules has been investigated. A number of new differently functionalized. PVP 3-11 have been successfully obtained demonstrating that the presence of the bulky PVP chain did not hamper the reactivity of the carboxy group. This would imply that in solution the carboxyl group is not buried inside the coil, but well exposed to the solvent, as further confirmed by a molecular dynamics conformational study. (c) 2008 Wiley Periodicals, Inc.