13C and 1H NMR investigation of pilocarpine hydrochloride in water solution

Abstract

Dynamic and geometric features of pilocarpine in water solution were delineated by interpreting 13C and 1H NMR spin-lattice relaxation rates and nuclear Overhauser effects. The motional correlation time was evaluated at 53 ± 5 ps at 298 K. 1H—1H distances, as calculated from double-selective 1H spin-lattice relaxation rates, and 13C—1H distances, as calculated from selective 13C–{1H} Overhauser effects, gave evidence of a C7 puckered conformation of the furanone ring and of an angle of ca. 50° between the two rings.