Carbon-13 magnetic resonance spectroscopy of drugs II: antihistamines.

The natural abundance carbon-13 magnetic resonance spectra of a series of antihistamines (pheniramine, chlorpheniramine, methapyrilene, tripelennamine, pyrilamine, and thonzylamine) were detemined using the pulse Fourier transform technique. The chemical shifts were assigned with the aid of long-range carbon-13-hydrogen coupling constants.