Conformational populations for antihistamines and antihypertensives in solution.

The conformations in aqueous solution were determined for the XCH2CH2N systems of some antihistamines (H1-receptor antagonists) and some adrenergic neuron blocking agents, including the antihypertensive drugs guanethidine and guanoclor. The rotameric species thought to be the pharmacologically active one is often not the only rotamer present in solution.