Comparisons of rotamer populations of nialamide, azaperone, and chloroquine in solid state and in solution

IR and NMR spectroscopy were combined with previously published X-ray crystallographic data to determine the solution conformations of the -(CH2)n- fragments of nialamide, azaperone, and chloroquine. The solution conformation of these compounds then was compared to the solid-state conformation. In addition, the limits of the IR-X-ray method are discussed. This paper shows that a combination of IR, NMR, and X-ray crystallographic data can lead to a complete picture of the conformations available to drugs. In addition, the danger of using solid-state conformational data alone to make pharmacological suggestions is illustrated.