IR spectra and crystal structure of hydrochlorides and complex salts of 2,3-polymethylene-3,4-dihydroquinazolines and-4-quinazolones

IR spectra are reconsidered on the basis of the results of x-ray structural analysis of the crystal structures of hydrochlorides and complex salts of 2,3-polymethylene-3,4-dihydroquinazolines and-4-quinazolones. It has been established that two absorption bands (Nl⁺–H) in the complex salts characterize different energies of formation of an H-bond, which is weaker than in the corresponding hydrochlorides. The nature of an absorption band in the 3400–3500 cm^–1 region has been established from the XSA results.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 364–367, May–June, 1999.