Crystal structure and spectra of 6,7-dimethoxy-3,3-dimethyl-3,4-dihydroisocarbostyril azine

Crystal and molecular structures of 6,7-dimethoxy-3,3-dimethyl-3,4-dihydroisocarbostyril azine (I) were determined using X-ray diffraction analysis and IR and electronic absorption spectroscopy. Compound I was found to exist in the form of an azine isomer, in which the N=C double bonds are located outside the tetrahydroisoquinoline fragments, while the H atoms migrate toward the N(1) atoms of these moieties. Model quantum-chemical calculations were performed. © 2001 MAIK "Nauka/Interperiodica".