Synthesis and spectroscopic characterization of 3-(3,4-dimethoxyphenylethylamino)-methylidene-1,2,3,9-tetrahydropyrrolo[ 2,1-b]-quinazolin-9-one and crystal structure of its hydrochloride

The structure of 3-(3,4-dimethoxyphenylethylamino)-methylidene-1,2,3,9-tetrahydropyrrolo[2,1-b]-quinazolin-9-one hydrochloride was determined by single-crystal X-ray diffraction at 100 K. The compound crystallizes in the monoclinic space group Cc, with a = 4.7149(18), b = 30.075(12), c = 14.199(6) angstrom, beta = 91.852(8)degrees, Z = 4, V = 2012.4(14) angstrom(3). The crystallographic study revealed E configuration of the C11 = N9 ' bond. Electrostatic interactions between the organic cation and the chloride anion and classical N-H horizontal ellipsis Cl hydrogen bonds stabilize this salt. A Hirshfeld surface analysis revealed that H center dot center dot center dot H, H center dot center dot center dot C/C center dot center dot center dot H, and H center dot center dot center dot O/O center dot center dot center dot H represent the most prominent Van-der-Waals contacts. For the neutral parent molecule, nuclear magnetic resonance spectroscopy in deuterated chloroform solution showed that two tautomeric forms coexist in 3:1 ratio.