Download citation
Download citation

link to html
The racemic title compound, C17H23N3O3, isolated from the reaction of L-(-)-tyrosine hydrazide with triethyl ortho­propionate in the presence of a catalytic quantity of p-toluene­sulfonic acid (p-TsOH), crystallizes with Z' = 1 in a centrosymmetric monoclinic unit cell. The mol­ecule contains two planar fragments, viz. the benzene and imidazole rings, linked by two C-C single bonds. The dihedral angle between the two planes is 59.54 (5)° and the mol­ecule adopts a synclinal conformation. The HOMA (harmonic oscillator model of aromaticity) index, calculated for the benzene ring, demonstrates no substantial inter­action between the two [pi]-electron delocalization regions in the mol­ecule. In the crystal structure, there is an O-H...N hydrogen bond that links the mol­ecules along the c axis.

Download citation
Download citation

link to html
The title compound, C15H11N3O, (I), was obtained by the air oxidation of 3,5-diphenyl-4,5-dihydro-1,2,4-triazin-6(1H)-one. In the crystal structure, (I) forms centrosymmetric hydrogen-bonded dimers through pairs of N—H...N hydrogen bonds. The mol­ecular structure of (I) deviates somewhat from planarity in the crystalline state, whereas a density functional theory (DFT) study predicts a completely planar conformation (Cs point-group symmetry) for the isolated mol­ecule. The solid-state conformation of (I) is stabilized by intra­molecular hydrogen bonds, viz. one C—H...O inter­action, which forms a six-membered ring, and three C—H...N inter­actions that each form five-membered rings. To estimate the influence of the intra­molecular hydrogen-bonded rings on the aromaticity of the phenyl rings, the HOMA (harmonic oscillator model of aromaticity) descriptor of π-electron delocalization has been calculated for conformations of (I) with and without intra­molecular hydrogen bonds. In the planar conformation of (I), the HOMA values for both benzene rings are lower than in hypothetical conformations without intra­molecular hydrogen bonds.
Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds