Unclassical hydrogen bonds of C–H⋯O and C–H⋯Cl in the crystals of 1,4-diaryl Hantzsch esters

Three novel N1-substituted derivatives of Hantzsch ester were synthesized and the molecular structures were studied by using X-ray crystallography. Two types of unclassical hydrogen bonds C–H⋯O and C–H⋯Cl were presented in the crystals. The formation of such a hydrogen bond is dependent on the nature of the substituent at C23.