Efficient Synthesis and Comprehensive Characterization of bis‐Pyrazole Derivatives: Including X‐Ray Crystallography and Hirshfeld Surface Analysis

ABSTRACT Straightforward synthetic access to bis ‐pyrazole derivatives has presented. The titled bis ‐pyrazole derivative: 3′,5‐diphenyl‐1′,2‐ bis (5,6,7,8‐tetrahydrobenzo[4,5]thieno[2,3‐d]pyrimidin‐4‐yl)‐1′H,2H‐[3,4′‐ bis pyrazol]‐5′‐ol 3 was obtained from the reaction of pyran‐2,4‐dione 1 and 4‐hydrazineyl‐5,6,7,8‐tetrahydrobenzo[4,5]thieno[2,3‐d]pyrimidine 2 in ethanol in a one‐step reaction. The other bis‐pyrazole derivative: 5,5′‐diphenyl‐1′H,2H‐[3,4′‐bispyrazol]‐3′‐ol 5 formed from hydrazinolysis of pyran‐2,4‐dione 1 or (E)‐3‐((allylamino)(phenyl)methylene)‐6‐phenyl‐2H‐pyran‐2,4(3H)‐dione 4 in ethanol. The molecular structure of both compounds elucidated by X‐ray crystallographic identification and spectrophotometric tools. The supramolecular structure of 3 could be described as a hydrogen bonded dimer via O–H…N interactions which are further connected by π…π contacts. Hirshfeld analysis showed the significance of the N…H, O…H, C…H, C…C, N…N, C…O and H…H interactions. These contacts contributed by 14.4%, 3.2%, 16.4%, 3.9%, 1.0%, 0.4% and 42.7%, respectively from the whole interactions occurred in the crystal. The d norm, shape index and curvedness maps revealed the importance of π–π stacking interactions in the molecular packing where the % C…C is 3.9%. In case of 5, the short N…H, C…H, and H…H contacts contributed by 15.5%–17.0%, 28.3%–36.7% and 37.8%–45%, respectively in the molecular packing. Straightforward synthetic access to bis‐Pyrazole derivatives: X‐ray single crystal analysis.