Synthesis and crystal structure of bis-chalcone-derived fused-ring pyrazoline having an unusual substitution pattern

Abstract

Pyrazolines are an important class of heterocyclic compounds with diverse applications. A novel bis-chalcone-derived fused ring pyrazoline has been obtained by the reaction of bis-chalcone with hydrazine hydrate in acetic acid solvent having a catalytic amount of HCl and characterized by IR, 1H and 13C NMR, GC–MS, and finally by X-ray single crystal analysis. Interestingly, the in situ post-cyclization substitution pattern on pyrazoline ring nitrogen is entirely different from the previously reported related pyrazoline derivatives. The new compound crystallizes out from its ethanolic solution, which has monoclinic crystal lattice with P21/c space group, a = 6.1001(4) A, b = 38.602(2) A, c = 7.7332(5) A, α = 90°, β = 113.039(3)°, γ = 90°, V = 1675.73(19) A3, Z = 4, crystal size = 0.38 × 0.30 × 0.18 mm3, and R int = 0.043.