Fused Imidazopyrazoles: Synthetic Strategies and Medicinal Applications

The current review summarizes the known synthetic routes of fused imidazopyrazoles. This review is classified into two main categories based on the type of annulations, for example, annulation of the imidazole ring onto a pyrazole scaffold or annulation of the pyrazole ring onto an imidazole scaffold. Some medicinal applications of imidazopyrazoles are mentioned

5-(4-Fluoro­phen­yl)-3-[5-methyl-1-(4-methyl­phen­yl)-1H-1,2,3-triazol-4-yl]-4,5-dihydro-1H-pyrazole-1-carbothio­amide

In the title compound, C20H19FN6S, the pyrazole ring has an envelope conformation, with the methine C atom being the flap atom. The dihedral angle between the least-squares plane through the pyrazole and triazole rings is 7.59 (9)°, and the triazole and attached benzene ring form a dihedral angle of 74.79 (9)°. The thio­urea group is coplanar with the pyrazole ring [N—N—C—S torsion angle = −179.93 (11)°], which enables the formation of an intra­molecular N—H⋯N hydrogen bond. In the crystal, inversion-related mol­ecules associate via N—H⋯S hydrogen bonds and eight-membered {⋯HNCS}2 synthons feature in the crystal packing. These synthons are connected into supra­molecular chains along the a axis via N—H⋯F hydrogen bonds, and the chains are consolidated into layers in the ab plane via C—H⋯S and C—H⋯F contacts

4-{1-[4-(4-Bromo­phen­yl)-1,3-thia­zol-2-yl]-5-(4-fluoro­phen­yl)-4,5-dihydro-1H-pyrazol-3-yl}-5-methyl-1-(4-methyl­phen­yl)-1H-1,2,3-triazole

In the title compound, C28H22BrFN6S, the central pyrazole ring has an envelope conformation, with the methine C atom being the flap atom. The dihedral angles between the least-squares plane through this ring and the adjacent thia­zole [18.81 (15)°] and triazole [1.83 (16)°] rings indicate a twist in the mol­ecule. A further twist is evident by the dihedral angle of 64.48 (16)° between the triazole ring and the attached benzene ring. In the crystal, C—H⋯N, C—H⋯F, C—H⋯π and π–π inter­actions [occurring between the thia­zole and triazole rings, centroid–centroid distance = 3.571 (2) Å] link mol­ecules into a three-dimensional architecture. The sample studied was a non-merohedral twin; the minor twin component refined to 47.16 (7)%

Synthesis and structural characterization of Isostructural 4-(4-Aryl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazoles

4-(4-Chlorophenyl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole (4) and 4-(4-fluorophenyl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole (5) have been synthesized in high yields. Crystallization of 4 and 5 from dimethylformamide solvent produced samples suitable for structure determination by single crystal diffraction. The materials are isostructural with triclinic, PĪ and symmetry and comprise two independent molecules in the asymmetric unit. The two independent molecules in the asymmetric unit assume similar conformation. The molecule is essentially planar apart from one of the two fluorophenyl groups, which is oriented roughly perpendicular to the plane of the rest of the molecule

Crystal structure of 2-((3-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl)methylene)-1H-indene-1,3(2H)-dione, C28H19N5O2

Abstract C28H19N5O2, monoclinic, Cc (no. 9), a = 13.9896(9) Å, b = 21.9561(14) Å, c = 7.1643(5) Å, β = 91.782(6)°, V = 2199.5(3) Å3, Z = 4, R gt(F) = 0.0632, wR ref(F 2) = 0.1727, T = 150(2) K.</jats:p

Crystal structure of (E)-5-((4-chlorophenyl)diazenyl)-2-(5-(4-fluorophenyl)-3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-methylthiazole, C23H17ClFN5S2

Abstract C23H17ClFN5S2, monoclinic, P21/c (no. 14), a = 20.9691(12) Å, b = 11.5316(6) Å, c = 9.2546(4) Å, β = 95.484(4)°, V = 2227.6(2) Å3, Z = 4, R gt(F) = 0.0468, wR ref(F 2) = 0.1126, T = 296 K.</jats:p

Crystal structure of 1-phenyl-N′-(1-phenyl-5-(thiophen-2-yl)-1H-pyrazole-3-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-3-carbohydrazide, C28H20N6O2S2

C28H20N6O2S2, triclinic, P1̅ (no. 2), a = 10.6738(6) Å, b = 11.7869(7) Å, c = 12.5381(7) Å, α = 112.842(6)°, β = 91.963(4)°, γ = 116.129(6)°, V = 1264.38(15) Å3, Z = 2, Rgt(F) = 0.0523, wRref(F2) = 0.1390, T = 296(2) K

Crystal structure of 4-(benzofuran-2-yl)-2-(3-(4-fluorophenyl)-3,3a,4,5-tetrahydro-2H-benzo[g]indazol-2-yl)thiazole, C28H20FN3OS

Abstract C28H20FN3OS, triclinic, P1̅ (no. 2), a = 9.5719(5) Å, b = 10.7499(6) Å, c = 10.9238(5) Å, α = 95.470(4)°, β = 102.133(4)°, γ = 97.962(4)°, V = 1079.30(10) Å3, R gt(F) = 0.0482, wR ref(F 2) = 0.1143, T = 150(2) K.</jats:p

The crystal structure of 5-(2-(4-fluorophenyl)hydrazono)-4-methyl-2-((3-(5-methyl-1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl)methylene) hydrazono)-2,5-dihydrothiazole dimethylformamide monosolvate, C30H25FN10S?C3H7NO

C30H25FN10S⋅C3H7NO, triclinic, P1̄ (no. 2), a = 10.9189(6) Å, b = 12.3898(7) Å, c = 13.9206(7) Å, α = 199.412(4)°, β = 110.024(5)°, γ = 105.904(5)°, V = 1631.17(17) Å3, Z = 2, Rgt(F) = 0.0536, wRref(F2) = 0.1471, T = 296 K

The crystal structure of 2-(3-(4-bromophenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-8H-indeno[1,2-d]thiazole, C25H17BrFN3S

C25H17BrFN3S, triclinic, P1̄ (no. 2), a = 11.2926(6) Å, b = 11.5832(4) Å, c = 16.9974(9) Å, α = 109.211(4)°, β = 90.211(4)°, γ = 95.290(4))°, V = 2089.21(18) Å3, Z = 4, R gt(F) = 0.0580, wR ref(F 2) = 0.1797, T = 296 K