Synthesis and Crystal Structures of Ethyl 2-(4-Methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate Dihydrate and Its Building Block 4-Fluoro-3-nitrobenzoic Acid

Abstract

The title compound, ethyl 2-(4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate dihydrate (5), was synthesized and its crystal structure was studied by single-crystal X-ray diffraction technique. Compound 5 is crystallized in the centrosymmetric triclinic space group $$P\bar {1}$$ with Z = 4 and Z′ = 2, and unit-cell parameters of a = 8.9190 (3) A, b = 12.6888 (4) A, c = 14.7111 (5) A, α = 98.4855 (10)°, β = 101.6379 (9)°, γ = 95.4346 (10)° and V = 1599.43 (9) A3. Its starting material, 4-fluoro-3-nitrobenzoic acid (1), is crystallized in the non-centrosymmetric monoclinic space group P21 and Z = 4 with unit-cell parameters of a = 3.7170 (4) A, b = 12.6475 (13) A, c = 15.5237 (15) A, α = 90°, β = 91.9786 (16)°, γ = 90° and V = 729.35 (13) A3. It was noted that strong hydrogen bonds play important roles in the crystal packing of both compounds, especially in 5, in which the co-crystallized water molecules act as both strong hydrogen bond donor and strong hydrogen bond acceptor. Two molecule of compound 5 crystallized in a non symmetrical manner with four co-crystallized water molecules which play an important role in the crystal packing as strong hydrogen-bond donors.