Green Synthesis and Crystal Structure of 4,7-Diaryl-2-oxo(thio)-1,2,3,4,5,6,7,8-octahydroquinazoline-5-one Derivatives

A green and convenient approach to the synthesis of novel 4,7-diaryl-2-oxo(thio)-1,2,3,4,5,6,7,8-octahydroquinazoline-5-one derivatives from appropriate aromatic aldehydes and 5-aryl-1,3-cyclohexanedione with urea or thiourea in the presence of dilute HCl as catalyst in water is described. This method provides several advantages such as environmental friendliness, low cost, high yields, and simple workup procedure. The structures of all compounds were characterized by elemental analysis, IR, MS, and H-1 NMR. The crystal and molecular structure of 4-(4'-chlorophenyl)-7-(4'-methoxyphenyl)1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-dione 5m have been determined by single crystal X-ray diffraction analysis. The crystal of compound 5m belongs to monoclinic with space group P-2(1)/c, a = 1.4353 (4) nm, b = 1.4011 (4) nm, c = 0.9248 (3) nm, alpha = 90.00 degrees, beta = 101.242 (6)degrees, gamma = 90.00 degrees, Z = 4, V = 1.8241 (9) nm(3), R-1 = 0.0448, and wR(2) = 0.1022.