Synthesis and Crystal Structure of 1-(3-Fluorophenyl)-2-thioxo-2,3-dihydroquinazolin-4(1H)-one

The base catalyzed intramolecular nucleophilic cyclization of 1-(2-bromobenzoyl)-3-(2-fluorophenyl)thiourea ( 1) in the presence of N,N-dimethyl formamide (DMF) afforded the 1-(3-fluorophenyl)-2-thioxo-2,3-dihydroquinazolin-4(1 H)-one ( 2) by an intramolecular nucleophilic substitution S NAr mechanism. The structure was supported by the spectroscopic data and unambiguously confirmed by the single crystal X-ray diffraction data. It crystallizes in the orthorhombic space group P na2 1 with unit cell dimensions a = 22.430(4), b = 8.1478(16), c = 13.522(3) ？, V = 2471.2(9) ？ 3. There are two independent molecules per asymmetric unit that are linked to centrosymmetric AB-dimers via intermolecular N-H…S bonds.