Fluoro-substituted Rings Research Articles

Crystal structure of ethyl 4-(2-fluoro-phen-yl)-6-methyl-2-sulfanyl-idene-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate.

The title compound, C14H15FN2O2S, crystallizes with two mol­ecules in the asymmetric unit. In each mol­ecule, the pyrimidine ring adopts a sofa conformation with the sp 3-hybridized C atom forming the flap and the fluoro-substituted ring in an axial position. In the crystal, mol­ecules are linked via N—H⋯S hydrogen bonds, forming chains of R 2 2(8) rings along [100]. In one independent mol­ecule, an intra­molecular C—H⋯O hydrogen bond is observed.

Synthesis and Crystal Structures of N-Substituted Pyrazolines

Four pyrazole compounds, 3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (1), 5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbaldehyde (2), 1-[5-(4-chlorophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone (3) and 1-[3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]propan-1-one (4), have been prepared by condensing chalcones with hydrazine hydrate in the presence of aliphatic acids, namely formic acid, acetic acid and propionic acid. The structures were characterized by X-ray single crystal structure determination. The dihedral angles formed between the pyrazole and the fluoro-substituted rings are 4.64(7)° in 1, 5.3(4)° in 2 and 4.89(6)° in 3. In 4, the corresponding angles for molecules A and molecules B are 10.53(10)° and 9.78(10)°, respectively.