Mujahid Hussain Bukhari

Novel quinolyl-thienyl chalcones and their 2-pyrazoline derivatives with diverse substitution pattern as antileishmanial agents against Leishmania major

A series of twenty-two new pyrazoline derivatives was prepared from quinoline-based chalcones which in turn were synthesized by condensing formylquinolines with diverse acetylthiophenes. The titled compounds were characterized by spectroscopic techniques (NMR, IR and MS) and elemental analysis. All the compounds were screened for antileishmanial activities. Compounds 1e, 1f, 2a, 2c, 2d, 2g, 2k, and 4a were found potentially active antileishmanial agents. Bioassay results show that the type and positions of the substituents seem to be critical for their antileishmanial activities.

Synthesis and anti-bacterial activities of some novel pyrazolobenzothiazine-based chalcones and their pyrimidine derivatives

A novel series of fifteen pyrimidine derivatives was prepared from pyrazolobenzothiazine-based chalcones by refluxing with guanidine hydrochloride. The starting materials 4-(3,4-dimethyl-5,5-dioxidobenzo[4,3-c][1,2]thiazin-2(4-H)yl)phenyl)ethanone (2) or 4-(3,4-dimethyl-5,5-dioxidobenzo[4,3-c][1,2]thiazin-2(4-H)yl)benzaldehyde (3) were obtained by N-arylation of 3,4-dimethyl-2,4-dihydrobenzo[e]pyrazolo[4,3-c][1,2]thiazine 5,5-dioxide (1) with 4-fluoroacetophenone or 4-fluorobenzaldehyde, respectively, using phase transfer catalyst, hexadecyl-tri-n-butylphsophonium bromide. The N-arylated product (2) or (3) was reacted in MeONa/MeOH with diversified aromatic aldehydes or ketones to furnish two series of new chalcones 4 and 5. Refluxing of 4 or 5 with guanidine hydrochloride in KOH(aq) and H2O2/EtOH yielded the 2-(4-(2-amino-6-arylpyrimidin-4-yl)phenyl)3,4-dimethyl-2,4-dihydrobenzo[e]pyrazolo[4,3-c][1,2]thiazine-5,5-dioxide (6). The structures of chalcones (4 or 5) and corresponding pyrimidines (6) were confirmed with spectral data and elemental analysis. Several chalcones as well as pyrimidines showed marked activity against E. coli and S. aureus.

4-(4-Fluoro-phen-yl)-6-(2-fur-yl)pyrimidin-2-amine.

Molecules of the title compound, C14H10FN3O, are essentially planar and in the crystal structure they form dimers via hydrogen bonds, involving pyrimidinyl N atoms and amino H atoms, about inversion centers. The centroids of the furyl and pyrimidinyl rings are separated by 3.489 (2)Å, indicating π–π stacking interactions.

(2E)-3-(4-Chloro-phen-yl)-1-(1H-pyrrol-2-yl)prop-2-en-1-one.

In the molecule of the title compound, C13H10ClNO, the benzene and pyrrole rings are oriented at a dihedral angle of 7.37 (12)°. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into centrosymmetric R 2 2(10) dimers. There are C—H⋯π interactions between benzene and pyrrole rings and a benzene C—H group. A weak π–π interaction between the pyrrole rings [centroid–centroid distance 3.8515 (11) Å] further stabilizes the structure. There is also a π interaction between the pyrrole ring and the carbonyl group, with a carbon–centroid distance of 3.4825 (18) Å.

Erratum to: Synthesis and biological studies of a novel series of 4-(4-(1H-imidazol-1-yl)phenyl)-6-arylpyrimidin-2-amines

A novel series of eleven 4-(4-(1H-imidazol-1-yl)phenyl)-6-arylpyrimidin-2-amines has been prepared from synthesized 3-[4-(1H-imidazol-1-yl) phenyl]prop-2-en-1-ones and evaluated for phosphodiesterase (PDE) inhibition and antimicrobial activities. N-arylation of imidazole with 4-fluorobenzaldehyde using hexadecyltrimethylammonium bromide as catalyst gave 4-(1H-imidazol-1-yl) benzaldehyde which on treatment with substituted acetophenones yielded corresponding chalcones (1a–1k). Each chalcone on further reaction with guanidine hydrochloride resulted in title compounds (2a–2k). Pyrimidines thus synthesized were subjected to biological studies. Some compounds showed marked activities in PDE inhibition and anti-bacterial and anti-fungal bioassays.

4-(4-Bromo-phen-yl)-6-(4-chloro-phen-yl)-pyrimidin-2-ylamine.

The title compound, C16H11BrClN3, contains pairs of molecules lying about inversion centers linked by amino–pyrimidine N—H⋯N hydrogen bonds. The eight-membered rings thus formed are represented by the R 2 2(8) motif in graph-set notation. The second H atom of the amine group shows a rather weak interaction with two Br atoms, resulting in bifurcated N—H⋯(Br,Br) hydrogen bonds. The dihedral angles between the mean planes of the benzene rings and the mean plane of the heterocyclic ring are 8.98 (15) and 35.58 (10)°. The Br and Cl atoms show substitutional disorder, with site-occupancy factors of 0.599 (2) and 0.401 (2), respectively.

Methyl 4-hydr­oxy-2H-1,2-benzothia­zine-3-carboxyl­ate 1,1-dioxide

The asymmetric unit of the title compound, C10H9NO5S, contains two independent molecules. The heterocyclic thiazine rings in both molecules adopt half-chair conformations, with the S atoms in each molecule displaced by 0.455 (3) and 0.539 (3) Å and the N atoms displaced in the opposite direction by 0.214 (3) and 0.203 (3) Å, from the planes defined by the remaining ring atoms. The crystal structure is stabilized by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds involving both inter- and intramolecular interactions.

3-[4-(3,4-Dimethyl-5,5-dioxo-2H,4H-pyrazolo-[4,3-c][1,2]benzothia-zin-2-yl)phen-yl]-2-hy-droxy-1-mesitylprop-2-en-1-one hexane hemisolvate.

In the title compound, C29H27N3O4S·0.5C6H14, the heterocyclic thiazine ring adopts a half-chair conformation with the S and N atoms displaced by 0.500 (5) and 0.229 (5) Å, respectively, on opposite sides from the mean plane formed by the remaining ring atoms. The mean planes of the pyrazole ring and the benzene ring bonded to it form a dihedral angle of 35.76 (11)° and an intramolecular O—H⋯O hydrogen bond ocurs. The crystal structure features O—H⋯O and C—H⋯O hydrogen bonds. There is a half-molecule of hexane in the asymmetric unit lying about an inversion center. It is disordered over two sets of sites with occupancy factors 0.590 (9) and 0.410 (9).