Naghmana Rashid

Synthesis, characterization and biological evaluation of some thiourea derivatives bearing benzothiazole moiety as potential antimicrobial and anticancer agents.

Five series of thiourea derivatives bearing benzothiazole moiety (20 compounds) were efficiently synthesized and evaluated for antimicrobial and anticancer activities. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed higher activity against fungi than bacteria. Compounds 1b, 2b, 3b, 4b and 5b exhibited the greatest antimicrobial activity. Preliminary study of the structure-activity relationship revealed that electronic factors in benzothiazole rings had a great effect on the antimicrobial activity of these compounds. In preliminary MTT cytotoxicity studies, the thiourea derivatives (2d, 5c and 5d) were found most potent. In MCF-7 and HeLa cells, the IC(50) values were observed in the range of 18-26 microM and 38-46 microM, respectively.

Synthesis, spectroscopic characterization, crystal structure and antifungal activity of thiourea derivatives containing a thiazole moiety

AbstractFour novel thiourea derivatives containing a thiazole moiety were synthesized and characterized by IR, 1H and 13C NMR, mass spectrometry and elemental analysis. The crystal structure of 1a was determined from single crystal X-ray diffraction data. It crystallizes in monoclinic space group P21/n with unit cell dimensions a = 11.7752(6) Å, b= 3.8677(2) Å, c= 27.4126(13) Å and β = 92.734(5) Å. There is a strong intramolecular hydrogen bond of the type N-H⋯O, with H⋯O distance of 2.5869(19) Å. The mass fragmentation pattern has also been discussed. The antifungal activity of the synthesized compounds was studied by broth micro-dilution method and poisoned food technique. The compounds 1b and 1c possessed a broad spectrum of antifungal activity.

Vibrational spectra and DFT study of anticancer active molecule 2-(4-Bromophenyl)-1H-benzimidazole by normal coordinate analysis

FT-IR and FT-Raman spectra of the 2-(4-Bromophenyl)-1H-benzimidzole were recorded and analyzed in the solid phase. The optimized molecular geometry, the vibrational wavenumbers, the infrared intensities and the Raman scattering activities were calculated by using Hartree-Fock and density functional method (B3LYP) with 6-31G(d,p) basis set. The potential surface scan study was carried out for the conformation of theoretical structure. Detailed interpretation of the vibrational spectra had been carried out with the aid of the normal coordinate analysis. Chemical interpretation of hyperconjugative interaction was done by natural bond orbital analysis.

Cis-Diastereoselectivity in Pictet–Spengler Reactions of L-Tryptophan and Electronic Circular Dichroism Studies

The diastereoselective synthesis of optically active 1,3-disubstituted tetrahydro-β-carbolines using polar protic Pictet-Spengler cyclization of (S)-tryptophan methyl ester with five aldehydes RCHO (R═CH(3), C(2)H(5), C(3)H(7), C(4)H(9), and C(6)H(5)) was studied. As an alternate route, the cyclization of (S)-tryptophan with the same aldehydes and subsequent methylation of the resulting tetrahydro-β-carboline carboxylic acids were also performed for comparison. (13)C NMR and electronic circular dichroism (ECD) studies and time-dependent density functional theory ECD calculations data established the relative 1,3 cis/trans and the absolute configuration (1S,3S/ 1R,3S) of the synthesized compounds. The solid-state and solution ECD study of the prepared compounds, supported by ECD calculation and X-ray data, afforded a reliable ECD method for the configurational assignment of 1,3-disubstituted tetrahydro-β-carbolines and revealed the stereochemical factors that determine the characteristic ECD data.

1-(4-Bromo­phen­yl)-1-(4-nitro­benzo­yl)thio­urea

The title compound, C14H10BrN3O3S, crystallizes as two concomitant polymorphs that differ in colour (one yellow and one colourless). Only the structure of the colourless form could be determined. The molecule exists in the thioamide form with an intramolecular N—H⋯O=C hydrogen bond across the thiourea system. Molecules are linked into layers parallel to (120) by Br⋯Onitro contacts [3.103 (1) Å], classical hydrogen bonds from the other NH function to the S atom and Nnitro⋯O=C contacts. The layers are linked by weak C—H⋯Onitro hydrogen bonds to produce the observed three-dimensional network.

Semiconducting nanostructured copper sulfide thin films from bidentate copper(II) complexes of N-(dialkylcarbamothioyl)-nitrosubstituted benzamides by chemical vapour deposition

Copper(II) complexes of various N-(dialkylcarbamothioyl)-nitrosubstituted benzamide [dialkyl = di-n-butyl (1a, 2a); hexyl, methyl (3a); butyl, ethyl (4a)] have been synthesized and characterized by elemental analysis, IR spectroscopy and atmospheric pressure chemical ionization-mass spectrometry (MS-APCI). The molecular structure of the complex 2a was determined by single-crystal X-ray diffraction. These complexes were used as single-source precursors for the deposition of copper sulfide thin films by aerosol assisted chemical vapour deposition (AA-CVD) at 350 °C. The powder X-ray diffraction (p-XRD) patterns of the thin films of complexes 3a and 4ashowed the deposition of rhombohedral digenite Cu9S5 phase, and complex 1a deposited monoclinic roxbyite Cu7S4 phase at 350 °C with spherical crystallites. Complex 2a deposited orthorhombic anilite Cu7S4 phase with spherical crystallites. The degree of roughness of the film surface was determined by atomic force microscopy (AFM). The scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) results showed the uniform distribution of copper sulfide in the films, which makes them useful semiconducting materials on a structured surface.

Nickel(II) complexes of N-(dialkylcarbamothioyl)-4-nitrobenzamide as single-source precursors for the deposition of nanostructured nickel sulfide thin films by chemical vapor deposition

Nickel(II) complexes of N-(di-alkyl-carbamothioyl)-4-nitrobenzamide (alkyl = ethyl or n-propyl) have been synthesized and characterized by infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry. The structures of bis[N-(diethylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2a) and bis[N-(dipropylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2b) have been determined by X-ray crystallography. FTIR and NMR of the nickel complexes showed the absence of the N–H proton resonance and the N–H stretch and shift of ν C=O and ν C=S as expected. Both complexes have been used as single-source precursors for the deposition of nickel sulfide nanostructured thin films by aerosol-assisted chemical vapor deposition. The nanostructured thin films were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and atomic force microscopy.

Nanoparticles and nanocrystals of a new bidentate nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide: synthesis, characterization, and crystal structures

The nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide has been synthesized and characterized by Fourier transform-infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry (atmospheric pressure chemical ionization mass spectrometry). The single-crystal X-ray structures of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide (1) and bis[N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide]nickel(II) (2) have been determined from single-crystal X-ray diffraction data. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the νC=O and νC=S stretching vibrations confirm formation of the metal complex. These studies show that the metal complex is neutral in cis-configuration. The complex has been used as a single-source precursor for the deposition of nickel sulfide nanocrystals by thermolysis. The nickel sulfide nanocrystals were characterized by X-ray powder diffraction and transmission electron microscopy.

4-Nitro-N-(4-nitro­benzo­yl)benzamide

The central acetylacetamide moiety in the title compound, C14H9N3O6, is buckled [e.g. the C—N—C—O torsion angle is 14.3 (6)°] but the r.m.s. deviation for the five atoms is 0.044 Å. The benzene rings lie on the same side of the central plane, forming dihedral angles of 37.17 (15) and 28.58 (19)° with it. The dihedral angle between the two rings is 17.8 (2)° indicating that the molecule is curved. The carbonyl groups are syn to each other and anti to the amino H atom. This allows for the formation of N—H⋯O hydrogen bonds in the crystal, which leads to twisted chains along the b axis. Positional disorder (50:50) of the O atoms was modelled for both the nitro groups.

Ethyl 2-[3-(4-nitro­benzo­yl)thio­ureido]benzoate

In the title compound, C17H15N3O5S, the nitro and thioureido groups are twisted by 7.2 (7) and 21.4 (2)°, respectively, from the nitrobenzene ring plane whereas the thioureido and the ethyl ester group make dihedral angles of 43.0 (1) and 18.0 (2)°, respectively, with the benzene rings to which they are attached. Intramolecular N—H⋯O hydrogen-bonding interactions are observed. In the crystal, intermolecular N—H⋯O hydrogen bonds connect the molecules into chains running along the a axis.