Muhammad Naeem Ahmed

Synthesis, crystal structure, anti-HIV, and antiproliferative activity of new pyrazolylthiazole derivatives

The development of new HIV-1 non-nucleoside reverse transcriptase inhibitors offers the possibility of generating novel structures of increased potency. Based on the bioisosteric principle, new series of N′-benzylidene-2-(5-(4-chlorophenyl)-3-phenyl-4,5-dihydropyrazol-1-yl)thiazole-4-carbohydrazide schiff bases 5a–x containing 1,3-thiazole clubbed with 2-pyrazoline was synthesized and characterized by spectroscopic techniques. The structure of the synthesized compounds was unambiguously confirmed by single-crystal X-ray diffraction analysis of compound 5k. All the new analogs were evaluated in vitro for antiviral activity against the replication of HIV-1 and HIV-2 in MT4 cells using MTT assay. The results showed that only compounds 5n, and 5r possess potent activity against HIV-1 replication (IC50 = 0.50, 0.45 μM, SI = 3 and 5), respectively. None of the compounds are active against HIV-2. Furthermore, compounds 5a, 5i, 5n, and 5r were evaluated for their antiproliferative activity against two solid tumor-derived cell lines consisting MCF-7 (breast cancer) and Hep-G2 (human hepatocarcinoma).

Thiamine-functionalized silver nanoparticles for the highly selective and sensitive colorimetric detection of Hg2+ ions

Hg2+ contamination is a serious threat to the environment; hence, the development of methods for its trace level detection is urgently required. To contribute in this domain, we report for the first time the application of a highly sensitive and selective colorimetric sensing platform for Hg2+ ions using thiamine-functionalized silver nanoparticles (Th-AgNPs). Upon the addition of Hg2+ ions to the solution, the AgNPs exhibited a noticeable color change from yellow to violet-blue. This color change was monitored by the UV-vis spectrophotometric observation of a significant decrease in the absorption band at 395 nm along with the appearance of a new peak at 550 nm. The designed sensor demonstrated good sensitivity in the concentration range of 1 × 10−8 to 5 × 10−6 M with a detection limit of 5 nM. The sensor also showed high selectivity for Hg2+ when tested in the presence of several competing metal ions. Moreover, the method was found to be applicable to river water samples with satisfactory percentage recoveries.

Ethyl 2-[1-(3-methyl-but-yl)-4-phenyl-1H-1,2,3-triazol-5-yl]-2-oxo-acetate.

In the title compound, C17H21N3O3, the non-planar (r.m.s. deviation = 0.212 Å) ethyl (oxo)acetate group is oriented towards the phenyl substituent. The triazole and benzene rings are twisted with respect to each other, making a dihedral angle of 41.69 (6)°. In the crystal, molecules are arranged into centrosymmetric R 2 2(10) dimers via pairs of C—H⋯O interactions involving the ethyl (oxo)acetate groups. In addition, the triazole rings show π–π stacking interactions, with their centroids at a distance of 3.745 (2) Å.

Crystal structure of 4-(3-carb-oxy-pro-pan-amido)-2-hy-droxy-benzoic acid mono-hydrate.

In the title hydrate, C11H11NO6·H2O, the organic molecule is approximately planar (r.m.s. deviation for the non-H atoms = 0.129 Å) and an intramolecular O—H⋯O hydrogen bond closes an S(6) ring. In the crystal, the benzoic acid group participates in an O—H⋯O hydrogen bond to the water molecule and accepts a similar bond from another water molecule. The other –CO2H group forms a carboxylic acid inversion dimer, thereby forming an R 2 2(8) loop. These bonds, along with N—H⋯O and C—H⋯O interactions, generate a three-dimensional network.

Ethyl 6-(4-cyclo­propyl-1H-1,2,3-triazol-1-yl)pyridine-3-carboxyl­ate

In the title compound, C13H14N4O2, which has approximate mirror symmetry, the dihedral angles between the triazole ring and the cyclopropane and pyridine rings are 87.1 (2) and 7.60 (9)°, respectively. In the crystal, inversion dimers linked by pairs of both C—H⋯N and C—H⋯O interactions generate R 2 2(6) and R 2 2(18) loops, respectively. Further C—H⋯N interactions form R 2 2(10) loops and link the dimers into [110] chains.