An Unusual Observation in the Synthesis of Thiozoles

Dibromoacetyl benzene derivatives on condensation with thiourea give 2-amino-4-arylthiazoles instead of the expected 2-amino-4-aryl-5-bromothiazoles. Attempts have been made to find the reaction pathway.     

Identification of Druggable Targets for Acinetobacter baumannii Via Subtractive Genomics and Plausible Inhibitors for MurA and MurB

Emergence of the multidrug-resistant pathogens has rendered the current therapies ineffective thereby, resulting in the need for new drugs and drug targets. The accumulating protein sequence data has initiated a drift from classical drug discovery protocols to structure-based drug designing. In the present study, in silico subtractive genomics approach was implemented to find a set of potential drug targets present in an opportunist bacterial pathogen, Acinetobacter baumannii (A. baumannii). Out of the 43 targets identified, further studies for protein model building and lead-inhibitor identification were carried out on two cell-essential targets, MurA and MurB enzymes (of A. baumannii designated as MurA_Ab and MurB_Ab) involved in the peptidoglycan biosynthesis pathway of bacteria. The homology model built for each of them was further refined and validated using various available programs like PROCHECK, Errat, ProSA energy plots, etc. Compounds showing activity against MurA and MurB enzymes of other organisms were collected from the literature and were docked into the active site of MurA_Ab and MurB_Ab enzymes. Three inhibitors namely, T6361, carbidopa, and aesculin, showed maximum Glide score, hydrogen bonding interactions with the key amino acid residues of both the enzymes and acceptable ADME properties. Furthermore, molecular dynamics simulation studies on MurA_Ab–T6361 and MurB_Ab–T6361 complexes suggested that the ligand has a high binding affinity with both the enzymes and the hydrogen bonding with the key residues were stable in the dynamic condition also. Therefore, these ligands have been propsed as dual inhibitors and promising lead compounds for the drug design against MurA_Ab and MurB_Ab enzymes.     

Stereo structure of norkhusinoloxide,a new ntipodal C14 terpenoid from vetiver oil. Confirmation of stereostructural features by biological evaluation,a new tool for prediction of stereostructure in cadinanes

From the alcoholic fraction of North Indian vetiver oil ($\text{Vetiveria}$$\text{zizanioides}$) a new C₁₄ terpenoid, norkhusinoloxide has been isolated. Stereostructure has been assigned to it on the basis of chemical correlation coupled with spectral data. This stereostructure was further confirmed on the basis of the comparison of its plant growth activity with that displayed by khusinol oxide of known stereostructure. It is the first report where biological evaluation has been used as a tool to confirmstereo structure of a naturally occurring terpenoid.     

High spin states in 121Te

High spin states of ¹²¹Te, populated in the ¹¹⁴Cd (¹¹B, p3n) reaction, have been studied through γ-ray spectroscopy. The level scheme has been established up to J^π = 51/2^?. Three-quasiparticle states, based on the ^πg _7/2 ² ? vh_11/2 and πg _7/2d_5/2 ? vh_11/2 configurations, have been identified. A favoured 39/2^? state is suggested to be the fully aligned [πg_7/2 ²]6 + ? [vh _11/2 ³]_27/2? yrast non-collective oblate configuration. This assignment is supported by Total Routhian Surface (TRS) calculations which also suggest a similar oblate assignment to the states at J^π = 21/2^? and 23/2^?. A higher 47/2^? state is also found and is suggested to be the fully aligned [πg_7/2 ²]₆+ ? [vh _11/2 ⁵]_35/2? configuration.     

Application of the sum peak method to study perturbed angular correlation parameters as a function of pH value and gelatin concentration in the decay of160Dy

The - sum peak method based on the phenomenon of perturbed angular correlation has been applied to see the effect of chemical environment on the directional correlation coefficients of various cascades and to check the suitability of¹⁶⁰Tb as a probe. No change in sum peak intensity ratios for different pH and gelatin concentration values have been seen.     

On the estimation of ordered means of two exponential populations

Let random samples of equal sizes be drawn from two exponential distributions with ordered means _i . The maximum likelihood estimator _i ^* of _i is shown to have a smaller mean square error than that of the usual estimator X_i, for each i=1,2. The asymptotic efficiency of _i ^* relative to X_i has also been found.     

pH-Dependent self-assembly of water-soluble sulfonate-tetraphenylethylene with aggregation-induced emission

The fabrication of well-defined nanostructures with luminescent properties in the solid or aggregated state is of intense interest due to their applications in nano- and biotechnology. We report the synthesis of water-soluble tetraphenylethylene bearing four sulfonate groups as a sodium salt (Su-TPE), and investigations concerning its AIE characteristics by the addition of organic solvent into the aqueous solution, which is the reverse procedure to conventional AIE-active TPE derivatives. The resultant compound is weakly emissive in pure water, however, emits strongly upon addition of THF solvent (with THF fraction > 60%). The emission properties and the morphologies of the aggregates were greatly dependent upon the solution pH. Su-TPE self-assembled into variety of structures in water/THF mixture with pH control, for the first time. Well-defined uniform nanorods with a width of about 200 nm and a length of up to 10 μm were obtained at solution pH of 1. The Su-TPE showed very good mechanochromic properties were observed during the process of grounding and fuming.     

Photochemical mediated reactions in five-membered O-heterocycles synthesis

Photochemical mediated synthesis in organic chemistry is a highly expanding area. This is a widely exploited area of research for the construction of new pharmaceutically significant heterocycles. Recently many reports appeared for the synthesis of heterocycles photochemically due to a wide range of biological activities associated with them. In this article, I have described the synthesis of a number of oxygen-bearing five-membered heterocycles.