Synthesis and Antimicrobial Screening of Some Novel 2‐(5‐(4‐(1H‐Benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols Incorporated by Triazole Moiety

A novel series of 2‐(5‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols derivative has been synthesized from (E)‐3‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐ones in ethanol and hydrazine hydrate under reflux condition. The synthesized compounds were screened for antibacterial activity against Gram‐positive bacteria viz Staphylococcus aureus and Bacillus subtilis and Gram‐negative bacteria viz Escherichia coli and Salmonella typhi, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, ¹H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.     

Simple and Efficient Synthesis of 5-Substituted-3-phenyl-2-thioxoimidazolidin-4-one Derivatives from S-Amino Acids and Phenylisothiocyanate in Et3N/DMF-H2O

A concise approach for the transformation of various S-amino acids into the 5-alkyl-3-phenyl-2-thioxoimidazolidin-4-one heterocycles using phenylisothiocyanate is described. Phenylthiohydantoins of amino acid were synthesized at room temperature in Et₃N/DMF-H₂O with easy workup and excellent yields.     

Meet the Board of ChemistryOpen: Sheshanath V. Bhosale

Sheshanath V. Bhosale received his PhD from Freie University Berlin (Germany) in supramolecular chemistry under the supervision of Prof. J. H. Fuhrhop in 2004. He then pursued his postdoctoral studies with Prof. S. Matile at University of Geneva (Switzerland) under the auspices of a Roche Foundation Fellowship. This was followed by a stay at Monash University (Australia) for 5 years as an ARC-APD Fellow. He worked at RMIT University, Melbourne (Australia) for 6 years as ARC-Future Fellowship. Currently, Prof. Bhosale is working at the Department of Chemistry, Goa University (India) as a UGC-FRP Professor, His research interests lie in the design and synthesis of π-functional materials, especially small molecules, for sensing, biomaterials, and supramolecular chemistry applications. So far, Prof. Bhosale has produced 185 research articles and his work has been cited more than 4400 times, giving him an h-index of 32. He currently serves as an active Editorial Board member for ChemistryOpen.     

Synthesis,Characterization, and Thermal and Antibacterial Studies of Diorganotin(Iv) Derivatives of Amino Acids

Abstract

Six diorganotin(IV) derivatives of α-aminoacids with general formulae [(CH₃)₂ SnAACl]₂ and [(CH₃CH₂CH₂CH₂)₂SnAACl]₂, where AA = L-alaninate, L-phenylalaninate, and L-isoleucinate, have been synthesized by reacting dimethyltin(IV) dichloride (M) and dibutyltin(IV) dichloride (B) with L-alanine (A) or L-phenylalanine (PA) or L-isoleucine (I) using acetonitrile as the solvent and designated as MA, MPA, MI, BA, BPA, and BI. These complexes have been characterized by elemental analysis, infrared (IR), ¹H NMR, ¹³C NMR, and ¹¹⁹Sn NMR spectroscopy. Thermal studies of all of the synthesized complexes were also carried out using thermogravimetric (TG) and differential scanning calorimetry (DSC) techniques. The thermal decomposition mechanisms were similar for MA, BA, MI, and BI and occurred in one step, while in compounds MPA and BPA, it occurred in two consecutive steps. The TG curves of MPA and BPA suggest the loss of the ligand (AA) in the first step, with probable formation of a tin oxide R₂SnO as an intermediate, and in the second step, free tin is obtained, similar to MA, BA, MI, and BI, in accordance with the stoichiometry of the related derivatives. The diorganotin(IV) complexes have also been screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa. The minimum inhibitory concentration values of these complexes show enhanced activity.     

TFA-catalysed tandem double cyclisation: A one-pot,metal-free routes for novel indolo-imidazo[1,2-a]pyridine derivatives

A transition-metal free, one-pot tandem synthetic routes for novel indole and imidazo[1,2-a]pyridine derivative hybrids have been established. An efficient three-component reaction was designed with incorporation of two sequential Groebke–Blackburn–Bienayme (GBB) and cyclization reaction in one-pot under mild acidic condition. The salient feature of this protocol is atom economy, good yield and operational simplicity. A molecular prospective library of 32 compounds was synthesized by utilizing the various substituted aryl aldehydes and 2-aminopyridine.     

Chalcogen Bond Mediated Enhancement of Cooperative Ion‐Pair Recognition

A series of heteroditopic receptors containing halogen bond (XB) and unprecedented chalcogen bond (ChB) donors integrated into a 3,5‐bis‐triazole pyridine structure covalently linked to benzo‐15‐crown‐5 ether motifs exhibit remarkable cooperative recognition of halide anions. Multi‐nuclear ¹H, ¹³C, ¹²⁵Te and ¹⁹F NMR, ion pair binding investigations reveal sodium cation–benzo‐crown ether binding dramatically enhances the recognition of bromide and iodide halide anions, with the chalcogen bonding heteroditopic receptor notably displaying the largest enhancement of halide binding strength of over two hundred‐fold, in comparison to the halogen bonding and hydrogen bonding heteroditopic receptor analogues. DFT calculations suggest crown ether sodium cation complexation induces a polarisation of the sigma hole of ChB and XB heteroditopic receptor donors as a significant contribution to the origin of the unique cooperativity exhibited by these systems.     

Synthesis,characterization, and hyperpolarizability measurements of main‐chain azobenzene molecules

A series of new AB type azobenzene monomers based on various substituted phenols and higher order fused/extended aromatic rings were synthesized and their hyperpolarizability tensor β determined by hyper‐Rayleigh scattering (HRS) measurement in methanol. The electron donor (? OH) and acceptor units (? COOH) were kept constant in the series, but the effective conjugation length was varied by varying the number and position of substituents as well as the number of aromatic rings. The effect of substitution of the phenolic ring on the β value was investigated and it was found to range from 15 × 10^?30 to 42 × 10^?30 esu. The effect of intramolecular hydrogen bonding on the nonlinear optical (NLO) property was also examined. The nonlinearity was in the following order of phenol derivative: α‐naphthol > phenyl phenol > 2,6‐dimethyl phenol > o‐cresol > cardanol > phenol > β‐naphthol. The unusually low values for the β‐naphthol‐based chromophore compared with its isomer (α‐naphthol) could be rationalized based on hydrogen bonding of the o‐hydroxyl group with the β nitrogen of the azo bridge. These azobenzene NLO chromophoric monomers were polymerized to form main‐chain polymers with a head to tail structure. The polymers had high thermal stability and rather low solubility in common organic solvents. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4455–4468, 2005     

一步法2-氨基-1-苯乙酮盐酸盐、醛和巯基乙酸三组分反应高效合成噻唑烷酮

采用一步法在二异丙基乙胺存在下由2-氨基-1-苯乙酮盐酸盐、芳香醛和巯基乙酸三组分反应高效合成了噻唑烷酮。该反应显示出很好的化学选择性。首先2-氨基-1-苯乙酮的N原子与芳香醛选择性反应生成席夫碱,然后巯基乙酸的S原子亲核进攻席夫碱的C原子,最后N原子与羧酸基团环加成生成噻唑烷酮。合成的化合物用光谱技术进行了表征。     

A New Isolate from Fusarium proliferatum (AUF-2) for Efficient Nitrilase Production

A fungal isolate from Fusarium proliferatum strain AUF-2 has been found to have a high nitrilase activity (≥1,000 U/l culture). The present work describes optimization of growth conditions and production medium to achieve maximum nitrilase production. The most effective carbon and nitrogen sources for nitrilase production were glucose and sodium nitrate, respectively. ε-Caprolactam was found to be the best inducer for maximum nitrilase production with 80 g/l wet cell biomass and 26 U/g nitrilase activity. An overall nitrilase activity of ≥2,000 U/l culture was obtained in this study, which is one of the best activities reported so far in any Fusarium strain. Chemo-profiling has shown that the strain is versatile in its ability to hydrolyze both aliphatic as well as aromatic nitriles. Efforts are being made to use the strain for biotransformation of pharmaceutical substrates.     

Synthesis of a 1,3,5-benzotriazepine-2,4-dione based library

A library of benzotriazepines have been synthesised employing microwave-mediated synthesis, supported resins and parallel synthesis methodology.