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This study contains synthesis, antimicrobial activity, density functional modelling and molecular docking studies of benzoxazole derivative: 2-(p-chloro-benzyl)-5-[3-(4-ethly-1-piperazynl) propionamido]-benzoxazole. The synthetic procedure of investigated compound is given in detail. The newly synthesized benzoxazole compound and standard drugs were evaluated for their antimicrobial activity against some Gram-positive, Gram-negative bacteria and fungus C. albicans and their drug-resistant isolates. The benzoxazole compound has been characterized by using 1H-NMR, IR and MASS spectrometry and elemental analysis techniques. The molecular structure of the compound in the ground state has been modelling using density functional theory (DFT) with B3LYP/6-311++g(d,p) level. The molecular docking of 2-(p-chloro-benzyl)-5-[3-(4-ethly-1-piperazynl) propionamido]-benzoxazole with COVID-19 main protease has been also performed by using optimized geometry and the experimentally determined dimensional structure of the main protease (M-pro) of COVID-19., Graphical abstract Image, graphical abstract

© 2020 Taylor & Francis Group, LLC.In this study, p-tert-butyl at position 2 and acetamide bridged 4-substituted piperazine/piperidine at position 5 bearing benzoxazole derivatives were evaluated for their in vitro inhibitory activity against AChE, BChE and Tyrosinase, which are important targets in reducing the adverse effects of Alzheimer’s disease. The most active 1 g inhibited the BChE at a concentration of 50 µM by 54 ± 0.75%. Molecular docking studies of the compounds against BChE (PDB: 4BDS) were performed with Schrödinger and AutoDock Vina and the results were compared. Schrödinger docking scores were found to be more consistent. Estimated ADME profiles and bioactivity scores of the compounds were calculated and found to be compatible with Lipinski and other limiting rules. Geometric optimization parameters, MEP analysis and HUMO and LUMO quantum parameters of the most active 1 g were calculated by using DFT/B3LYP theory and 6-311 G (d,p) base set and results was viewed.

Unver, Huseyin/0000-0003-3968-4385; Polat, Kamran/0000-0001-7617-2480 WOS: 000347495400004 Synthesis, crystal structure, Fourier transform infrared spectroscopy (FT-IR) and quantum mechanical studies of the 2-(4-bromobenzyl)-5-ethylsulphonyl-1,3-benzoxazole (C16H14NO3SBr) have been reported. The molecular structure obtained from X-ray single-crystal analysis of the investigated compound in the ground state has been compared using Hartree-Fock (HF) and density functional theory (DFT) with the functional B3LYP and B1B95 using the 6-311++G(d,p) basis set. In addition to the optimized geometrical structures, atomic charges, molecular electrostatic potential (MEP), natural bond orbital (NBO), nonlinear optical (NLO) effects and thermodynamic properties of the compound have been investigated by using DFT. The potential energy surface (PES) scans about four important torsion angles are performed by using B3LYP/6-311++G(d,p) level of theoretical approximation for the compound. The experimental (FT-IR) and calculated vibrational frequencies (using DFT) of the title compound have been compared. The total molecular dipole moment (mu), linear polarisability (alpha), and the first-order hyperpolarisability (beta) were predicted by using DFT with different basis sets 6-31G(d), 6-31+G(d,p), 6-31++G(d,p), 6-311+G(d) and 6-311++G(d,p) for investigating the effects of basis sets on the NLO properties. Our computational results yield that beta(tot) for the title compound is greater than those of urea. The standard thermodynamic functions were obtained for the title compound with the temperature ranging from 200 to 450 K. (C) 2014 Elsevier B.V. All rights reserved.

A series of 2-( p -substituted-phenyl)-5-substitued-carbonylamino benzoxazole derivatives ( 5 – 22 ) was synthesized and their antimicrobial activities determined in comparison to several control drugs. The synthesized compounds were tested in vitro against Staphylococcus aureus , Streptococcus faecalis and Bacillus subtilis as Gram-positive, Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and the yeast Candida albicans . Microbiological results showed that the compounds possessed a diffuse spectrum of antibacterial activity against these microorganisms. Compound 9 which bears a phenylacetamido moiety at position 5 and a 4-fluorophenyl group at the 2-position of benzoxazole ring was the most active derivative against S. aureus , S. faecalis and P. aeruginosa with a MIC value of 12.5 μg/ml. Compound 11 provided higher potency than the other tested compounds against B. subtilis at a MIC value of 12.5 μg/ml. Compounds 5 – 22 showed antifungal activity against C. albicans with MIC values between 50 and 12.5 μg/ml.

The synthesis of some N -( o -hydroxyphenyl)benzamides and benzacetamides ( 2a – 2p ) in order to determine their in vitro antimicrobial activity against two Gram-positive bacteria, three Gram-negative bacteria and the fungus Candida albicans is described. The new compounds were compared with several control drugs. The derivative 2g , 4-amino- N -( o -hydroxyphenyl)benzamide, was found active at an MIC value of 25 μg/ml against the Gram-negative microorganism Klebsiella pneumoniae . Most of the compounds exhibited antibacterial activity at an MIC value of 25 μg/ml against Pseudomonas aureginosa. For the antifungal activity against C. albicans , compounds 2e , 2h and 2m were found more active than the other derivatives (MIC 12.5 μg/ml). The antimicrobial activity of some of these benzamide and phenylacetamide derivatives ( 2a , 2b , 2f , 2g , 2h and 2k ), possible metabolites of benzoxazoles, was also compared with that of the cyclic analogues 3 – 8 . Compound 2f possesses two dilutions better antifungal activity than its cyclic analogue the benzoxazole derivative 5 against C. albicans, while having one dilution better antibacterial activity against Streptococcus faecalis and K. pneumoniae .

The synthesis of a new serie s of 2/-1-3 ,4-dihydro- 1 ,4-bcnzoxazin-3-one derivatives 1-8 is accomplished in order to determine their antimicrobial activities and study th eir structure -ac tivit y relati onships (SA R). The sy nthesized compounds have bee n tested in virro against two Gram-positive, three Gram-negative bacteria and the fungu s Candida a/bicans. The in vi rro act ivit y results show that the sy nthesized compounds cxibit MIC va lu es between 50- 12.5 J..lg/mL for th e antimi crob ial activity against the tes ted microorga ni sms. The antibacterial and antifungal act ivities or the co mpounds 1-8 are al so compared to several standard drugs. Virtanen et a/ 1 - 4 have iso lated 2,4-dihydroxy-1 ,4benzoxazin-3-one (DIBOA) as a glycos ide from rye pl ant. Since th en a number of analogous of I ,4benzoxazine have been fo und in nature. Only, limited number of compound s containin g I ,4 -benzoxazin c rin g sys tem have been studi ed for th eir chemotherap euti c actiVIt y. The most interesting observation that ofloxacin molecule posseses th e I ,4benzoxazine rin g system in it s structure 5 · 6 , prompted us to investigate thi s heterocyc li c nuclei to ascertain if it would offer any advantage over the other known clini ca ll y used antimi crobial drugs.

Bu calismada 2-(p-klorofenoksi)metil-5-(p-klorofenoksi)asetamidobenzoksazol, 2,4-diaminofenol ve p-klorofenoksiasetik asitin trimetilsilil polifosfat esteri (PPSE) katalizorlugunde kondensasyonu ile sentez edildi. Yapisi IR, 1H NMR ve mass analiz yontemleri ile aydinlatildi. Bilesigin antimikrobiyal etkisi bazi Gram-pozitif, Gram-negatif bakteri ve Candida albicans ve onlarin antibiyotiklere direncli suslarina karsi belirlenmistir. Bilesigin Minimum Inhibitor Konsantrasyon (MIK) degerleri bazi antibakteriyal ve antifungal ilaclarla mukayese edilmistir