an efficient and environmentally friendly procedure for one-pot synthesis of 13-acetyl-9-methyl-11-ox-8-oxa-10,12-diazatricyclo [7.3.1. ] trideca-2,4,6-triene from salicylaldehyde, acetylaceton and urea via biginelli condensation and intramolecular michael-addition by using magnesium bromide as an expensive and easily available catalyst under solvent-free condition is desired. the structural el...

Objectives: The emergence of carbapenem resistance in biofilm producer Gram-negative bacteria poses a substantial challenge to manage infections. This study aimed evaluate production and molecular characterization rods. Methods: Total 46 were isolated from various clinical samples, including blood, CSF, urine, sputum, saliva, tracheal secretion, pus. Following the standard guidelines for bacter...

Carbapenemase production is an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates. This study aimed to report the detection of bla(OXA-58) gene in multiresistant clinical isolates of Acinetobacter baumannii recovered from inpatients in a public hospital. Polymerase chain reaction tests were performed to detect the bla(OXA-23-like), bla(OXA-24-like), bla(OX...

An enantioselective oxa-Michael addition of oximes to β-CF3-β-disubstituted nitroalkenes catalyzed by a chiral bifunctional cinchona alkaloid-based thiourea has been developed. A variety of trifluoromethylated oxime ethers possessing a tetrasubstituted carbon stereocenter were obtained in good yields with high enantioselectivities.

Tetrahydroxanthenones, which can be easily prepared by a domino oxa-Michael aldol condensation, offer various possibilities for diastereoselective functionalization, giving access to the stereocontrolled synthesis of stereochemical triades or tetrades, which represent privileged structural motifs. In most cases, the relative stereochemistry was unequivocally established by crystal structure ana...

The first enantioselective total syntheses of virosaine A and bubbialidine are described. Key transformations include the formation of a tetracyclic intermediate via an intramolecular aza-Michael addition, generation of a N-hydroxy-pyrrolidine through a Cope elimination and an intramolecular [1,3]-dipolar cycloaddition to generate a complex 7-oxa-1-azabicyclo[3.2.1]octane ring system.

An organocatalytic Michael-cyclization cascade of aldehydes with 4-oxa-α,β-unsaturated carboxylic acids has been developed, giving functionalized γ-lactols with high yields and enantioselectivities. The products could be easily transformed into complex trisubstituted γ-lactones and γ-lactams.