Bicyclic molecule

About: Bicyclic molecule is a research topic. Over the lifetime, 29587 publications have been published within this topic receiving 451252 citations. The topic is also known as: bicyclic molecule.

Phosphine-catalyzed intramolecular formal [3+2] cycloaddition for highly diastereoselective synthesis of bicyclo[n.3.0] compounds.

Abstract: Ylides have been widely applied in constructing small-ring compounds such as epoxides, cyclopropanes, and aziridines. Recently, several ylide cyclizations that go beyond the formation of three-membered rings have also been developed. Lu and co-workers demonstrated in a number of elegant studies that phosphines are good catalysts for the construction of cyclopentenes. Krische and co-workers developed the first intramolecular variant of the cycloaddition. Catalytic asymmetric [3+2] cycloadditions have been reported by both Zhang and Fu, with their respective coworkers. Recently, Aggarwal and co-workers documented an elegant protocol for the asymmetric synthesis of epoxideand aziridine-fused heterocycles through a sulfur ylide route. In a previous study on ylide chemistry, we reported a tandem ylide Michael addition–elimination–substitution reaction for the controllable synthesis of 2H-chromenes 2a and 4H-chromenes 2a’ (Scheme 1). To further extend the reaction scope, 3a was synthesized and subjected to the reaction. However, the desired compound 4a’was obtained in only 15% yield under the same conditions. To improve the yield, other potential catalysts such as PPh3 and 1,4diazabicyclo[2.2.2]octane (DABCO) were tested instead of THT. When triphenylphosphine was used, the bicyclic compound 4a was, unexpectedly, isolated as the sole product in 30% yield with excellent diastereoselectivity (Scheme 1). Herein, we wish to report the preliminary results of this cyclization. Further studies showed that the desired product was not observed in the absence of PPh3. In the presence of PPh3 (20 mol%) with Na2CO3 as a base, bromide 3b afforded the corresponding benzobicyclo[4.3.0] compounds (4b/4b’) in 95% yield with excellent diastereoselectivity (entry 1, Table 1). To study the generality of the current reaction,

Preparation and antibacterial activities of new 1,2,3-diazaborine derivatives and analogues.

Abstract: 1,2-Dihydro-1-hydroxy-2-(organosulfonyl)areno[d] [1,2,3]diazaborines 2 (arene = benzene, naphthalene, thiophene, furan, pyrrole) were synthesized by reaction of (organosulfonyl)hydrazones of arene aldehydes or ketones with tribromoborane in the presence of ferric chloride. The activities of 2 against bacteria in vitro and in vivo (Escherichia coli) were determined and structure-activity relationships are discussed. Included in this study are 2,3-dihydro-1-hydroxy-2-(p-tolylsulfonyl)-1H-2,1-benzazaborole+ ++ (3) and 1-hydroxy-1,2,3,4-tetrahydro-2-(p-tolylsulfonyl)-2,1-benzazabor ine (4) as well as the carbacyclic benzodiazaborine analogue 4-hydroxy-3-(p-tolylsulfonyl)isoquinoline (7). The nature of the active species is briefly discussed.

Synthesis and characterization of the "chiral wall" porphyrin: a chemically robust ligand for metal-catalyzed asymmetric epoxidations

Abstract: Preparation d'une porphyrine substituee par le binaphtalene et complexation avec Mn(III). Etude des proprietes catalytiques du complexe au cours de l'epoxydation d'alcenes

Bicyclic Boronate VNRX-5133 Inhibits Metallo- and Serine-β-Lactamases.

Abstract: The bicyclic boronate VNRX-5133 (taniborbactam) is a new type of β-lactamase inhibitor in clinical development. We report that VNRX-5133 inhibits serine-β-lactamases (SBLs) and some clinically important metallo-β-lactamases (MBLs), including NDM-1 and VIM-1/2. VNRX-5133 activity against IMP-1 and tested B2/B3 MBLs was lower/not observed. Crystallography reveals how VNRX-5133 binds to the class D SBL OXA-10 and MBL NDM-1. The crystallographic results highlight the ability of bicyclic boronates to inhibit SBLs and MBLs via binding of a tetrahedral (sp3) boron species. The structures imply conserved binding of the bicyclic core with SBLs/MBLs. With NDM-1, by crystallography, we observed an unanticipated VNRX-5133 binding mode involving cyclization of its acylamino oxygen onto the boron of the bicyclic core. Different side-chain binding modes for bicyclic boronates for SBLs and MBLs imply scope for side-chain optimization. The results further support the "high-energy-intermediate" analogue approach for broad-spectrum β-lactamase inhibitor development and highlight the ability of boron inhibitors to interchange between different hybridization states/binding modes.