Aza-pyridinoxazoline ligands, a new class of C(1)-symmetric ligands, are described and tested in the heterogeneous enantioselective catalysis of a cyclopropanation reaction, with the aim of improving surface confinement effects by the clay support on the reaction stereoselectivity. In the case of trans/cis diastereoselectivity, these surface effects lead to a systematic reversal of selectivity,...

tin(ii)-ion-selective electrode consisting of dibenzo-18-crown-6 (db18c6) as an ionophore inpvc matrix was developed. the influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. the electrodeshowed a near nernstian response for sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 m with a slope of 27...

A silica-supported copper (Cu/SiO2) catalyst containing highly dispersed Cu nanoparticles was prepared via a crown-ether-assisted impregnation method. 12-crown-4-ether-assisted Cu/SiO2 outperformed several catalysts with various organic additives in the dehydrogenation of 2,3- and 1,4-butanediol. It found that catalytic activity, i.e., formation rate acetoin from 2,3-butanediol γ-butyrolactone ...

The quantitative analysis and identification of the radiolytic products of dicyclohexano-18-crown-6 (DCH18C6), 4',4''(5'')-di-tert-butyldicyclohexano-18-crown-6 (DtBuCH18C6) and benzo-18-crown-6 (B18C6) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C4mim][NTf2]) ionic liquid after irradiation were performed for the first time. It was found that the yield for radiolytic des...

A new chiral Brønsted acid-catalyzed aza-Diels-Alder reaction of cyclic C-acylimines with cyclopentadiene has been developed. The reaction provides optically active aza-tetracycles in good yields with high diastereo- and enantioselectivities under mild reaction conditions.

Special attention has been paid to understanding the structural effect on electronic structure and absorption spectra for an extensive series of functionalized aza-BODIPY molecules. We have employed the quadratic response theory as well as a sum-over-states approach involving few intermediate states to calculate the two-photon cross section (δmax). The results suggest that chemical modification...

Study of interaction between catechol and tetraethylene glycol dichloride in the n-butanol media, resulting with benzo-15-crown-5 production. Production of nitroand amino-derivatives of benzo-15-crown-5. Determination of their thermogravimetric characteristics. keywords: benzo-15-crown-5, catechol, tetraethylene glycol dichloride, crown ether, gas liquid chromatography, chromate-mass spectrometry

The study reports the convenient and efficient synthesis of several new analogues of 3β-substituted amides of 17a-aza-Dhomo-4-androsten-17-one (3a-3e) from commercially available Diosgenin as the starting material. The structures of newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and Mass spectrometry. We herein report the 5αreductase inhibitory, antimicrobial and antioxidant ...

In the title compound, C(29)H(25)NS(2), both the Cl atoms of the aza-diene precursor 4,4-dichloro-1,1-diphenyl-2-aza-buta-1,3-diene are replaced by two vicinal S-p-tolyl substituents attached to the terminal C atom of a π-conjugated 2-aza-butadiene array. The aza-diene chain is planar to within 0.01 Å. One of the phenyl rings seems to be slightly π-conjugated with the aza-diene core [dihedral a...

Significance: This paper describes the palladiumcatalyzed enantioselective aza-Morita–Baylis–Hillman reaction of acrylonitriles with imines. The bulky pincer ligand enabled the synthesis of enantioenriched α-methylene-β-aminonitriles in high yield. Comment: The palladium–pincer complex preferably activates acrylonitrile, even in the presence of ethyl acrylate. The palladium ketenimide is a key ...