Trifluoromethylated organic compounds, especially chiral quaternary alcohols bearing trifluoromethyl group are of important intermediates in drugs, agrochemicals and etc.An efficient epoxidation of β-CF3-β,β-disubstituted unsaturated ketones (6) has been developed with environmental benign hydrogen peroxide as the oxidant and F5-substituted chiral qua...

an efficient, one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. in this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,wit...

ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g* for a single point total energy calculation are reported for the importantenergy-minimum conformations and transition-state geometries of 1, 3-diazacyclohepta-1, 2-diene (2) and 1, 3-diazacycloocta-1, 2-diene (3). the c2 symmetric twist-chair (2-tc)conformation of 2 is calculated to be 7.4 kj...

A new chromatographic procedure was proposed for the separation of propranolol (PRN) enantiomers based upon enantioselective chiral ligand-exchange chromatography. The separation was carried out on a short C8 column leading to considerably short separation time. L-alanine and Cu2+ were applied as chiral selector and central bivalent complexing ion, respectively. It was found that the kind of co...

An efficient, one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,wit...

Herein is reported the first asymmetric utilization of aryldiazonium cations as a source of electrophilic nitrogen. This is achieved through a chiral anion phase-transfer pyrroloindolinization reaction that forms C3-diazenated pyrroloindolines from simple tryptamines and aryldiazonium tetrafluoroborates. The title compounds are obtained in up to 99% yield and 96% ee. The air- and water-tolerant...

The title compound, C(24)H(29)N(3)O(5)S, is a chiral mol-ecule which crystallizes in a centrosymmetric space group as a racemate. The thia-zolidine ring forms the dihedral angles of 29.22 (12) and 67.79 (10)° with the benzene and pyridine rings, respectively. The benzene and pyridine rings are tilted by dihedral angle of 67.18 (9)°. In the crystal, inter-molecular C-H⋯O hydrogen bonds link the ...

The complete proof of a theorem announced in [1] on the consistent interactions for (non-chiral) exterior form gauge fields is given. The theorem can be easily generalized to the analysis of anomalies. Its proof amounts to computing the local BRST cohomology H0(s|d) in the space of local n-forms depending on the fields, the ghosts, the antifields and their derivatives. [email protected], bknae...

Chiral symmetry provides the protection for a large class of topological edge states. It exists in non-Hermitian systems as well, and same anticommutation relation between Hamiltonian linear chiral operator, i.e., ${H,\mathrm{\ensuremath{\Pi}}}=0$, now warrants symmetric spectrum about origin complex energy plane. Utilizing two general approaches to identify generate symmetry, we first show tha...

We study the free energy of the pure glue QCD string with a torus target space and the gauge groups SU(N) and (chiral) U(N). It is highly constrained by a strong/weak gauge coupling duality which results in modular covariance. The string free energy is computed exactly in terms of modular forms for worldsheet genera 1 8. It has a surprisingly mild singularity in the weak gauge coupling/small ar...