Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentameth...

The configurational and conformational behavior of some new 3,3,9,9-tetrasubstituted-2,4,8,10-tetraoxaspiro[5.5]undecane derivatives with axial chirality was investigated by conformational analysis and variable temperature NMR experiments.

Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(η(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric re...

Mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1), obtained from the reaction of N-acyl-N-alkylglycines (2) with trifluoroacetic anhydride, react with amidines to give 5-trifluoroacetylimidazoles (3) in moderate yield. The novel ring transformations of 1 into 3 occur via an initial attack of amidines on the C-2 position of the ring.

The kinetics of the reactions of some imidazoles, benzimidazoles and benzotriazoles with benzhydrylium ions (diarylcarbenium ions) have been studied photometrically in DMSO, acetonitrile, and aqueous solution at 20 degrees C. The resulting second-order rate constants have been used to determine the nucleophile-specific parameters N and s of these azoles according to the linear-free-energy relat...

A new class of 4H-imidazoles was synthesized starting from fused-ring aromatic dinitriles. Strong bathochromic shifts of the longest wavelength absorptions were observed in the corresponding UV/vis spectra due to a conversion of the merocyanine chromophores into cyanines/(aza)oxonoles upon protonation/deprotonation of the 4H-imidazoles. Novel boratetraazapentalenes were synthesized via a cycliz...

This paper reports the synthesis of nitrogen containing heterocyclic compounds such as quinoxalines (5-7), imidazoles (8, 9,10,11), aminothiazole (12), aminooxazole (13), aminoimidazole (14) and benzothiazine (17) from the reaction with unsymmetrical diketone 4, 3 and 4a respectively. The aforementioned compounds with 4-pyridyl,4fluorophenyl groups have different positions in their ring skeleto...

A series of 1-(2-methyl-4-nitro-imidazol-1-yl)-3-arylaminopropan-2-ones (2a-e), 2-methyl-5-nitro-1-{2-[arylmethoxy]ethyl}-1H-imidazoles (5a-d), and N-(3-hydroxyphenyl)-2-(substituted imidazol-1-yl)alkanamides (8a-e) were synthesized with the aim to develop novel imidazole analogs with broad-spectrum chemotherapeutic properties. Title compounds were evaluated for their anti-HIV and antibacterial...

Room temperature zinc-mediated diastereoselective allylation or propargylation of isatin-derived N-tert-butanesulfinyl ketimines for synthesis of highly enantiomerically enriched tetrasubstituted 3-aminooxindoles is described.