Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.

Potentiometric pKa and polarographic behaviour of I ,3-indandione-monoxime-2-phenyl azo and four of its substituted derivatives were investigated in buffer solution of pH -2-12. The results showed that the compounds are in the azo-form, where its reduction wave precedes that of the oxime. A mechanism for the electrodic processes was proposed. Half-wave potentials showed fair correlation with Ha...

The partitioning of space with Hirshfeld surfaces enables the analysis of fingerprint molecular interactions in crystalline environments. This study uses the decomposition of the crystal contact surface between pairs of interacting chemical species to derive an enrichment ratio. This quantity enables the analysis of the propensity of chemical species to form intermolecular interactions with the...

Heterocyclic nitrogen compounds are extensively used as intermediates in the manufacture of pesticides and herbicides, while their toxicity has been little reported (Chen et al, 1997). In this paper, we report the toxicity of 14 heterocyclic nitrogen compounds to Photobacterium phosphoreum measured by Microtox® test which has been proposed as a cost-effective prescreening procedure to eliminate...

In this study, the flavor substances of soypaste were extracted by a simultaneous distillation method and identified by GC-MS. The characteristic aroma components of soypaste were determined by the GC-O technique and the FD value of the characteristic aroma components was determined by AEDA method. It could be inferred that the aroma of the soypaste should be attributed to the presence of heter...

A large variety of unique heterocyclic natural marine products, without terrestrial counterparts, have been isolated from marine invertebrates, mainly sponges, ascidians, and soft corals. Many of these compounds display interesting biological activity. In this review, we report our recent studies on nitrogen-containing heterocyclic compounds (“alkaloids”), as well as some containing sulfur and ...

using the density functional theory (dft) level by means of 3-21g, 6-31g and 6-31+g (d) basissets, the structural optimization of isolated pyrazole and pyrazoline was done in the gas phase. then,the calculation about the solvent effect on the stability energies of pyrazole and pyrazoline wasperformed for the ten solvents using pcm model method at b3lyp/6-31+g(d) and then the dielectriceffects o...