Pyrido- and pyrrolo[2,3-d]oxazoles can be conveniently prepared in high yield from the Ritter reaction of nitriles and in situ generated chiral cyclic N-acyliminium ions. cis-4-Hydroxy-5-acylaminopyrrolidines and cis-5-hydroxy-6-acylaminopiperidines can be readily obtained by acid hydrolysis of these bicyclic heterocyclic compounds, respectively.

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.

a new series of thiazolidinedione derivatives were synthesized. the structures of these compounds were established by means of ir, 1h-nmr and elemental analysis. all of the compounds were screened for antidiabetic activity on albino rats. most of the compounds showed significant antidiabetic activity when compared with the standard drug glibenclamide.

some n¬-acyl-n'-aryl thiourea derivatives 4(a-f) have been prepared by the reaction of acyl halides ammonium thiocyanate and aryl amines. the structures of synthesized compounds have been characterized by ir, 1hnmr spectral studies. the synthesized compounds 5(a-f) have been screened for antibacterial activity. the effect of the structure of the investigated compounds on the antibacterial activ...

This paper presents a discussion of fundamental problems of the speciation analytics of organometallic compounds occurring at low concentration levels in samples involving a complex matrix. It points out differences in analytical procedures for speciation analyses and those for determinations of total contents of a metal present in the studied sample in a number of different species.

In the original publication of the article, a part of Scheme 12 was missed. The correct version of Scheme 12 was provided in this correction article. The original article has also been corrected. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, ...

Quaternary ammonium compounds, effective as sanitizing agents for food plant equipment under certain conditions, are not well suited as sanitizers for water of high mineral content. Mueller and Seeley (1951) have demonstrated under controlled conditions that various metallic cations can decrease the germicidal action of a quaternary in solution. Knowledge of how such interference takes place co...