Digesta samples from the ovine rumen and pure ruminal bacteria were incubated with linoleic acid (LA) in deuterium oxide-containing buffer to investigate the mechanisms of the formation of conjugated linoleic acids (CLAs). Rumenic acid (RA; cis-9,trans-11-18:2), trans-9,trans-11-18:2, and trans-10,cis-12-18:2 were the major CLA intermediates formed from LA in ruminal digesta, with traces of tra...

Solvolysis of trichloroacetate esters of 2-methoxy-1,2-dihydro-1-naphthols shows a remarkably large difference in rates between the cis and trans isomers, k(cis)/k(trans) = 1800 in aqueous acetonitrile. This mirrors the behaviour of the acid-catalysed dehydration of cis- and trans-naphthalene-1,2-dihydrodiols to form 2-naphthol, for which k(cis)/k(trans) = 440, but contrasts with that for solvo...

Synthesis and X-ray diffraction structures of cis and trans isomers of ruthenium and osmium metal complexes of general formulas (nBu4N)[cis-MCl4(NO)(Hind)], where M = Ru (1) and Os (3), and (nBu4N)[trans-MCl4(NO)(Hind)], where M = Ru (2) and Os (4) and Hind = 1H-indazole are reported. Interconversion between cis and trans isomers at high temperatures (80-130 °C) has been observed and studied by...

cis-Cyclopropane fatty acids (cis-CFAs) are widespread constituents of the seed oils of subtropical plants, membrane components of bacteria and protozoa, and the fats and phospholipids of animals. We describe a systematic approach to the synthesis of enantiomeric pairs of four cis-CFAs: cis-9,10-methylenehexadecanoic acid, lactobacillic acid, dihydromalvalic acid, and dihydrosterculic acid. The...

Amide cis-trans isomerization (CTI) in methyl 2-deoxy-2-acylamido-d-glucopyranosides was investigated by (1)H and (13)C NMR spectroscopy. Singly (13)C-labeled methyl 2-deoxy-2-formamido-d-glucopyranoside (MeGlcNFm) anomers provided standard (1)H and (13)C chemical shifts and (1)H-(1)H and (13)C-(13)C spin-coupling constants for cis and trans amides that are detected readily in aqueous solution....

Context. Observations of the different isomers molecules in interstellar medium (ISM) have revealed that both low- and high-energy can be present space despite low temperature conditions. It has been shown presence these may due to tunneling effects. Aims. We carried out a theoretical study cis–trans isomerization reactions two astrophysically relevant acids, formic acid (HCOOH) thioformic (HC(...

1. An enzyme for the cycloisomerization of 2- and 3-chloro-cis,cis-muconic acid was isolated from 3-chlorobenzoate-grown cells of Pseudomonas sp. B13. It was named muconate cycloisomerase II, because it could it clearly be differentiated by its Km and Vmax. values from an ordinary muconate cycloisomerase, which functioned in benzoate catabolism and exhibited low activity with the chlorinated su...