The formation of alkyl and alkenyl methanesulfonates and their reduction to hydrocarbons

Alkene-assisted cis-to-trans isomerization of non-conjugated polyunsaturated alkenes

Complex [Cp*Ru(NCMe)₃][PF₆], 1a, has been identified as a cis-to-trans isomerization catalyst of various non-conjugated cis-polyalkenes under exceptional kinetic control as no alkene conjugation was observed. According to the experimental and theoretical data, the cis-trans isomerization occurred via an alkene-assisted mechanism in which one cis-double bond always served as an anchoring site. Using a combination of multinuclear NMR spectroscopic evidence and mathematical methods it was possible to determine the extent of trans isomerization.

Homologous synthesis: a method for the preparation of mixed substrates and individual compounds

Equimolar mixtures of several homologous or vinylogous alkyl methanesulfonates (mesylates) are converted, by a series of reactions, into equimolar mixtures of compounds having one methylene group more, per molecule, than the starting material. Such mixtures can be used for studying the specificity of an enzymatic reaction in a single experiment in vivo or in vitro. The simultaneous synthesis of a mixture of compounds is also of great advantage in the preparation of a series of radioactively labelled substances. It is more convenient and much more efficient to prepare several labelled compounds of a homologous or vinylogous series in a single reaction, and to isolate each of them by chromatographic methods, than to synthesize the individual substances separately.

Furanoid fatty acids from fish lipids

Fatty acids, recently reported as constituents of certain fish lipids, were identified to be derivatives of furan (furanoid fish fatty acids). 12,15-Epoxy-13,14-dimethyleicosa-12,14-dienoic acid is predominant among the furan acids and is associated with bis-homologs in regard to chain length. Monomethyl acids, such as 12,15-epoxy-13-methyleicosa-12,14-dienoic, are present in appreciable amounts. The structures were concluded from oxidative degradations, from mass spectrometry of methyl esters of the novel acids and fatty acids derived from them by opening the ring, and from nuclear magnetic resonance, infrared, and Raman spectra. The results from chemical procedures and from spectrometric methods were in agreement with those obtained with authentic methyl 9,12-epoxyoctadeca-9,11-dienoate. The number of substituents at the furan ring greatly influences hydrogenation, hydrogenolysis, and hydrolysis reactions of the ring.