Intermediacy of ion neutral complexes in the fragmentation of short-chain dialkyl sulfides
摘要:
The main fragmentation processes after electron ionization of butyl methyl and butyl ethyl sulfides are rationalized by the intermediacy of the ion neutral complex [RSH . methylcyclopropane](+.) as demonstrated by extensive labeling and collision activation studies. Copyright (C) 1999 John Wiley & Sons, Ltd.
Highly Efficient Direct Carboxylation of Propane into Butyric Acids Catalyzed by Vanadium Complexes
作者:Marina V. Kirillova、José A. L. da Silva、João J. R. Fraústo da Silva、António F. Palavra、Armando J. L. Pombeiro
DOI:10.1002/adsc.200600575
日期:2007.7.2
A direct and highlyefficient carboxylation of propane by carbon monoxide into butyric acids (mainly isobutyric and, in a smaller amount, n-butyric), in the presence of potassium peroxodisulphate (K2S2O8) and in trifluoroacetic acid solution, has been achieved by using a vanadium catalytic system based on Ca[VON(CH(CH3)COO)2}2] (synthetic amavadine), its model compounds Ca[VON(CH2COO)2}2] or [VON(CH2CH2O)3}]
Opticallypureenantiomers of N-acyl-homoserine lactones and thiolactones, whose optical purities were unambiguously determined by chiral stationary phase HPLC analyses, were firstly synthesized. Bioassays revealed that L-isomers were essential as the autoinducers in quorum sensing, while no effect was observed with D-isomers.
The potential role of fatty acid initiation in the biosynthesis of the fungal aromatic polyketide aflatoxin B<sub>1</sub>
作者:Susan W. Brobst、Craig A. Townsend
DOI:10.1139/v94-031
日期:1994.1.1
Earlier work in this laboratory has shown the intact incorporation of [1-13C]hexanoate into averufin (1), a key intermediate in aflatoxin B1 biosynthesis. Parallel experiments with equimolar amounts of [1-13C]butyrate, [1-13C]-3-oxo-octanoate, and [1-13C]-5-oxo-hexanoate gave no detectable specific incorporation of heavy isotope but low and equivalent background incorporation comparable to [1-13C]acetate