Polyols and organic sulfates have recently been identified in the secondary organic aerosol (SOA) formed in the photooxidation of isoprene in both the laboratory and under ambient atmospheric conditions. Nuclear magnetic resonance methods were used to monitor the bulk reaction kinetics of acid-catalyzed hydrolysis reactions for isoprene- and 1,3-butadiene-derived epoxides in order to determine ...

nogenic activity (4). Chrysene, which has one more benzene ring than does phenanthrene, is a symmetrical molecule with 2 identical bay regions (Chart 1). Chrysene has weak activity in carcinogenicity tests (4, 11). Quantum mechanical aspects of the bay region theory predict (6) that bay-region 1,2-diol 3,4-epoxides of chrysene and phenanthrene should have sim ilar chemical reactivities. Kinetic...

A mass spectrometric method has been delineated for the identification of the epoxide functionalities in unknown monofunctional analytes. This method utilizes gas-phase ion/molecule reactions of protonated analytes with neutral trimethyl borate (TMB) followed by collision-activated dissociation (CAD) in an ion trapping mass spectrometer (tested for a Fourier-transform ion cyclotron resonance an...

The soluble epoxide hydrolase appears to be a promising target for the development of antihypertensive therapies based on a previously unexplored mechanism of action. Epoxide hydrolases are enzymes that add water to three membered cyclic ethers known as epoxides. The soluble epoxide hydrolase in mammalian systems (sEH) is a member of the alpha/beta-hydrolase fold family of enzymes and it shows ...

Isoprene is the precursor for number of alcohol, organosulfate, and organonitrate species observed in ambient secondary organic aerosol (SOA). Recent laboratory and field work has suggested that isoprene-derived epoxides may be crucial intermediates that can explain the existence of these compounds in SOA. To confirm this hypothesis, the specific hydroxy epoxides observed in gas phase isoprene ...

The homologous human glutathione transferases (GSTs) M1-1 and M2-2 have similar catalytic activities with many electrophilic substrates, but differ strikingly in their conjugation of epoxides with glutathione. Residue 210, Thr in GST M2-2 and Ser in GST M1-1, is a key active-site component in determining the activity profile with epoxide substrates. This residue is hypervariable in Mu class GST...

A β-diiminato-zinc-N(SiMe3)2 complex (1) was synthesised and fully characterised, including an X-ray diffraction study. The activity of catalyst 1 towards the coupling reaction of CO2 and various epoxides, including propylene oxide (PO), cyclohexene oxide (CHO), styrene oxide (SO), limonene oxide (LO), octene oxide (OO) and epichlorohydrin (ECH), was investigated. Terpolymerisation of CO2, PO a...

1,3-Butadiene (BD), a gas used widely in production and synthesis of rubber, plastics, and resins, is metabolized to three different epoxide metabolites: butadiene monoxide (BMO), butadiene bisoxide (BBO) and epoxybutanediol (ED). We have examined the role of stereochemistry in the chemical and enzyme-mediated conjugation of R- and S-BMO; RR-, SS-, and meso-BBO; and SR-, RS-, RR-, and SS-ED wit...

Leukotriene (LT)A₄ and closely related allylic epoxides are pivotal intermediates in lipoxygenase (LOX) pathways to bioactive lipid mediators that include the leukotrienes, lipoxins, eoxins, resolvins, and protectins. Although the structure and stereochemistry of the 5-LOX product LTA₄ is established through comparison to synthetic standards, this is the exception, and none of these highly unst...

Dibenzo(a,e)fluoranthene (DBF), a powerful carcinogenic nonalternant aromatic hydrocarbon, has been metabolized in vitro by incubation in mouse and rat liver microsomal homogenates. Five major stable metabolites were separated by highpressure liquid chromatography and then analyzed by spectroscopic procedures and comparison with synthetic model com pounds. Three of them are phenols correspondin...