Chemical constituents of Euphorbia hyberna L. (Euphorbiaceae).

Chemical investigation of the aerial part and the roots of Euphorbia hyberna L. subs. hyberna.

Electrospray tandem mass spectrometry of 2H-chromenes.

Several 2H-chromenes derived from carbazoles were analyzed by electrospray tandem mass spectrometry. The 2H-chromenes constitute an important class of compounds that exhibit photochromic activity. The fragmentation pathways of the protonated molecular species [M+H]+ were studied, and main fragmentation pathways of these compounds were identified.

Characteristics of p-hydroxybenzoic acid oxidation using Fenton's reagent.

The objective of this work was to investigate the oxidation of p-hydroxybenzoic acid by the Fenton's reagent. Batch experiments were carried out to investigate the influence of the most important process variables: hydrogen peroxide and ferrous salt concentrations, pH, and temperature. The optimal results obtained indicate that p-hydroxybenzoic acid can be effectively degraded using Fenton's oxidation within 10-min reaction time by using a molar ratio H2O2: p-hydroxybenzoic acid of 4:1 and H2O2:Fe2+ of 15:1, at 30 degrees C and pH=3.

Jatrophane and lathyrane diterpenoids from Euphorbia hyberna L.

A new diterpene tetraester, from the jatrophane family, and two new diterpene triesters, with a lathyrane skeleton, have been isolated from the chloroform extract of the roots of Euphorbia hyberna L. The structures of these compounds have been established by spectroscopic methods, including 2D NMR experiments.