Phorbol esters are the tetracyclic diterpenoids generally known for their tumor promoting activity. The phorbol esters mimic the action of diacyl glycerol (DAG), activator of protein kinase C, which regulates different signal transduction pathways and other cellular metabolic activities. They occur naturally in many plants of the family Euphorbiacaeae and Thymelaeaceae. The biological activitie...

les composes organophosphores en general et les esters phosphoriques en particulier, suscitent un interet, sans cesse grandissant , qui peut se justifier par l'importance de ces produits (nucleotides, phospholipides, etc.) dans les processus biologique. dans ce mernoire nous presentons les etudes des polyesters phosphoriques surtout sur le plan purement chimique. apres avoir mentionne les ...

To examine the biochemical metabolism of aroma volatiles derived from fatty acids, pear fruits were incubated in vitro with metabolic precursors of these compounds. Aroma volatiles, especially esters, were significantly increased, both qualitatively and quantitatively, in pear fruits fed on fatty acid metabolic precursors. Cultivars having different flavor characteristics had distinctly differe...

a highly efficient method for the oxidation of aldehydes to carboxylic acids using polyvinylpolypyrrolidone supported - boron trifluoride (pvpp-bf3) in the presence of 35% hydrogen peroxide has been developed in acetonitrile at 60 °c. this procedure cleanly oxidizes variety of aldehydes to the corresponding carboxylic acids. oxidative esterification of benzaldehyde utilizing pvpp-bf3/h2o2(35%) ...

reaction of dialkyl acetylenedicarboxylates 1a-c andpyrrole derivatives 2a-e in the presence of triphenylphosphite (tpp) was investigated and the effect of the pyrrole substitution was established. diastereoselectivity is observed with pyrroles, 2a,b, yieldingphosphonate ester derivatives 3a-f and 4,and their relative configuration is determined by 1h/13c and 31p nmr and confirmed by single x-r...

Two different cyclic amino esters are synthesized by palladium-catalyzed cross-coupling reaction of diazoesters with N-substituted-2-iodoanilines. Aryldiazoacetates lead to cyclic α-amino esters with an α-quaternary carbon centre in the presence of CO. Additionally, arylvinyldiazoacetates afford cyclic α,β-unsaturated γ-amino esters.

Methods for the deprotection of pinanediol and pinacol esters of various boronic acids via fluoroborane intermediates were evaluated. Treatment of the boronate esters with potassium hydrogen difluoride normally gives trifluoroborate salts; in the case of alpha-amido alkyl or o-amido phenyl boronate esters, aqueous workup gives difluoroboranes. Procedures for transformation of both trifluorobora...

Natural esters of fatty acids of Rhizopus arrhizus Fischer increased during the first 48 hr of growth. During the 48- to 72-hr period, there was a shift in concentration from the methyl esters to the ethyl esters of fatty acids.