1481-98-7Relevant academic research and scientific papers
Dioxomolybdenum Complexes as Excellent Catalysts for the Deoxygenation of Aryl Ketones to Aryl Alkenes
Fernandes, Tiago A.,Fernandes, Ana C.
, p. 3503 - 3507 (2015/11/10)
This work describes a new methodology for the selective deoxygenation of aryl ketones to the corresponding aryl alkenes catalyzed by dioxomolybdenum complexes using silanes as reducing agents. The best results were obtained with the system PhSiH3/MoO2Cl2(H2O)2 (5-10 mol %), which was very efficient for the deoxygenation of a large variety of aryl ketones to alkenes in excellent yields. This new methodology has the advantages of using an inexpensive, environmentally friendly, easily prepared, and air-stable catalyst in ether solution.
Hydration of the Flavylium Ion
McClelland, Robert A.,Gedge, Sherrin
, p. 5838 - 5848 (2007/10/02)
A spectral and kinetic investigation has been carried out of the transformations undergone in aqueous solution by the parent flavylium ion and its 4'-methyl and 4'-methoxy derivatives.Evidence is reported for the existence at some time under some condition of seven species, the flavylium ion (F+), two pseudobases, a 2-hydroxy adduct (B2) and 4-hydroxy adduct (B4), the cis-2-hydroxychalcone and its ionized form (cC and cC-), and the trans-2-hydroxychalcone and its ionized form (tC and tC-).At pH 6.5-8.5, F+ is relatively rapidly hydrated producing a mixture of B4, B2, and cC.The latter two are in equilibrium, their equilibration proceeding far more rapidly than F+ is hydrated.B4 is a kinetic product of the hydration only; over a short period of time it rearranges via F+ to the equilibrium mixture of B2 and cC.In base solution the behavior is similar, but the B2 cC equilibrium is displaced toward the chalcone since it ionizes.Thus, at pH 12, F+ reacts very rapidly with OH- producing a mixture of B4 and cC-, the latter coming from B2 initially formed.This is followed by the rearrangement of B4, the kinetic product, to cC-.In acid solutions, pH 2-6, an acid-base type equilibrium is relatively rapidly established between the cationic F+ and the neutral species B2 and cC.In all of these solutions, with the exception of strong acids, a slow further reaction occurs resulting eventually in complete transformation to tC or, in base, tC-.The upper limit on the relative amount of cis-chalcone or pseudobase present in equilibrium with the trans-chalcone after complete reaction is 0.02percent.For a scheme B4F+B2cC(cC-)-->tC(tC-), rate constants and equilibrium constants for each reaction stage have been obtained by a kinetic and spectral analysis.
