Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Tartrate oxidative cleavage

Immobilization of glyoxylate represents a versatile means of gaining access to many biologically relevant compounds. Thus, reaction of potassium monoethyl tartrate with chloromethylated resin and subsequent oxidative cleavage of the resulting supported tartrate (549) with H5IO6 smoothly afforded the polymer-supported glyoxylate 550 in its hydrated form [397] (Scheme 113). [Pg.298]

An improved method has been described for the preparation of glyoxylic acid esters by oxidative cleavage of the corresponding tartrates use of ethereal periodic acid necessitates no work-up procedure, obviating the problem of water solubility of the lower glyoxylates. j8-Keto-csters are dehy ated to the corresponding acetylenic esters by oxidation of the derived 5-pyrazolones with thallium(in) nitrate (Scheme 36). [Pg.144]

A crystal structure of the C02 derivative of (8), K[Co(salen)( 71-C02)], haso been reported in which the Co—C bond is 1.99 A, the C—O bonds are both equivalent at 1.22 A and the O-C-O angle is 132°.125 Carboxylation of benzylic and allylic chlorides with C02 in THF-HMPA was achieved with (8) electrogenerated by controlled-potential electrolysis,126 in addition to reductive coupling of methyl pyruvate, diethyl ketomalonate and / -tolylcarbodiimide via C—C bond formation. Methyl pyruvate is transformed into diastereomeric tartrates concomitant with oxidation to the divalent Co(salen) and a free-radical mechanism is proposed involving the homolytic cleavage of the Co—C bond. However, reaction with diphenylketene (DPK) suggests an alternative pathway for the reductive coupling of C02-like compounds. [Pg.11]

Alternatively, treatment of a mixture of bulbocapnine N-oxides with acetic anhydride at 0 °C led to dehydrobulbocapnine, which could be reduced with zinc and acid to racemic bulbocapnine. Resolution using the tartrate salt provided ( - )-bulbocapnine. The methylenedioxy and the methoxyl groups were sequentially cleaved, by treatment with boron trichloride, to produce the triphenol (29) cleavage with boron tribromide gave rise to the hydrobromide of tetraphenol (30) in good yield. ... [Pg.132]

The nonstoichiometric sugar oxidation process in the presence of alkali is used for both qualitative and quantitative determination of reducing sugars (Fehling s reaction with alkaline cupric tartrate Nylander s reaction with alkaline trivalent bismuth tartrate or using Benedict s solution, in which cupric ion complexes with citrate ion). Hydroxyaldehydes and hydroxyketones are formed by chain cleavage due to retroaldol reaction under nonoxidative conditions using dilute alkali at elevated temperatures or concentrated alkali even in the cold. [Pg.267]


See other pages where Tartrate oxidative cleavage is mentioned: [Pg.205]    [Pg.140]    [Pg.31]    [Pg.100]    [Pg.205]    [Pg.769]    [Pg.778]    [Pg.516]    [Pg.12]    [Pg.263]    [Pg.22]    [Pg.249]    [Pg.413]    [Pg.993]    [Pg.159]    [Pg.346]    [Pg.459]    [Pg.138]    [Pg.259]   
See also in sourсe #XX -- [ Pg.298 ]




SEARCH



Tartrate

© 2024 chempedia.info