نتایج جستجو برای: β diketones
تعداد نتایج: 177869 فیلتر نتایج به سال:
A series of novel 1,4diazepines have been synthesized from β-diketones / β-ketoesters of 4acetylaminobenzene sulphonyl chloride. Desired compounds were prepared by the reaction of novel βdiketone / β-ketoester derivatives of [N4-(4acetylamino) benzene sulphonyl piperazinylN1-1bromopropane] with ethylenediamine to get 1, 4dizapines. All the newly synthesized compounds were characterized with IR ...
We report the experimental determination of the intramolecular enol-enol tautomerization rate of an unsymmetric β-diketone, benzoylacetone, with femtosecond transient absorption in the ultraviolet. Initially, there is an equilibrium of two possible enolic structures in solution, which is disturbed upon UV excitation by exciting a disproportionate fraction of one enolic form. Comparison to symme...
Cuticular wax composition greatly impacts plant responses to dehydration. Two parallel pathways exist in Triticeae for manipulating wax composition: the acyl elongation, reduction, and decarbonylation pathway that is active at the vegetative stage and yields primary alcohols and alkanes, and the β-diketone pathway that predominates at the reproductive stage and synthesizes β-diketones. Variatio...
A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.
An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different...
Reaction of Ti(OiPr)(4) with various bis(β-diketones) and bis(β-ketoesters) (LH(2)) results in the formation of dimeric complexes [Ti(OiPr)(2)L](2), where each metal centre is coordinated by two terminal OiPr ligands and two bridging β-diketonate or β-ketoesterate groups (L). Macrocycles containing two M(OiPr)(2) moieties are thus formed. Reaction of Zr(OiPr)(4) with the same bis(β-diketones) a...
The reduction of 1,3-diketones and β-hydroxyketones with NaBH(4) in aqueous acetonitrile is highly stereoselective in the presence of stoichiometric amounts of bovine or human albumin, giving anti 1,3-diols with d.e. up to 96%. The same reaction, without albumin, gives syn and anti 1,3-diols in approximately 1:1 ratio. The presence of an aromatic carbonyl group is essential for diastereoselecti...
Reaction of [Mn3(OAc)6O·3H2O](+) (1) with ferrocenyl β-diketones of the type FcCOCH2COR with R = CF3 (2a) and CH3 (2b), Ph = C6H5 (2c), and Fc = Fe(II)(η(5)-C5H4)(η(5)-C5H5) (2d) yielded a series of ferrocene-functionalized β-diketonato manganese(III) complexes 3a-3d, respectively, of general formula [Mn(FcCOCHCOR)3]. The mixed-ligand β-diketonato complex [Mn(FcCOCHCOFc)2(FcCOCHCOCH3)] (4) was ...
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