نتایج جستجو برای: sodium alkoxide
تعداد نتایج: 188270 فیلتر نتایج به سال:
Combination of sol-gel and hydrothermal routes in the metal alkoxide binary system of Al(OR)3-Ti(OR)4 (R= -CH(CH3)2 or -CH2CH2OCH3) were investigated to prepare single phase aluminum titanate (tialite). The effects of various parameters, such as hydrothermal processing temperature, solvent polarity and the type of alkoxide precursor, in phase development of the product powders have been investi...
The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO(-) or MeO(-)) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transfor...
Controlled hydrolysis of donor-substituted titanium-salan complexes led to the formation of well-defined dinuclear complexes. Structure determination by means of X-ray and NMR-studies revealed the presence of a single μ-oxo bridge and one labile alkoxide ligand per titanium center. Concomitant cytotoxicity assays of the isolated dinuclear complexes showed cytotoxicities in the low micro-molar r...
This study proposes a direct synthetic route to single titanate sheets through the mild and versatile conditions of the “chimie douce”. The stages of the production include the complexation of the titanium alkoxide precursor by benzoic acid, the formation of titanium oxo-clusters and their controlled transformation into single sheet titanates during the hydrolysis stage. The resulted material a...
INTRODUCTION Phase-transfer catalysis (PTC) involves the use of environmentally benign organocatalysts, mild reaction conditions, and simple experimental procedures that are insensitive to air/moisture and amenable to large-scale processes. Furthermore, the use of inexpensive inorganic bases such as NaOH in place of expensive moisture-sensitive hydride, alkoxide and amide bases makes PTC an att...
A highly enantioselective and practical synthesis of the HIV-1 reverse transcriptase inhibitor efavirenz (1) is described. The synthesis proceeds in 62% overall yield in seven steps from 4-chloroaniline (6) to give efavirenz (1) in excellent chemical and optical purity. A novel, enantioselective addition of Li-cyclopropyl acetylide (4a) to p-methoxybenzyl-protected ketoaniline 3a mediated by (1...
Ta2O5 nanoparticles have been synthesized from alkoxy carboxylates of tantalum via the sol-gel route. Tantalum alkoxides were reacted with chlorocarboxylic acids in order to lower the susceptibility hydrolysis. When these modified alkoxy carboxylates were used in the sol-gel synthesis, they yielded Ta2O5 nanoparticles of better properties than those of the alkoxide-derived Ta2O5 nanoparticles. ...
The use of Me3SiO(-)/Bu4N(+) as a general activator of organotrimethylsilanes for addition reactions has been established. The broad scope of the method offers trimethylsilanes (including acetate, allyl, propargyl, benzyl, dithiane, heteroaryl, and aryl derivatives) as bench-stable organometallics that can be readily utilized as carbanion equivalents for synthesis. Reactions are achieved at rt ...
The stannous alkoxides [Sn(OR)2] [R = i-Pr, t-Bu, C(Et)Me2, CHPh2, CPh3] have been synthesised by reaction of Sn(NR'2)2 with two equivalents of HOR [R' = Me, R = i-Pr; R' = SiMe3, R = t-Bu, C(Et)Me2, CHPh2, CPh3]. Single crystal X-ray diffraction analysis of the bis(diphenylmethoxide) (4) and bis(triphenylmethoxide) (5) species have shown them to comprise three-coordinate Sn(ii) centres through...
A reaction between (E)-trimethyl(3,3,3-trifluoroprop-1-en-1-yl)silane (1) and arylaldehydes 2 was triggered by fluoride anions to afford aryl 3,3,3-trifluoropropyl ketones 3 in moderate to good yield. A mechanistic study of this reaction indicated that it occurred via an allyl alkoxide (4). A subsequent 1,3-proton shift of the benzylic proton of 4 forms 3. This reaction involves oxidative 3,3,3...
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