نتایج جستجو برای: alkyl halides
تعداد نتایج: 17469 فیلتر نتایج به سال:
BACKGROUND AND AIMS The colons of patients with pneumatosis cystoides coli produce excessive H2. Exposure to alkyl halides could explain this. Six consecutive patients who had pneumatosis cystoides coli while taking chloral hydrate (1-5+ g/day) are reported. Patients 2 and 3 were investigated after they had ceased chloral hydrate treatment. One produced methane, the other did not. (Pneumatosis ...
چکیده ندارد.
A highly efficient copper-catalyzed system using commercially available racemic 1,1′-binaphthyl-2,2′-diol (rac-BINOL) as the ligand was eveloped for amination of aryl halides and heteroaryl halides with alkyl amines and N H heterocycles. Good to high yields were obtained for aryl romides and heteroaryl chlorides. The commercially available rac-BINOL ligand with excellent stability and high effi...
Some N-alkyl pia-hydroxy styryl pyridinium halides, the alkyl moieties being methyl, hexyl and decyl, have been synthesised and the acid dissociation constants of these compounds in aqueous and surfactant solutions have been determined using spectrophotometric method . The alkyl chain does not have any substantial effect on the pKa values in aqueous and cationic surfactant (cetyl trimethylammon...
Vicinal stereocenters are found in many natural and unnatural compounds. Although metal-catalyzed cross-coupling reactions of unactivated alkyl electrophiles are emerging as a powerful tool in organic synthesis, there have been virtually no reports of processes that generate, much less control, vicinal stereocenters. In this investigation, we establish that a chiral nickel catalyst can mediate ...
Tri-isopropylsilyl thio-glycosides (TIPS S-glycosides) were synthesized through base promoted SN2 substitution of glycosyl halides with TIPS-SH or by Lewis acid promoted glycosylation of TIPS-SH with glycosyl acetates or p-methoxyphenyl glycosides. Various thioglycoside derivatives were obtained in high yields by one-pot fluoride-mediated de-silylation and thiol alkylation with alkyl halides or...
An efficient and odourless procedure for a one-pot synthesis of thioesters by the reaction of benzoic anhydrides, thiourea and various organic halides (primary, allylic, and benzylic) or structurally diverse, electron-deficient alkenes (ketones, esters, and nitriles) in the presence of Et3N has been developed. In this method, thiobenzoic acids were in situ generated from the reaction of thioure...
A new ligand, Cp*CH2PPh2 (Cp* = 1,2,3,4,5-pentamethyl-2,4-cyclopentadienyl), was prepared, and was used as a ligand for nickel-catalysed cross-coupling reaction of alkyl halides with aryl Grignard reagents, which nickel-phosphine complexes had never made possible.
We have developed a highly effective copper-catalyzed decarboxylative coupling of alkynylcarboxylic acids with various aryl and alkyl halides at 2 mol% loading of copper. This method is simple, economical and practical for the synthesis of disubstituted alkyne compounds.
A new method for the regioselective three-component cross-coupling of alkyl halides, alkynes, or enynes with organomagnesium or organozinc reagents in the presence of a nickel catalyst and a dppb ligand has been developed.
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