نتایج جستجو برای: amines

تعداد نتایج: 20593  

Journal: :Organic & biomolecular chemistry 2011
Qiang Kang Yugen Zhang

Aza-Michael addition of amines, including aromatic and aliphatic amines, with α, β-unsaturated ketones was realized employing N-Heterocyclic Carbene (NHC) as organocatalyst, yielding β-amino ketones with up to 98% yield.

The one-pot synthesis of symmetrical triaryl amines using aryl halides and 5-Methyl-1,3,4-Thiadiazole-2-Amine as a nitrogen-transfer reagent is reported. Copper oxide nanoparticles that does not require the presence of any additional ligand, improved rate and facility of the synthesis of triaryl amines. The introduction of a new N-source, using green solvents PEG/H2O, normal atmospheric conditi...

A simple, efficient, and cost-effective procedure for the N-tert-butoxycarbonylation and N-formylation of amines (primary, secondary) respectively, with di-tert-butyl dicarbonate and 85% aqueous formic acid under solvent-free condition using B(OSO3H)3/SiO2 (SBSA) as a heterogeneous and recyclable catalyst has been developed. We demonstrated that the resulting catalyst is applicable to various a...

Journal: :Chemical communications 2009
Phillip A Shelton Yue Zhang Thi Hoang Ha Nguyen Lisa McElwee-White

Oxidative carbonylation of amines using NaIO(4) as the oxidant and NaI as a promoter affords good to excellent yields of ureas from primary amines in the absence of transition metal catalysts.

Journal: :Chemical communications 2010
Lingling Chu Feng-Ling Qing

The benzoyl peroxide (BPO)-promoted oxidative functionalization of tertiary amines under transition-metal-free reaction conditions was developed. Various 1-trifluoromethylated tetrahydroisoquinoline derivatives were prepared by employing this method. It constitutes the first example of direct trifluoromethylation of tertiary amines.

2001
S. Pizzarello

L-enantiomeric excesses have been determined for some amino acids of the Murchison and Murray meteorites [1-4]. The finding has taken a particular significance in view of the homochiral distribution of biochemical molecules and the possible contribution of asymmetry-carrying organics to the early Earth by meteorite and cometary delivery. So far, evidence of nonracemic compounds in meteorites ha...

Journal: :The Journal of experimental biology 1989
J R Groome W H Watson

The biochemical mechanisms by which octopamine, catecholamines and the peptide proctolin exert their actions on Limulus cardiac muscle were investigated. Amines produced long-lasting increases in the amplitude of contractions evoked by electrical stimulation. At 10(-5) mol l-1, the apparent order of potency for amine-induced increases in evoked contraction amplitude was dopamine approximately e...

Journal: :Organic Letters 2021

Dichloromeldrum's acid is introduced as a bench-stable, nonvolatile reagent for the dichloroacetylation of anilines and alkyl amines to produce α,α-dichloroacetamides, which are important motifs medicinal chemistry. Products formed in good excellent yields with grade solvents, and, only byproducts acetone CO2, no column chromatography required. Thus, this practical, efficient, green primary ami...

Journal: :Journal of the American Chemical Society 2005
Michael J Barany Robert P Hammer R B Merrifield George Barany

The 1,2,4-dithiazolidine-3,5-dione heterocycle, also referred to as a dithiasuccinoyl (Dts)-amine, serves as a readily removable amino protecting group for building blocks used in syntheses of peptides, glycopeptides, and PNA; it is also useful as a masked isocyanate and (inversely) as a sulfurization reagent for trivalent phosphorus. Bis(chlorocarbonyl)disulfane, the two-sulfur analogue of suc...

Journal: :Organic & biomolecular chemistry 2012
Yu-Huang Wang Jian-Liang Ye Ai-E Wang Pei-Qiang Huang

We have developed a one-pot method for the direct intermolecular reductive hydroxyalkylation or alkylation of amines using lactones or esters as the hydroxyalkylating/alkylating reagents. The method is based on the in situ amidation of lactones/esters with DIBAL-H-amine complex (for primary amines) or DIBAL-H-amine hydrochloride salt complex (for secondary amines), followed by reduction of the ...

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