نتایج جستجو برای: disubstituted urea
تعداد نتایج: 40692 فیلتر نتایج به سال:
In this work, copper(II) heterogeneous nanocatalyst supported on modified AlPO4 (Cu(II)-DA@Nano AlPO4) was used for the synthesis of some biological active heterocyclic molecules, particularly for the efficient conversion of a wide range of non-activated terminal alkynes to β-hydroxy 1,4-disubstituted 1,2,3-triazolethrough a three-component “click” reaction at room temperature in water. The reg...
The strict application of IUPAC rules for the numbering of tropane alkaloids is not always applied by authors and there is hence a lot of confusion in the literature. In most cases, the notation of 3, 6/7-disubstituted derivatives has been chosen arbitrarily, based on NMR and MS data, without taking into account the absolute configuration of these two carbons. This paper discusses the problem a...
The Pictet-Spengler reaction (PSR) involves the condensation and ring closure between a β-arylethylamine and a carbonyl compound. The combination of dopamine and ketones in a PSR leads to the formation of 1,1'-disubstituted tetrahydroisoquinolines (THIQs), structures that are challenging to synthesize and yet are present in a number of bioactive natural products and synthetic pharmaceuticals. H...
Several 3,5-disubstituted isoxazoles were obtained in good yields by regiospecific 1,3-dipolar cycloaddition reactions between aromatic nitrile oxides, generated in situ from the corresponding hydroxyimidoyl chlorides, with non-symmetrical activated alkynes in the presence of catalytic amounts of copper(I) iodide. Effects of 3,5-disubstituted isoxazoles on nitric oxide and reactive oxygen speci...
New 2,4-disubstituted 1,5-benzodiazepine derivatives containing different functional groups have been synthesized and screened for their antibacterial activity. The 2,4-disubstituted 1,5benzodiazepine derivatives were synthesized by reacting substituted chalcones synthesized using aldol condensation with o-phenylenediamine. QSAR studies of synthesized derivatives were performed. QSAR equation s...
Seventy-three N,N-disubstituted amides of long-chain, principally C(18), fatty acids were screened for antimicrobial activity against bacteria, yeasts, and molds. Amides containing an epoxy group exhibit a broad spectrum of antimicrobial activity which is further enhanced by unsaturation. Mono-unsaturation alone does not contribute a broad level of activity to the N,N-disubstituted amides of th...
The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C=N-CN under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C=N-substituted quinazoline derivatives, respectively. These products were formed by [4+2] cycloaddition between the aza-diene moieties of the N-arylsubstituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline deri...
The rhodium-catalyzed regio- and enantioselective amination of racemic tertiary allylic trichloroacetimidates with a variety of aniline nucleophiles is a direct and efficient route to chiral α,α-disubstituted allylic N-arylamines. We describe the first dynamic kinetic asymmetric transformations of racemic tertiary allylic electrophiles with anilines utilizing a chiral diene-ligated rhodium cata...
A novel and mild Rh(III)-catalyzed [5+1] oxidative cycloaddition between arylguanidines and alkynes efficiently affords C4-disubstituted 1,4-dihydroquinazolin-2-amines. Members of this family of heterocycles, which contain the relevant cyclic guanidine units, have shown interesting pharmacological properties. The mechanism probably involves the formation of an eight-membered rhodacycle in which...
The cycloisomerization reactions of allenes bearing cyclic acetal, thioacetal and dithioacetal subunits, when triggered either by the catalytic action of AgSbF6 or by one equiv. of CF3COOH, gave rise to four different classes of indeno-fused 1,4-dioxa, oxathia and dithia heterocycles, in most cases as a single diastereomer. Acyclic acetals and dithioacetals are also suitable starting materials ...
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