نتایج جستجو برای: hydrazines

تعداد نتایج: 684  

Journal: :Molecules 2006
Javier Figueroa Esther Caballero Pilar Puebla Fernando Tomé Manuel Medarde

The reactivity of 6-(nitrophenyl or trimethoxyphenyl)-4-tert-butyldimethyl- siloxy-1,2,3,6-tetrahydropyridine derivatives with hydrazines under acid conditions is described. The structure of the products isolated - hydrazones, pyrazolines or pyridazinones - depended on the conditions used. In addition, a systematic study of the reaction outcomes was carried out by introducing variations on the ...

2011
Ranjana Aggarwal Vinod Kumar Rajiv Kumar Shiv P Singh

The biological and medicinal properties of 5-aminopyrazoles have prompted enormous research aimed at developing synthetic routes to these heterocyles. This review focuses on the biological properties associated with this system. Various synthetic methods developed up to 2010 for these compounds are described, particularly those that involve the reactions of β-ketonitriles, malononitrile, alkyli...

Journal: :Organic letters 2007
Aleksei Bredihhin Ulrich M Groth Uno Mäeorg

Formation and use of a nitrogen dianion for selective hydrazine alkylation is reported. The scope and limitations of a new method were demonstrated. The novel method provides fast and easy access to substituted hydrazines, which are widely used as drugs, pesticides, and precursors for a variety of compounds in organic synthesis. [reaction: see text]

2014
Eric T. Kool Pete Crisalli Ke Min Chan

Hydrazones and oximes are widely useful structures for conjugate formation in chemistry and biology, but their formation can be slow at neutral pH. Kinetics studies were performed for a range of structurally varied hydrazines, and a surprisingly large variation in reaction rate was observed. Structures that undergo especially rapid reactions were identified, enabling reaction rates that rival o...

Journal: :Chemical communications 2014
Wanfang Li Matthias Beller Xiao-Feng Wu

Various sulfonamides have been synthesized from triazenes and sulfur dioxide. In the presence of just a catalytic amount of BF3·OEt2, a series of 1-aryl-triazenes were converted into sulfonyl hydrazines in good to excellent yields. When using CuCl2 as the catalyst, the corresponding sulfonamides can be produced from the 1-aryl triazenes in good yields.

Journal: :Chemical communications 2011
Nis Halland Marc Nazaré Jorge Alonso Omar R'kyek Andreas Lindenschmidt

A versatile and efficient palladium catalyzed domino reaction leading to a broad range of substituted 1-aminoindoles has been developed. The title compounds were prepared from 2-halo-phenylacetylenes and simple hydrazines in good to excellent yields in just a few hours under mild conditions.

Journal: :Chemical communications 2014
Yuanyuan An Danqing Zheng Jie Wu

A three-component reaction of 2-(allyloxy)anilines, sulfur dioxide and hydrazines under mild conditions is developed, which gives rise to 1-(2,3-dihydrobenzofuran-3-yl)-methanesulfonohydrazides in good yields. This radical process involves an intramolecular 5-exo-cyclization and insertion of sulfur dioxide.

Journal: :Chemical communications 2012
Shengqing Ye Jie Wu

A novel and efficient route to aryl N-aminosulfonamides via a palladium-catalyzed three-component coupling of arylboronic acids, sulfur dioxide and hydrazines in the presence of a balloon of dioxygen is reported. The reaction proceeded smoothly under mild conditions and DABCO·(SO(2))(2) was used as the source of sulfur dioxide.

Journal: :Organic & biomolecular chemistry 2012
Pei Liu Ying-Ming Pan Yan-Li Xu Heng-Shan Wang

A convenient one-pot Mannich-type-cyclization-oxidation tandem process has been developed for the synthesis of 1,3,5-trisubstituted pyrazoles derivatives from aldehydes, hydrazines and alkynes using p-toluenesulfonic acid monohydrate (PTSA) as a multifunctional catalyst. This method provides a flexible and rapid route to 1,3,5-trisubstituted pyrazoles.

2013
S. Shashikanth Ganesh L. Hegde

A simple versatile method for the conversion of benzy1idene)-hydrazines to 1 -aryl-phthalazines using polyphosphate ester (PPE) is described 1 -aroyl-2-( substituted Podophyllotoxin ( I ) , a cytotoxic constituent of the plant species podophyllum peltatum has attracted considerable research activities, which culminated in the synthesis of tenoposides, and etoposides, which are now clinically us...

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