نتایج جستجو برای: imines

تعداد نتایج: 2655  

Ahmed Ali Hullio, Ghulam Murtaza Mastoi

Nicotine-based ionic liquid has been used as a green catalyst for pyridine-catalyzed Huisgen reaction. It promoted addition of dimethylacetylenedicarboxylate to aldehydes or N-tosyl imines leading to efficient synthesis of 2-benzoylfumarates and 1-azadienes respectively under pyridine free odorless ionic liquid conditions. The improved results were obtained in terms of enhanced yields, with min...

Ahmed Ali Hullio, Ghulam Murtaza Mastoi

Nicotine-based ionic liquid has been used as a green catalyst for pyridine-catalyzed Huisgen reaction. It promoted addition of dimethylacetylenedicarboxylate to aldehydes or N-tosyl imines leading to efficient synthesis of 2-benzoylfumarates and 1-azadienes respectively under pyridine free odorless ionic liquid conditions. The improved results were obtained in terms of enhanced yields, with min...

2004
Kimihisa Yamamoto Masayoshi Higuchi

Dendritic polyphenylazomethines (DPAs) were synthesized as novel topological polymer ligands with π-conjugated structures by the convergent method via dehydration of aromatic ketones with aromatic amines in the presence of TiCl4. DPA G4 molecules are revealed to have a sphere-like structure with a 2.3-nm diameter and are regularly assembled without deformation of the molecule on a plate as obse...

Journal: :Chemical & pharmaceutical bulletin 2000
M Takamura Y Hamashima H Usuda M Kanai M Shibasaki

A general asymmetric Strecker-type reaction is reported, catalyzed by the Lewis acid-Lewis base bifunctional catalyst 1. The reaction of trimethylsilyl cyanide (TMSCN) with various fluorenyl imines, including n-aldimines and alpha,beta-unsaturated imines, proceeds with good to excellent enantioselectivities in the presence of a catalytic amount of phenol as additive (20 mol%) (catalytic system ...

Journal: :Synthesis 2021

Abstract An aza-Peterson olefination methodology to access 1,3-dienes and stilbene derivatives from the corresponding allyl- or benzyltrimethylsilane is described. Silanes can be deprotonated using Schlosser’s base added N-phenyl imines ketones directly give desired products in high yields.

2016
Marija Zbačnik Branko Kaitner

This work presents a study on thermo-optical properties of three Schiff bases (imines) in the solid state. The Schiff bases were obtained by means of mechanochemical synthesis using monosubstituted o-hydroxy aromatic aldehydes and monosubstituted aromatic amines. The keto-enol tautomerism and proton transfer via intramolecular O∙∙∙N hydrogen bond of the reported compounds was found to be influe...

Journal: :Chemical science 2017
Barry M Trost Xiaoxun Li

Herein is reported the first example of palladium-catalyzed asymmetric allylic alkylation (AAA) reactions involving 2-aza-π-allyl palladium intermediates. The 2-aza-π-allyl complex was generated via a novel mode of activation of N-allyl imines. Pd-catalyzed C(sp3)-H activation of N-allyl imines and subsequent nucleophilic attack by glycinates delivered vicinal diamino derivatives as the sole re...

Journal: :The Journal of organic chemistry 2014
Adam D J Calow Jorge J Carbó Jessica Cid Elena Fernández Andrew Whiting

A combination of in situ IR spectroscopy (ReactIR) and DFT calculations have been used to understand what factors govern the selectivity in the addition of primary amines to α,β-unsaturated aldehydes and ketones, i.e., 1,2- versus 1,4-addition. It has been found that the 1,2-addition products (α,β-unsaturated imines following addition and elimination) usually predominate for most systems. Howev...

Journal: :Organic & biomolecular chemistry 2017
Wei He Junpeng Zhuang Zhanhui Yang Jiaxi Xu

The [2 + 2] cycloadditions of thioketenes and imines are named as thio-Staudinger cycloadditions. The diastereoselectivity in thio-Staudinger cycloaddtions of alkyl/alkenyl/aryl-substituted thioketenes is rationalized. The steric effects of the thioketenes play an extremely important role in deciding the diastereoselectivity (cis/trans selectivity) through controlling exo- and endo-attack and s...

Journal: :Journal of the American Chemical Society 2003
Janez Kosmrlj Leland O Weigel David A Evans C Wade Downey Jimmy Wu

This paper describes an operationally simple deracemization process of aldehydes and ketones. This new crystallization-induced dynamic resolution (CIDR) protocol allows for nearly complete conversion of the racemic mixture into one enantiomer. Crystallization of imines derived from racemic ketones or aldehydes 1 and trans-(1R,2R)-1-amino-6-nitroindan-2-ol (2) afforded diastereomerically pure, c...

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