Synergistic substrate and catalyst effects in the addition of trimethylsilyl cyanide to imines derived from lactic acid

Trimethylsilylcyanide was added to various imines derived from (2S)-ethyl lactate in the presence of Lewis acids to provide both syn- and anti- β-hydroxy-α-aminonitrile stereoisomers. Syn-products were found to be the major in most instances, however, anti-products were formed in good yield and selectivity in the presence of ZnI₂ & BF₃·OEt₂ and N-(−)-α-methylbenzyl substituents via double stereo differentiation.     

Expeditious and efficient synthesis of Strecker’s α-aminonitriles catalyzed by sulfated polyborate

A straightforward, mild, efficient, and environmentally benign protocol for a three-component Strecker reaction of aldehydes or ketones, amines, and trimethylsilyl cyanide catalyzed by sulfated polyborate has been described to afford α-aminonitriles under solvent-free reaction conditions. The major advantages of the present method are excellent yields, shorter reaction time, simple experimental procedure, easy workup procedure, recyclability of the catalyst, solvent-free reaction conditions and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards.     

Highly efficient three-component Strecker-type reaction catalyzed by MgI2 etherate under solvent-free conditions

A concise, straightforward and efficient method has been developed for the synthesis of α-aminonitriles by an one-pot three-component condensation of aldehydes or ketones, amines and trimethylsilyl cyanide catalyzed by MgI₂ etherate under solvent-free conditions. This protocol has some advantages such as mild reaction condition, simple work-up, short reaction time and high product yields.     

Synthesis of α-amino nitriles through Strecker reaction of aldimines and ketoimines by using nanocrystalline magnesium oxide

Strecker reactions of various aldimines as well as ketoimines with TMSCN proceeded smoothly under mild conditions to give the corresponding α-amino nitriles and α,α-disubstituted α-amino nitriles, respectively, in good to excellent yields in the presence of nanocrystalline magnesium oxide. The reaction proceeds through hypervalent silicate species by coordination to O²⁻/O⁻ (Lewis basic site) of nanocrystalline magnesium oxide, proved by ²⁹Si NMR.     

One-pot three-component synthesis of α-amino nitriles catalyzed by nano powder TiO_2 P 25

A simple and efficient method has been developed for the synthesis ofα-amino nitriles from aldehydes,amines and trimethylsilyl cyanide（Me₃SiCN） in the presence of a catalytic amount of cyanuric acid at room temperature.     

Iodine Catalyzed Three-component Strecker-type Synthesis of α-Aminonitriles from Aldehydes, Amines and Tributyltin Cyanide

A simple and efficient one-pot method has been developed for the synthesis of a-aminonitriles from aldehydes, amines and tributyltin cyanide in the presence of a catalytic amount of iodine with high yields. The reactions proceeded smoothly at room temperature via very simple procedure.     

Cu(OTf)2 or Et3N-catalyzed three-component condensation of aldehydes, amines and cyanides: a high yielding synthesis of α-aminonitriles

Copper(II) triflate or Et₃N have been found to catalyze, under ambient conditions, the addition of a cyanide anion, such as trimethylsilyl cyanide or acetone cyanohydrin, onto in situ generated imines, furnishing α-aminonitriles in excellent yields.     

Features of switchable multicomponent heterocyclizations of salicylic aldehydes and 5-aminopyrazoles with pyruvic acids and antimicrobial activity of the reaction products

Three-component reactions of 5-aminopyrazoles and salicylic aldehydes with pyruvic acids were studied. The method of tuning of the selectivity of the heterocyclizations allowing to change its direction by variation of the reaction parameters was worked out. The treatment involving pyruvic acid can be selectively directed to the formation to either 3-aryl-10,11-dihydro-4,10-methano-pyrazolo[4,3-c][1,5]benzoxazocine-4-carboxylic acids or 3,6-diarylpyrazolo[3,4-b]pyridine-4-carboxylic acids, while the reaction involving arylpyruvic acid leads only to 7-hydroxy-2,5,6-triaryl-4,5,6,7-tetrahydro-pyrazolo[1,5-a]pyrimidine-7-carboxylic acids. Antimicrobial activity of the compounds obtained was also studied: Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) were found sensitive to the substances tested, however, only in the highest concentration.     

Multicomponent reactions (MCRs) of arylmethyl bromides,arylamidines and elemental sulfur toward unsymmetric 3,5-diaryl 1,2,4-thiadiazoles

A base-promoted three-component reaction between arylmethyl bromides, arylamidines and elemental sulfur was developed, leading to unsymmetric 3,5-diaryl-1,2,4-thiadiazoles in moderate to good yields with chemical diversity and complexity. This procedure shows broad substrates scope by employing elemental sulfur and commercially available starting materials under transition-metal free conditions.     

Rhodium(III) iodide hydrate catalyzed three-component coupling reaction: synthesis of α-aminonitriles from aldehydes, amines, and trimethylsilyl cyanide

Aryl imines formed from aldehydes and amines undergo smoothly in situ nucleophilic addition with trimethylsilyl cyanide (TMSCN) in the presence of catalytic amount of hydrated rhodium(III) iodide to afford the corresponding α-aminonitriles in excellent yield. The low catalytic loading (2 mol %), mild experimental conditions, and short reaction time (mostly within 13 min) represent the key features of this novel catalytic system.     

Highly efficient microwave-assisted fluorous Ugi and post-condensation reactions for benzimidazoles and quinoxalinones

The efficiency of an Ugi/de-Boc/cyclization strategy for construction of heterocyclic compounds has been improved through the incorporation of microwave and fluorous technologies. In the synthesis of substituted quinoxalinones and benzimidazoles, a fluorous-Boc protected diamine is employed for the Ugi reactions. Both the Ugi and the post-condensation reaction proceed rapidly under microwave irradiation and the reaction mixtures are purified by solid-phase extraction (SPE) over FluoroFlash^TM cartridges.     

苯丙氨酸锂催化醛和胺以及三甲基硅腈三组分的Strecker反应(英文)

以苯丙氨基酸锂为催化剂,成功催化了醛、胺和三甲基硅腈三组分的Strecker反应,并结合一系列氨基酸盐催化剂的筛选以及各种溶剂的选择优化了反应条件.结果表明,利用所述反应可以得到较高收率的α-氨基腈;该三组份的Strecker反应具有反应条件温和、反应收率较高、操作简便、无需繁琐的分离步骤、催化剂便宜且环境友好等优点.     

Synthesis of [1,2,4,5]tetrazino[6′,1′:2,3]imidazo[4,5-c]isoquinolin-5-ones by microwave-assisted three-component reaction

An efficient and original Ugi multicomponent reaction of aminopyridines and aminopyrimidines is reported. Starting from aminotetrazine 6 or 7, an isocyanide and an ortho-carboxybenzaldehyde, tetrazinoimidazoisoquinolinones were isolated, after few minutes of microwave irradiation, in good to excellent yields. The scope of this method was extended by using different isocyanides.     

A DMAP-catalyzed mild and efficient synthesis of 1,2-dihydroquinazolines via a one-pot three-component protocol

An efficient and simple method for the synthesis of 1,2-dihydroquinazolines catalyzed by 4-(N,N-dimethylamino)pyridine (DMAP) from readily available aromatic or heteroaromatic aldehydes, 2-aminobenzophenone, and ammonium acetate under mild conditions is described. The scope and limitations of the method are discussed.     

A green and convenient protocol for the synthesis of novel pyrazolopyranopyrimidines via a one-pot,four-component reaction in water

Novel tricyclic fused pyrazolopyranopyrimidines containing both biologically active pyranopyrazole and pyranopyrimidine templates are synthesized using a one-pot, four-component reaction involving ethyl acetoacetate, hydrazine hydrate, benzaldehydes, and barbituric acid catalyzed by DABCO in water. Pure target compounds are obtained in very good to excellent yields over short reaction times and with a straightforward work-up procedure.     

An easy and general protocol for multicomponent coupling reactions of aldehydes, amides, and dienophiles

An improved procedure for the three-component coupling reaction of aldehydes, amides, and dienophiles (AAD-reaction) has been developed. The use of microwave technology enables the endo-selective synthesis of N-acyl cyclohexenylamines via condensation of readily available aldehydes and amides, and subsequent Diels-Alder reaction with electron-deficient dienophiles in significantly improved yields. Advantageously, there is no need of employing additional solvents and reaction times are drastically reduced compared to similar thermal reactions.     

An efficient protocol for the one-pot multicomponent synthesis of polysubstituted pyridines by using a biopolymer-based magnetic nanocomposite

A biopolymer cellulose-based magnetic composite nanocatalyst was prepared and characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Then, it was used efficiently in the multicomponent synthesis of polysubstituted pyridines under mild reaction conditions and using an easy work-up procedure at room temperature in ethanol. The nanocatalyst can be recovered easily and reused several times without significant loss of catalytic activity.     

Double nucleophilic reaction of amines to the imidazole nucleus and selective synthesis of 5-aminoimidazoles

Reaction of 2-(1-chloro-2,2-dimethylpropyl)-1-methyl-1H-imidazole with an excess of N,N-dimethylamine at room temperature gave an abnormal adduct, trans-4,5-bis(dimethylamino)-1-methyl-2,2-dimethylpropyl-2-imidazoline, which was derived from a serial, double nucleophilic addition into the imidazole nucleus in 74% yield together with a normal S_N product, 1-methyl-2-(1-dimethylamino-2,2-dimethylpropyl)-1H-imidazole in 15% yield. The former was easily converted to 1-methyl-5-(dimethylamino)-2-(2,2-dimethylpropyl)-1H-imidazole by only reflux in toluene in 90% yield. The scope, mechanism and limitation of these reactions are discussed.     

Iodine as a novel and efficient reagent for the synthesis of α-aminonitriles by a three-component condensation of carbonyl compounds, amines, and trimethylsilyl cyanide

A straightforward and general method has been developed for the synthesis of α-aminonitriles by simply combining aldehydes or ketones, amines, and trimethylsilyl cyanides in the presence of a catalytic amount of molecular iodine at room temperature.