Reductive cleavage of an SiCl3 group by amine hydrochlorides and base

A new procedure has been developed for removing the SiCl₃ group from α-trichlorosilyl-substituted amines. In this procedure the trichlorosilyl substrate is treated first with amine hydrochloride in CH₃CN, followed by hydrolysis with aqueous hydroxide. Using this sequence, amines corresponding to replacement of the trichlorosilyl group with hydrogen can be conveniently isolated in good yields for all tested cases. Evidence suggests the intermediacy of an unstable chlorosilane species formed by probable nucleophilic attack of chloride. In conjunction with the addition reaction fo HSiCl₃ to enamines to form the α-trichlorisilyl amines, the cleavage completes a new method for the transformation of enamines to amines which could be a useful alternative to either catalytic hydrogenation or metal hydride reduction.     

Synthetic studies on 3-arylquinazolin-4-ones: intramolecular nucleophilic aromatic substitution reaction of 2-carboxamido-3-arylquinazolin-4-ones and its application to the synthesis of secondary aryl amines

The general synthesis and a novel intramolecular nucleophilic aromatic substitution (S_NAr) reaction of 2-carboxamido-3-arylquinazolin-4-ones, a potentially useful scaffold in the field of medicinal chemistry, are described. The synthetic utility of the S_NAr reaction as a tool for the synthesis of secondary aryl amines, including diaryl amines, is also demonstrated.     

Highly Regioselective 5-endo-tet Cyclization of 3,4-Epoxy Amines into 3-Hydroxypyrrolidines Catalyzed by La(OTf)3

Highly regioselective intramolecular aminolysis of 3,4-epoxy amines has been achieved. Key features of this reaction are (1) chemoselective activation of epoxides in the presence of unprotected aliphatic amines in the same molecules by a La(OTf)₃ catalyst and (2) excellent regioselectivity for anti-Baldwin 5-endo-tet cyclization. This reaction affords 3-hydroxy-2-alkylpyrrolidines stereospecifically in high yields. DFT calculations revealed that the regioselectivity might be attributed to distortion energies of epoxy amine substrates. The use of this reaction was demonstrated by the first enantioselective synthesis of an antispasmodic agent prifinium bromide.     

Highly chemoselective nitration of aromatic amines using the Ph3P/Br2/AgNO3 system

The use of PPh₃/Br₂/AgNO₃ provides a new reagent system for the novel and highly chemoselective nitration of aromatic amines under mild reaction conditions.     

A practical and efficient method for the preparation of sulfonamides utilizing Cl3CCN/PPh3

Cl₃CCN in combination with PPh₃ proved to be a highly reactive reagent for the conversion of sulfonic acids to the corresponding sulfonyl chlorides in refluxing CH₂Cl₂. Upon reaction with amines, the corresponding sulfonamides were obtained in good to excellent yields.     

Synthesis of 3-keto-quinolines from enaminones,anilines and DMSO: Transition metal free one pot cascade

An efficient and transition metal-free approach for the synthesis of functionalized 3-ketoquinolines from readily available anilines, enaminones and DMSO in the presence of K₂S₂O₈ has been conducted. This one pot tandem reaction proceeds through [3+2+1] cycloaddition reaction involving DMSO, enaminones and amines. In this environmental benign approach, DMSO acts as both a one carbon source and the solvent. A broad range of variously substituted amines and enaminones are successfully employed in this one pot tandem process to access a broad range of substituted 3-ketoquinolines.     

Reaction of alkyl- and arylamines with 2-(hydroxyimino)-3-oxobutanal

The condensation of 2-(hydroxyimino)-3-oxobutanal with primary aliphatic amines, cyclohexanamine, and amines containing an adamantane fragment afforded 4-(alkylamino)- and 4-(cyclohexylamino)-3- nitrosobut-3-en-2-ones. Analogous reaction with substituted anilines RC₆H₄NH₂ (R = H, 4-Me, 4-OMe, 4-NH₂, 4-Br, 4-I, 3-NO₂) led to the formation of 4-aryl-3-hydroxyiminobutan-2-ones.     

Simple and efficient synthesis of 3-aminopropenones and 3-aminopropenoates catalyzed by copper(II) nitrate trihydrate under solvent-free conditions

A simple, efficient and environmentally begin method has been developed for the synthesis of 3-aminopropenones and 3-aminopropenoates through the reaction of 1,3-dicarbonyl compounds with amines in the presence of Cu(NO₃)₂ · 3H₂O under solvent-free conditions. Correspondence: Geng-Chen Li, School of Material Science and Engineering, Shijiazhuang Railway Institute, Shijiazhuang 050043, China.     

Reactions of 3-cyanochromones with primary amines: structures of the products

Reactions of 3-cyanochromones with primary aromatic amines in boiling benzene gave mixtures of Z- and E-3-arylamino-2-(2-hydroxyaroyl)acrylonitriles and 2-amino-3-(aryl-iminomethyl)chromones. The latter can easily be obtained in the individual state when the reaction is carried out in the presence of triethylamine. In the case of primary aliphatic amines, the open-chain reaction product immediately undergoes cyclization into 3-alkyliminomethyl-2-aminochromones. The structures of the products were examined by 1D and 2D ¹H, ¹³C, and ¹⁵N NMR spectroscopy in DMSO-d₆ and CDCl₃.     

Tailoring the surface structure of iron compounds to optimize the selectivity of 3-nitrostyrene hydrogenation reaction over Pt catalyst

Selective hydrogenation of substituted nitroarenes is an important reaction to obtain amines.Supported metal catalysts are wildly used in this reaction because the surface structure of supports can tune the properties of the supported metal nanoparticles （NPs） and promote the selectivity to amines.Herein,Pt NPs were immobilized on Fe OOH,Fe₃O₄andα-Fe₂O₃nanorods to synthesize a series of iron compounds supported Pt catalysts by liquid phase reduction me...     

Synthesis of 1,3-Disubstituted Symmetrical/Unsymmetrical Ureas via Cs2CO3-Catalyzed Transamination of Ethylene Carbonate and Primary Amines

Cs₂CO₃-catalyzed transamination of primary amines and ethylene carbonate proceeds to form 1,3-disubstituted symmetrical/unsymmetrical ureas in excellent yields. The effect of different reaction parameters such as influences of bases, temperature, and reaction time were investigated for the title reaction.     

Aqueous Synthesis of N-Phenyl/alkyl-2-quinolinone-3-carboxylic Acids from Coumarin-3-carboxylic Acids

An efficient, ecofriendly aqueous synthesis of aromatic/aliphatic amines with coumarin-3-carboxylic acid in a one pot reaction in a sealed tube or InCl₃/ H₂O in open vessel to afford N-phenyl/alkyl-2-quinolinones is achieved. This method provides high yield of products in shorter time, making it a useful process for the synthesis of structurally diversified 2-quinolinones from corresponding coumarins.     

Catalytic Enantioselective Intermolecular Benzylic C(sp3)−H Amination

A practical general method for asymmetric intermolecular benzylic C(sp³)?H amination has been developed by combining the pentafluorobenzyl sulfamate PfbsNH₂ with the chiral rhodium(II) catalyst Rh₂(S‐tfptad)₄. Various substrates can be used as limiting components and converted to benzylic amines with excellent yields and high levels of enantioselectivity. Additional key features for the reaction are the low catalyst loading and the ability to remove the Pfbs group under mild conditions to give NH‐free benzylic amines.     

An Improved Protocol for Regioselective Ring-Opening of Sulfonyl Aziridines with Iodine Promoted by PPh3

A new route to synthesize β-iodo amines from sulfonyl aziridines and iodine was developed in the presence of PPh3. This ring-opening reaction was an efficient and simple process to give fl-iodo amines in excellent yields with high chemoselectivity.     

Highly efficient and regioselective allylic amination of allylic alcohols catalyzed by [Mo3PdS4] cluster

A highly efficient and regioselective allylation reaction of amines with allylic alcohols under mild conditions catalyzed by the cubane-type sulfido cluster [(Cp∗Mo)₃S₄Pd(dba)][PF₆] with H₃BO₃ as an additive has been developed. A variety of amines and allylic alcohols are investigated, and in the case of allylic alcohols bearing substituents at either α- or γ-position only linear allylic amination products are obtained.     

Ag2CO3-catalyzed efficient synthesis of internal or terminal propargylicamines and chalcones via A3-coupling under solvent-free condition

Several simple, fast and practical protocols have been developed to synthesize internal or terminal propargylamines and chalcones via A³-coupling reaction of aldehydes, amines, and alkynes catalyzed by an easily available catalyst Ag₂CO₃ under solvent-free condition. The reaction proceeded smoothly to deliver various products in good-to-excellent yields with good functional group tolerance. Gram-scale preparation, bioactive molecule synthesis and asymmetric substrates have been demonstrated. Furthermore, plausible mechanisms for the synthesis of different products have been proposed.     

Fluoroindenes. 12. Interaction of perfluorinated 3-methyl- and 3-ethylindenes, 1-methylene-, 1-ethylidene-, and 1-vinylindans with ammonia and aliphatic amines

In the reactions with ammonia and alkylamines, perfluoro-3-ethylindene is more reactive than perfluoro-1-ethylideneindan, whereby the last two compounds undergo mutual conversion in the presence of F^–. In the interaction of perfluoro-1-ethylideneindan with aqueous amines, products of the substitution of the vinyl F atom in the initial compound are obtained; in the case of dry amines in the presence of CsF, the products of the substitution of the F atom at the double bond of perfluoro-3-ethylindene are chiefly obtained. The monoamino derivatives, which contain an available atom of H, are converted to the disubstituted derivatives by the action of an excess of the amines. Both the amine and the hydroxy anion may thereby emerge as the nucleophile in the reaction of 2-aminoperfluoro-3-ethylindene, as well as perfluoro-1-ethylideneindan, with aqueous dialkylamines. The perfluoro-1-vinylindan and aqueous NH₃ yield 1-(aminocyanomethylene)octafluoroindan and 2-amino-3-(iminocyanomethyl)hexafluoroindene; and perfluoro-1-methyleneindan yields 2-amino-3-cyanohexafluoroindene. The last is formed together with 2-aminoperfluoro-3-methylindene in the reaction of perfluoro-3-methylindene with aqueous NH₃.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1856–1865, August, 1990.     

A NEW SYNTHESIS OF CIS-3-SUBSTITUTED CHROMAN-4-OLS

ABSTRACT

3,3-Dibromochroman-4-ones on reaction with different heterocyclic secondary amines gave 3-substituted chromones. These on reduction with NaBH₄ gave exclusively cis-3-heterocycle substituted chroman-4-ols in good yields.     

Green chemistry approach to the synthesis of 3-substituted-quinazolin-4(3H)-ones and 2-methyl-3-substituted-quinazolin-4(3H)-ones and biological evaluation

ABSTRACT

A synthesis of two series of 3-substituted quinazolinones was performed utilizing a green chemistry approach, deep eutectic solvents and microwaves, namely. 2-Methyl-3-substituted-quinazolin-4(3H)-one derivatives were synthesized in a two-step reaction, using choline chloride:urea deep eutectic solvent (DES). 3-Substituted-quinazolin-4(3H)-ones were synthesized in one-pot one-step reaction of anthranilic acid, amines and orthoester in a microwave reactor. For the synthesis of 2-methyl-3-substituted-quinazolin-4(3H)-ones, first conventional synthesis of benzoxazinone, as an intermediate, was performed. Further, benzoxazinone in reaction with corresponding amines, in choline choline:urea deep eutectic solvent, furnished desired compounds. These procedures are based on green principles with the aim of developing synthetic routes for the potential antitumor agents. All compounds were characterized by LC/MS, ¹H NMR and ¹³C NMR spectral techniques. Compound 1 bearing trifluoromethoxyphenyl group showed promising activity against HuT-78 cell line with IC₅₀ of 51.4?±?5.1?µM.     

A One-Pot Synthesis of Tetrahydro-2,5-dioxofuran-3-yl Alkylcarbamodithioates

An efficient one-pot synthesis of tetrahydro-2,5-dioxofuran-3-yl alkylcarbamodithioates via three-component reaction of maleic anhydride, CS₂, and primary amines in good yields is described.