Synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines via intramolecular aza Diels-Alder reaction

An efficient and convenient one-pot intramolecular aza Diels-Alder approach for the synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines has been reported. Particularly valuable features of this methodology include simple execution, inexpensive catalyst, and good product yields.     

A convenient and mild synthesis of new 2-aryl-3-hydroxy-6,7-dihydro-1H-indol-4(5H)-ones via a one-pot,three-component reaction in water

A simple and convenient synthesis of 2-aryl-3-hydroxy-6,7-dihydro-1H-indol-4(5H)-ones is achieved in high yields via the one-pot, three-component reaction of arylglyoxals, 1,3-cyclohexanedione, and ammonium acetate in water under reflux conditions.     

A novel and facile synthesis of 2-(cyclohexylamino)-6,7-dihydro-3-aryl-1H-indole-4(5H)-ones via a one-pot multi-component reaction

A simple and efficient synthesis of 2-(cyclohexylamino)-6,7-dihydro-3-aryl-1H-indole-4(5H)-ones was achieved via a one-pot multi-component reaction of cyclohexyl isocyanide, an aldehyde, a 1,3-dicarbonyl compound, and ammonium acetate in the presence of a catalytic amount of KHSO₄ in acetonitrile.     

The first diastereoselective nitroaziridination of N-tosylaldimines with 1-bromonitroalkanes

The first expeditious nitroaziridination of N-tosylaldimines is reported. The protocol involves operationally simple catalyst-free reaction of N-tosylaldimines, 1-bromonitroalkanes and NaOAc to afford 2-nitro-1-tosylaziridines in excellent yields with high Z-diastereoselectivity in a one-pot procedure under ambient conditions.     

A rapid and practical entry into cis-1,4-aminocyclohexanols

A selective and practical approach for the formation of cis-1,4-aminocyclohexanol was developed. The key transformation involves a one-pot imine formation/ Lewis acid-directed imine reduction and results in a highly selective attack of the reducing agent. This simple and practical method is easily amenable to large-scale synthesis.     

Microwave-assisted one-pot synthesis of benzo[b][1,4]thiazin-3(4H)-ones via Smiles rearrangement

The synthesis of benzo[b][1,4]thiazin-3(4H)-one derivatives in a simple and efficient method from the one-pot reaction of substituted 2-chlorobenzenthiols, chloroacetyl chloride, and primary amines via Smiles rearrangement under microwave irradiation gave high yields (65-92%) of the products with short reaction time (15-20 min).     

Novel heterocyclic β-nitroenamines-based on a one-pot three-component reaction: a facile synthesis of fully substituted 1H-pyrrolo[1,2-a]-fused-1,3-diazaheterocycles

A one-pot multicomponent synthesis of a novel class of 2,3-dihydro-1H-pyrrolo[1,2-a]imidazoles, 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrimidines, and 2,3,4,5-tetrahydro-1H-pyrrolo[1,2-a][1,3]diazepines, starting from simple and readily available inputs including diveres diamines, l,l-bis(methylthio)-2-nitroethen and diaroylacetylene, in excellent yields is described.     

Diketene as an alternative substrate for a new Biginelli-like multicomponent reaction: one-pot synthesis of 5-carboxamide substituted 3,4-dihydropyrimidine-2(1H)ones

5-Carboxamide substituted 3,4-dihydropyrimidine-2(1H)one derivatives were synthesized in a simple and efficient method from the one-pot four-component reactions of an aliphatic or aromatic amine, diketene, an aromatic aldehyde and urea or thiourea in the presence of p-toluenesulfonic acid as a catalyst under mild reaction conditions at ambient temperature.     

EDTA-catalyzed synthesis of 3,4-dihydroquinoxalin-2-amine derivatives by a three-component coupling of one-pot condensation reactions in an aqueous medium

This paper describes a simple and efficient one-pot synthetic approach for the preparation of biologically interesting 3,4-dihydroquinoxalin-2-amine derivatives using EDTA-catalyzed three-component reactions of o-phenylenediamines, carbonyl compounds, and isocyanides in an aqueous medium. This method is of great value because of its environmentally benign character, high yields, and ease of handling.     

One-pot three-component synthesis of functionalized spirolactones by means of reaction between aromatic ketones, dimethyl acetylenedicarboxylate, and N-heterocycles

A simple and convenient one-pot multi-component reaction has been described for the synthesis of functionalized spirolactones. This strategy demonstrated three-component reaction between aromatic ketones (11H-indeno[1,2-b]quinoxalin-11-one) and dimethyl acetylenedicarboxylate (DMAD) in the presence of N-heterocycles, such as pyridine, quinoline, and isoquinoline in CH₂Cl₂ at ambient temperature without use of any catalyst or activator.     

Ca(OH)2-mediated efficient synthesis of 2-amino-5-hydroxy-4H-chromene derivatives with various substituents

A variety of novel 2-amino-5-hydroxy-4H-chromene derivatives with various substituents on the 4H-chromene ring were efficiently synthesized by one-pot reactions of substituted resorcinols and various 2-benzylidenemalononitriles in the presence of calcium hydroxide in methanol at room temperature. This simple method provided 2-amino-5-hydroxy-4H-chromenes with high yields under mild reaction conditions.     

A simple and efficient synthesis of pyrazoles in water

A simple, highly efficient, and environmentally friendly method for the synthesis of substituted 1H-pyrazoles by one-pot condensation reaction of α,β-unsaturated carbonyl compounds with tosyl hydrazide in water was developed. The reaction system exhibited tolerance with various functional groups, Aromatic moiety with both electron-rich and electron-deficient substituents could give desired products in good to excellent yields.     

An efficient route for the construction of cyclopenta[b]quinoline derivatives via intramolecular cyclopropanation

A one-pot process to introduce diazoacetoacetate functionality into quinoline was identified with excellent yield and regioselectivity. An intramolecular cyclopropanation of the resulting adducts gave tetracyclic cyclopenta[b]quinoline derivatives in nearly quantitative yields. A synthetic utility of the tetracyclic derivatives was examined by a simple ring opening reaction to afford cyclopenta[b]quinoline in a good yield.     

Regioselective ortho-nitration of N-phenyl carboxamides and primary anilines using bismuth nitrate/acetic anhydride

An efficient and one-pot synthetic method for the regioselective ortho-nitration of the N-phenyl carboxamides and primary anilines has been developed by using bismuth nitrate and acetic anhydride as the nitrating reagents. Reaction proceeds at room temperature and results in corresponding ortho-nitrated products in moderate to excellent yields. This method provides an operationally simple, regioselective, and efficient access to synthesize o-nitro anilines under the mild conditions.     

Baker’s yeast catalyzed one-pot three-component synthesis of polyfunctionalized 4H-pyrans

Baker’s yeast catalyzed one-pot three-component cyclocondensation of aryl aldehydes, malononitrile, and β-dicarbonyls in organic medium has been carried out to obtain polyfunctionalized 4H-pyrans. The reaction has been carried out at room temperature in organic solvent, dimethylacetamide and the products obtained in good to moderate yields with simple work up procedure.     

A versatile combined N-heterocyclic carbene and base-catalyzed multiple cascade approach for the synthesis of functionalized benzofuran-3-(2H)-ones

Functionalized 2,2-disubstituted benzofuran-3-(2H)-ones have been synthesized from simple aldehyde building blocks in a combined NHC- and base-catalyzed one-pot cascade reaction in moderate to excellent yields. This modular approach comprises a NHC-catalyzed hydroacylation/Stetter reaction sequence followed by a retro-Michael, 1,3-H shift and oxa-Michael cascade rearrangement promoted by strong bases.     

Novel tocopheryl compounds XX. 1,3,8-Trioxaphenanthrenes derived from γ-tocopherol

Condensation of γ-tocopherol with aldehydes provides 2,4-disubstituted 1,3,8-trioxaphenanthrenes in a simple one-pot reaction. The reaction proceeded under acid catalysis according to a two-step alkylation-acetalisation mechanism in yields between 58 and 81%. The title compounds are precursors for the thermal generation of ortho-quinone methides, which can be in situ reduced to give antioxidants of the 5a-substituted α-tocopherol-type. The products were analytically characterized by NMR and HRMS.     

Three-component imino Diels-Alder reaction with essential oil and seeds of anise: generation of new tetrahydroquinolines

A simple and efficient one-pot method for the synthesis of 4-anisyl-2-phenyl-1,2,3,4-tetrahydroquinoline derivatives using a three-component imino Diels-Alder cycloaddition (Povarov reaction) between anilines, benzaldehyde, and trans-anethole in the presence of acidic catalysts is shown. New substituted tetrahydroquinolines are reported and their direct preparation from the anise essential oil is described. Also, a simple procedure of the same tetrahydroquinolines from the anise seeds under supercritical fluid (CO₂) conditions has been reported.     

A convenient and efficient synthesis of C-carbamoyl-1,2,3-triazoles from alkyl bromide by a one-pot sequential addition: conversion of ester to amide using Zr(Ot-Bu)4

A convenient and efficient one-pot sequence has been developed for the synthesis of C-carbamoyl-1,2,3-triazoles from alkyl bromide using (i) sodium azide, (ii) methyl propiolate and copper iodide, and (iii) amines, zirconium tert-butoxide, and 1-hydroxybenzotriazole, under microwave irradiation. The sequential reactions in one-pot provided the desired C-carbamoyl-1,2,3-triazoles in excellent yields.     

pTSA-catalyzed condensation of xylenols and aldehydes under solvent-free conditions: One-pot synthesis of 9H-xanthene or bisphenol derivatives

A simple and efficient procedure for the synthesis of 9H-xanthene or bisphenol derivatives has been developed by one-pot condensation of xylenols with aromatic aldehydes in the presence of p-toluenesulfonic acid (pTSA) as a catalyst under solvent-free conditions at 100 °C. It is noteworthy that the condensation reaction of 3,5-xylenol with aldehydes produces 9H-xanthene derivatives, while the reaction with other xylenols leads to the corresponding bisphenol derivatives. Different types of aromatic aldehydes are used in the reaction and in every case the products were obtained in good to excellent yields. The structures of these compounds were established on the basis of IR, ¹H NMR, ¹³C NMR and CHN data.