Functionalized N‐Aryl‐Substituted Cyclens by Nucleophilic Aromatic Substitution

The reaction of trifold protected cyclen with fluorinated dinitroarenes yields aryl‐substituted or aryl‐bridged cyclen derivatives in good yield. The two arene nitro groups, necessary for the nucleophilic aromatic substitution, are subsequently selectively reduced to amines and further functionalized by amide formation. As an example, a cyclen derivative bearing a heterocyclic oligoamide with potential DNA binding ability was prepared.     

Synthesis of 2‐Substituted 4,5‐Diphenyloxazoles under Solvent‐Free Microwave Irradiation Conditions

A novel method for the direct conversion of deoxybenzoin into 2‐alkyl‐4,5‐diphenyloxazoles and 2‐aryl‐4,5‐diphenyloxazoles has been developed using treatment of HTIB and nitriles under solvent‐free microwave irradiation conditions.     

Microwave‐Induced Conversion of Acid Hydrazides to N,N′‐Diacylhydrazines in Solvent‐Free Conditions

A new and efficient method of converting acid hydrazides 1 to the corresponding N,N′‐diacylhydrazines 2 under microwave irradiation and in solvent‐free conditions has been described.     

Chemoselective and Solvent‐Free Thioacetalization of Aldehydes by a Catalytic Amount of NBS

A chemoselective, straightforward, and rapid method for thioacetalization of aldehydes by use of 1,2‐ethandithiol and a catalytic amount of N‐bromosuccinimide under solvent‐free conditions is reported. The reaction takes place in excellent yields and short reaction times.     

Solvent‐Free Synthesis of 3‐Amino‐2,4‐dicarbonitrile‐5‐methylbiphenyl by a Grinding Method

A convenient, environmentally friendly, and solvent‐free procedure has been developed for the synthesis of 3‐amino‐2,4‐dicarbonitrile‐5‐methylbiphenyl derivatives. Compared with the classical reaction condition, this new synthetic method has the advantages of excellent yields, easy setup, mild reaction conditions, and environmental friendlines.     

Efficient and Environmentally Friendly Approach to the Synthesis of Ferrocenyl‐Substituted 1,5‐Diketone Compounds Under Solvent‐Free Conditions

Abstract

This article describes a fast, efficient, economical, and environmentally friendly method for the preparation of a series of ferrocenyl‐substituted 1,5‐diketone compounds via Michael addition of ferrocenyl‐substituted chalcones with deoxybenzoin or dibenzyl ketone under solvent‐free conditions, and affords the corresponding Michael adducts with excellent yields of 77–93%.     

Copper‐ and Amine‐Free Sonogashira Reaction of N,N‐Disubstituted Propargylamine: Synthesis of Substituted Aryl Propargylamine

A copper‐ and amine‐free Sonogashira reaction of N,N‐disubstituted propargylamine (DEP) is reported. The procedure was mild and tolerated a series of aryl bromides, affording the substituted aryl propargylic amines in good to excellent yield.     

First Synthesis of N‐Substituted Amino and N‐Sulfonylaminated Methylthiopyrimidines: Reaction of Dimethyl N‐Cyanodithioiminocarbonate With Substituted Hydrazides

A novel and efficient method for the synthesis of a new variety of methylsulfanylpyrimidines by the reaction of dimethyl N‐cyanodithioiminocarbonate with substituted hydrazides. The synthetic potential of the method is demonstrated.     

Convergent One‐Pot Synthesis of 3‐Substituted Quinazolin‐4(3H)‐ones under Solvent‐Free Conditions

A convenient method for the synthesis of 3‐substituted quinazolin‐4(3H)‐ones using the convergent reactions of formic acid, a primary amine, and isatoic anhydride under solvent‐free conditions and with brief microwave irradiation is described.     

Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways

By exploring lithium–bromide exchange reactivity of aromatic Schiff's bases with tert-butyllithium (tBuLi), we have revealed unprecedented competitive intermolecular and intramolecular cascade annulation pathways, leading to valuable compounds, such as iso-indolinones and N-substituted anthracene derivatives. A series of reaction parameters were probed, including solvent, stoichiometry, sterics and organolithium reagent choice, in order to understand the influences that limit such ring-closing pathways. With two viable reactivity options for the organolithium on the imine; namely, nucleophilic addition or lithium–bromide exchange, a surprising competitive nature was observed, where nucleophilic addition dominated, even under cryogenic conditions. Considering the most commonly used solvents for lithium–bromide exchange, tetrahydrofuran (THF) and diethyl ether (Et₂O), contrasting reactivity outcomes were revealed with nucleophilic addition promoted in THF, while Et₂O yielded almost double the conversion of cyclic products than in THF.     

Green Procedure for the Synthesis of β-Nitro Sulfides by Michael Addition of Thiols to Nitroolefins

Michael addition of thiols to nitroolefins was carried out in water at room temperature without any catalyst, and β-nitro sulfides were obtained in excellent yields. This is the first example of Michael addition of thiols to nitroolefins in water without use of any catalyst. It provides a highly efficient, general, and practical green route to synthesis of β-nitro sulfides. Twenty-four new β-nitro sulfides were synthesized using this technique.     

Solvent‐Free Aerobic Chemoselective Oxidation of β‐Ionone catalyzed by N‐Hydroxyphthalimide/Co(acac)2

β‐Ionone was oxidized with O₂ under solvent‐free conditions catalyzed by an N‐hydroxyphthalimide/Co(acac)₂ system in mild conditions with high conversion and excellent selectivity to oxo‐β‐ionone or 5,6‐epoxy‐β‐ionone in different reaction conditions, respectively.     

Introduction of N‐Containing Heterocycles into Pyrazole by Nucleophilic Aromatic Substitution

Abstract

The nucleophilic aromatic substitution on 5‐chloropyrazoles activated by the electron‐withdrawing formyl group offers a useful method to introduce a wide range of N‐containing heterocycles into them. The rate of reaction was greatly affected by the electronic nature of the N‐1 substitution.     

Solvent‐Free Stereoselective Synthesis of cis‐1‐Carbomethoxy‐2‐Aryl‐3,3‐Dicyanocyclopropanes by Grinding

Abstract

The novel route of high stereoselective synthesis of cis‐1‐carbomethoxy‐2‐aryl‐3,3‐dicyanocyclopropanes by grinding is described. This process is simple, efficient, and environmentally benign.     

Efficient Synthesis of Phosphono‐ and Phosphinoxidomethylated N‐Heterocycles under Solvent‐Free Microwave Conditions

Simple N‐heterocycles were converted to N‐phosphono‐ and phosphinoxidomethyl derivatives by a solvent‐free microwave‐assisted condensation of the heterocycle, paraformaldehyde, and diethylphosphite or diphenylphosphine oxide in a convenient and, in most cases, efficient way. In contrast to an earlier report, imidazole proved to be unreactive in this type of phospha‐Mannich reaction.     

Mild and Efficient Michael Addition of Activated Olefins to Indoles using TBAB as a Catalyst: Synthesis of 3‐Substituted Indoles

A mild and efficient method for the synthesis of 3‐substituted indoles by treatment of activated olefins with indoles using TBAB as a catalyst afforded the corresponding products in excellent yields. The method is general for the preparation of a wide variety of 3‐substituted indoles.     

Novel and Efficient Synthesis of Water‐Soluble [60]Fullerenol by Solvent‐Free Reaction

Abstract

Water‐soluble fullerenol was conveniently synthesized via the direct solvent‐free reaction of fullerene with a mixture of H₂O₂ and NaOH under grinding conditions in air at room temperature. This practical method provides a novel and efficient access to water‐soluble fullerenol in excellent yield.     

Enantioselective Addition of Alkynyl Ketones to Nitroolefins Assisted by Brønsted Base/H-Bonding Catalysis

Various sets of enolizable alkynyl ketones (including methyl ynones with α-aryl, α-alkenyl, and α-alkoxy groups) were able to react smoothly with nitroolefins with the assistance of bifunctional Brønsted base/H-bond catalysts to provide adducts with two consecutive tertiary stereocenters in a highly diastereo- and enantioselective fashion. Further transformation of the obtained adducts into optically active acyclic and polycyclic molecules, including some with intricate carbon skeletons, was also demonstrated.     

Efficient Green Procedure for the Synthesis of Coumarin Derivatives by a One‐Pot,Three‐Component Reaction under Solvent‐Free Conditions

A simple, efficient, and general method has been developed for the synthesis of coumarin derivatives through a one‐pot reaction of aromatic aldehydes, 2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione and 5,5‐dimethyl‐1,3‐cyclohexanedione, in the presence of TEBA under solvent‐free conditions using grinding methods. The mild reaction conditions, simple protocol, high yields, and cleaner reaction make this protocol practical and economically attractive.     

Solvent‐Free Claisen Condensation of Isophorone and Verbenone with para‐Hydroxyethylaminobenzaldehydes

A solvent‐free Claisen condensation between isophorone or verbenone on two para‐hydroxyethylaminobenzaldehydes is described. The method provides the condensation products quickly and, in most cases, without chromatography.