A Simple Strategy for the Preparation of 6-Substituted 3H-Benzoxazol-2-ones and 3H-Benzothiazol-2-ones

The double metallation of 6-bromo-3H-benzothiazol-2-one and 6-bromo-3H-benzoxazol-2-one with methyl magnesium bromide and alkyllithium bases is described. Alkylation with a variety of electrophiles occurs at the 6-position of the heterocycles in good yields.      

Novel and Efficient Synthesis of tert-Butyl-2-(4-(2-aminoethyl)phenylthio)-2-methylpropanoate,a Key Intermediate in the Synthesis of Ureido Thioisobutyric Acid

A convenient and cost-effective synthesis of pharmacologically important tert-butyl-2-(4-2-aminoethyl)phenylthio)-2-methylpropanoate from commercially available 2-2-phenyl-1-ethanol is described.     

Convenient Synthesis of 5-Alkylfuran-2(5H)-ones

A convenient synthesis of 5-alkylfuran-2(5H)-ones are described starting from 3-nitropropanoate and aldehydes, promoted by neutral alumina, in 35–60% overall yields, via a condensation–lactonization–elimination pathway.      

Synthesis of 2-Arylbenzimidazoles in Water

A simple and efficient procedure for the synthesis of 2-arylbenzimidazoles through a one-pot condensation of o-phenylenediamines with aryl aldehydes in water is described. Short reaction time, large-scale synthesis, easy and quick isolation of the product, and excellent yield are the main advantages of this procedure.     

One-Pot Synthesis of Substituted 4H-Chromenes by Three-Component Reaction of Alkyl Isocyanides,Dialkyl Acetylenedicarboxylates,and N-Aryl-3-hydroxynaphthalene-2-carboxamide

The reactive intermediate generated by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates was trapped by N-aryl-3-hydroxynaphthalene-2-carboxamide for the preparation of substituted 4H-chromenes in good yields.      

Synthesis and Biological Activities Evaluation of New 4-(2,4-Difluorophenyl)-N-aryl-5-(1H-1,2,4-triazol-1-yl)thiazol-2-amine

Fifteen new thiazol-2-amine derivatives containing the 2,4-difluorophenyl unit and 1H-1,2,4-triazole moiety were synthesized. Their structures of all these new compounds have been confirmed by ¹H NMR spectra and elemental analysis. The antifungal and plant-growth-regulatory activities of the title compounds are discussed.      

Biginelli-Like Cyclocondensation Reaction: Efficient Synthesis of 4,6-Diarylpyrimidin-2(1H)-one Under Solvent-Free Conditions

An efficient and facile synthesis of 4,6-diarylpyrimidin-2(1H)-one via a Biginelli-like reaction of aromatic aldehydes, aromatic ketones, and urea in the presence of NaOH under solvent-free conditions using a heating method has been developed. Compared with the classical reaction conditions, this new synthetic method has the advantages of excellent yields, shorter reaction time, and mild reaction conditions.      

Reaction of Methylenecyclobutanes with NXS-H2O System

Reactions of methylenecyclobutanes (MCBs) with NXS-H₂O system were investigated. The results were quite different from that of methylenecyclopropanes (MCPs), and an interesting aryl-transfer reaction happened to give substituted cyclobutyl ketones as products when disubstituted MCBs were employed. When monosubstituted MCBs were employed, the direct halohydroxylation gave the cyclobutyl ring untouched adducts. All of these analogs have potential application value in organic synthesis.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.      

Mild and Efficient Deoxygenation of Sulfoxides to Sulfides with Cp2TiCl2/Gallium System

The Cp₂TiCl₂/Ga system was found to be a new reagent for reducing a variety of sulfoxides to the corresponding sulfides in good to excellent yields under mild conditions.      

Elegant One-Pot Synthesis of Quinolino[2′,3′:7,6]-cyclohept[1,2-b]indole Through Friedländer and Pfitzinger Annulation Reaction

A rapid, simple, and efficient method for the preparation of various quinolino[2′,3′:7,6]cyclohept[1,2-b]indoles has been developed through the Friedländer and Pfitzinger condensations of 1-oxo-cyclohept[b]indole with o-amino benzophenone and isatin respectively. Reactions were performed by under different reaction conditions.     

Synthetic Approach to 4a-Methyltetrahydrofluorene-Type Diterpenoids via an Aromatic Oxidation of Phenol Derivatives

An intramolecular aromatic oxidation of a phenolic compound with a hypervalent iodine reagent afforded the coupling product, in which the coupling took place at the para-position of the methoxy goup of the starting material instead of the desired para-position of the isopropenyl group, unfortunately.      

The Reaction of 2-Arylvinamindinium Perchlorates with Sodium Borohydride and Sodium Cyanoborohydride

In the last few years, numerous efforts have been directed to the development of acetonylation methods¹. Recent works in this laboratory have shown that O, O-t-butyl and O-isopropenyl peroxycarbonate 1 can be regarded as a good acetonylation reagent; its decomposition in solution results in the substitution of an hydrogen atom by an acetonyl group on each compound Σ-H able to undergo free radical addition reactions to alkenes². The following free radical chain reaction mechanism has been proposed:      

Cu(ClO4)2 · 6H2O as an Efficient Catalyst for the Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Under Solvent-Free Conditions

Cu(ClO₄) · 6H₂O efficiently catalyzes the three-component Biginelli reaction of aldehyde, β-dicarbonyl compounds, and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones in excellent yields.      

Regioselective Intramolecular Carbon-Hydrogen Insertion in Copper-Catalyzed Carbenoid Decompositions of cis-1-Methyl-3-Arylcyclohexane-1-Diazomethyl Ketones : Some Synthetic Applications

Recently, we have developed¹ a new route for the stereo-specific introduction of an angular carboxyl or functionalized methyl groups² in a rigid hydrophenanthrene moiety. The key step in this approach is a regioselective intramolecular α-keto carbenoid insertion across the benzylic C-H bond (at C-4a) in CuSO₄-catalyzed thermal decomposition of the diazoketones and to the corresponding tetracyclic ketones and in moderate to good yields. A modified procedure³ of carbenoid decomposition of these diazoketones, in the presence of Cu₂O under irradiation with tungsten filament lamp, improves the yields of the desired C-H insertion products. Thus, the ketones and have been prepared now in consistently higher yields (53-55%) from the pure diazoketones , m.p. 125-127°, and , m.p.     

Disodium Hydrogen Phosphate as an Efficient and Cheap Catalyst for the Synthesis of 2-Aminochromenes

An efficient and convenient method for the synthesis of 2-aminochromene by the one-pot, three-component reaction of an aromatic aldehyde, malononitrile, and α- or β-naphthol in the presence of a catalytic amount of disodium hydrogen phosphate under solvent-free conditions is described.