Simple Synthesis of γ-Lactones from Olefinic Nitriles

The reaction of substituted 4-pentenonitriles with 50% sulphuric acid at 100 °c afforded γ-lactones in moderate to good yield.     

Amberlyst-15–Catalyzed Synthesis of 2-Substituted 1,3-Benzazoles in Water under Ultrasound

A clean and general method has been developed for the synthesis of benzothiazole, benzoxazole, and benzimidazoles using Amberlyst-15 as a recyclable catalyst under ultrasound irradiation in water. The methodology is operationally simple, free from the use of hazardous organic solvents, and does not require the use of inert or anhydrous atmosphere. A number of 1,3-benzazole derivatives were prepared in good to excellent yields by using this methodology.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Zinc Chloride–Catalyzed Expeditious Route to Nitriles

Zinc chloride has been found to be an excellent catalyst for a one-pot synthesis of nitriles from araldehydes and hydroxylammonium chloride under solvent-free conditions. The features of the present method are short reaction time, easy workup procedure, and good yields of the nitriles.     

Zinc Hydroxyapatite–Catalyzed Efficient Synthesis of 5‐Substituted 1H‐Tetrazoles

Zinc hydroxyapatite (ZnHAP) is an effective heterogeneous catalyst for the (2+3)‐cycloaddition of sodium azide with nitriles to afford 5‐substituted 1H‐tetrazoles in good yields. The catalyst is recovered and reused for several cycles with consistent activity.     

L-Proline Catalyzed Solvent-Free Knoevenagel Condensation for the Synthesis of 3-Substituted Coumarins

L-Proline was utilized as an efficient organo-catalyst for the environmentally benign synthesis of 3-substituted coumarins by the Knoevenagel condensation of substituted 2-hydroxybenzaldehydes with reactive methylene compounds under solvent free conditions.     

Aluminium Chloride–Catalyzed Synthesis of 4-Benzyl Cinnolines from Aryl Hydrazones

An efficient synthesis of 4-benzyl cinnolines from aryl phenylallylidene hydrazone is described. In this report aluminium chloride as a Lewis acid catalyst and toluene as a solvent are used for the synthesis. This method is expected to more advantageous than the other reported methods of synthesis of the cinnoline rings because of its low cost, better yield, and benign reaction conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Silica Chloride–Catalyzed Synthesis of Thiiranes from Oxiranes Under Solvent-Free Conditions

A mild, simple, and efficient method for the synthesis of thiiranes from epoxides using a catalytic amount of silica chloride under solvent-free conditions has been developed. Experimental simplicity, simple work-up procedure, and solvent-free reaction conditions are important features of the present protocol.     

Novel Process for Synthesis of 1,2,4‐Triazoles: Ytterbium Triflate–Catalyzed Cyclization of Hydrazonyl Chlorides with Nitriles

Abstract

A series of 1,3,5‐trisubstituted 1,2,4‐triazoles were synthesized via the intermolecular cyclization of hydrazonyl chlorides with nitriles catalyzed by ytterbium triflate [Yb(OTf)₃]. The amount of catalysis was discussed and Yb(OTf)₃ could be reused without loss of activity.     

A Convenient Synthesis of α-Phenylsclcno-α, β-unsaturated Nitriles via Arsonium Salt

a-Phenylseleno-a,0-unsaturatednitrilesareusefulintermediatesinorganicsynthesisinconsequenceoftheconsiderableversatilityofthetransformationofseleno"andcyano.gooddienophilesandradicophiles'.However,onlyonemethodfortheirpreparationhavebeenreported,'butitsyieldisverylow.Recently,ourinterestinsynthesisandapplicationofa-selenoarsoniumylidesledustoexploita-selenenylationofarsoniumsalt1andconsequentcondensationwitharomaticaldehydesunderweaklybasiccondition.Hereinwewishtoreportanefficientonepotsynthesi…     

Phosphomolybdic Acid (H3Mo12O40P) as a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted 1H-Tetrazoles via [2 + 3] Cycloaddition of Nitriles and Sodium Azide

An efficient and practical protocol for the preparation of 5-substituted 1H-tetrazole derivatives is reported using phosphomolybdic acid as an effective heterogeneous catalyst. Good yields, simple methodology, and easy workup make this protocol more attractive for the diversity-oriented synthesis of these heterocycle libraries. The catalyst can be recycled three times with good yields.     

Facile Synthesis of 1‐Aryl‐2‐propanones from Aromatic Amine

A facile synthesis of aryl propanones using aromatic amines as precursors, via an improved Meerwein arylation reaction under mild conditions, is reported.     

Laccase from Basidiomycetous Fungus–Catalyzed Synthesis of Substituted Benzopyranocoumarins via Domino Reaction

The present investigation provides a simple and convenient route to organic synthesis of substituted benzopyranocoumarin, which is important because it is a probable HIV protease inhibitor. The reaction of α,β-unsaturated derivatives of coumarins with catechol or 1,4-hydroquinones was catalyzed using laccase in an aqueous medium. Quinones, generated in situ by the oxidation of the corresponding catechol or 1,4-hydroquinones, underwent a domino reaction with chalcones to produce benzopyranocoumarins.     

Cupric Chloride–Catalyzed Synthesis of Symmetrical Azo Compounds from Primary Aromatic Amines

Symmetrical azo compounds were synthesized from primary aromatic amines using n-BuMgBr as a base, oxygen as an oxidant, and CuCl₂ as a catalyst.     

Molecular Iodine–Catalyzed Synthesis of 1,2,3,6-Tetrahydropyrimidines

A short and simple synthesis of tetrahydropyrimidine derivatives were accomplished in good to excellect yields at room temperature by the reaction of dimethylacetalynedicarboxylate, aniline, and formaldehyde in the presence of 5 mol% of molecular iodine at room temperature in ethanol for 5 min.     

Synthesis of α,β-Unsaturated Nitriles from the Iodine Catalyzed Reaction of Chloroacetonitrile with Aldehydes Promoted by Tri-n-Butylarsine and Magnesium

α,β-Unsaturated nitriles were synthesized from the iodine catalyzed reaction of chloro-acetonitrile with aldehydes promoted by tri-n-butylarsine and magnesium.     

Vinyl Triphenylphosphonium Salt–Mediated Synthesis of Functionalized Alkenes

Deoxybenzoin undergoes a smooth reaction with acetylenic esters in the presence of triphenylphosphine to produce phosphorus ylides. Only the tert-butyl phosphorus ylide undergoes an intramolecular Wittig reaction to produce highly strained cyclobutenes in boiling toluene, which spontaneously undergoes ring-opening reactions to produce highly functionalized 1,3-dienes. The unstable ylides undergo a 1,2-proton transfer and the loss of PPh₃ to produce functionalized alkenes.     

Triflic Salt–Catalyzed Coupling: Iron Triflate–Catalyzed Homocoupling of Aryl Bromides in the Presence of Metallic Magnesium

In the presence of metallic magnesium, the homocoupling reaction of aryl bromides catalyzed by iron triflate was carried out readily in one pot. The catalyst was used successfully in this coupling reaction without preparation of Grignard reagent in advance. Meanwhile, the catalyst was recovered easily and reused smoothly with only a little loss of its activity.     

Synthesis of Symmetric Diketones from Imidazolinium Salt and Bis-Grignard Reagents

In our earlier paper, we reported a convenient method for the synthesis of symmetricdiketones from benzimidazolium salts and his-Grignard reagents'. The yields of productobtained by the reported method are better then that of the former methods2' 3. Howeverthe method suffers from dramatic expensive material, such as o-phenyldiamine, whichmakes it not to be useful for large-scale preparation.In order to overcome this disadvantage and find a new method which can be utilizedin industry, we have e…     

PPA-SiO2–Catalyzed Multicomponent Synthesis of Amidoalkyl Naphthols

Silica gel–supported polyphosphoric acid (PPA-SiO₂) was found to be an efficient catalyst for the multicomponent condensation reaction of aryl aldehydes, 2-naphthol, and urea or amides to afford the corresponding 1-amidoalkyl-2-naphthols in good to excellent yields. This new approach consistently had short reaction times, high conversions, clean reaction profiles, and simple experimental and workup procedures.