A Convenient Synthesis of 2-Amino-1,3- selenazoles Using Ionic Liquid and Microwave Irradiation

Abstract

A simple and environmentally benign synthesis of 2-amino-1,3-selenazoles by microwave irradiation using 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄) ionic liquid (IL) is described. Acyl halides, phenacyl halides, and α-bromo-β-keto esters easily undergo condensation with selenourea in ([Bmim]BF₄) by microwave irradiation to afford the desired products of good purity in excellent yields. The ionic liquid can be easily recovered and reused at least 10 times without losing its activity. The duration of the reaction ranges from 4–6 min.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

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Synthesis of New 1-Naphthol Aza Oxa Thia Crowns

Abstract

New dinaphthosulfide aza oxa thia crowns from 1-naphthol were prepared. At first, 2,2′-thiobis(1-hydroxynaphthalene) (a dinaphthol) was prepared from 1-naphthol. Then diester was prepared from the reaction of dinaphthol and methylchloroacetate. Aza crowns were synthesized from the reaction of diester and diamines (ethylene diamine, 1,3-diaminopropane, 1,4-diaminobutane, and 1,6-diaminohexane) in methanol.

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Microwave-Assisted Synthesis of Disulfides

Abstract

A new microwave-assisted synthesis methodology for the preparation of substituted disulfide derivatives is presented. 4-Substituted sulfenimides were reacted with 4-substituted thiols under neat (to right doughy consistency) conditions in chloroform, with both microwave heating and conventional methods. The resulting 4-substituted disulfide derivatives were obtained at higher yields and in shorter reaction times with microwave heating. Their chemistry was confirmed by ¹H-NMR, ¹³C-NMR, infrared (IR), and elemental analysis.

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Knoevenagel Condensation Catalyzed by Sodium Silicate Under Solvent-Free Conditions

Abstract

Sodium silicate pentahydrate has been utilized as an efficient catalyst for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds to afford substituted olefins in yields of 80.6%～98.9% under solvent-free conditions at room temperature within a short time. The advantages of this procedure are mild reaction conditions, excellent yields, cleaner reaction profiles, and operational simplicity.

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Eco-Friendly One-Pot Synthesis of 2,4-Disubstituted Thiazoles by Grinding Under Catalyst- and Solvent-Free Conditions

Abstract

An efficient and facile synthesis of 2,4-disubstituted thiazoles is achieved by a one-pot reaction of aldehydes and α-bromoketones with thiosemicarbazide by grinding under catalyst- and solvent-free conditions. This method has notable advantages in terms of simple workup, neat conditions, high yield, reasonably rapid reaction rate, and environmental friendliness.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

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Ultrasound-Mediated Willgerodt–Kindler Reactions: Non-thermal Synthesis of Thioacetamides

Abstract

Non-thermal, solvent-free condensation of several aryl methyl ketones with amines and elemental sulfur is efficiently conducted using ultrasonic irradiation within short time periods. Consequently, various thioacetamides are conveniently synthesized. Similar experiments at controlled temperature (25 ± 1° C) resulted in comparable yields, showing the promotional role of ultrasound irradiation in the progress of the reaction.

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One-Pot Green Synthesis of 3'-(2-Aminobenzimidazolyl)-2-Phenyl Spiro[4H-Benzopyran-4,2'-Thiazolidin]-4-Ones and Acylation Using Trifluoroacetic Anhydride

Abstract

An expeditious one-pot synthesis of a novel heterocyclic system, 3′-(2-aminobenzimidazolyl)-2-phenyl spiro[4H-benzopyran-4,2′-thiazolidin]-4-ones, has been accomplished by condensing substituted hydrazinobenzimidazole, flavanone, and mercaptoacetic acid by conventional heating in ethanol or toluene, and in an ionic liquid, viz., 1-butyl-3-methyl-imidazolium hexafluorophosphate. Excellent yields (85%–90%) and higher purity are obtained in the ionic-liquid-mediated synthesis as compared with the conventional procedure (55%–60%). Further, these compounds were acylated with trifluoroacetic anhydride. The structures of the compounds were confirmed by IR, ¹H NMR, ¹³C NMR, mass spectral data, and elemental analysis. The compounds, upon evaluation for their antibacterial, antifungal, and insecticidal activities, exhibited excellent results.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Table S1, S2, and S3]

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Ionic Liquid Promoted Efficient Three-Component Synthesis of 2-Thioxo-2H-Thiopyrans

Abstract

An efficient one-pot three-component method for the synthesis of a variety of 2-thioxo-2H-thiopyrans has been described. Fairly good yields are obtained by cyclization reactions of arylidenemalononitriles, derived in situ from ketones and malononitrile, with carbon disulfide in the presence of a base in the ionic liquid 1-butyl-3-methylimidazolium bromide as reaction medium.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Selected Data.]

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Superoxide Ion–Promoted Facile One-Pot Synthesis of O-Alkyl-S-methyl Dithiocarbonates from Alcohol Under Mild Reaction Conditions

Abstract

A new, mild, and efficient protocol for the one-pot synthesis of O-alkyl-S-methyl dithiocarbonates (xanthates) has been described in reasonably good yields from a variety of alcohols employing carbon disulfide and methyl iodide using superoxide ion at room temperature.

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Trimethylsilyl Protection of Alcohols Over Phosphorus Pentoxide Supported on Silica Gel

Abstract

An eco-friendly and mild protocol for trimethylsilyl protection of alcohols over phosphorus pentoxide supported on silica gel using hexamethyldisilazane has been described. Solvent-free and ambient reaction conditions, easy workup, short reaction times, excellent yields, and reusability of the catalyst are the noticeable features of this methodology.

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A Simple Synthesis of Oxaphospholes

Abstract

Stable derivatives of oxaphospholes were obtained from the reaction between electron-deficient acetylenic compounds and phenacyl bromide or its derivatives in the presence of triphenylphosphine in acetonitrile as the solvent in excellent yields.

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Succinimide-N-Sulfonic Acid: A Mild,Efficient, and Reusable Catalyst for the Chemoselective Trimethylsilylation of Alcohols and Phenols

Abstract

Succinimide-N-sulfonic acid (SuSA) is easily prepared by the reaction of succinimide with chlorosulfonic acid. This reagent is able to efficiently catalyze the chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS). All reactions were performed under mild reaction conditions, giving excellent yields.

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A Facile Synthesis of 3H-Benzo[1,2]Dithiole-3-Thiones and Their Condensation with Active Methylene Compounds

Abstract

3H-Benzo[1,2]-dithiole-3-thiones were prepared from potassium sulfide and 2-halobenzaldehydes in moderate-to-good yields, and a plausible mechanism for this catalyst-free intramolecular heteroannulation reaction has been proposed. The Knoevenagel condensation reactions of 3H-benzo[1,2]dithiole-3-thiones with active methylene compounds such as ethyl 2-cyanoacetate and diethyl malonate, and the three-component one-pot reactions of potassium sulfide, 2-halobenzaldehydes, and ethyl 2-cyanoacetate, affording the corresponding products, have been developed.

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