One-Pot Synthesis of β-Phosphonomalonates Catalyzed by Molecular Iodine

A one-pot procedure has been developed for the synthesis of β-phosphonomalonates via P-C bond formation through tandem Knoevenagel–phospha–Michael reaction catalyzed by iodine as a new, inexpensive, nonmetallic, and commercially available catalyst.

[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.]     

Hypervalent Iodine–Catalyzed Cycloaddition of Nitrile Oxides to Alkenes

A new and convenient method for preparation of isoxazolines was developed by a catalytic cycloaddition of nitrile oxides generated in situ from aldoximes to alkenes in the presence of a catalytic amount of iodobenzene. In this protocol, iodobenzene was first oxidized into the hypervalent iodine intermediate by m-chloroperbenzoic acid, which then transformed aldoximes into nitrile oxides, and a 1,3-dipolar cycloaddition of nitrile oxides to alkenes to provide the isoxazolines in moderate to good yields.

[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.]     

Molecular Iodine–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[a]xanthene-11-one and Diazabenzo[a]anthracene-9,11-dione Derivatives

An efficient one-pot condensation of β-naphthol, aldehydes, and cyclic 1,3-dicarbonyl compounds has been achieved with molecular iodine as a catalyst, thus a variety of tetrahydrobenzo[a]xanthene-11-one and diazabenzo[a]anthracene-9,11-dione derivatives were prepared in good yields.     

Simple and Efficient Procedure for the One‐Pot Synthesis of β‐Acetamido‐β‐aryl‐propiophenones by Molecular Iodine–Catalyzed Tandem Reaction

Molecular iodine efficiently catalyzes the four‐component tandem reaction of araldehydes, arylmethyl ketones, acetyl chloride, and acetonitrile to afford the corresponding β‐acetamido‐β‐aryl‐propiophenones. The new protocol gives high yields of the products, and the reactions go to completion within 10–15 min on a hot plate at 80–85°C.     

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.     

Novel Synthesis of 3‐Indolylquinones catalyzed by Molecular Iodine under Ultrasonic Irradiation

The conjugate addition reactions of indoles with quinones were catalyzed efficiently by molecular iodine under ultrasonic irradiation to afford 3‐indolylquinones in good to excellent yields, which provided a novel, mild, convenient approach for the preparation of 3‐indolylquinones.     

Novel and Efficient Approach to Fluorinated β‐Aminobutanones Catalyzed by Molecular Iodine

A variety of fluorinated compounds of β‐amino ketones could be obtained in good to excellent yields at room temperature through a three‐component Mannich reaction of aldehydes, anilines, and acetones catalyzed by iodine.     

Iodine Catalyzed Three-component Strecker-type Synthesis of α-Aminonitriles from Aldehydes, Amines and Tributyltin Cyanide

A simple and efficient one-pot method has been developed for the synthesis of a-aminonitriles from aldehydes, amines and tributyltin cyanide in the presence of a catalytic amount of iodine with high yields. The reactions proceeded smoothly at room temperature via very simple procedure.     

Efficient Synthesis of N,N′‐Disubstituted Ureas/Thioureas Catalyzed by Iodine

Iodine is an efficient catalyst for the synthesis of symmetrically N,N′‐disubstituted ureas/thioureas by heating respective amines or phenyl hydrazine and urea/thiourea on a preheated hot plate at 90–95°C, under solvent‐free conditions. The yields are excellent, and the reactions go to complete within 5–10 min.     

Iodine‐Catalyzed,One‐Pot,Solid‐Phase Synthesis of Benzothiazole Derivatives

Molecular iodine was utilized in a one‐pot, solid‐phase, solvent‐free reaction between 2‐aminothiophenol and benzoic acid derivatives to obtain highly economical and excellent yield of benzothiazole derivatives in comparison to polyphosphoric acid- and [pmIm]‐Br‐catalyzed microwave synthesis reactions. The results of the studies revealed that the new method reduces cost by approximately 17‐fold in comparison to polyphosphoric acid and has a significant cost reduction in comparison to [pmIm]‐Br. Moreover, it becomes even more economical because no additional chemicals and solvents are necessary for the reaction.     

Amberlyst-15–Catalyzed Facile Synthesis of α-Amino Phosphonates

A simple and efficient method has been developed for the synthesis of sulfonamide phosphonates from N-tosyl aldimines and dimethyl trimethylsilyl phosphite at 0 °C in the presence of Amberlyst-15 as a heterogeneous catalyst.

Molecular Iodine–Catalyzed,Mild, Effective,Ecofriendly, Microwave-Assisted,One-Pot Synthesis of 5-Arylmethylidene-2-phenyloxazol-4-ones (Azalactones) Under Solvent-Free Conditions

Fourteen azalactones have been synthesized in excellent yields under solvent-free conditions by heating an aldehyde, hippuric acid, and acetic anhydride in the presence of molecular iodine as a catalyst in a microwave oven. The short reaction time, cleaner reaction, and easy workup make this protocol practical and economically attractive.     

Efficient Iodine‐Catalyzed Preparation of Benzylidene Acetals of Carbohydrate Derivatives

An efficient preparation of benzylidene acetals of carbohydrate derivatives catalyzed by iodine has been developed. Yields were excellent in every case.     

Practical and Phase Transfer–Catalyzed Synthesis of 6‐Methoxytryptamine

A convenient and cost‐effective synthesis of 6‐methoxytryptamine (1), starting from commercially available phthalimide and 1‐bromo‐3‐chloropropane via PTC N‐alkylation, PTC C‐alkylation, Japp–Klingemann reaction, hydrolysis, and decarboxylation, has been accomplished with a 44% overall yield.     

Tartaric Acid–Catalyzed Synthesis of α-Aminophosphonates Under Solvent-Free Conditions

A facile procedure is developed for the synthesis of α-aminophosphonates, using tartaric acid as a stable, environmentally benign, low cost, and easily available organocatalyst. In the presence of tartaric acid (10 mol%), triethyl phosphite reacts with imines (generated in situ from an aldehyde and an amine) to yield the corresponding α-aminophosphonates. The organocatalyst tartaric acid is more stable during reaction. The catalyst provides easier workup, affords better yields, and takes less reaction time in comparison to generally used Lewis acid catalysts.

Magnesium Chloride–Catalyzed Thiolysis of Epoxides: Synthesis of β-hydroxy Sulfides

A mild and convenient ring opening of epoxides with thiophenol and its derivatives takes place at room temperature in the presence of magnesium chloride as catalyst to afford the corresponding β-hydroxy sulfides along with minor amounts of 2-chlorocycloalkanols in good yields. When the crude reaction mixtures are treated with aqueous sodium hydroxide solution, pure 2-arlythiocycloalkanols are obtained in good yields.     

Single-Pot Synthesis of Spiroannulated Dihydrofurans by Iodine–Ammonium Acetate–Mediated Reaction of Dimedone with Aldehydes

Iodine–ammonium acetate–mediated annealation of dimedone with aldehydes led to facile formation of spirodihydrofuran in good yields through tandem Knoevenagel–Michael iodonation and cyclodehydroiodonation reactions in a single pot.     

New Synthesis of β-Anilinochalcones by Regioselective Oxidation of β-Anilinodihydrochalcones Using Iodine–DMSO

β-Anilinodihydrochalcones readily undergo oxidation α to the carbonyl group region in the presence of a catalytic amount of iodine in dimethyl sulfoxide at 130 °C in good yield. Oxidation of allyloxy-substituted β-anilinodihydrochalcones to β-anilinochalcones is a preferred reaction over deallylation.     

Molecular Iodine as a Versatile Reagent for the Synthesis of Thiazoloquinoline—A Potential Antibacterial Agent

Abstract

A series of 3-(2-aminothiazol-4-yl)quinolin-2[1H]-ones 3 was prepared by neat reaction of quinolin-2[1H]-ones 1 with thioureas 2 in the presence of molecular iodine. The synthesized compounds were evaluated for their in vitro antimicrobial activities against Escherichia coli, Paedococcus sp., Lactobacillus, Yersinia enterocolitica, and Staphylococcus aureus. The green chemical approach for the synthesis of thiazoloquinolinone 3 was performed under neat conditions using molecular iodine as catalyst as well 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 to view the free supplemental file.

GRAPHICAL ABSTRACT