One‐Pot Synthesis of 4‐Oxo‐2‐thioxohexahydropyrimidines Catalyzed by Potassium Carbonate Under Ultrasound

Abstract

The one‐pot condensation of aldehydes, ethyl cyanoacetate and thiourea catalyzed by potassium carbonate in ethanol results 4‐oxo‐2‐thioxohexahydropyrimidines in 20–90% yields under ultrasound irradiation.     

One‐Pot Synthetic Route to a Class of Polydental Pyridylphosphines

Abstract

A one‐pot synthetic route is presented for convenient preparation of di‐2‐pyridylphenylphosphine (Py₂PPh, 1), di[(2‐pyridyl)phenylphosphino]methane (DPyPM, 2), and two new, long‐chain polydental pyridylphosphines: di[2‐(6‐diphenylphosphino)pyridyl]phenylphosphine (P₃N₂, 3) and bis[2‐(6‐diphenylphosphinopyridyl)phenylphosphino]methane (P₄N₂, 4).     

One‐Pot Synthesis of Trifluoromethylated 4‐Cyanoalka‐1,4‐dienes with Predominant Z‐Selectivity

The consecutive reaction of diethyl (1‐cyanobut‐3‐enyl)phosphonate with n‐butyllithium, trifluoroacetic anhydride, and Grignard reagents gave trifluoromethylated 4‐cyano‐alka‐1,4‐dienes in 45–89% yields with predominant Z‐selectivity (Z∶E=89–78∶11∶22). Two isomers could be easily separated by column chromatography.     

One‐Pot,High‐Yielding Synthesis of Novel Dihydrothiazolo[3,2‐a]pyrimidinones

Reaction between 6‐(un)substituted‐2‐thiouracils and E‐ethyl 4‐bromocrotonate under basic conditions at room temperature is an easy, mild, high‐yielding, and regioselective method for the preparation of 7‐(un)substituted dihydrothiazolo[3,2‐a]pyrimidinone derivatives.     

Convenient One‐Pot Heterogeneous Catalytic Method for the Preparation of 3,4‐Dihydropyrimidin‐2(1H)‐ones

A new, simple, environmentally friendly synthesis of dihydropyrimidinones from aromatic and aliphatic aldehydes, ethyl acetoacetate, and urea or thiourea using a small‐pore‐size zeolite as catalyst is described. Compared with the classical Biginelli reaction conditions, this method has the advantage of high yield, shorter reaction time, and recyclable and reusable catalyst.     

One‐Pot Synthesis of Benzimidazoles from o‐Nitroanilines under Microwaves via a Reductive Cyclization

An efficient microwave irradiation synthesis of 2‐substituted benzimidazoles in one step via the Na₂S₂O₄ reduction of o‐nitroanilines in the presence of aldehydes is described. The method is simple and a good option to obtain the title compounds in a very short time.     

Synthesis of Novel Pyrrolo[1′,5′‐a]‐1,8‐naphthyridine Derivatives through a Facile One‐Pot Process

Novel pyrrolo[1′,5′‐a]‐1,8‐naphthyridine compounds have been synthesized through a facile one‐pot process by the reaction of the corresponding 1,8‐naphthyridines with aliphatic anhydride. The structures were established by spectroscopic data. Further X‐ray crystal analysis of 4′‐acetyl‐7‐methyl‐pyrrolo[1′,5′‐a]‐1,8‐naphthyridine (1) identifies its intriguing molecular structure and reveals the strong π‐π stacking.     

D,L‐Proline‐Catalyzed One‐Pot Synthesis of Pyrans and Pyrano[2,3‐c]pyrazole Derivatives by a Grinding Method under Solvent‐Free Conditions

D,L‐Proline was found to efficiently catalyze the one‐pot condensation of aromatic aldehydes, malononitrile, and dimedone (1,3‐cyclohexanedione or 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one) 2‐Amino‐3‐cycano‐4‐aryl‐7,7‐dimethyl‐5,6,7,8‐tetrahydrobenzo[b]pyrans and 6‐amino‐5‐cyano‐4‐aryl‐1,4‐dihydropyrano[2,3‐c]pyrazoles were synthesized by a grinding method under solvent‐free conditions. The reaction proceeded cleanly at room temperature to afford the products in good yields.     

One‐Pot Syntheses of Amides from N‐Acylation of Nitroarenes with Esters Mediated by Samarium Diiodide

Abstract

Mediated by samarium diiodide, various amides were prepared directly from nitroarenes and esters under mild conditions in a one‐pot procedure.     

Europium Triflate–Catalyzed One‐Pot Synthesis of 2,4,5‐Trisubstituted‐1H‐imidazoles via a Three‐component Condensation

A simple, efficient, and practical procedure for synthesis of 2,4,5‐trisubstituted‐1H‐imidazoles via the condensation of benzoin or acetoin, aromatic aldehydes, and ammonium acetate using europium triflate [Eu(OTf)₃] as a novel catalyst in high yields is described. The catalyst can be recovered conveniently and reused at least four times without any loss of activity.     

First Report on the Abnormal Dearylation/Alkylation Reaction in One‐Pot Hantzch Synthesis with 6‐Amino‐1,3‐Dimethyl Uracil

Abstract

First report on the abnormal dearylation/dealkylation reaction occurring during dehydrogenation in one‐pot, three‐component condensation of dihydropyrido[2,3‐d]pyrimidines.     

Organic Reactions in Ionic Liquids: Ionic Liquid‐Accelerated One‐Pot Synthesis of 2‐Arylimidazo[1,2‐a]pyrimidines

Abstract

The room‐temperature ionic liquid n‐butylpyridinium tetrafluoroborate (BPyBF₄) is used as a recyclable alternative to classical molecular solvents in the one‐pot synthesis of 2‐arylimidazo[1,2‐a]pyrimidines by reaction with ketones, [hydroxy(tosyloxy)iodo]benzene, and 2‐aminopyrimidine. Significant rate enhancements and improved yields have been observed.     

A Simple and Convenient Synthesis of HEPT Analogues via a One‐Pot Reduction–Sulfenylation Reaction

Abstract

The one‐pot reduction–sulfenylation of 5‐alkyl‐6‐chlorouracils (1) with diaryl disulfides (2) and sodium borohydride in methanol was carried out to afford 1‐[(2‐hydroxyethoxy)methyl]‐6‐(phenylthio)thymine HEPT analogues in good to excellent yields.     

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.     

One‐Pot Synthesis of 3,5‐Disubstituted Pyridin‐2‐ones by Annulation of β‐Keto‐amides with 2‐Dimethylaminomethylene‐1,3‐bis(dimethylimonio)propane Diperchlorate

β‐Keto‐amides react with 2‐dimethylaminomethylene‐1,3‐bis(dimethylimonio)propane diperchlorate salt to give the corresponding 3‐acetyl‐5‐formylpyridin‐2‐ones. The annulation reactions proceed with excellent yields.     

Sulfamic Acid–Catalyzed One‐Pot Synthesis of 3‐(4,6‐Dimethyl‐oxazolo[4,5‐c]quinolin‐2‐yl)‐chromen‐2‐ones using the Conventional Method and Microwave Irradiation

A rapid and efficient method for the preparation of 3‐(4,6‐dimethyl‐oxazolo[4,5‐c]quinolin‐2‐yl)‐chromen‐2‐ones by the reaction between 3‐amino‐2,8‐dimethyl‐quinolin‐4‐ol and 2‐oxo‐2H‐chromen‐3‐carboxylic acid using sulfamic acid as a acid catalyst and dimethyl formamide as a solvent using the conventional method and microwave irradiation is reported.     

Convenient One‐Pot Preparation of Dimethyl Bicyclo[2.2.2]octane‐1,4‐dicarbolylate,a Key Intermediate for a Novel Adenosine A1 Receptor Antagonist

Dimethyl bicyclo[2.2.2]octane‐1,4‐dicarboxylate (4), a key starting material for a novel adenosine A₁ receptor antagonist, was prepared in a one‐pot reaction with convenient workup and improved yield.     

One‐Pot Resolution of trans‐2‐Iodo‐cyclohexanol with O,O′‐Dibenzoyl‐(2R,3R)‐tartaric Acid in Solid Phase

A one‐pot, solid‐state resolution of racemic‐trans‐2‐iodo‐cyclohexanol by O,O′‐dibenzoyl‐(2R,3R)‐tartaric acid was performed. By mixing the solid racemate with half an equivalent resolving agent, the (1R,2R)‐isomer of the alcohol remains uncomplexed and can be sublimated at lower temperature. By increasing the temperature, the complex decomposes and the (1S,2S)‐isomer can be gained as a second fraction of the sublimation and the resolving agent remains back.     

Reaction of Imidazo[1,2‐a]pyridines with Aliphatic Aldehydes: A Simple and Efficient Method for the Preparation of Novel C‐3 Vinylic Derivativesof Imidazo[1,2‐a]pyridines

A simple and efficient method for the preparation of novel C‐3 vinylic derivatives of imidazo[1,2‐a]pyridines has been developed by the reaction of imidazo [1,2‐a]pyridines with appropriate aliphatic aldehydes in acetic acid in a sealed tube.     

One‐Pot Preparation of Unsymmetrical Biaryls via Suzuki Cross‐Coupling Reaction of Aryl Halide using Phase‐Transfer Catalyst in a Biphasic Solvent System

A one‐pot synthetic method of unsymmetrical biaryls was developed via the Suzuki cross‐coupling reaction of aryl halide using a phase‐transfer catalyst in a biphasic solvent system.