Ammonium Chloride–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[α]xanthen-11-one Derivatives Under Solvent-Free Conditions

A one-pot, multicomponent reaction of aldehydes, dimedone, and β-naphthols is described for the preparation of 12-aryl- or 12-alkyl-8,9,10,12-tetrahydrobenzo[α]xanthen-11-one derivatives using ammonium chloride as a mild, inexpensive, and environmentally benign catalyst under solvent-free conditions. Different types of aldehyde and β-naphthol derivatives are used in the reaction, and in all cases the products were synthesized successfully.

Caro's Acid–Silica Gel: An Efficient and Versatile Catalyst for the One-Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives

An efficient one-pot synthesis of tetrahydrobenzo[b]pyran is described. This involved the three-component reaction of aromatic aldehydes, molononitrile, and dimedone in the presence of a catalytic amount of Caro's acid supported on silica gel in ethanol/water under reflux.     

Ammonium Chloride–Catalyzed One-Pot Synthesis of 4(3H)-Quinazolinones Under Solvent-Free Conditions

Ammonium chloride, which is a very inexpensive and readily available reagent, can efficiently catalyze three-component, one-pot condensation reactions of 2-amino-benzoic acid esters, ortho esters, and aromatic amines to afford the corresponding 4(3H)-quinazolinones in good to excellent yields under solvent-free conditions.     

OH−/Silica-Mediated One-Pot Synthesis of Dithiocarbamates Under Solvent-Free Conditions

Abstract

An efficient, versatile, and environmentally benign method for the synthesis of dithiocarbamates under solvent-free conditions is reported. The Michael addition of electron-deficient alkenes with alkyl or aryl amines and CS₂ in the presence of OH^?/silica in a one-pot three-component reaction protocol gave the corresponding dithiocarbamates in good to excellent yields. This method is suitable for a wide range of amines and a variety of Michael acceptors in solvent-free conditions. The results of the present work show the desired products in excellent yields.     

Fe3O4@SiO2—CPTMS—Guanidine—SO3H-catalyzed One-Pot Multicomponent Synthesis of Polysubstituted Pyrrole Derivatives under Solvent-Free Conditions

Russian Journal of Organic Chemistry - A highly efficient procedure for the one-pot synthesis of polysubstituted pyrrole derivatives by the reaction between of aniline derivatives, β-diketones...     

One-Pot Synthesis of Tetrahydrobenzo-[b]-pyran Derivatives in Aqueous Media

In modem organic chemical research, 4H-benzo-[b]-pyran and their derivatives have attracted strong interest due to their useful biological and pharmacological properties. Herein, we report a clean one-pot synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydro-benzo-[b]-pyrans from aromatic aldehyde, malononitrile and 5,5-dimethyl-1,3-cyclohexadione using hexadecyl trimethyl ammonium bromide (HTMAB) as the catalyst. This method provides several advantages such as high yield, simple work-up procedure and environmental friendliness. All the products were characterized by 1H NMR and IR analyses.     

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.     

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.

ZrOCl2·8H2O: An Efficient Catalyst for One-Pot Synthesis of α-Amino Phosphonates Under Solvent-Free Conditions

A highly efficient protocol has been developed for the three-component reaction of an amine, an aldehyde, and diethyl phopshite catalyzed by ZrOCl₂·8H₂O, an environmentally friendly catalyst, at ambient temperature. The catalyst exhibited remarkable activity and tolerated a wide variety of functional groups, providing the desired amino phosphonates in excellent yields under solvent-free conditions. Alternatively, the reaction rate can be significantly enhanced by carrying out the reaction in a monomode microwave reactor as a promoter.     

Ionic Liquid–Catalyzed One-Pot Synthesis of 1H-Pyrano[2,3-d]pyrimidin-2(8aH)-one Derivatives via Three-Component Reaction under Solvent-Free Conditions

A series of 1H-pyrano[2,3-d]pyrimidin-2(8aH)-one derivatives were synthesized via one-pot, three-component reaction of aromatic aldehydes, urea or thiourea, and 3,4-dihydro-2H-pyran using the green and inexpensive Brønsted acidic ionic liquid 1-methyl-2-pyrrolidinone hydrosulfate ([Hnmp]HSO₄) as catalyst under solvent-free conditions. The method has several advantages such as mild conditions, shorter reaction time, good yields, and environmentally benign procedure. Moreover, the catalyst could be recovered conveniently and reused at least four times without evident loss of activity.     

Efficient Synthesis of Tetrahydrobenzo[b]pyrans under Solvent‐Free Conditions at Room Temperature

A range of tetrahydrobenzo[b]pyrans have been synthesized in very good yields under solvent‐free conditions by grinding α‐cyanocinnamonitrils or β‐cyano‐β‐carbethoxy styrene and 5,5‐dimethyl‐1,3‐cyclohexanedione in the presence of TEBA as catalyst. The short reaction time, cleaner reaction, and easy workup make this protocol practical and economically attractive.     

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.     

Potassium–Tertiary Butoxide–Assisted Addition of Thioglicolic Acid to Chalcone Derivatives Under Solvent-Free Conditions

A series of chalcone derivatives containing thioglicolic acid (4a–j) was prepared by addition of thioglicolic acid to the chalcones (3a–j) in the presence of KOt-Bu under solvent-free conditions. The mechanistic pathway of the reaction can be explained by the Michael-type addition of thioglicolic acid to chalcone derivatives (3a–j).     

Solvent-Free One-Pot Synthesis of Spiro[indoline-3,4′(1H′)-pyrano[2,3-c]pyrazol]-2-one Derivatives by Grinding

The solvent-free one pot synthesis of spiropyranyl-oxindole in the presence of NaHCO₃ under grinding has been achieved. This process is simple, fast, efficient and environmentally benign.      

Diammonium Hydrogen Phosphate: An Efficient and Versatile Catalyst for the One‐Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives in Aqueous Media

Diammonium hydrogen phosphate was used as a mild, efficient, neutral, and cheap catalyst for the synthesis of various 4H‐benzo[b]pyran derivatives via a one‐pot, three‐component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media.     

Synthesis of Calix[4]resorcinarene Amide Derivatives

Three different synthetic routes were developed to introduce carbamoyloxy functional groups at the upper periphery of two calix[4]resorcinarenes. By treating activated esters 2a-b with excess corresponding amine such as 3-(dimethylamino)propylamine 3, ct-phenethylamine 4 and triethylenetetramine 5, six amide derivatives 6a-8b were obtained in high yield (Route 1). The pyridine-linked amide derivatives 9a-b were prepared by using acid chloride intermediate (Route 2).The amide derivatives 10a-b were obtained in moderate yields by direct alkylation of phenolic hydroxyl groups of la-b with N,N-dipropylchloroacetoamide in the presence of K2CO3/KI in acetone (Route 3).     

Brønsted Acidic Ionic Liquid–Catalyzed One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Thiones Under Solvent-Free Conditions

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of ethylacetoacetate, aldehydes, and urea or thiourea in the presence of methylimidazolium hydrogensulfate is described. Aromatic and aliphatic aldehydes reacted easily to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones and thiones under solvent-free conditions. The use of nontoxic and inexpensive materials, straightforward and clean workup, short reaction times, and good yields are the advantages of this method.

One-Pot Synthesis of Thieno[2,3-b]pyridine and Pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine Derivatives

Russian Journal of Organic Chemistry - 2-Acyl-4,5,6-trialkyl-3-aminothieno[2,3-b]pyridines,...     

Facile Sol-Gel Synthesis of Co3O4 Nanoparticles — An Efficient and Recyclable Catalyst for the Synthesis of 1,2-Disubstituted Benzimidazoles Under Solvent-Free Conditions

Russian Journal of Organic Chemistry - High-surface-area Co3O4 nanoparticles have been prepared as a potential heterogeneous catalyst by the sol-gel method using starch as an inexpensive and a...