An Efficient and Green One‐pot Synthesis of 12‐Aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one Derivatives Promoted by Sulfamic Acid in [BMIM]BF4 Ionic Liquid

An efficient and green procedure for the synthesis of novel 12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives has been described through one‐pot condensation of 2‐naphthol, arylaldehyde and 5,5‐dimethyl‐cyclohexane‐1,3‐dione in the presence of sulfamic acid (NH₂SO₃H) in ionic liquid 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF₄). These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.     

One‐Pot Three‐Component Synthesis of Benzo[f]thiopyrano[3,4‐b]quinolin‐11(8H)‐one Derivatives

A series of novel benzo[f]thiopyrano[3,4‐b]quinolin‐11(8H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and β‐naphthylamine in glacial acetic acid. This protocol features mild reaction conditions, high yields, and short reaction time.     

One‐Pot Microwave‐Assisted Synthesis of Benzopyrano[2,3‐c]pyrazol‐3‐one Derivatives

A convenient one‐pot microwave‐assisted synthesis of Benzopyrano[2,3‐c]pyrazol‐3‐one derivatives was developed, where Knoevenagel condensation and hydrazinolysis reactions were continuously performed under microwave irradiation without separation and purification of the intermediates until the last cyclocondensation reaction except the substrates addition. The one‐pot procedure exhibited shorter reaction times and higher yields (25–55%) of the objects than the conventional heating method.     

[BMIM]Cl Catalyzed One‐Pot Synthesis of α‐Aminophosphonate Derivatives Containing a 4‐Phenoxyquinazoline Moiety under Microwave Irradiation

[BMIM]Cl catalyzed three component Mannich‐type reaction of 4‐(quinazolin‐4‐yloxy)benzenamine and aldehyde with dialkyl phosphite under microwave irradiation has been described. The salient features of the reaction leading to new α‐aminophosphonates include shorter reaction time and good yields. The method is environmentally friendly and does not require toxic catalysts or solvents. To the best of our knowledge, this is the first report for [BMIM]Cl induced one‐pot synthesis of α‐aminophosphonate derivatives.     

TiO2–SiO2 in PEG: A Highly Efficient Green Catalytic System for One‐Pot Synthesis of Benzo[a]xanthen‐11‐ones

Polyethylene glycol was found to be an inexpensive non‐toxic and effective medium for the one‐pot synthesis of benzo[a]xanthen‐11‐ones in the presence of TiO₂–SiO₂ as the catalyst in good to excellent yield. The salient features of this protocol are the simplicity of the procedure, the ready accessibility of the catalyst, its cost effectiveness, and reusable catalyst in relatively short reaction times.     

Microwave Promoted One‐Pot Synthesis of Some Novel N‐Aryl Isoquinoline Derivatives

Homophthalic anhydride 1 reacts with different aromatic amines to produce N‐substituted homophthalimides 2 under microwave irradiation. A rapid microwave‐assisted chemical synthesis of condensed 4‐substituted furo[2,3‐c]isoquinoline‐1,5(2H,4H)‐diones 3 and 5‐substituted‐2,3‐dihydro‐1H‐pyrano[2,3‐c]isoquinoline‐1,6(5H)‐diones 4 involving the condensation of a variety of alkanoyl chlorides with 2‐arylisoquinoline‐1,3‐diones 2 in the presence of base and aprotic solvent is described for the first time. By contrast, the facile ring opening reaction of furo[2,3‐c]isoquinoline‐1,5(2H,4H)‐dione 3 with Vilsmeier–Haack reagent under microwave irradiation yielded the α‐β unsaturated carboxyaldehyde 5 . This novel and clean one‐pot methodology, which is characterized by very short reaction time and easy workup procedure, can be exploited to generate some novel condensed isoquinoline derivatives.     

Iodine-Catalyzed Synthesis of 12-Aryl-8,9,10,12-tetrahydro-benzo[a]xanthen-11-one Derivatives via Multicomponent Reaction

Iodine efficiently catalyzes the one-pot, three-component reaction of aryl aldehyde, 2-naphthol, and cyclic 1,3-dicarbonyl compound under solvent-free conventional heating conditions to afford the corresponding 12-aryl-8,9,10,12-tetrahydro-benzo[a]xanthen-11-one derivatives. The present approach offers several advantages such as shorter reaction times, good yields, low cost, and mild reaction conditions.     

Guanidine Hydrochloride: A Highly Efficient Organocatalyst for the Synthesis of 12‐Aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthene‐11‐ones Under Solvent‐Free Conditions

A new green protocol has been developed for the synthesis of 12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐ones using guanidine hydrochloride as an organocatalyst under solvent‐free conditions. Operational simplicity, mild reaction conditions, enhanced rates, high isolated yields of the pure products, and purification of products by nonchromatographic methods are significant advantages of the protocol presented here.     

One‐Pot Green Synthesis of Thiazolo[3,2‐a]pyridine Derivatives via Tandem Cyclization in Aqueous Media

Facile, three‐component domino reactions of readily available thioglycolic acid/ethyl thioglycolate, aromatic aldehydes, and malononitrile/ethyl cyanoacetate in aqueous potassium carbonate at room temperature afforded thiazolo[3,2‐a]pyridine derivatives chemoselectively in good to excellent yield. All the formed 4H‐chromenes were characterized by spectral and X‐ray methods.     

Convenient and Efficient Synthesis of 11‐Amino‐2,8‐substituted‐2,3,8,9‐tetrahydrobenzo[4,5]thieno[2,3‐b]quinolinone Derivatives

The Gewald reactions of 5‐substituted‐1,3‐cyclohexanedione, malononitrile, and powdered sulfur were carried out to give the corresponding products 2‐amino‐5‐substituted‐7‐oxo‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carbonitrile derivatives 1 . The intermediate enamines 2 were prepared by reaction of compounds 1 and 5‐substituted‐1,3‐cyclohexanedione with hydrochloric acid as catalyst. The title compounds 11‐amino‐2,8‐substituted‐2,3,8,9‐tetrahydrobenzo[4,5]thieno[2,3‐b]quinolinone 3 were synthesized by cyclization of compounds 2 in the presence of K₂CO₃ and Cu₂Cl₂. The structures of all compounds were characterized by elemental analysis, IR, MS, and ¹H‐NMR spectra.     

Three‐Component Uncatalyzed Eco‐Friendly Reactions for One‐Pot Synthesis of 4,7‐Dihydro[1,2,4]triazolo[1,5‐a]pyrimidine Derivatives

A three‐component system of one‐pot synthesis of [1,2,4]triazolo[1,5‐a]pyrimidine derivatives using condensation of 1,3‐dicarbonyl compounds, aldehydes, and 5‐amino[1,2,4]triazole in ethanol without any catalyst was reported in high yields via simple, efficient, and environmentally friendly process. The method reported herein considered a green process; this method has significant advantages of simple workup procedure, excellent yield, minimal environmental pollution, and short reaction time over classical reported methods.     

Sulfamic Acid‐Catalyzed Multicomponent One‐Pot Synthesis of Poly‐Substituted Pyridines and Their Antimicrobial Activity

A novel series of poly‐substituted pyridines (7‐(substituted aryl)‐3,11‐dimethoxy‐5,6,8,9‐tetrahydro‐dibenzo[c,h]acridines) were synthesized via one‐pot multicomponent approach using sulfamic acid as a catalyst and evaluated for their antimicrobial activity. The results indicate that the poly‐substituted series ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i ) showed weak to moderate antibacterial activity. However, compound ( 4c ) had shown good antifungal activity against Candida rugosa with standard antifungal drug Amphotericin‐B. Analogue ( 4c ) was considered to be a lead compound for subsequent standard optimization.     

1,4‐Diazabicyclo[2.2.2]octane‐Catalyzed One‐Pot Synthesis of Pyrazolo[1,2‐a][1,2,4]triazole‐1,3‐diones under Ultrasound Acceleration

1,4‐Diazabicyclo[2.2.2]octane has been explored as an efficient catalyst to effect the three‐component condensation reactions between malononitrile, 4‐arylurazoles, and aromatic aldehydes in ethanol under ultrasound irradiation conditions. The reactions proceeded very rapidly under mild conditions to furnish the corresponding pyrazolo[1,2‐a][1,2,4]triazole‐1,3‐dione derivatives in excellent yields.     

Ultrasound‐Assisted One‐Pot Synthesis of Octahydroquinazolinone Derivatives Catalyzed by Acidic Ionic Liquid [Tbmim]Cl2/AlCl3

Acidic ionic liquid [tbmim]Cl₂/AlCl₃ catalysed an efficient synthesis of octahydroquinazolinone derivatives under ultrasound‐irradiation. This method provides several advantages such as environment benign, high yields and simple work‐up procedure.     

Efficient One‐Pot Synthesis of Spiro[indoline‐3,1′‐pyrazolo[1,2‐b] phthalazine] Derivatives via Three‐Component Reaction

An efficient one‐pot synthesis of spiro[indoline‐3,1′‐pyrazolo[1,2‐b]phthalazine] derivatives via three‐component reaction of phthalhydrazide, isatin, and malononitrile (cyanoacetic ester) is described. This new protocol has the advantages of high efficiency, mild reaction conditions, one‐pot procedure, and convenient operation.     

One‐Pot Synthesis of Pyrimido[1,2‐a]benzimidazoles under Solvent‐Free Conditions

A series of pyrimido[1,2‐a]benzimidazoles were obtained from aldehydes, 2‐aminobenzimidazole and ethyl acetoacetate in good‐to‐excellent yields by a simple, mild, and efficient procedure utilizing N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide (TBBDA) and poly(N‐bromo‐N‐ethylbenzene‐1,3‐disulfonamide) (PBBS) as catalysts.     

氨基磺酸催化下三组分一锅法无溶剂合成苯并[4,5]咪唑并[1,2-a]嘧啶类衍生物

无溶剂条件下,用氨基磺酸催化芳香醛,2-氨基苯并咪唑和β-二羰基化合物的三组分反应,简单而方便地得到了苯并[4,5]咪唑并[1,2-a]嘧啶类衍生物.该法具有产率高,成本低廉,环境友好,适应性广简捷方便等优点.     

Diversity‐Oriented Synthesis of Novel 2′‐Aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] Derivatives via a One‐Pot Four‐Component Reaction

A sequential one‐pot four‐component reaction for the efficient synthesis of novel 2′‐aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] derivatives 5 in the presence of AcONH₄ as a neutral, inexpensive, and dually activating catalyst is described (Scheme 1). The syntheses are achieved by reacting ninhydrin ( 1 ) with benzene‐1,2‐diamines 2 to give indenoquinoxalines, which are trapped in situ by malono derivatives 2 and various α‐methylenecarbonyl compounds 4 through cyclization, providing the multifunctionalized 2′‐aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] analogs 5 . This chemistry provides an efficient and promising synthetic way of proceeding for the diversity‐oriented construction of the spiro[indenoquinoxalino‐pyran] skeleton.     

Ph3P Catalyzed One‐Pot Synthesis of Heterocyclic Derivatives of Biological Active Curcumin

The natural product curcumin with different biological activity reacts smoothly with electron–deficient acetylenic compounds in the presence of Ph₃P to produce different new curcumin derivatives which is containing coumarin and furan functional fragments in moderate yields. The reaction based on the aromatic electrophilic substitution reaction between phenol moieties of curcumin and vinyltriphenylphosphonium salts under mild conditions.