One‐pot synthesis of pyrido[2,3‐d]pyrimidines via efficient three‐component reaction in aqueous media

A short and facile synthesis of pyrido[2,3‐d]pyrimidine derivatives was accomplished in good yields via the three‐component reaction of aldehydes, alkyl nitriles and aminopyrimidines in water in the presence of triethylbenzylammonium chloride (TEBAC). The structures of these compounds were characterized by elemental analysis, IR and ¹H NMR spectra and further confirmed by single crystal X‐ray diffraction analysis.     

One‐pot Three‐component Synthesis of Spiro[pyrazolo[3,4‐b]pyridine‐4,3′‐indoline] Derivatives Catalyzed by Melamine Trisulfonic Acid

Novel spiro[pyrazolo[3,4‐b]pyridine‐4,3′‐indoline] derivatives were prepared by the three‐component reaction of isatins 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine and Meldrum's acid in the presence of a catalytic amount of melamine trisulfonic acid. This protocol provides a simple one‐step procedure with the advantages of easy work‐up, mild reaction conditions and environmentally benign.     

One‐pot synthesis of novel substituted pyrrolo[2,3‐d]pyrimidines using dry media

A convenient solvent‐free one‐pot synthesis of 1,3,5,7‐tetraaryl‐1,3,4,7‐tetrahydro‐2‐thio‐xopyrrolo[2,3‐d]pyrimidin‐4‐one derivatives using supported reagents under microwave irradiation is described. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:617–621, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20355     

A convenient synthesis of pyrazolo[3,4‐d]pyrimidine‐4,6‐dione and pyrazolo[4,3‐d]pyrimidine‐5,7‐dione derivatives

Pyrazolo‐[3,4‐d]pyrimidine‐4,6‐diones 5 and pyrazolo[4,3‐d]pyrimidine‐5,7‐diones 7 were synthesized by Curtius rearrangement of pyrazolic mono‐esters 2 and 3 followed by hetero‐cyclization via the ureas derivatives 4 and 6 under alkaline conditions.     

One‐pot Sequential Reactions Featuring a Copper‐catalyzed Amination Leading to Pyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines and Dihydropyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines

Tetracyclic skeletons combining an imidazo[1,2‐a]pyridine moiety with a quinoline framework such as pyrido[2′,1′:2,3]imidazo[4,5‐b]quinoline are stimulating increasing interests since they are close isosteres of a series of powerful antiproliferative compounds. In this paper, we report a novel methodology for the synthesis of pyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines through one‐pot sequential reactions of commercially available or readily obtainable 2‐aminopyridines, 2‐bromophenacyl bromides, aqueous ammonia, and aldehydes. Moreover, dihydropyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines could also be obtained in a similar manner by using various ketones as the substrates in place of aldehydes. Notably, the whole procedure combines condensation/amination/cyclization reactions in one pot to give complex compounds in a simple and practical manner. Compared with literature methods, the synthetic strategy reported herein has the advantages of readily available starting materials, structural diversity of products, good functional group tolerance, and obviation of step‐by‐step operations.     

An efficient synthesis of new benzo[1′,2′:6,7]quinolino[2,3‐d]‐pyrimidine derivatives via three‐component microwave‐assisted reaction

A series of benzo[1′,2′:6,7]quinolino[2,3‐d]pyrimidine derivatives were synthesized via condensation of an aromatic aldehyde, 2‐hydroxy naphthalene‐1,4‐dione and 2,6‐diaminopyrimidin‐4‐one in mixed solvent of acetic acid and glycol (3:1,V:V) under microwave irradiation. This one‐pot protocol has the advantage of good yield (86‐91%), simple workup procedure and rapid reaction time (4‐8min).     

One‐pot three‐component synthesis of 2‐substituted 4‐aminoquinazolines

A facile and rapid synthesis of the title compounds via one‐pot reaction of 2‐aminobenzonitrile, orthoesters and ammonium acetate under solvent‐free and microwave condition is described.     

One‐pot Two‐step Reaction for Synthesis of Poly‐substituted Pyrano[3,2‐c]pyridones and Spiro[indoline‐3,4′‐pyrano[3,2‐c]pyridine]‐2,5′(6′H)‐diones in Water

An efficient four‐component approach for the synthesis poly‐substituted pyrano[3,2‐c]pyridones and spiro[indoline‐3,4′‐pyrano[3,2‐c]pyridine]‐2,5′(6′H)‐diones in water has been established. During the reaction, the products were readily achieved through one‐pot two‐step reaction using solid acid as catalyst. The advantages of atom and step economy, the recyclability of heterogeneous solid acid catalyst, easy workup procedure, and the wide scope of substrates make the reaction a powerful tool for assembling pyrano[3,2‐c]pyridone skeletons of chemical and medical interest.     

Alum (KAl(SO4)2·12H2O) Catalyzed Multicomponent Transformation: Simple,Efficient, and Green Route to Synthesis of Functionalized Spiro[chromeno[2,3‐d]pyrimidine‐5,3′‐indoline]‐tetraones in Ionic Liquid Media

The combination of isatin, barbituric acid, and cyclohexane‐1,3‐dione derivatives in the presence of alum (KAl(SO₄)₂·12H₂O) as a catalyst for 15 min was found to be a suitable and efficient method for the synthesis of spiro[chromeno[2,3‐d]pyrimidine‐5,3′‐indoline]‐tetraones.     

Three‐component 1,3‐dipolar cycloaddition reactions in synthesis of spiro[pyrrolidine‐2,3′‐oxindoline] derivatives

Regio‐ and stereospecific syntheses of several spiro[pyrrolidine2,3′‐oxindole] derivatives by cycloaddition trapping of azomethine ylides generated in situ, via decarboxylative condensation of isatin with α‐amino acids or by reaction of secondary amines with isatin, are reported. 2,6‐Dibenzylidenecyclohexanone, 2‐arylidene‐1‐tetralone, and arylidenemalononitrile derivatives have been efficiently used as trapping dipolarophiles. The regio‐ and stereochemistry of the additions are controlled by both frontier orbital and steric interactions. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:324–329, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10038     

One‐pot Multicomponent Synthesis of Isoxazolyl Spiro[indoline‐3,2′‐pyrrolidine]‐2,4′‐diones Catalyzed by CAN

An efficient CAN‐catalyzed synthesis of isoxazolyl spiro[indoline‐3,2′‐pyrrolidine]‐2,4′‐diones has been developed via one‐pot three‐component reaction of isoxazole amine, differently substituted isatins, and acetone at room temperature. Several catalysts and solvents have been screened for the efficiency, but the optimum results were obtained with CAN in THF.     

Three‐component,one‐pot synthesis of pyrimido[4,5‐b]‐quinoline and pyrido[2,3‐d]pyrimidine derivatives

Reaction of 6‐amino‐2‐methylthiouracil and 6‐amino‐1,3‐dimethyluracil with equimoler amounts of cyclic ketones or cyclic 1,3‐diketones and the appropriate aromatic aldehydes yielded regioselectivity a series of polycyclic pyrimido[4,5‐b]quinoline and pyrido[2,3‐d]pyrimidine derivatives in good yields.     

Nanomagnetically modified thioglycolic acid (γ‐Fe2O3@SiO2‐SCH2CO2H): Efficient and reusable green catalyst for the one‐pot domino synthesis of spiro[benzo[a]benzo[6,7]chromeno[2,3‐c]phenazine] and benzo[a]benzo[6,7]chromeno[2,3‐c]phenazines

Superparamagnetic nanoparticles of modified thioglycolic acid (γ‐Fe₂O₃@SiO₂‐SCH₂CO₂H) represent a new, efficient and green catalyst for the one‐pot synthesis of novel spiro[benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazine] derivatives via domino Knoevenagel–Michael–cyclization reaction of 2‐hydroxynaphthalene‐1,4‐dione, benzene‐1,2‐diamines, ninhydrin and isatin. This novel magnetic organocatalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least six times without significant loss in its activity. The catalyst was fully characterized using various techniques. This procedure was also applied successfully for the synthesis of benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazines.