Synthesis and biological evaluation of new benzo[f]furo[2,3‐h]‐and benzo[f]pyrano[2,3‐h]coumarin derivatives.

Furocoumarins 3,5 and pyranocoumarin 7 were synthesized from the reaction of furonaphthalenediones 2,4 and pyranonaphthalenedione 6 respectively with carbethoxymethylene(triphenyl)phosphorane in refluxing DCM for 3‐6 hours or under microwave irradiation in toluene for a few minutes. Compounds 3,5,7 and their precursors were tested as anti‐inflammatory/antioxidant agents. They were found to compete significantly high DMSO for OH radicals, to scavenge O₂^? and to inhibit lipoxygenase to a high extent.     

Synthesis of new benzo[h]‐ and benzo[f]chromeno[2,3‐b]‐pyridine‐5‐ones

A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152     

Three‐component one‐pot synthesis of pyrazolo[3,4‐b]quinolin‐5(6H)‐one derivatives in aqueous media

A series of 4‐aryl‐3,7,7‐trimethyl‐1‐phenyl‐7,8‐dihydro‐1H‐pyrazolo[3,4‐b]quinolin‐ 5(6H)‐ones were synthesized by the three‐component reaction of aromatic aldehydes, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine, and 5,5‐dimethyl‐1,3‐cyclohexandione in the presence of sodium 1‐dodecanesulfonate in aqueous medium. Compared to the previous methods, this new protocol has the advantages of convenient operation, higher yields, lower cost, and environmentally benign procedure. J. Heterocyclic Chem., (2012).     

A new synthesis of benzo[f]ninhydrin

A new four step synthesis of benzo[f]ninhydrin is described. This method utilizes affordable, readily available materials and reagents and is amenable to large scale production.     

I2‐catalyzed reactions of schiff base and alkyl aldehyde towards benzo[f]quinoline derivatives

A mild, efficient, and general method for the synthesis of benzo[f]quinoline derivatives via a molecular iodine‐catalyzed reaction of Schiff base with alkyl aldehydes has been described. The structure of 3o was confirmed by X‐ray diffraction study.     

Facile synthesis of 3‐substituted [1,2,4]triazino[3,4‐f]purine‐4,6,8‐trione derivatives

A new synthetic route to build the [1,2,4]triazino[3,4‐ f]purine nucleus is described. The novel [1,2,4]‐triazino[3,4‐ f]purine‐4,6,8(l H,7 H,9 H)‐trione derivatives were obtained by condensation of 8‐hydrazinotheophylline with appropriate glyoxylic acids via the intermediate hydrazones.     

One-pot synthesis of pyrano[2,3-d]pyrimidinone derivatives catalyzed by L-proline in aqueous media

An efficient protocol has been developed for the synthesis of various pyrano[2,3-d]pyrimidinones from condensation of aromatic aldehydes, malononitrile and barbituric-or thiobarbituric acid in aqueous ethanol using L-proline as a neutral bifunctional catalyst.     

N‐Bromosulfonamides catalyzed synthesis of new spiro [indoline‐3,4'‐pyrano[2,3‐c]pyrazole] derivatives

An efficient approach for the synthesis of pharmacologically important spiro[indoline‐3,4'‐pyrano[2,3‐c]pyrazole] derivatives from tandem, four component reaction of various hydrazines, isatins, β‐ketoesters, and malononitrile or methyl(ethyl)cyanoester in the presence of N,N,N',N'‐tetrabromobenzene‐1,3‐disulfonamide [ TBBDA ] and poly(N,N'‐dibromo‐N‐ethyl‐benzene‐1,3‐disulfonamide) [ PBBS ] as efficient organocatalysts was reported.     

以聚(4-乙烯基吡啶)硫酸氢盐为催化剂三组分一锅法合成苯并[f]茚并喹啉(英文)

7‐Aryl‐8H‐benzo[f]indeno[2,1‐b]quinoline‐8‐one derivatives were synthesized by means of a one‐pot condensation of 2‐naphthylamine, aromatic aldehydes, and indane‐1,3‐dione in ethanol under refluxing conditions in the presence of poly(4‐vinylpyridinium) hydrogen sulfate, a solid acid catalyst. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity. The structure of the novel compounds was confirmed by IR, 1H NMR, and 13C NMR spec-troscopy and elemental analysis.     

Green and efficient synthesis of pyrazolo[3,4‐b]quinolin‐5‐ones derivatives by microwave‐assisted multicomponent reaction in hot water medium

Novel simple, efficient, and eco‐friendly synthetic procedure for preparation of pyrazolo[3,4‐b]quinolin‐5‐ones based on three‐component microwaves‐assisted heterocyclization reaction of 5‐aminopyrazoles, aromatic aldehydes, and dimedone in hot‐water medium was developed. The new method allows obtaining target heterocycles in good and excellent yields and with high degree of purity. J. Heterocyclic Chem., (2011).     

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.     

SO3H‐functionalized ionic liquids catalyzed the synthesis of α‐aminophosphonates in aqueous media

SO₃H‐functionalized halogen‐free ionic liquids were prepared and used as efficient and recyclable catalysts for the synthesis of α‐aminophosphonates at room temperature via the one‐pot three‐component condensation reaction in aqueous media with good yields of 80–96%. The postprocessing was simple, and the catalysts could be reused at least six times without noticeably decreasing the catalytic activity. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:546–550, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20644     

An efficient synthesis of pyrazolo[3,4‐b]quinolin‐5(6H)‐one derivatives in ionic liquid

A series of 4‐aryl‐3,7,7‐trimethyl‐1‐phenyl‐7,8‐dihydro‐1H‐pyrazolo[3,4‐b]quinolin‐5(6H)‐ones were synthesized via the three‐component reaction of aromatic aldehydes, 5,5‐dimethyl‐1,3‐cyclohexandione and 5‐amino‐3‐methyl‐1‐phenylpyrazole in ionic liquid without using any catalyst. This protocol has the advantages of easier work‐up, milder reaction conditions, short reaction time, and environmentally benign procedure. J. Heterocyclic Chem., (2011).     

A convenient synthesis of 2-aryl substituted benzo[f] [1,2,4]triazolo[1,5-a]azepine derivatives

A convenient synthetic pathway to 2-aryl-5,6-dihydro-4H-benzo[f][1,2,4]triazolo[1,5-α]azepine derivatives 7 was developed. The synthesis was based on the cycloaddition of the 1,2,3,4-tetrahydronaphthalene a-acetoxy azo compounds 3 with Ar-CN in the presence of AlCl3 and the consecutive ring enlargement.