One‐pot synthesis of new 3‐substituted coumarins by tandem reactions

The synthesis of new 3‐substituted coumarins appended to imidazolium, pyridinium, 3‐dimethylamino pyridinium, 3‐chloro pyridinium and 3‐bromo pyridinium salts is reported. These salts were prepared by tandem reactions, followed by quantitative anionic metathesis. The structure of these new 3‐substituted coumarins was established by NMR (¹H, ¹³C) and high‐resolution mass spectrometry.     

A novel synthesis of 1‐substituted 2H‐isoquinolin‐3‐ones

The intramolecular cyclization of 2‐acylphenylacetonitriles 1 under strongly acidic conditions easily affords 1‐substituted 2H‐isoquinolin‐3‐ones 2 in excellent yields.     

One‐pot synthesis of 3,4‐dihydropyridin‐2‐ones via tandem reaction of Blaise reaction intermediate and acrylic ester

An efficient method for the synthesis 3,4‐dihydropyridin‐2‐ones has been developed via tandem one‐pot Michael‐type addition and cyclization of the Blaise reaction intermediate and acrylic ester. A series of readily available nitriles, bromoacetic esters and acrylic esters have been employed to examine the scope of substrates for this method. Copyright © 2015 John Wiley & Sons, Ltd.     

Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation

One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO₃ have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism.     

One‐pot synthesis of tetrahydroindeno[1,2‐b]pyrrolo‐3‐carboxylates derivatives

Tetrahydroindeno [1,2‐b]pyrrole‐3‐carboxylate were synthesized in a one‐pot procedure by the reaction of 1,3‐dicarbonyl and activated carbonyl compounds such as benzyl or ninhydrin in ethanol/water in the presence of ammonium acetate. J. Heterocyclic Chem., (2011).     

One‐pot dual size‐ and shape selective synthesis of tetrahedral Pt nanoparticles

One‐pot dual size‐ and shape‐selective synthesis of tetrahedral Pt nanoparticles is achieved using the pre‐prepared Pt nanoparticles as the ‘external seeds’, and controlling the slow diffusional growth under hydrogen reduction in the presence of PVP as the capping agent. Copyright © 2006 John Wiley & Sons, Ltd.     

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.     

An Efficient One‐pot Synthesis of 2‐Amino‐5‐arylidenethiazol‐4‐ones Catalyzed by MgO Nanoparticles

A mild and efficient protocol for the synthesis of 2‐amino‐5‐arylidene‐1,3‐thiazol‐4(5H)‐ones is reported by three component reaction of aldehydes, rhodanine and secondary amines in the presence of magnesium oxide nanoparticles as heterogeneous nanocatalyst in good yields and short reaction times.     

One‐pot synthesis of polyrotaxane by clipping and cyclopolymerization of α,ω‐diethynyl isophthalamide with pyridiniumdicarboxamide chloride

The one‐pot synthesis of a main chain‐type polyrotaxane composed of axle molecules threaded through the macrocyclic units on the polymer main chain was achieved via the combination of cyclopolymerization and clipping procedures. The cyclopolymerization of an α,ω‐diethynyl monomer bearing an isophthalamide moiety ( 1 ), which clips onto an axle component bearing a pyridiniumdicarboxamide moiety ( 2·Cl ) through a chloride anion was carried out in chloroform with the monomer concentration of 0.06 mol L^?1 at 40 °C using [Rh(nbd)Cl]₂/Et₃N as a catalyst to afford a gel‐free polymer. The resulting polymer was assigned to the main chain‐type polyrotaxane with a poly(phenylacetylene) backbone (poly‐ 3·Cl ) based on size exclusion chromatography and ¹H NMR measurements. The diffusion‐order two‐dimensional NMR and circular dichroism spectra provided definitive proof of the rotaxaned architecture in the polymer. The mole fraction of the rotaxane unit in the total cyclic repeating unit was determined to be 26.3%. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A new efficient synthesis of 3‐(hydroxymethyl)‐4H‐chromen‐4‐ones

An efficient and versatile synthesis of variously substituted 3‐(hydroxymethyl)‐4H‐chromen‐4‐ones is reported. The compounds are prepared by hydroxymethylation of the precursor 2‐hydroxy‐4‐chromanones followed by acid dehydration.     

One‐pot synthesis of hyperbranched glycopolymers by RAFT polymerization

Soluble hyperbranched glycopolymers were prepared by copolymerization of glycan monomers with reversible addition‐fragmentation chain transfer polymerization (RAFT) inimers in a simple one‐pot reaction. Two novel RAFT inimers, 2‐(methacryloyloxy)ethyl 4‐cyano‐4‐(phenylcarbonothioylthio)pentanoate (MAE‐CPP) and 2‐(3‐(benzylthiocarbonothioylthio)propanoyloxy)ethyl acrylate (BCP‐EA) were synthesized and used to prepare hyperbranched glycopolymers. Two types of galactose‐based saccharide monomers, 6‐O‐methacryloyl‐1,2:3,4‐di‐O‐isopropylidene‐D ‐galactopyranose (proGal‐M) and 6‐O‐(2′‐acrylamido‐2′‐methylpropanoate)‐1,2:3,4‐di‐O‐isopropylidene‐D ‐galactopyranose (proGal‐A), containing a methacrylate and an acrylamide group, respectively, were also synthesized and polymerized under the mediation of the MAE‐CPP and BCP‐EA inimers, respectively. In addition, hyperbranched poly(proGal‐M), linear poly(proGal‐A), and hyperbranched poly(proGal‐A) were generated and their polymerization kinetics were studied and compared. An unexpected difference was observed in the kinetics between the two monomers during polymerization: the relationship between polymerization rate and concentration of inimer was totally opposite in the two monomer–inimer systems. Branching analysis was conducted by using degree of branching (DB) as the measurement parameter. As expected, a higher DB occurred with increased inimer content. Furthermore, these polymers were readily deprotected by hydrolysis in trifluoroacetic acid solution resulting in water‐soluble polymers. The resulting branched glycopolymers have potential as biomimetics of polysaccharides. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

One‐pot synthesis of novel 2′‐deoxyuridine derivatives containing α‐aminophosphonate moieties

A series of α‐aminophosphonate derivatives of 2′‐deoxyuridine ( 8a–k ) have been prepared from 5′‐O‐tert‐butyldimethylsilyl‐3′‐amino‐2′, 3′‐dideoxyuridine in good yields. The structures of all the products were confirmed by ¹H NMR, ³¹P NMR, ³¹C NMR, and IR spectroscopy, and mass spectrometry and elemental analyses. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:230–235, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20288     

One‐pot PTC synthesis of polyfused pyrazoles

Thienopyrazole 2 , 3 , 5 , or 6 and thienopyrazolothiazepine 7, 9 , and 11 derivatives were prepared via the reaction of the 3‐aminopyrazoline‐5‐one 1 with CS₂ and different molar ratio of a variety of halo compounds having an active methylene under PTC conditions. Also, treatment of 1 with CS₂ and alcoholic KOH in 2:1:1 molar ratio afforded dipyrazolopyridine derivatives 12 and 14 . On other hand, the pyrazolothiadiazineone derivative 13 was obtained by treating compound 1 with CS₂ and alcoholic KOH in 1:2:2 molar ratio. Under PTC conditions, compound 1 , CS₂, and ethyl cyanoacetate or malononitrile to gave the pyrazolopyridine derivatives 16 and 17 . Coupling of compound 1 with diazonium acetates afforded the hydrazone derivatives 18a,b , which were oxidized with bromine to give pyrazolotriazoles 19a,b or cyclized with aldehydes to give pyrazolotriazine derivatives 20a–e . Bromination of compound 1 afforded monobromopyrazole derivative 21 , which could be condensed to a dipyrazolopyrazindione 23 . Finally, the dibromopyrazole derivative 22 was cyclized with 2‐mercaptoethanol or o‐phenylenediamine to give the spiropyrazoles 24a,b . © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:211–217, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10129     

One‐pot synthesis of 2‐acylimino‐3‐aryl‐1,3‐thiazoline derivatives in aqueous media

The one‐pot two‐step synthesis for acyliminothiazolines by treatment of N,N'‐substituted thioureas with α‐bromocarbonyl compounds under aqueous media was described. Compared to classical reaction in organic solvents, this method consistently has the advantages of short reaction time and being environmentally friendly.     

A convenient one‐pot synthesis of new 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones

Anhydrous zinc bromide catalysed reactions of arylidine‐3‐acetyl coumarins ( 1a‐c ) and 5,6‐benzoanalogs of arylidine 3‐acetyl coumarins ( 4a,4b ) with 1,3‐cyclohexanedione gives ‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐ones ( 3a, 3c ) and 5,6‐benzoanalogs of 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐one ( 5a,5b ). Under similar conditions arylidine‐3‐acetylcoumarins ( 1a, 1b,1d, 1e, 1f ) and 5,6‐benzoanalog of arylidine 3‐acetyl coumarin ( 4b ) react with 5,5‐dimethyl‐1,3‐cyclohexanedione (dimedone) yielding 3‐(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones ( 3d‐3h ) and the 5,6‐benzoanalog of 3.(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐one ( 5c ).     

One‐pot synthesis of 2,3‐disubstituted‐2,3‐dihydroquinazolin‐4(1H)‐ones using [Hmim][NO3]: An eco‐friendly protocol

An efficient method for the synthesis of a series of 2,3‐disubstituted‐2,3‐dihydroquinazolin‐4(1H)‐ones is described via one‐pot condensation reaction of isatoic anhydride, aryl aldehydes, and primary amines using a Brønsted acidic ionic liquid, [Hmim][NO₃], as a catalyst and medium. The present protocol enjoys convenient reaction and simple work‐up, greenness, short reaction times, and reusable catalyst as well as mild reaction conditions. J. Heterocyclic Chem., (2011).     

Asymmetric Proline‐Catalyzed Addition of Aldehydes to 3H‐Indol‐3‐ones: Enantioselective Synthesis of 2,3‐Dihydro‐1H‐indol‐3‐ones with Quaternary Stereogenic Centers

The proline‐catalyzed addition of various aliphatic aldehydes to sterically hindered 2‐aryl‐substituted 3H‐indol‐3‐ones affords 2,2‐disubstituted 2,3‐dihydro‐1H‐indol‐3‐one derivatives with excellent enantioselectivities. In addition, the synthesis of a chiral derivative, (S)‐2‐(2‐bromophenyl)‐2,3‐dihydro‐2‐(2‐hydroxyethyl)‐1H‐indol‐3‐one, which can be used as an intermediate for the preparation of the natural product hinckdentine A was accomplished with a high level of enantioselectivity.