A novel synthesis of some 2‐imino‐4‐thiazolidinone derivatives

An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α‐Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate.     

Microwave induced synthesis of the thiazolidine‐2,4‐dione motif and the efficient solvent free‐solid phase parallel syntheses of 5‐benzylidene‐thiazolidine‐2,4‐dione and 5‐benzylidene‐2‐thioxo‐thiazolidine‐4‐one compounds

Novel microwave induced method for the synthesis of thiazolidine‐2,4‐dione motif under solvent phase conditions is developed. Further we report an efficient, microwave assisted method for the parallel syntheses of biologically important 5‐benzylidene‐thiazolidine‐2,4‐dione and 5‐benzylidene‐2‐thioxothiazolidine‐4‐one compounds under solid‐phase and solvent‐free conditions. A comparative study between the developed microwave methods and the conventional methods is described. We have also illustrated the possible mechanism behind to address the reason why piperidine, acetic acid and silica gel enhanced the Knoevenagel condensation reaction.     

Synthesis and stereochemical studies of 2‐substituted thiazolidine‐4‐carboxamide derivatives

A series of new 2‐substituted thiazolidine‐4‐carboxamide derivatives which have potentially useful immunological properties, have been synthesized in a stereoselective manner by coupling 2‐subsituted thiazolidine‐4‐carboxylic acids with amines or amino esters. The structure of these compounds was established by combination of NMR methods and by X‐ray analysis.     

Microwave‐assisted synthesis of some 1,2,4‐triazol‐5‐one derivatives

A series of 3‐alkyl(aryl)‐4‐(p‐hydroxy‐phenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 2 were obtained from the reaction of alkyl (aryl) ester ethoxycarbonyl hydrazones 1 with p‐hydroxy aniline. The reaction of 1 with 1,4‐diamino benzene (1:1) to afford 3‐alkyl(aryl)‐4‐(p‐aminophenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 3 . The reaction of 3 with benzaldehyde gave 3‐alkyl(aryl)‐4‐(4′‐benzilidenamino)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 4 . All of the above reactions occurred under microwave heating and conventional methods. Their structures were confirmed by ¹H NMR, ¹³C NMR, IR, and elemental analyses. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:38–42, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20381     

A rapid and efficient catalysis system for the synthesis of 4‐vinylbiphenyl derivatives

A series of 4‐vinylbiphenyl derivatives were synthesized by Pd(OAc)₂/PCy₃‐catalyzed Suzuki–Miyaura reaction in the presence of K₃PO₄.3H₂O as base in toluene at 80°C for only 10–30 min, and the corresponding products achieved 65–98% yields. According to this efficient C―C bond‐forming method, the obtained yields of 4‐vinylbiphenyl liquid crystal compounds were up to 92–96%. Copyright © 2013 John Wiley & Sons, Ltd.     

An efficient synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives under catalyst‐free and solvent‐free conditions

A simple, efficient and convenient one‐pot synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives under solvent‐free and catalyst‐free conditions by the reaction of aromatic aldehydes, isatoic anhydride, and ammonium acetate was reported. The advantages of this protocol include short reaction time, mild reaction conditions, easy work‐up, high yields, and environmental friendliness. J. Heterocyclic Chem., (2011).     

An efficient synthesis of new class of pyrazolo[3,4‐b]pyridine‐6‐one derivatives by a novel cascade reaction

A novel cascade reaction of 4‐arylidene‐2‐phenyl‐1,3‐oxazol‐5(4H)‐one with 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine was described and a number of new pyrazolo[3,4‐b]pyridine‐6‐one derivatives were synthesized. This new protocol has the advantages of shorter time, higher yields, and lower cost as well as easier operation.     

A facile one pot synthesis of 2, 4‐diamino‐6‐substituted s‐triazine derivatives

A novel and facile one‐pot procedure for the preparation of 2,4‐diamino‐6‐substituted‐s‐triazine derivatives (IIa‐n) was reported. The scope of its application was demonstrated with a number of examples. The new procedure involved treatment of proguanil or chloroproguanil with acyl chloride or alky chlorooxoacetate in pyridine at ice cold temperature followed by reflux overnight to give good yields of the desired products.     

A simple one‐pot synthesis of 1,2,3,4‐tetrahydro‐2‐thioxopyrimidine derivatives

5‐Benzoyl‐4‐(substituted phenyl)‐6‐phenyl‐1,2,3,4‐tetrahydro‐2‐thioxopyrimidines ( 4a‐d ) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β‐diketone, arylaldehyde, and thiourea in acetic acid under reflux condition in approximately 52‐65% yields. The acetylation of compounds 4a‐d gave 3‐acetyl thioxopyrimidine derivatives 5a‐d . Also, pyrimidothiazine compounds 6a‐d were prepared by a simple one‐pot condensation reaction of starting pyrimidine derivatives 4a‐d and 3‐bromopropionic acid. The structures of compounds were characterized on the basis of elemental analyses, IR, ¹H and ¹³C‐NMR spectra.     

Convenient synthesis of some 2‐substituted 4(3H)‐quinazolinone derivatives

A series of 2‐substituted‐4(3H)‐quinazolinones 13‐20 has been synthesized in good yields using the reaction of double lithiated 2‐methylquinazolinone‐4 with a variety of aromatic aldehydes. They have been easily transformed in high yields into the corresponding 2‐substituted conjugated derivatives 21‐28 bearing terminal aryl groups by F₃CCOOH mediated dehydration.     

An efficient one‐pot synthesis of polyhydrobenzoacridine‐1‐one derivatives under microwave irradiation without catalyst

A series of 3,3‐dimethyl‐9‐substituted‐1,2,3,4,9,10‐hexahydrobenzo[c] acridine‐1‐ones and 3,3‐dimethyl‐9‐substituted‐1,2,3,4,9,10‐hexahydrobenzo[a] acridine‐1‐ones were synthesized by the reaction of an aldehyde, α‐naphthylamine or β‐naphthylamine and dimedone under microwave irradiation with short times and high yields.     

Microwave‐assisted synthesis of some 2,4‐thiazolidinedione derivatives

The condensation of 5‐[4′‐(2″‐halo‐ethoxy)benzylidenyl]‐2,4‐thiazolidinediones 2 when separately carried with different 2‐amino thiazoles 3 and different sulphanilamides 4 in DMF, using potassium hydroxide in the presence of a catalytic amount of a phase transfer catalyst, gave new 5‐[4′‐(4″‐aryl‐thiazol‐2″‐yl‐aminoethoxy)‐3′/5′‐substituted benzylidenyl]‐2,4‐thiazolidinediones 5 and 5‐[4′‐(2″/4″‐sulphonamidophenyl aminoethoxy)‐3′/5′‐substituted benzylidenyl]‐2,4‐thiazolidinediones 6 derivatives in good yields, respectively. The structures of all new compounds were established from analytical and spectral data. All the reaction sequences were carried under microwave irradiation, as an efficient tool. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:151–156, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20528     

An efficient synthesis of new pyrido[4′,3′:4,5]thieno[2,3‐d]‐pyrimidin‐4(3H)‐one derivatives

The carbodiimides 5 , obtained from reactions of iminophosphorane 4 with aromatic isocyanates, reacted with amines, phenols or ROH to give 2‐substituted 5,6,7,8‐tetrahydropyrido[4′,3′:4,5]thieno[2,3‐d]‐pyrimidin‐4(3H)‐one 7 in the presence of catalytic amount of sodium alkoxide or solid potassium carbonate in satisfactory yields.     

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.     

Syntheses of some new 1H‐pyrazole,pyridazin‐3(2H)‐one,and oxazin‐4‐one derivatives

The new 1H‐pyrazole‐3‐carboxylic acid 2 , pyridazin‐3(2H)‐one 3 , and their various derivatives were prepared by the reactions of the 4‐benzoyl‐5‐phenyl‐2,3‐dihydro‐2,3‐furandione 1 and 2,5‐dichlorophenylhydrazine. Pyrazolo[3,4‐d]pyridazine 7 was obtained from cyclization of the pyrazole‐3‐carboxylic acid 2 with 2,5‐dichlorophenylhydrazine. The reaction of 1 and pyrazole‐3‐carbonitriles 6 gave the new oxazin‐4‐one 9 derivatives. The structures of compounds were characterized on the basis of elemental analyses, mass, IR, ¹H, and ¹³C NMR spectra. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:8–12, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20170     

Synthesis of some novel derivatives of 1,10‐phenanthroline

The synthesis is described of a set of new N‐heterocyclic compounds which are derivatives of 1,10‐phenanthroline. The compounds are designed to be general purpose chelating agents which could function as tri‐, tetra‐ or hexadentate ligands with transition metal ions. Fused‐ring molecular components have been included in the design of the compounds so that they may function as binding agents to DNA through intercalation. This includes the synthesis of substituted derivatives of pyrazino[2,3‐f][1,10]phenanthroline and dipyrido[3,2‐a:2′3′‐c]phenazine.     

A simple and efficient one-step synthesis of 3-substituted-4-hydroxyquinolin-2-one derivatives

A new simple and efficient one-step procedure for the preparation of 3-substituted-4-hydroxyquinolin-2-one derivatives was developed. Product isolation is simple, isolated yields are good to excellent and this method tolerates a variety of substitution patterns.