Synthesis of some pyridine,thiopyrimidine, and isoxazoline derivatives based on the pyrrole moiety

Abstract  Condensation of 2-acetylpyrrole with 5-methylfuran-2-carboxyaldehyde and 4-chlorobenzaldehyde in 20% NaOH give the corresponding 2-chalconylpyrroles. Some new 2-alkoxy-3-cyano-4,6-diarylpyridines were synthesized by condensation of chalcones with malononitrile, followed by cyclization in sodium alkoxide. The reactivity of chalcones towards nitrogen nucleophiles such as thiourea and hydroxylamine hydrochloride to provide thiopyrimidines and isoxazolines was investigated. Graphical Abstract        

Synthesis of 3-(quinoxalin-2-yl)-2H-chromen-2-ones under microwave irradiation

Abstract  A facile procedure for the synthesis of quinoxalines is being reported starting from 3-(2-bromoacetyl)coumarins or 3-(2-bromobutanoyl)coumarins and substituted o-phenylenediamines. The reactions were carried out under catalyst-free and microwave irradiation conditions producing the title compounds in moderate to excellent yields in a short time with easy workup. The structures of all new compounds have been confirmed on the basis of their IR, ¹H NMR, ¹³C NMR, and HRMS data. Graphical Abstract        

An efficient 1,3-allylic carbonyl transposition of chalcones

Abstract  A very simple, convenient, and efficient procedure is reported for the 1,3-allylic carbonyl transposition of chalcones. The transposition can be achieved by reduction of chalcones to 1,3-diarylpropan-1-ols and dehydration of the latter to give 1,3-diarylpropenes followed by benzylic/allylic oxidation. Graphical abstract        

Amino acid derivatives, X [1]: synthesis and antimicrobial evaluation of α-amino acid esters bearing a N1-protected tryptophan side chain

Abstract  A series of peptide derivatives conjugated with N¹-protected tryptophan residue was synthesized. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying different degrees of antibacterial activities or inhibitory actions. Graphical Abstract        

Synthesis of imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridones and imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridines as potential antibacterial agents

Abstract  New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl₃. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug. Graphical abstract        

New route to 2-arylthieno[2,3-d]pyrimidin-4(3H)-ones and isolation of the unoxidized intermediates

Abstract  A new route to the synthesis of 2-arylthieno[2,3-d]pyrimidin-4(3H)-ones has been developed through heterocyclization of 2-amino-4,5-dimethylthiophene-3-carboxamide with aromatic aldehydes in boiling glacial acetic acid followed by air oxidation. The unoxidized intermediates, 2-aryl-2,3-dihydrothieno[2,3-d]pyrimidin-4(1H)-ones, are isolated when the reactions are carried out either at room temperature or under a nitrogen atmosphere. Graphical Abstract        

An efficient and convenient protocol for the synthesis of novel 1′H-spiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione derivatives

Abstract  An efficient and direct procedure for the synthesis of novel spiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione derivatives is described. The process employs a condensation reaction of 2-aminobenzamides and isatins in the presence of a catalytic amount of KAl(SO₄)₂.12H₂O (alum) in ethanol under reflux. Graphical Abstract        

A highly efficient and ecofriendly procedure for tetrahydropyranylation of alcohols and phenols in the presence of in-situ generated I2 under heterogeneous and neutral conditions

Abstract  Molecular iodine generated in situ from Fe(NO₃)₃·9H₂O/NaI acts as a highly efficient catalyst for tetrahydropyranylation of various alcohols and phenols with 3,4-dihydro-2H-pyran in almost quantitative yields. The reaction occurs rapidly in dichloromethane at room temperature, and use of toxic molecular iodine is avoided. Graphical Abstract        

C-Furyl glycosides, II: synthesis and antimicrobial evaluation of C-furyl glycosides bearing pyrazolines, isoxazolines, and 5,6-dihydropyrimidine-2(1H)-thiones

Abstract  New C-furyl glycosides bearing pyrazolines, isoxazolines, and dihydropyrimidine-2(1H)-thiones were synthesized in order to increase the number of tested compounds screened for antimicrobial activity. The antimicrobial activity screening showed that the pyrazoline derivatives were the most active compounds. Graphical abstract        

A mild and expedient one-pot synthesis of substituted benzimidazoles in water using a phase-transfer catalyst

Abstract  1-Alkyl/phenyl-2-arylbenzimidazoles have been synthesized in very good to excellent yields by a one-pot condensation of N-alkyl/phenyl-o-phenylenediamines with aryl aldehydes in water at room temperature using cetylpyridinium bromide as a cheap and eco-friendly catalyst. Graphical abstract        

Heterocycles [<Emphasis Type="Italic">h</Emphasis>]-fused to 4-oxoquinoline-3-carboxylic acid. Part VII: synthesis of some 6-oxoimidazo[4,5-<Emphasis Type="Italic">h</Emphasis>]quinoline-7-carboxylic acids and esters

Abstract  A series of ethyl 2-(substituted)-9-cyclopropyl-4-fluoro-6-oxo-1H-imidazo[4,5-h]quinoline-7-carboxylates has been prepared from ethyl 7,8-diamino-1,4-dihydroquinoline-3-carboxylate via thermally induced reactions with model alkanoic acids or via microwave-assisted cyclocondensation with some arene carboxaldehydes. Acid-catalysed hydrolysis of the resulting ester derivatives furnished the corresponding imidazoquinoline-7-carboxylic acids. The structures of these new acid and ester derivatives are based on microanalytical and spectral (IR, MS, and NMR) data. Graphical abstract        

Synthesis of benzohetero[3, 2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines using cyclic β-keto lactone as a building block

Abstract  A novel method for the synthesis of 3-(2-substituted ethyl)-2-methylbenzohetero[3,2-a]pyrimidines in high yield (80–85%) was achieved, which involves a dihydrofuranone intermediate, readily obtained from β-ketolactone to 2-aminobenzoheterocycles. The major advantage of the methodology is the high yield and product purity. Graphical Abstract        

Polyvinylpolypyrrolidone-supported boron trifluoride: a high-loaded,polymer-supported Lewis acid for the Ritter reaction

Abstract  A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl alcohols was also achieved. Graphical abstract        

A one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from thioamides or thioureas and 2-chloro-1,3-dicarbonyl compounds in an ionic liquid

Abstract  A simple one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from the reaction of 2-chloro-1,3-dicarbonyl compounds with thioureas or thioamides in the presence of 1-butyl-3-methylimidazolium trifluoromethanesulfonate is described. Graphical abstract        

A diol-functionalized ionic liquid: an efficient, simple, and recoverable “capture and release” reagent for aldehydes

Abstract  A new diol-functionalized ionic liquid, 2,2-bis(1-(1-methylimidazolium)methylpropane-1,3-diol hexafluorophosphate, was synthesized and applied as a facile, efficient, and recoverable “capture and release” reagent for aldehydes. This method has the advantages of homogeneous reaction, heterogeneous separation, and recyclable uses. Graphical abstract        

Synthesis and antioxidant activity of some thiazolidin-4-one derivatives

Abstract  4-Fluorobenzaldehyde was used for the preparation of 2-(4-fluorophenyl)thiazolidin-4-one derivatives which were allowed to react with chloroacetonitrile and acrylonitrile to produce 3-(2-(4-fluorophenyl)-4-oxothiazolidine3-yl)acetonitrile and 3-(2-(4-fluorophenyl)-4-oxothiazoledine-3-yl)propanenitrile. Biological evaluation of some of the compounds showed that many had promising antioxidant activity. Graphical Abstract        

Synthesis of imatinib: a convergent approach revisited

Abstract  A classical convergent approach for the synthesis of the anticancer drug imatinib has been substantially improved. Imatinib was assembled by coupling the amine and carboxylic acid precursors by using N,N′-carbonyldiimidazole (CDI) as a condensing agent. Both intermediates have been synthesized by novel efficient methods. Graphical abstract        

Synthesis and biological evaluation of 5-substituted benzo[b]thiophene derivatives as anti-inflammatory agents

Abstract  5-Aminobenzo[b]thiophene-2-carboxylic acid was converted to the corresponding 5-(2-chloroacetamido)benzo[b]thiophene-2-carboxylic acid by reaction with chloroacetyl chloride. This acetamido product was treated with different alkyl, cycloalkyl, aryl, and heterocyclic amines to afford a series of C5-substituted benzo[b]thiophenes. These compounds were found to possess potent anti-inflammatory activity. Graphical abstract        

Electrochemical production of novel products from 2,3-dimethylhydroquinone in the presence of some β-diketones

Abstract  Electrochemical oxidation of 2,3-dimethylhydroquinone has been studied in the presence of β-diketones as nucleophiles in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the derivatives of 2,3-dimethylhydroquinone participate in a Michael addition reaction to form the corresponding benzofuran derivatives. The electrochemical synthesis has been successfully performed at pH 7.0 and E = 0.1 V versus an Ag|AgCl|KCl (3 M) in an undivided cell in good yield and purity. Graphical Abstract        

Three-components condensation catalyzed by molecular iodine for the synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions

Abstract  One-pot, three-components synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones was performed under solvent-free conditions using molecular iodine as the catalyst in moderate to good product yields. Graphical abstract