Synthesis of-4-((4-trimethylsilyl-1H-1,2,3-triazol-1-yl)methyl)-2H-chromen-2-ones: A novel class of heteroaryl anionic synthon

A one-pot synthesis of some novel anionic scaffolds: the substituted-4-((4-trimethylsilyl-1H-1,2,3-triazol-1-yl)methyl)-2H-chromen-2-one is reported. Reaction of 10 different substituted bromomethylcoumarins with trimethylsilylacetylene and sodium azide in the presence of copper(I) iodide catalyst gave the corresponding heteroaryl conjugates: the substituted-4-((4-trimethylsilyl-1H-1,2,3-triazol-1-yl)methyl)-2H-chromen-2-one in 70–92% yields. The structures of the synthesized compounds have been completely characterized by spectral and elemental analyses. For the first time, the representative single-crystal X-ray structure analysis of 6-methoxy-4-((4-trimethylsilyl-1H-1,2,3-triazol-1-yl)methyl)-2H-chromen-2-one is reported which confirms the formation of anionic synthon which bears the trimethylsilyl-group.     

Synthesis of Novel 2-(4-Oxo-3,4- Dihydroquinazolin-2-Ylsulfinylmethyl)-3H-Quinazolin-4-One

Abstract

Condensation of 2-mercapto-3H-quinazolin-4-one (1) with chloroacetic acid gave 4-oxo-3,4-dihydroquinazoline-2-yl-sulfanyl)-acetic acid (2) that with anthranilamide (3) gave 2-(4-oxo-3,4-dihydroquinazolin-2-ylsulfanylmethyl)-3H-quinazolin-4-one (4). Oxidation of 4 with sodium hypochlorite in alkaline medium gave the novel product, 2-(4-oxo-3,4- dihydroquinazolin-2-ylsulfinyl methyl)-3H -quinazolin-4-one) (5). The entire sequences of reactions in this work have been carried out using eco-friendly solvents and green conditions.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and Antibacterial Evaluation of Novel 3,6-Disubstituted Coumarin Derivatives

A novel series of 3,6-disubstituted coumarin derivatives were synthesized by the reaction of ethyl-2-(3-acetyl-2-oxo-2H-chromen-6-yl)-4-methylthiazole-5-carboxylate with thiosemicarbazide and various phenacyl bromides / 3-(2-bromoacetyl)-2H-chromen-2-ones / 2-(2-bromoacetyl)-3H-benzo[f]chromen-3-one in ethanol having catalytic amount of acetic acid under reflux conditions with good yields. All the synthesized compounds were fully characterized by spectral studies and evaluated for their in vitro antibacterial activity against Pseudomonas aeruginosa, Bacillus subtilis (Gram positive), Escherichia coli, and Azatobacter (Gram negative) bacterial strains. Activity results revealed that the compound 6h against Escherichia coli and compound 6i against Pseudomonas aeruginosa and Escherichia coli have shown maximum zones of inhibition. Remaining compounds showed moderate to good activity against all the tested bacterial strains compared with the standard drug cefotaxime.     

Efficient stepwise and one pot three-component synthesis of 2-amino-4-(2-oxo-2H-chromen-3-yl)thiophene-3-carbonitriles

Environmentally benign conditions have been developed for the synthesis of 2-amino-4-(2-oxo-2H-chromen-3-yl)thiophene-3-carbonitriles (3) starting from 3-acetyl-2H-chromen-2-one (1) through the intermediacy of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)malononitrile (2) using the Knoevenagel condensation followed by the Gewald reaction. Alternatively, 3 could also be prepared in a one pot method by treating equimolar amounts of 1, malononitrile, and elemental sulfur. The merits of this preparation are mild reaction conditions, easy work-up procedure, and good yields.     

Synthesis and anticancer activity evaluation of 3-(4-oxo-2-thioxothiazolidin-5-yl)-1H-indole-carboxylic acids derivatives

Abstract

A mild and efficient method for the synthesis of 1-oxo-9H-thiopyrano[3,4-b]indole-3-carboxylic acids and dimerized 3-(4-carboxy-1H-3-indolyl)-2-propenoic acids via alkaline hydrolysis of 3-(rhodanin-5-yl)-1H-indole-2-carboxylic acids derivatives was elaborated. Anticancer activity screening in NCI60-cell lines assay allowed identification of 5-fluoro-3-(4-oxo-2-thioxothiazolidin-5-ylidenemethyl)-1H-indole-2-carboxylic acid methyl ester 2a with significant antimitotic activity at micromolar and submicromolar concentrations.     

Effective Synthesis of Polysubstituted Pyrroles from (E)-Dimethyl 2-(Bromomethyl)-3-(diethoxyphosphoryl) Fumarate

Methyl 1-alkyl-4-(diethoxyphosphoryl)-5-oxo-2,5-dihydro-1H-pyrroles-3-carboxylate 4 was synthesized from the reaction of dimethyl 2-(bromomethyl)-3-(diethoxyphosphoryl) fumarate 3- E and primary amines in good yields.     

Short Synthesis of 1-(3-tert-Butyl-1-phenyl-1H-pyrazol-5-yl)-3-(5-(2-morpholinoethoxy)-2H-chromen-8-yl) Urea Derivatives

A short and efficient synthesis of 1-(3-tert-butyl-1-phenyl-1H-pyrazol-5-yl)-3-(5-(2-morpholinoethoxy)-2H-chromen-8-yl) urea derivatives (1a–c), a novel type of p38 MAPK inhibitors, is described. The Claisen thermal rearrangement of arylpropargyl ethers was employd as a key step to synthesize the chromene core. The solvent effect on the ratio of the resultant two isomers of Claisen thermal rearrangement, namely 2-methylbenzofuran and 2H-chromen, was also investigated.     

4-(3-Cyanopyridin-2-ylthio)acetoacetates in synthesis of heterocycles

Substituted 2-amino-4-aryl-3-cyano-5-oxo-5,6-dihydro-4H-pyrano[2,3-d]pyrido[3",2":4,5]thieno[3,2-b]pyridines were synthesized by the reactions of 4-hydroxy-1H-thieno[2,3-b;4,5-b]dipyridin-2-ones with arylidenemalononitriles or by the three-component reactions of hydroxythienodipyridinones with aldehydes and malononitrile in DMF in the presence of triethylamine. Methods for syntheses of substituted 3-alkoxycarbonyl-6-amino-4-aryl-2-(3-cyanopyridin-2-ylthiomethyl)-4H-pyrans were developed on the basis of the reactions of 4-(3-cyanopyridin-2-ylthio)acetoacetates and arylidenemalononitriles or aldehydes and malononitrile. Ethyl 4-(3-cyanopyridin-2-ylthio)acetoacetate and 4-methoxybenzylidenecyanothioacetamide were used for the synthesis of 6-(pyridin-2-ylthiomethyl)-3-cyanopyridine-2(1H)-thione.     

Bis coumarinyl bis triazolothiadiazinyl ethane derivatives: Synthesis,antiviral activity evaluation,and molecular docking studies

A series of novel 3,3′-(3,3′-(dihydroxy/hydroxyethane-1,2-diyl)bis(7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-6,3-diyl))bis(2H-chromen-2-ones) were prepared by the condensation of thiocarbohydrazide with tartaric acid or malic acid followed by various 3-(2-bromoacetyl)-2H-chromen-2-ones in two steps with good yields. All the synthesized compounds were characterized by analytical and spectral (IR, ¹H NMR, ¹³C NMR, and mass) data. These synthesized bis(triazolothiadiazinyl coumarin) compounds were evaluated for broad spectrum of antiviral activity. Among all the tested compounds, compound 5f exhibited antiviral activity against H1N1 virus. The molecular docking studies of these compounds against H1N1 neuraminidase enzyme were performed. The binding affinity and binding values were compared with standard drugs.     

Chemoenzymatic synthesis of both enantiomers of 3-hydroxy-2,3-dihydro-4H-chromen-4-one

4-Oxo-3,4-dihydro-2-chromen-3-yl acetate is synthesized using manganese(III)acetate starting from 2,3-dihydro-4H-chromen-4-one. K₂CO₃ mediated hydrolysis of 4-oxo-3,4-dihdro-2-chromen-3-yl acetate furnished 3-hydroxy-2,3-dihydro-4H-chromen-4-one in high yield.The enantioselective hydrolysis of (±)-4-oxo-3,4-dihydro-2-chromen-3-yl acetate in various organic solvent-phosphate buffer (pH7) systems and enantioselective transesterification of (±)-3-hydroxy-2,3-dihydro-4H-chromen-4-one in organic solvents was investigated by screening a range of lipases. The lipase Amano PS, PPL, PLE and CCL-catalyzed asymmetric ester hydrolysis and transesterification afforded the enantiomers of 3-hydroxy-2,3-dihydro-4H-chromen-4-one and 4-oxo-3,4-dihydro-2-chromen-3-yl acetate with high enantiomeric excess (up to 97% ee) and in good yields.     

One-Pot Synthesis and Methylation of 3-[2-(1H-Benzimidazol-2-yl-Sulfanyl)-Acetyl]-Chromen-2-Ones

Abstract

3-(2-Bromoacetyl)coumarins (I), when treated with 2-mercatobenzimidazole (II) in acetone containing K₂CO₃ (mild base) and tetrabutylammonium bromide (TBAB) as a phase transfer catalyst, at room temperature yielded the title compound 3-[2-(1H-benzimidazole-2-yl-sufanyl)-acetyl]-chromen-2-one (III) in a one-pot synthesis. Alternatively, III could also be prepared by treating dithiocarbonic acid O-ethyl ester, S-[2-oxo-2-(2-oxo-2H-chromen3-yl)-ethyl] ester (V), with o-phenylenediamine (VI). The methylation of the title compound III was performed with dimethyl sulfate (DMS), in acetonitrile containing TBAB and K₂CO₃ at room temperature, resulting in 3-[2-(N-methyl-benzimidazol-2-yl-sulfanyl)]-acetyl-chromen-2-ones (VII). Alternatively, methylation of III could also be performed with DMS in acetonitrile containing K₂CO₃ as base and clay as surface catalyst. All the compounds were synthesized in good yields and their structures were confirmed by spectral and analytical data.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: ¹H NMR of IIIB, VB and VIIB]     

Cyclopropanation of 3-(2-Oxo-2<Emphasis Type="Italic">H</Emphasis>-chromen-3-yl-carbonyl)-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-one with Zinc Enolates Derived from 1-Aryl-2,2-dibromoalkanones

Zinc enolates derived from 1-aryl-2,2-dibromoalkanones react with 3-(2-oxo-2H-chromen-3-ylcarbonyl)-2H-chromen-2-one to give 1-alkyl-1-aroyl-1a-(2-oxo-2H-chromen-3-ylcarbonyl)-1a, 7b-dihydrocyclopropa[c]-chromen-2(1H)-ones as a single stereoisomer.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 131–133.Original Russian Text Copyright © 2005 by Shchepin, Russkikh, Uzun, Silaichev.     

Studies on Antimicrobial Evaluation of Some 1-((1-(1H-Benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1, 2-dihydropyridine-3,5-dicarbonitriles

A new series of 1-((1-(1H-benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles (4a–o) have been synthesized for the development of antimicrobial agents. Newly synthesized compounds were evaluated for their in vitro antibacterial activity against Gram-positive bacteria (Pseudomonas aeruginosa, Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Staphylococcus aureus), and antifungal activity (Candida albicans, Aspergillus niger, Aspergillus clavatus). These compounds were characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectra. The synthesized compounds 4b, 4e, 4 h, and 4k showed potent antimicrobial activity against tested microorganisms.     

Synthesis, reactions and antineoplastic activity of 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromene derivatives

The key 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromen-5-yl acetates 3 were synthesized in high yields by cyclocondensation of 4-oxo-4H-chromen-3-carbaldehydes 1 with coumarin-3-acetic acids 2 under mild conditions. The reaction pathway involves aldol condensation and subsequent intramolecular lactonization to afford 2-oxo-2H,5H-pyrano[3,2-c]chromene skeleton 3. Further treatment of acetates 3 with alcohols, water or nitrogen containing compounds led to 5-alkoxy-, 5-hydroxy- or 5-acylamino-2H,5H-pyrano[3,2-c]chromen-2-ones 4-6 via nucleophilic substitution of acetyloxy group at C-5. Acetates and hydroxyl derivatives 3 and 5 undergo facile rearrangement in an acid medium yielding 5-hydroxypyrano[2,3-b]chromen-2(10aH)-ones 7. Twelve prepared compounds were evaluated on their antineoplastic activities on 60 human tumour cell line panels in NCI USA. The obtained biological results confirmed that 3-(2-oxo-2H-chromen-3-yl)-2H,5H-pyrano[3,2-c]chromen-2-one represents a new leading skeleton suitable for further antitumour activity study.     

Enantioselective synthesis of 2-amino-4-(nitromethyl)-4H-chromene-3-carbonitriles from 2-iminochromenes

A series of medicinally important 2-amino-4-(nitromethyl)-4H-chromene-3-carbonitriles were synthesized using enantioselective conjugate addition of nitromethane to 2-iminochromenes. The reactions were performed using L8-Cu (II) catalytic system and moderate to good enantioselectivities (62–88%) and yields (66–96%) were obtained.     

Reactions of 5,6,7,8-Tetrafluoro-4-hydroxy-2H-chromen-2-ones with methylamine

5,6,7,8-Tetrafluoro-4-hydroxy-2H-chromen-2-one reacts with methylamine to give methylammonium 5,6,7,8-tetrafluoro-2-oxo-2H-chromen-4-olate, regardless of the solvent. The reaction of 3-acetyl-5,6,7,8-tetrafluoro-4-hydroxy-2H-chromen-2-one with the same amine in ethanol or acetonitrile leads to the formation of methylammonium 3-acetyl-5,6,7,8-tetrafluoro-2-oxo-2H-chromen-4-olate, while in dimethyl sulfoxide 5,6,8-trifluoro-7-methylamino-3-(1-methylaminoethylidene)-3,4-dihydro-2H-chromene-2,4-dione is formed. The latter is also formed in the reaction of 5,6,7,8-tetrafluoro-4-hydroxy-3-(1-iminoethyl)-2H-chromen-2-one with methylamine in DMSO, whereas in ethanol and acetonitrile 5,6,7,8-tetrafluoro-3-(1-methylaminoethylidene)-3,4-dihydro-2H-chromene-2,4-dione is obtained. 5,6,7,8-Tetrafluoro-3-(1-methylaminoethylidene)-3,4-dihydro-2H-chromene-2,4-dione reacts with methylamine, yielding 7-mono-or 5,7-bis(methylamino)-substituted derivatives.     

Synthesis of 1-(2-hydroxyphenyl)-2,4-imidazolidinedione derivatives through cyclic transformations of ethyl 2-oxo-3(2H)-benzoxazoleacetate derivatives

A series of ethyl 2-oxo-3(2H)-benzoxazoleacetate derivatives 2 have been synthesized. By reaction with ammonia, primary amines or hydrazine, these compounds 2 were transformed into 1-(2-hydroxyphenyl)-2,4-imidazolidinedione derivatives 4, 5 and 6 , respectively. Some of these new hydantoins 4 , treated with phosphorus oxychloride, gave 3H-2-oxoimidazo[2,1-b]benzoxazole derivatives 9 . Ethyl 2-oxo-3(2H)-benzoxazolepropionate ( 10 ) was prepared by a Michaël reaction of ethyl acrylate with 2-benzoxazolone ( 1a ). With 10 , no cyclic transformation was observed in the presence of ammonia or alkylamine.     

Reactions of 1-Aryl-2,2-dibromobutan-1-ones with Zinc and Alkyl 6-Bromo-2-oxo-2-H-chromen-3-carboxylate

Zinc enolates formed from 1-aryl-2,2-dibromobutan-1-ones and zinc react with alkyl 6-bromo-2-oxo-2-H-chromen-3-carboxylates affording alkyl 1-aroyl-6-bromo-2-oxo-1-ethyl-1,7b-dihydrocyclopropa[c]-chromen-1a(2H)-carboxylates as a single isomer.     

A convenient ultrasound-promoted synthesis of some new thiazole derivatives bearing a coumarin nucleus and their cytotoxic activity

Successful implementation of ultrasound irradiation for the rapid synthesis of a novel series of 3-[1-(4-substituted-5-(aryldiazenyl)thiazol-2-yl)hydrazono)ethyl]-2H-chromen-2-ones 5a-h, via reactions of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene) thiosemicarbazide (2) and the hydrazonoyl halides 3(4), was demonstrated. Also, a new series of 5-arylidene-2-(2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinyl)thiazol-4(5H)-ones 10a-d were synthesized from reaction of 2 with chloroacetic acid and different aldehydes. Moreover, reaction of 2-cyano-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)-acetohydrazide (12) with substituted benzaldehydes gave the respective arylidene derivatives 13a-c under the conditions employed. The structures of the synthesized compounds were assigned based on elemental analyses and spectral data. Also, the cytototoxic activities of the thiazole derivative 5a was evaluated against HaCaT cells (human keratinocytes). It was found that compound 5a possess potent cytotoxic activity.     

Convenient synthesis of 4H-chromenyl-tetrahydro-2H-pyrancarboxylates and cleavage of chromone and pyran rings leading to 5-(2-hydroxybenzoyl)-2-(trifluoromethyl)-1,2-dihydropyridine-3-carboxylates

4H-Chromenyl-tetrahydro-2H-pyrancarboxylates 3a–k have been conveniently prepared by the reaction of 3-formylchromones 1a–k and ethyl 4,4,4-trifluoro-3-oxobutanoate 2a with good yields. Thus obtained 4H-chromenyl-tetrahydro-2H-pyrancarboxylates 3a–k were reacted with amines 4a–e to provide series of 5-(2-hydroxybenzoyl)-2-(trifluoromethyl)-1,2-dihydropyridine-3-carboxylates 5a–o. The reaction proceeded via Michael addition (C-N bond formation) and followed by cleavage of chromone and pyran rings (C-O bond cleavage) in one pot.