A simple procedure for the synthesis of 3-(substituted-sulfanyl)-4-hydroxy-6-substituted-pyran-2-ones

A series of 3-(substituted sulfanyl)-4-hydroxy-6-substituted-pyran-2-ones were synthesized for Human immunodeficiency virus-1 protease inhibition. These compounds were synthesized in a simple and convergent fashion to allow us a rapid preparation of many structurally diversified analogues. Thus the condensation of trimethylsilyl enol ethers of corresponding ketones, with 2-(S-substituted)propane-1,3-dioates afforded the corresponding pyrones in 24–70% isolated yields.     

Synthesis and antioxidant screening of new 2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl amide derivatives and some pyrazole-based heterocycles

Abstract

The high functionality compound namely 2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl chloride (1) was utilized as a building block synthon via reactions with some nitrogen and sulfur nucleophilic reagents. The present work was planned to study the effect of 2-cyano group on the reactivity and stability of C₂–C₃ double bond toward different strong-to-weak nucleophiles, in addition to its facility of nucleophilic addition at C₂–C₃ double bond to construct new heterocyclic derivatives. The proclivity toward some mono-, 1,2-, 1,3-, 1,4-, and 1,5-binucleophiles was investigated. The reaction with 2-cyanoacetohydrazide was mainly dependent on the reaction conditions. Some new heterocycles integrated with pyrazole scaffold were successfully synthesized, such as benzoxazinone, indoline, isoindoline, pyrazolone, chromene, and pyrimidopyrimidine derivatives. Some of the newly synthesized compounds were screened for their antioxidant activity using ABTS method, and the results revealed that some compounds exhibited promising inhibitory antioxidant activity.     

A simple approach to the synthesis of 2-(2-amino-4-arylthiazol-5-yl)pyrimidines

The synthesis of 2-(2-amino-4-arylthiazol-5-yl)pyrimidin-4(3H)-ones from the available 2-(2-oxo-2-arylethylidene)-2,3-dihydropyrimidin-4(1H)-ones was developed.     

A facile synthesis of novel benzofuran-2-yl(9-methyl-9H-carbazol-3-yl)methanones

A facile synthesis of hitherto unreported benzofuran-2-yl(9-methyl-9H-carbazol-3-yl)methanones (3a?Cl) is described. The synthesis mainly relies on the ultrasound-assisted Rap?CStoermer reaction of 3-chloroacetyl-9-methyl-9H-carbazole (1) with a variety of salicylaldehydes, as well as 2-hydroxy-1-naphthaldehyde (2) in CH₃CN, with the presence of PEG-400 as a catalyst. This procedure offers easy access to benzofuran-2-yl(carbazolyl)methanone derivatives in a short reaction time and the products are achieved in good yields.     

Green synthesis of novel (E)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)-3-(1H-indol-3-yl)acrylonitriles

Green synthesis of novel title compounds (6) has been developed from 3-(1,4-dioxo-3,4-dihydrophthalazin-(1H)-yl)-3-oxopropanenitrile (3) and indole-3-aldehyde (4) using Knoevenagel condensation followed by alkylation with alkylating agents. Compound 6 could also be synthesised by alkylation of 4 followed by condensation with 3. In an alternate sequence of reactions, 6 could be synthesised either from treatment of 3 with N,N-dimethylformamide dimethyl acetal to form (E)-3-(dimethlamino)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)acrylonitrile 8 followed by reaction with 10 or by the reaction 8 with 9 followed by alkylation.     

3-(Carbazol-2-yl)- and 3-(Carbazol-3-yl)-dl-alanines

A facile transformation of 2- and 3-methylcarbazoles into 3-(carbazol-2-yl)-and 3-(carbazol-3-yl)-dl-alanines compounds is described.     

Synthesis of novel heterocycles from 2-amino-3-(cyanomethylsulfonyl)thiophene

The synthesis and selected reactions of 2-amino-3-(cyanomethylsulfonyl)thiophene is reported. In particular, cyclization reaction of the versatile aminothiophene yielded a number of novel thieno[3,2-b][1,4]-thiazine 1,1-dioxides, as well as the analogous thieno[2,3-e][1,3,4]thiadiazine 4,4-dioxide. Reaction of the thienothiazine system with hydrazine was subsequently explored, which resulted in either ring-opening of the thiazine and formation of an aminopyrazole or solely ring cleavage depending on the thiazine substituent. Additionally, the synthesis of bis(2-amino-3-thienyl)sulfone and the corresponding bis-acetamide is described.     

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.     

Molecular docking,synthesis and anticonvulsant activity of some novel 3-(2-substituted)-4-oxothiazolidine-3-yl)-2-phenylquinazoline-4(3H)-ones

Research on Chemical Intermediates - As the therapeutic potential of quinazolinone and thiazolidinone is well mentioned in literature for their versatile biological activities, their related...     

A simple green procedure for the synthesis of 2H-azirines

An efficient and environmentally friendly method preparing 2H-azirines in good yield has been achieved by microwave irradiation of vinyl azides in solvent free conditions.     

The synthesis of (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-ethoxyiminoacetic acid

The objective was to synthesize (Z)-2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-ethoxyiminoacetic acid (the side chain for Ceftaroline fosamil). Oximation and alkylation were used on cyanoacetamide to get 2-cyano-2-hydroxyiminoacetamide, which became 2-ethyoxyiminopropanedinitrile through reaction with phosphorus oxychloride, and then aminolysis to get 2-ethoxyiminopropanedinitrile, which became 2-ethoxyimion-2-(5-amino-1,2,4 thiadiazol-3-yl) acetonitrile by brominating and with KSCN, followed by hydrolysis to get (Z)-2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-ethoxyiminoacetic acid.     

A new synthesis of (PhPSe2)2 (Woollins reagent) and its use in the synthesis of novel P-Se heterocycles

A new and improved method for the preparation of (PhPSe2)2 (Woollins reagent (WR), 1) is reported. Reaction of dichlorophenylphosphine with Na2Se, (prepared from the reaction of elemental selenium and sodium in liquid ammonia) gives WR with excellent purity, high yield and on a larger scale than was previously possible. Four novel phosphorus-selenium heterocycles, including a spirocyclic heterocycle exhibiting a four-membered P2SeC ring, were obtained from the reaction of WR with two reactive substrates (diphenylcyclopropenone and methyl phenylpropiolate). Useful selenocarbonyl and thiocarbonyl compounds were obtained from the reaction of both WR and Lawesson's reagent with diphenylcyclopropenone. All new compounds were characterised spectroscopically and three demonstrative X-ray structures are reported.     

A novel method for the synthesis of coumarin laser dyes derived from 3-(1H-benzoimidazol-2-yl) coumarin-2-one under microwave irradiation

We want to achieve the synthesis of 3-(1H-benzoimidazol-2-yl)-7-(diethylamino) coumarin-2-one (1), 3-(1H-benzoimidazol-2-yl)-7-(dimethylamino) coumarin-2-one (2), 3-(1H-benzoimidazol-2-yl) coumarin-2-one (3) that are important dyes in industries (Soko owska et al., 2001). Methods for the synthesis of some of these compounds have been the title in some pervious patents, but enough information about separation and purification of them was not clearly indicated. We carried out several methods for the synthesis of the mentioned compound and purification with different yields. Now, we can synthesise these dyes under microwave irradiation in solid phase and solvent free methods with 80% yield, which is a high and remarkable percentage.     

Solid phase synthesis of 3-(5-arylpyridin-2-yl)-4-hydroxycoumarins

A solid phase strategy has been developed for the synthesis of 3-(5-arylpyridin-2-yl)-4-hydroxycoumarins. The key transformation is an intramolecular ipso substitution reaction which forms the coumarin heterocycle and culminates with cleavage of product from the polymer support. The pyridine moiety at C3 can be further modified with Suzuki coupling. A sample library with two diversity elements has been synthesized to demonstrate this ipso substation-based cyclo-elimination strategy.     

One-pot synthesis of 3-(pyridin-2-yl)-2,3-dihydroazetes via Rh(II)-catalyzed reaction of diazoesters with trimethylsilyl-protected 2-(pyridin-2-yl)-2H-azirines

Chemistry of Heterocyclic Compounds - A one-pot method for the synthesis of 3-(pyridin-2-yl)-2,3-dihydroazetes was developed on the basis of Rh2(esp)2-catalyzed reaction of diazoesters with...