Silica Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxy-2-acetonaphthone leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in solvent-free conditions at 90°;C in fairly good yields.     

Microwave Induced Reaction of Dialkyl 2-(1-Acetyl-2-Oxopropyl)-3-(triphenylphosphoranylidene) Succinates with Ninhydrin in the Presence of Magnesium Sulfate in Solvent-Free Conditions

Microwave catalyzed one-pot stereoselective synthesis of dialkyl 1,1-diacetyl-8 a -hydroxy-8-oxo-1,2,8,8 a -tetrahydrocyclopenta[ a ]indene-2,3-carboxylates in fairly high yields by the reaction of dialkyl 2-(1-acetyl-2-oxopropyl)-3-(triphenylphosphoranylidene) succinates and ninhydrin in the presence of MgSO 4 in solvent-free conditions.     

Silica Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(Imido- N -YL)-3-(triphenylphosphoranylidene)-butanedioates to Electron-Poor ( Z )- N -Vinylimides in Solvent-Free Conditions

Silica gel was found to catalyze the stereoselective conversion of dialkyl 2-(imido- N -yl)-3-(triphenylphosphoranylidene)butanedioates to electron-poor ( Z )- N -vinylimides in solvent-free conditions at 95°;C in high coversions.     

Silica Gel Catalyzed Conversion of Dialkyl 2-(1-Hydroxy-2-naphthyl)-3-(triphenylphosphoranylidene)butanedioates to Alkyl 2-Oxo-2 H -benzo[ h ]chromene-4-carboxylates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxynaphthalene leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(1-hydroxy-2-naphthyl)-3-(triphenylphosphanylidene)butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(1-hydroxy-2-naphthyl)-3-(triphenylphosphanylidene)butanedioates to alkyl 2-oxo-2 H -benzo[ h ]chromene-4-carboxylates in solvent-free conditions at 80°;C in fairly good yields.     

Magnesium Sulfate Catalyzed Intermolecular Wittig Reaction of Dialkyl 2-(1-acetyl-2-oxopropyl)-3-(triphenylphosphoranylidene) Succinates with Ninhydrin in Solvent-Free Conditions

A facial one-pot stereoselective synthesis of dialkyl 3,3-diacetyl-3 a -hydroxy-8-oxo-2,3,3 a ,8-tetrahydrocyclopenta[ a ]indene-1,2-dicarboxylates in fairly high yields by the intermolecular Wittig reaction of dialkyl 2-(1-acetyl-2-oxopropyl)-3-(triphenylphosphoranylidene) succinates and ninhydrin in the presence of MgSO 4 in solvent-free conditions at 100°;C is reported.     

Microwave-Induced Stereoselective Conversion of Dialkyl 2-(Imido-N-yl)-3-(triphenylphosphoranylidene) butanedioates to Electron-Poor ( Z )- N -Vinylimides in the Presence of Potassium Dihydrogen Phosphate and Sodium Dihydrogen Phosphate in Solvent-Free Conditions

Abstract

Potassium dihydrogen phosphate powder and sodium dihydrogen phosphate powder were found to catalyze stereoselective conversion of dialkyl 2-(imido-N-yl)- 3-(triphenylphosphoranylidene)butanedioates to electron-poor (Z)-N-vinylimides in solvent-free conditions under microwave irradiation in 5-6 minutes in high conversions.     

Silica Gel Catalyzed Conversion of Dimethyl 2-(5-Bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to Methyl 6-Bromo-2-oxo-2H-chromene-4-carboxylate in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate, by 4-bromophenol leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with conjugate base to produce dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate. Silica gel was found to catalyze conversion of dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to methyl 6-bromo-2-oxo-2H-chromene-4-carboxylate in solvent-free conditions at 80°C in fairly high yield.     

Vinyltriphenylphosphonium Salt Mediated One-Pot Stereoselective Synthesis of Dialkyl ( E )-2-(2-methyl-5-oxo-1-cyclopentenyl)-2-butenedioates

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by 2-hydroxy-3-methyl-2-cyclopenten-1-one leads to vinyltriphenylphosphonium salts, which undergo an intramolecular Wittig reaction to produce the corresponding cyclobutene derivatives. The cyclobutene derivatives are not isolable and undergo electrocyclic ring-opening reactions in CH 2 Cl 2 at room temperature to produce dialkyl ( E )-2-(2-methyl-5-oxo-1-cyclopentenyl)-2-butenedioates in moderate yields.     

An Efficient Method for the Synthesis of 3-Cyano-6-hydroxy-2(1H)-pyridinones under Microwave Irradiation and Solvent-free Conditions

Summary. Three component condensation of alkylacetoacetates, primary amines, and alkyl cyanoacetates catalyzed by solid supports under microwave irradiation gave N-alkyl 3-cyano-6-hydroxy-2(1H)-pyridinones with high yields. Upon carrying out the reaction under the same condition on acidic alumina, zeolite HY, silica gel, and montmorillonite K-10, the best yields were achieved by silica gel. Corresponding author. E-mail: balalaie@yahoo.com Received August 28, 2002; accepted September 3, 2002     

Dipotassium Hydrogen Phosphate Powder Catalyzed Stereoselective O-Vinylation of 1-(2-Hydroxy-1-naphthyl)-1-ethanone

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-(2-hydroxy-1-naphtyl)-1-ethanone leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with a conjugate base to produce corresponding stabilized phosphorus ylides. Dipotassium hydrogen phosphate powder was found to catalyze the conversion of stabilized phosphorus ylides to dialkyl (E, Z)-2-(1-acetyl-2-naphthyl)-2-butenedioates under thermal and microwave conditions in a solventless system.     

Manganese Dioxide is an Efficient Catalyst for the Stereoselective Conversion of Dialkyl 2-(Imido-N-yl)-3-(triphenylphosphoranylidene)butanedioates to Electron-Poor (Z)-N-vinylimides in Solvent-Free Conditions

Manganese dioxide was found to catalyze stereoselective conversion of dialkyl 2-(imido-N-yl)-3-(triphenylphosphoranylidene)butanedioates to electron-poor (Z)-N-vinylimides in solvent-free conditions at 95°C in high coversions.     

Intramolecular Cyclization of 4-Isocyanato-3-(2-naphthyl)-1-phenylpyrazole Under Friedel-Crafts Reaction Conditions

4-Isocyanato-3-(2-naphthyl)-1-phenylpyrazole cyclized under the influence of AlCl₃ to give 2H-benzo[h]pyrazolo[4,3-c]isoquinoline.     

Synthesis of 1-(2-Ethoxyethyl)-4-hydroxy-4-[2-(1-hydroxycyclohexyl)ethynyl]piperidine and Heterocyclization under the Conditions of Hydration

The reaction of 1-(2-ethoxyethyl)piperidin-4-one with ethynylcyclohexanol led to the synthesis of a glycol, the hydration of which gave a mixture of spirocyclic compounds with a carbonyl group at various positions in the furan ring. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1649–1652, November, 2005.     

Solvent-free microwave synthesis of 4-hydroxy-3-phenylquinolin-2(1H)-ones and variants using activated arylmalonates

The disclosure herein describes the rapid synthesis of 4-hydroxy-3-phenylquinolin-2(1H)-ones and variants via a solvent-free microwave cyclocondensation reaction using di-(2,4,6-trichlorophenyl)-2-phenylmalonate, which improves the general scope of this reaction.     

Microwave Assisted Synthesis of 3,3',3″,3'″-o-,p-Phenylenedi-methylidinetetrakis-(4-hydroxy-2H-1-benzopyran-2-one)

Under microwave irradiation,2,2'-alkoxy-bridging or 4,4'-alkoxy-bridging dibenzaldehydes reacted with 4-hydroxycoumarin in DMF to give a series of 3,3',3″,3'″-o-and 3,3',3″,3'″-p-phenylenedimethylidinetetrakis-(4-hydroxy-2H-1-benzopyran-2-ones) in moderate yields.The structures of the synthetic coumarin derivatives were characterized with IR,1H NMR and MS spectroscopy as well as X-ray single crystallography.     

NaHSO4.H2O Catalyzed Multicomponent Synthesis of 1-(Benzothiazolylamino) Methyl-2-Naphthols Under Solvent-Free Conditions

A one-pot, efficient three-component condensation of aldehydes, 2-naphthol, and 2-aminobenzothiazole in the presence of sodium hydrogen sulfate as an effective catalyst for the synthesis of 1-(benzothiazolylamino)methyl-2-naphthol derivatives under thermal and solvent-free conditions is described. These products involve two biologically active parts, Betti's base and benzothiazole. The present methodology offers several advantages, such as good yields, short reaction times, and easy work-up.     

Simple and Efficient Synthesis of 2-Aryl-2,3-Dihydroquinolin-4(1H)-ones Using Silica Chloride as a New Catalyst Under Solvent-Free Conditions

A mild, efficient, and high-yielding method for the synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones from their corresponding 2-amino chalcones using silica chloride (SiO₂Cl) under solvent-free conditions is described. A series of 2-aryl-2,3-dihydroquinolin-4(1H)-ones containing both electron-donating and electron-withdrawing substituents were synthesized.     

A convenient synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl) butanoates from malic acid

A synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl)butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride.The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently,which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.     

Syntheses of Heterocycles from the Sodium Salts of 3-(1-Adamantyl)-1-hydroxy-1-propen-3-one and 4-(1-Adamantyl)-1-hydroxy-1-buten-3-one

The interaction of the sodium salts of 3-(1-adamantyl)-1-hydroxy-1-propen-3-one and 4-(1-adamantyl)-1-hydroxy-1-buten-3-one with hydroxylamine, hydrazine, and guanidine leads to the synthesis of 5-(1-adamantyl)-5-hydroxy- and 5-(1-adamantylmethyl)-5-hydroxy-2-isoxazolines, 3-(1-adamantyl)- and 3-(1-adamantylmethyl)pyrazoles, 3-(1-adamantyl)-2-phenylpyrazole, and 4-(1-adamantyl)-2-amino- and 4-(1-adamantylmethyl)-2-aminopyrimidines.