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A variety of oxygen, nitrogen and sulfur heterocyclic compounds are synthesized via one-pot multicomponent Prins, aza-Prins, thia-Prins, oxonium-ene, iminium-ene and thionium-ene cyclization reactions. The reactions proceeds with high... more
A variety of oxygen, nitrogen and sulfur heterocyclic compounds are synthesized via one-pot multicomponent Prins, aza-Prins, thia-Prins, oxonium-ene, iminium-ene and thionium-ene cyclization reactions. The reactions proceeds with high diastereo- and regioselectivity. Importantly, C–C, C–N, C–O and C–S bonds are formed in a singsle step. These procedures are extended for the synthesis of biologically active molecules and natural products.1 Introduction2 Prins Cyclization Reactions3 Oxonium-Ene Cyclization Reactions4 Conclusion
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It was observed that the reaction of CFCl3 with thiophenoxide gave only 10% of the corresponding thioether. On the other hand, these thioethers could be prepared in excellent yield from diaryl disulfides and CFCl3 in the presence of... more
It was observed that the reaction of CFCl3 with thiophenoxide gave only 10% of the corresponding thioether. On the other hand, these thioethers could be prepared in excellent yield from diaryl disulfides and CFCl3 in the presence of sodium hydroxymethanesulfinate in aqueous DMF at 4 atm pressure of nitrogen. Dechlorination of the thioether (PhSCFCl2) with different reducing agents were studied. Most of the reducing agents eliminated both fluorine and chlorine functionalities or gave the hydrolyzed products. But its sulfone on treatment with Zinc in methanol gave monochlorofluoromethyl and fluoromethyl phenyl sulfone in good yields. Darzens reaction of these compounds was also studied.
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A TfOH-promoted, metal-free protocol has been unveiled for the synthesis of spiro-furan quinazolinones employing alkynol urea derivatives utilizing alkynyl Prins cyclization reaction. This methodology produces highly functionalized... more
A TfOH-promoted, metal-free protocol has been unveiled for the synthesis of spiro-furan quinazolinones employing alkynol urea derivatives utilizing alkynyl Prins cyclization reaction. This methodology produces highly functionalized spiro-heterocycles in excellent...
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An efficient methodology has been developed for the synthesis of tetra- and pentasubstituted pyrroles via oxidative self-dimerization of N-propargylamines catalyzed by silver benzoate in the presence of K2S2O8 in good yields. The protocol... more
An efficient methodology has been developed for the synthesis of tetra- and pentasubstituted pyrroles via oxidative self-dimerization of N-propargylamines catalyzed by silver benzoate in the presence of K2S2O8 in good yields. The protocol provides a simple route for the synthesis of both tetra- and pentasubstituted pyrroles with two carbonyl groups in the side chain. The methodology can be extended toward the synthesis of pyrrolo[3,4-d]pyridazine.
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A simple methodology for the regioselective synthesis of substituted dibenzocyclohepta[1,2-a]naphthalenes from phenylacetaldehydes and ortho-alkynyl benzyl alcohols in the presence of a Lewis acid has been developed.
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Propargyl amine can be efficiently converted to pyrazole N‐oxide from the reaction of sodium nitrite in acetic acid catalysed by AgOTf in excellent yields. The pyrazole N‐oxides can be converted into pyrazole by treatment of phosphorous... more
Propargyl amine can be efficiently converted to pyrazole N‐oxide from the reaction of sodium nitrite in acetic acid catalysed by AgOTf in excellent yields. The pyrazole N‐oxides can be converted into pyrazole by treatment of phosphorous trichloride in refluxing chloroform. The pyrazole N‐oxide could be converted to highly substituted 4‐chloropyrazole by treating DMF and POCl3. On the other hand, some substituted pyrazole can be converted to pyrazolo[4,3‐c]cinnoline and pyrazolo[4,3‐c]quinoline.
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Research Interests: Computer Science, Chemistry, Organic Chemistry, Catalysis, Medicine, and 13 moreAcknowledgement, Citation, CHEMICAL SCIENCES, Download, Ene Reaction, Cyclization, Esters, Trifluoromethanesulfonate, Molecular Structure, Aldehydes, Permission, Pharmacology and pharmaceutical sciences, and stereoisomerism
ABSTRACT The reaction of aldehydes with allyltrimethylsilane in arene solvents gives symmetrical 2,6-disubstituted-4-aryltetrahydropyrans in good yields. The reaction is highly stereoselective. (© Wiley-VCH Verlag GmbH & Co. KGaA,... more
ABSTRACT The reaction of aldehydes with allyltrimethylsilane in arene solvents gives symmetrical 2,6-disubstituted-4-aryltetrahydropyrans in good yields. The reaction is highly stereoselective. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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Hexahydrobenzo[de]isochromanes and hexahydropyrano[3,4,5-ij]isoquinolines are synthesizedviaFriedel–Crafts and oxa-Pictet–Spengler reaction of enol ethers mediated by triflic acid in good yields.
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Intramolecular cyclization of nitrogen tethered alkenols catalyzed by palladium chloride leads to substituted morpholines in good yields. The methodology was used for the total synthesis of (±)-chelonin A.
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The synthesis of O-tosylated azabicyclic compounds via Prins cyclization in which the p-toluene sulfonic acid acts as a Broensted acid as well as a nucleophile is reported.
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ABSTRACT Tetrahydrothiopyrans have been efficiently synthesized in good yields with excellent diastereoselectivity from aldehydes and substituted 5-methylhex-4-ene-1-thiol via (3,5)-thionium-ene cyclization reaction mediated by boron... more
ABSTRACT Tetrahydrothiopyrans have been efficiently synthesized in good yields with excellent diastereoselectivity from aldehydes and substituted 5-methylhex-4-ene-1-thiol via (3,5)-thionium-ene cyclization reaction mediated by boron trifluoride etherate.
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The combination of organometallic C−H activation and electro‐catalysis has emerged as a potent synthetic technique for various molecular scaffolds since it avoids the use of harmful and expensive chemical oxidants in stoichiometric... more
The combination of organometallic C−H activation and electro‐catalysis has emerged as a potent synthetic technique for various molecular scaffolds since it avoids the use of harmful and expensive chemical oxidants in stoichiometric amounts. Moreover, the pre‐functionalization of substrates is not required and newer ways to perform metal‐catalyzed C−H activation reactions are possible. Here, we have discussed eletrochemically driven C−H acyloxylation, acetoxylation, oxygenation, acylation, amination, alkylation, halogenation, olefinations and C−H/N−H annulation reactions using various transition‐metal‐catalyst such as Ru, Rh, Pd, Co, Ni, Ir, Cu, Mn and Au by anodic oxidation, followed by reductive elimination to form the corresponding C−O, C−C, C−N and C−X (X=Cl, Br, S etc.) bonds. This review covers recent developments in transition‐metal‐catalyzed electrochemical C−H activation from 2007 until 2022.
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A simple methodology for the regioselective synthesis of substituted dibenzocyclohepta[1,2-a]naphthalenes from phenylacetaldehydes and ortho-alkynyl benzyl alcohols in the presence of a Lewis acid has been developed.
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A facile synthesis of 3C-alkylated active methylene substituted 2H-indazoles from o-nitrocyclopropanes and primary arylamines catalyzed by Ni(ClO4)2.6H2O/SnCl2.2H2O is reported.
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An efficient approach for the synthesis of pyrimido[2,1-a]isoindolone and isoindolo[2,1-a]quinazolinone via intramolecular aza-Prins type reaction of N-acyliminium ions and amides in excellent yields is reported.
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An intramolecular Friedel–Crafts cyclization reaction catalyzed by indium(III) chloride for the formation of 4-vinyl-1,2,3,4-tetrahydroisoquinoline from N-tethered benzyl-alkenol in good yields has been described. The reaction is highly... more
An intramolecular Friedel–Crafts cyclization reaction catalyzed by indium(III) chloride for the formation of 4-vinyl-1,2,3,4-tetrahydroisoquinoline from N-tethered benzyl-alkenol in good yields has been described. The reaction is highly regioselective and generates an exocyclic vinyl functionality in the piperidine ring. The reaction is compatible with a wide range of functional groups. The strategy is demonstrated for the formal synthesis of (±)-isocyclocelabenzine alkaloid.