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Papers by Dr. Kalyan Kumar Rana

Research paper thumbnail of Ceric ammonium nitrate catalyzed mild and efficient α-chlorination of ketones by acetyl chloride

Arkivoc, 2004

A mild and efficient method of α-chlorination of ketones has been developed using acetyl chloride... more A mild and efficient method of α-chlorination of ketones has been developed using acetyl chloride as the chlorinating agent in the presence of a catalytic amount of ceric ammonium nitrate in good yield. The reaction is highly chemo and regio selective in nature.

Research paper thumbnail of Ceric Ammonium Nitrate Mediated Selective Bromoalkoxylation of Activated Cinnamyl Compounds Using Lithium Bromide

Synlett

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journa... more © Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or ...

Research paper thumbnail of Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -Cyclodextrin and Sodium Taurodeoxycholate

Chromatographia, 1994

Page 1. Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -... more Page 1. Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -Cyclodextrin and Sodium Taurodeoxycholate GN Okafo / KK Rana / P. Camilleri* SrnithKline Beecham, The Frythe, Welwyn, Herts. AL6 9AR, UK Key Words ...

Research paper thumbnail of Stereoselective synthesis of trisubstituted tetrahydrofurans by radical cyclisation reaction using a hypophosphite salt. Application to the total synthesis of (±)-dihydrosesamin

Research paper thumbnail of Mild and Efficient Iodine-Catalyzed Protection of Carbonyl Compounds as Oxathiolane Derivatives

Research paper thumbnail of ChemInform Abstract: A Mild and Efficient Method for the Deoxygenation of α,β-Epoxyketones to Enones

Research paper thumbnail of ChemInform Abstract: An Efficient Chemo- and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compounds Using Lithium Bromide and Ceric Ammonium Nitrate

ChemInform, 2001

An Efficient Chemo-and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compoun... more An Efficient Chemo-and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compounds Using Lithium Bromide and Ceric Ammonium Nitrate.-Oxidation of LiBr with cerium ammonium nitrate generates Br + in situ which readily attacks electron-rich arenes under mild conditions.-(ROY, SUBHAS CHANDRA; GUIN, CHANDRANI;

Research paper thumbnail of ChemInform Abstract: Stereoselective Synthesis of Trisubstituted Tetrahydrofurans by Radical Cyclization Reaction Using a Hypophosphite Salt. Application to the Total Synthesis of (.+-.)-Dihydrosesamin

Research paper thumbnail of ChemInform Abstract: Short and Stereoselective Total Synthesis of (.+-.)-Dihydrosesamin and (.+-.)-Acuminatin Methyl Ether by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of ChemInform Abstract: Ceric Ammonium Nitrate Mediated Selective Bromoalkoxylation of Activated Cinnamyl Compounds Using Lithium Bromide

Research paper thumbnail of ChemInform Abstract: Synthesis of Spirocyclic Ethers by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of Microwave Reactors: A Brief Review on Its Fundamental Aspects and Applications

OALib, 2014

Improved laboratory protocols for convenient and rapid transformations are highly desired in mode... more Improved laboratory protocols for convenient and rapid transformations are highly desired in modern synthetic chemistry. Microwave irradiated reactions have received considerable attention in recent years and it is a subject of intense discussion in the scientific community. Microwave heating is more efficient in terms of the energy used, produces higher temperature homogeneity and is considerably more rapid than conventional heating methods. This technique as an alternative to conventional energy sources for introduction of energy into reactions has become a recognized practical method in various fields of chemistry. Microwave-assisted organic synthesis (MAOS) is known for the spectacular accelerations produced in many reactions as a consequence of the increased heating rate, a phenomenon that cannot be easily reproduced by classical heating means. As a result, higher yields, milder reaction conditions and shorter reaction times can often be attained. Its specific heating method attracts extensive interest not only because of rapid volumetric heating, but also for suppressed side reactions, energy saving, decreased environmental pollutions and safe operations. In this review, we will try to represent an overview on origin and fundamental features of microwave ovens and its usefulness in MAOS.

Research paper thumbnail of ChemInform Abstract: A Mild and Efficient Method for the Deoxygenation of ������,������-Epoxyketones to Enones

Research paper thumbnail of Review on Medicinal Usefulness of <i>Vitex</i> <i>negundo</i> Linn

OALib, 2014

Vitex negundo Linn. is a woody plant found mainly in Indian subcontinent and its neighbouring cou... more Vitex negundo Linn. is a woody plant found mainly in Indian subcontinent and its neighbouring countries. Almost all the sections of the plant possess a massive amount of phytochemical secondary metabolites that impart an unparalleled variety of medicinal uses of the plant. Point to note that a single plant species finds use for treatment of a large spectrum of human health ailments in traditional as well as folk medicines, lion part of which have been experimentally proved to be absolutely true. In fact the plant is a constituent of a number of commercially available herbal formulations and has also shown an efficient bio-control instrument. Exercise of biotechnologically advanced procedures would provide resources of rapid proliferation and management of the plant species and from the point of view of phytochemistry, it furnishes opportunities for augmentation of the quality and quantity of the biologically potent secondary metabolites occurring in the plant. In this paper the already reported medicinal uses and pharmacological activities of different parts of the plant have been reviewed.

Research paper thumbnail of A short and stereoselective total synthesis of (±)-sesamin by radical cyclisation of an epoxide using a transition-metal radical source

Tetrahedron Letters, 2000

Due to the widespread occurrence in nature[1] and the broad range of biological activities, [2] l... more Due to the widespread occurrence in nature[1] and the broad range of biological activities, [2] lignans have attracted considerable interest over the years. A major subgroup of lignans is comprised of substituted 3,7-dioxabicyclo-octanes, the synthesis of which poses ...

Research paper thumbnail of An efficient chemo and regioselective oxidative nuclear bromination of activated aromatic compounds using lithium bromide and ceric ammonium nitrate

Tetrahedron Letters, 2001

A mild, efficient and highly chemo-and regioselective method for the bromination of electron rich... more A mild, efficient and highly chemo-and regioselective method for the bromination of electron rich aromatic molecules has been developed by electrophilic substitution of Br + , which was generated in situ from LiBr using ceric ammonium nitrate as the oxidant. Free aromatic amines remained unaffected under the reaction conditions.

Research paper thumbnail of A mild and efficient method for the protection of carbonyl compounds as oxathiolanes, dithiolanes and dithianes catalyzed by molybdenyl acetylacetonate

Tetrahedron Letters, 2003

Protection O 0345 A Mild and Efficient Method for the Protection of Carbonyl Compounds as Oxathio... more Protection O 0345 A Mild and Efficient Method for the Protection of Carbonyl Compounds as Oxathiolanes, Dithiolanes and Dithianes Catalyzed by Molybdenyl Acetylacetonate.

Research paper thumbnail of Stereoselective synthesis of trisubstituted tetrahydrofurans by radical cyclisation reaction using a hypophosphite salt. Application to the total synthesis of (±)-dihydrosesamin

Research paper thumbnail of Short and Stereoselective Total Synthesis of (±)-Dihydrosesamin and (±)-Acuminatin Methyl Ether by Radical Cyclisation of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of A Novel and Efficient Ceric Ammonium Nitrate Catalyzed Oxidative Nuclear Chlorination of Activated Aromatic Compounds by Acetyl Chloride

Synlett, 2003

Abstract A mild and efficient oxidative chlorination of activated aromatic compounds have been ac... more Abstract A mild and efficient oxidative chlorination of activated aromatic compounds have been achieved in excellent yields using acetyl chloride in the presence of a catalytic amount of ceric ammonium nitrate at room temperature. However, chlorination failed to occur with ...

Research paper thumbnail of Ceric ammonium nitrate catalyzed mild and efficient α-chlorination of ketones by acetyl chloride

Arkivoc, 2004

A mild and efficient method of α-chlorination of ketones has been developed using acetyl chloride... more A mild and efficient method of α-chlorination of ketones has been developed using acetyl chloride as the chlorinating agent in the presence of a catalytic amount of ceric ammonium nitrate in good yield. The reaction is highly chemo and regio selective in nature.

Research paper thumbnail of Ceric Ammonium Nitrate Mediated Selective Bromoalkoxylation of Activated Cinnamyl Compounds Using Lithium Bromide

Synlett

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journa... more © Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or ...

Research paper thumbnail of Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -Cyclodextrin and Sodium Taurodeoxycholate

Chromatographia, 1994

Page 1. Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -... more Page 1. Improved Separation of Diastereoisomers in Capillary Electrophoresis Using a Mixture of -Cyclodextrin and Sodium Taurodeoxycholate GN Okafo / KK Rana / P. Camilleri* SrnithKline Beecham, The Frythe, Welwyn, Herts. AL6 9AR, UK Key Words ...

Research paper thumbnail of Stereoselective synthesis of trisubstituted tetrahydrofurans by radical cyclisation reaction using a hypophosphite salt. Application to the total synthesis of (±)-dihydrosesamin

Research paper thumbnail of Mild and Efficient Iodine-Catalyzed Protection of Carbonyl Compounds as Oxathiolane Derivatives

Research paper thumbnail of ChemInform Abstract: A Mild and Efficient Method for the Deoxygenation of α,β-Epoxyketones to Enones

Research paper thumbnail of ChemInform Abstract: An Efficient Chemo- and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compounds Using Lithium Bromide and Ceric Ammonium Nitrate

ChemInform, 2001

An Efficient Chemo-and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compoun... more An Efficient Chemo-and Regioselective Oxidative Nuclear Bromination of Activated Aromatic Compounds Using Lithium Bromide and Ceric Ammonium Nitrate.-Oxidation of LiBr with cerium ammonium nitrate generates Br + in situ which readily attacks electron-rich arenes under mild conditions.-(ROY, SUBHAS CHANDRA; GUIN, CHANDRANI;

Research paper thumbnail of ChemInform Abstract: Stereoselective Synthesis of Trisubstituted Tetrahydrofurans by Radical Cyclization Reaction Using a Hypophosphite Salt. Application to the Total Synthesis of (.+-.)-Dihydrosesamin

Research paper thumbnail of ChemInform Abstract: Short and Stereoselective Total Synthesis of (.+-.)-Dihydrosesamin and (.+-.)-Acuminatin Methyl Ether by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of ChemInform Abstract: Ceric Ammonium Nitrate Mediated Selective Bromoalkoxylation of Activated Cinnamyl Compounds Using Lithium Bromide

Research paper thumbnail of ChemInform Abstract: Synthesis of Spirocyclic Ethers by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of Microwave Reactors: A Brief Review on Its Fundamental Aspects and Applications

OALib, 2014

Improved laboratory protocols for convenient and rapid transformations are highly desired in mode... more Improved laboratory protocols for convenient and rapid transformations are highly desired in modern synthetic chemistry. Microwave irradiated reactions have received considerable attention in recent years and it is a subject of intense discussion in the scientific community. Microwave heating is more efficient in terms of the energy used, produces higher temperature homogeneity and is considerably more rapid than conventional heating methods. This technique as an alternative to conventional energy sources for introduction of energy into reactions has become a recognized practical method in various fields of chemistry. Microwave-assisted organic synthesis (MAOS) is known for the spectacular accelerations produced in many reactions as a consequence of the increased heating rate, a phenomenon that cannot be easily reproduced by classical heating means. As a result, higher yields, milder reaction conditions and shorter reaction times can often be attained. Its specific heating method attracts extensive interest not only because of rapid volumetric heating, but also for suppressed side reactions, energy saving, decreased environmental pollutions and safe operations. In this review, we will try to represent an overview on origin and fundamental features of microwave ovens and its usefulness in MAOS.

Research paper thumbnail of ChemInform Abstract: A Mild and Efficient Method for the Deoxygenation of ������,������-Epoxyketones to Enones

Research paper thumbnail of Review on Medicinal Usefulness of <i>Vitex</i> <i>negundo</i> Linn

OALib, 2014

Vitex negundo Linn. is a woody plant found mainly in Indian subcontinent and its neighbouring cou... more Vitex negundo Linn. is a woody plant found mainly in Indian subcontinent and its neighbouring countries. Almost all the sections of the plant possess a massive amount of phytochemical secondary metabolites that impart an unparalleled variety of medicinal uses of the plant. Point to note that a single plant species finds use for treatment of a large spectrum of human health ailments in traditional as well as folk medicines, lion part of which have been experimentally proved to be absolutely true. In fact the plant is a constituent of a number of commercially available herbal formulations and has also shown an efficient bio-control instrument. Exercise of biotechnologically advanced procedures would provide resources of rapid proliferation and management of the plant species and from the point of view of phytochemistry, it furnishes opportunities for augmentation of the quality and quantity of the biologically potent secondary metabolites occurring in the plant. In this paper the already reported medicinal uses and pharmacological activities of different parts of the plant have been reviewed.

Research paper thumbnail of A short and stereoselective total synthesis of (±)-sesamin by radical cyclisation of an epoxide using a transition-metal radical source

Tetrahedron Letters, 2000

Due to the widespread occurrence in nature[1] and the broad range of biological activities, [2] l... more Due to the widespread occurrence in nature[1] and the broad range of biological activities, [2] lignans have attracted considerable interest over the years. A major subgroup of lignans is comprised of substituted 3,7-dioxabicyclo-octanes, the synthesis of which poses ...

Research paper thumbnail of An efficient chemo and regioselective oxidative nuclear bromination of activated aromatic compounds using lithium bromide and ceric ammonium nitrate

Tetrahedron Letters, 2001

A mild, efficient and highly chemo-and regioselective method for the bromination of electron rich... more A mild, efficient and highly chemo-and regioselective method for the bromination of electron rich aromatic molecules has been developed by electrophilic substitution of Br + , which was generated in situ from LiBr using ceric ammonium nitrate as the oxidant. Free aromatic amines remained unaffected under the reaction conditions.

Research paper thumbnail of A mild and efficient method for the protection of carbonyl compounds as oxathiolanes, dithiolanes and dithianes catalyzed by molybdenyl acetylacetonate

Tetrahedron Letters, 2003

Protection O 0345 A Mild and Efficient Method for the Protection of Carbonyl Compounds as Oxathio... more Protection O 0345 A Mild and Efficient Method for the Protection of Carbonyl Compounds as Oxathiolanes, Dithiolanes and Dithianes Catalyzed by Molybdenyl Acetylacetonate.

Research paper thumbnail of Stereoselective synthesis of trisubstituted tetrahydrofurans by radical cyclisation reaction using a hypophosphite salt. Application to the total synthesis of (±)-dihydrosesamin

Research paper thumbnail of Short and Stereoselective Total Synthesis of (±)-Dihydrosesamin and (±)-Acuminatin Methyl Ether by Radical Cyclisation of Epoxides Using a Transition-Metal Radical Source

Research paper thumbnail of A Novel and Efficient Ceric Ammonium Nitrate Catalyzed Oxidative Nuclear Chlorination of Activated Aromatic Compounds by Acetyl Chloride

Synlett, 2003

Abstract A mild and efficient oxidative chlorination of activated aromatic compounds have been ac... more Abstract A mild and efficient oxidative chlorination of activated aromatic compounds have been achieved in excellent yields using acetyl chloride in the presence of a catalytic amount of ceric ammonium nitrate at room temperature. However, chlorination failed to occur with ...