The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Akhila K Sahoo - One of the best experts on this subject based on the ideXlab platform.
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regioselective synthesis of 2 4 5 trisubstituted oxazoles and ketene aminals via hydroamidation and iodo imidation of ynamides
Journal of Organic Chemistry, 2017Co-Authors: Rajendra K Mallick, Baskaran Prabagar, Akhila K SahooAbstract:A novel and straightforward protocol is demonstrated for the synthesis of highly substituted oxazoles from readily accessible ynamides in the presence of ytterbium(III) trifluoromethanesulfonate [Yb(OTf)3], N-Iodosuccinimide (NIS), and acetonitrile. Multiple oxazole skeletons in the aryl periphery are constructed in a single operation for the first time. The hydroamidation and iodo-imidation of ynamides to trisubstituted and tetrasubstituted ketene aminals is exemplified. An isotope labeling experiment is used to identify the oxygen source in this transformation. The reactions are scalable to the gram scale, testifying the robustness of the transformations.
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Regioselective Synthesis of 2,4,5-Trisubstituted Oxazoles and Ketene Aminals via Hydroamidation and Iodo-Imidation of Ynamides
2017Co-Authors: Rajendra K. Mallick, B Prabagar, Akhila K SahooAbstract:A novel and straightforward protocol is demonstrated for the synthesis of highly substituted oxazoles from readily accessible ynamides in the presence of ytterbium(III) trifluoromethanesulfonate [Yb(OTf)3], N-Iodosuccinimide (NIS), and acetonitrile. Multiple oxazole skeletons in the aryl periphery are constructed in a single operation for the first time. The hydroamidation and iodo-imidation of ynamides to trisubstituted and tetrasubstituted ketene aminals is exemplified. An isotope labeling experiment is used to identify the oxygen source in this transformation. The reactions are scalable to the gram scale, testifying the robustness of the transformations
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dimethyl sulfoxide and n iodosuccinimide promoted 5 exo dig oxidative cyclization of yne tethered ynamide access to pyrrolidones and spiro pyrrolidones
ChemInform, 2016Co-Authors: B Prabagar, Sanatan Nayak, Rangu Prasad, Akhila K SahooAbstract:The scalable title cyclization offers access to variously functionalized pyrrolidinone derivatives.
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dimethyl sulfoxide and n iodosuccinimide promoted 5 exo dig oxidative cyclization of yne tethered ynamide access to pyrrolidones and spiro pyrrolidones
Organic Letters, 2016Co-Authors: B Prabagar, Sanatan Nayak, Rangu Prasad, Akhila K SahooAbstract:An unprecedented metal-free dimethyl sulfoxide (DMSO) and N-Iodosuccinimide mediated regioselective 5-exo-dig oxidative cyclization of an in situ generated enol equivalent of amides from ynamides bearing internal alkynes is demonstrated. The reaction allows easy access to functionalized pyrrolidone skeletons. Pyrrolidones having 3-o-biaryl motifs successfully undergo intramolecular electrophilic cyclization with the α,β-unsaturated olefin, furnishing spiro-pyrrolidone motifs. A one-pot sequential 5-exo-dig cyclization of the yne-tethered ynamides, followed by electrophilic cyclization of the pyrrolidone, is presented. The role of DMSO in the transformation is clarified, and a tentative reaction pathway is proposed.
Balaram Mukhopadhyay - One of the best experts on this subject based on the ideXlab platform.
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convergent synthesis of the hexasaccharide related to the repeating unit of the o antigen from e coli o120
RSC Advances, 2015Co-Authors: Darshita Budhadev, Balaram MukhopadhyayAbstract:Chemical synthesis of the hexasaccharide, α-L-Rhap-(1→4)-β-D-GlcAp-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→2)-α-D-Galp-(1→3)-β-D-GalNAcp, is reported by following a [2 + 4] convergent strategy. A disaccharide α-D-Galp-(1→3)-β-D-GalNAcp and a tetrasaccharide α-L-Rhap-(1→4)-β-D-GlcAp-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap were synthesized from commercially available monosaccharides through rational protecting group manipulations and stereoselective glycosylation involving activation of thioglycoside using N-Iodosuccinimide and H2SO4-silica. Final glycosylation between the tetrasaccharide donor and the disaccharide acceptor was achieved by the activation of trichloroacetimidate using H2SO4-silica alone. A late stage TEMPO-mediated oxidation installed the required uronic acid moiety. Finally, global deprotection furnished the target molecule. Successful chemical synthesis of the repeating unit of E. coli O120 will help to design suitable vaccine candidates against this deadly pathogen belonging to the STEC family.
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synthesis of two trisaccharides related to the hepatoprotective phenylethanoids leonoside e and f isolated from leonurus japonicus houtt
Carbohydrate Research, 2014Co-Authors: Darshita Budhadev, Balaram MukhopadhyayAbstract:The chemical synthesis of two trisaccharides related to leonoside E and F is reported. The target oligosaccharides were prepared in the form of their p-methoxyphenyl glycosides using a common disaccharide acceptor. All reaction steps were high yielding (>80%) and the stereoselective glycosylations were achieved by activation of the thioglycoside donors using N-Iodosuccinimide in the presence of La(OTf)3.
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concise synthesis of a tetra and a trisaccharide related to the repeating unit of the o antigen from providencia rustigianii o34 in the form of their p methoxyphenyl glycosides
RSC Advances, 2013Co-Authors: Prashant Ranjan Verma, Balaram MukhopadhyayAbstract:Concise synthesis of a tetra- and a trisaccharide related to the repeating unit of the O-antigen from Providencia rustigianii O34 is reported. Synthesis of the target oligosaccharides was achieved by rational protecting group manipulations on the commercially available monosaccharides followed by stereoselective glycosylations, using H2SO4-silica for trichloroacetimidate activation and in conjunction with N-Iodosuccinimide for thioglycoside activation.
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concise synthesis of two trisaccharides related to the cytotoxic triterpenoid saponin isolated from pithecellobium lucidum
Carbohydrate Research, 2009Co-Authors: Priya Verma, Balaram MukhopadhyayAbstract:Abstract Convergent synthesis of two trisaccharides related to the cytotoxic triterpenoid saponin isolated from Pithecellobium lucidum is reported. The trisaccharides are synthesized in the form of their propargyl glycosides to leave the scope for further glycoconjugate formation through various multi-component reactions. A simple protecting group manipulation is followed using commercially available monosaccharides, d -glucose, d -xylose, d -fucose and l -rhamnose. H 2 SO 4 immobilized on silica is used as the Bronsted acid source for the N -iodosuccinimide-mediated thioglycoside activation for stereoselective glycosylations and proved to be a better choice over traditional Lewis acid catalysts such as TMSOTf and TfOH.
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concise synthesis of a pentasaccharide related to the anti leishmanial triterpenoid saponin isolated from maesa balansae
Journal of Organic Chemistry, 2008Co-Authors: Vishal Kumar Rajput, Balaram MukhopadhyayAbstract:Concise synthesis of the glycone part (a pentasaccharide) of the anti-leishmanial triterpenoid saponin isolated from Maesa balansae is reported. A late-stage TEMPO-mediated oxidation of a primary hydroxyl group to carboxylic acid has been achieved under phase-transfer conditions. Glycosylations were performed either by thioglycoside or glycosyl trichloroacetimidate activation using sulfuric acid immobilized on silica (H2SO4−silica) in conjunction with N-Iodosuccinimide and alone, respectively. H2SO4−silica was proved to be a better choice as promoter than conventional Lewis acid promoters such as TfOH or TMSOTf.
Boshun Wan - One of the best experts on this subject based on the ideXlab platform.
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cyclization and n iodosuccinimide induced electrophilic iodocyclization of 3 aza 1 5 enynes to synthesize 1 2 dihydropyridines and 3 iodo 1 2 dihydropyridines
ChemInform, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:A metal-free approach to synthesize the title compounds selectively from readily available 3-aza-1,5-enynes is developed.
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Cyclization and N-Iodosuccinimide-Induced Electrophilic Iodocyclization of 3-Aza-1,5-enynes To Synthesize 1,2-Dihydropyridines and 3-Iodo-1,2-dihydropyridines
The Journal of organic chemistry, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:Metal-free cyclization and N-Iodosuccinimide-induced electrophilic iodocyclization of readily available 3-aza-1,5-enynes have been developed. The reactions selectively give 1,2-dihydropyridines and 3-iodo-1,2-dihydropyridines involving an aza-Claisen rearrangement and a 6π-electrocyclization step. Furthermore, the reaction could be carried out in 10 g scale for the synthesis of 1,2-dihydropyridines.
Dongping Wang - One of the best experts on this subject based on the ideXlab platform.
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dabco catalyzed synthesis of 3 bromo 3 iodo 2h pyrans from propargyl alcohols dialkyl acetylene dicarboxylates and n bromo n iodosuccinimides
Tetrahedron Letters, 2015Co-Authors: Qinglei Chong, Dongping Wang, Chunxiang Wang, Haolong Wang, Fan WuAbstract:The DABCO-catalyzed reaction of propargyl alcohols with dialkyl acetylene dicarboxylates and N-bromo-/N-Iodosuccinimides under mild conditions has been developed. The reactions give 3-bromo-/3-iodo-2H-pyrans in up to 98% yield.
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cyclization and n iodosuccinimide induced electrophilic iodocyclization of 3 aza 1 5 enynes to synthesize 1 2 dihydropyridines and 3 iodo 1 2 dihydropyridines
ChemInform, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:A metal-free approach to synthesize the title compounds selectively from readily available 3-aza-1,5-enynes is developed.
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Cyclization and N-Iodosuccinimide-Induced Electrophilic Iodocyclization of 3-Aza-1,5-enynes To Synthesize 1,2-Dihydropyridines and 3-Iodo-1,2-dihydropyridines
The Journal of organic chemistry, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:Metal-free cyclization and N-Iodosuccinimide-induced electrophilic iodocyclization of readily available 3-aza-1,5-enynes have been developed. The reactions selectively give 1,2-dihydropyridines and 3-iodo-1,2-dihydropyridines involving an aza-Claisen rearrangement and a 6π-electrocyclization step. Furthermore, the reaction could be carried out in 10 g scale for the synthesis of 1,2-dihydropyridines.
Xiaoyi Xin - One of the best experts on this subject based on the ideXlab platform.
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cyclization and n iodosuccinimide induced electrophilic iodocyclization of 3 aza 1 5 enynes to synthesize 1 2 dihydropyridines and 3 iodo 1 2 dihydropyridines
ChemInform, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:A metal-free approach to synthesize the title compounds selectively from readily available 3-aza-1,5-enynes is developed.
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Cyclization and N-Iodosuccinimide-Induced Electrophilic Iodocyclization of 3-Aza-1,5-enynes To Synthesize 1,2-Dihydropyridines and 3-Iodo-1,2-dihydropyridines
The Journal of organic chemistry, 2013Co-Authors: Xiaoyi Xin, Dongping Wang, Boshun WanAbstract:Metal-free cyclization and N-Iodosuccinimide-induced electrophilic iodocyclization of readily available 3-aza-1,5-enynes have been developed. The reactions selectively give 1,2-dihydropyridines and 3-iodo-1,2-dihydropyridines involving an aza-Claisen rearrangement and a 6π-electrocyclization step. Furthermore, the reaction could be carried out in 10 g scale for the synthesis of 1,2-dihydropyridines.