- Pummerer Cyclization Revisited: Unraveling of Acyl Oxonium Ion and Vinyl Sulfide Pathways
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Two viable pathways (vinyl sulfide and acyl oxonium ion) for the Pummerer cyclization have been unraveled that expand the reaction scope and capabilities. Use of Br?nsted-enhanced Lewis acidity was key to realization of the vinyl sulfide pathway, whereas selective complexation of the sulfur lone pair facilitated the unprecedented acyl oxonium ion pathway. Preliminary mechanistic investigations support these hypotheses. A range of substrates have been explored to understand the reaction parameters.
- Li, Xin,Carter, Rich G.
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supporting information
p. 5541 - 5545
(2018/09/25)
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- An efficient synthetic protocol for the synthesis of 2-(1H-Indol-5-yl)-ethanesulfonic acid methylamide: A potential synthetic precursor for naratriptan and its novel 3-substituted derivatives
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Background: The 3-Substituted indoles are found to possess a wide range of biological and pharmacological activities. The efficient and impurity free scalable preparation of 2-(1H-Indol-5-yl)-ethanesulfonic acid methylamide has been successfully achieved
- Behera, Ajaya Kumar,Majumdar, Poulomi,Mohanta, Prajna Parimita,Mishra, Sushanta Kumar
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p. 265 - 269
(2018/04/20)
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- Synthesis of 2-thioaldoses via BF3-promoted cycloaddition of β-methoxyvinyl sulfides with 2,3-O-isopropylidene derivatives of aldehydo-aldoses
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A highly stereoselective approach to the synthesis of 2-thioaldose derivatives via BF3-promoted cycloaddition of β-methoxyvinyl sulfides with 2,3-O-isopropylidene derivatives of aldehydo-aldoses is described. Georg Thieme Verlag Stuttgart · New
- Sugimura, Hideyuki,Kusakabe, Kousuke
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- PROCESS FOR PREPARING INDOLE DERIVATIVES
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The present invention provides a process for the preparation of indole derivatives, specifically N- methyl-1H-indole-5-ethanesulfonamide of formula (I), involving novel intermediate, which is used as key intermediate for the synthesis of naratriptan of formula (II), and its pharmaceutically acceptable salts thereof high yield and purity.
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Page/Page column 17-18
(2010/04/03)
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- Ionic liquid as catalyst and reaction medium: A simple, convenient and green procedure for the synthesis of thioethers, thioesters and dithianes using an inexpensive ionic liquid, [pmIm]Br
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An easily accessible and inexpensive room temperature ionic liquid, 1-pentyl-3-methylimidazolium bromide, [pmIm]Br efficiently catalyzes the reaction of alkyl halides or acyl halides with thiols without any solvent at room temperature leading to the synthesis of thioethers and thioesters in high yields. This reaction has also been extended for the preparation of dithianes and transthioetherification. The ionic liquid is recovered and recycled for subsequent runs.
- Ranu, Brindaban C.,Jana, Ranjan
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p. 1811 - 1818
(2007/10/03)
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- Skeletal reorganization of mercaptoacetaldehyde dialkyl acetal in acid: formation of disulphide, 1,2-bis(mercapto)ethylene and 1,1,2-tris(mercapto)ethane derivatives
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The reaction of mercaptoacetaldehyde dialkyl acetals 1a-c in the presence of sulfuric acid, polyphosphoric acid and zinc chloride is described. Other than the disulfide reported previously, new compounds 1,2-bis-(mercapto)ethylene, 1,2,3-tris-(mercapto)ethane and 1,2-bis-(mercapto)methane have been isolated for the first time.
- Ong, Chi Wi,Yen, Sin Fei,Chou, Yi Meen
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p. 601 - 605
(2007/10/03)
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- Synthesis and cycloaddition reactions of 1-(arylthio)-1,3-dienes. A combined experimental and theoretical study of bicyclic adducts structures
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A method giving simple access to various 1-(phenylthio)-4-substituted-1,3-dienes (5-10) is described. The influence of the different functionalizations introduced on the dienic systems has been tested in a set of classical [4 + 2] cycloaddition reactions. Both the endo/exo and regio selectivities have been investigated. While the endo compound is, as expected, the only or major isomer in all cases, the regio competition between sulfur and oxygen is in favor of the oxygen substituent in the case studied here, in contrast to related works. For one type of adduct, X-ray crystallographic analysis and NMR spectroscopy have been used in conjunction with ab initio and semiempirical AM1 calculations to determine the structure and conformations of products as well as the energetic pathway from the primary concave endo cycloadduct (28) to a rearranged bicyclic structure (39). The theoretical results fully support the occurrence of a photochemical [1,3] sigmatropic shift of the thiophenyl group.
- Maddaluno, Jacques,Gaonac'h, Odile,Marcual, Albert,Toupet, Loic,Giessner-Prettre, Claude
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p. 5290 - 5306
(2007/10/03)
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