- Envirocat (K10-MX)-catalyzed regioselective transformation of alkenes into iodohydrins and β-iodo ethers and further conversion of iodohydrins to epoxides using Al2O3-Na2Co3 under MWI
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Commercial K10 clay was converted to extremely efficient and environmentally friendly catalyst K10-MX for the preparation of iodohydrins and β-iodo ethers from alkenes (terminal as well as internal) using microwave irradiation. This method was further extended for the conversion of alkenes to epoxides via iodohydrin intermediate in a one-pot reaction system. Copyright Taylor & Francis Group, LLC.
- Shallu,Sharma,Singh, Jasvinder
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experimental part
p. 1306 - 1324
(2012/04/04)
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- S-Methylidene agents: preparation of chiral non-racemic heterocycles
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Reaction of sulfur ylide with aldehyde, imine, and ketone functionality affords the desired three-membered heterocycle in excellent yield. The sulfur ylide is generated in situ upon decarboxylation of carboxymethylsulfonium betaine functionality. Of the seven carboxymethylsulfonium betaine derivatives surveyed, the highest level of conversion of π-acceptor to heterocycle was obtained with the one having S-methyl and S-phenyl functionality bound to a thioacetate derivative. Methylene aziridinations and epoxidations involving the decarboxylation of carboxymethylsulfonium betaine functionality complements existing technologies with the advantages of the reaction protocol, levels of conversion, and scope. While moderate levels of diastereocontrol were observed in the aziridination of imine functionality, the four oxiranes resolved using Jacobsen's Co(II)-salen complex were obtained in both high yield and enantioselectivity. The isolated chiral non-racemic oxiranes constitute the formal synthesis of chelonin B and combretastatin starting from 3-bromo-4-methoxybenzaldehyde and 3,4,5-trimethoxybenzaldehyde, respectively.
- Forbes, David C.,Bettigeri, Sampada V.,Patrawala, Samit A.,Pischek, Susanna C.,Standen, Michael C.
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supporting information; experimental part
p. 70 - 76
(2009/04/06)
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- Ethanolamine derivatives having sympathomimetic and anti-pollakiuria activities
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This invention relates to new ethanolamine derivatives having gut selective sympathomimetic and anti-pollakiuria activities and represented by the general formula [I]: STR1 wherein R1 is aryl or a heterocyclic group, each of which may be substituted with halogen, etc., R2 is hydrogen, halogen, nitro, hydroxy, lower alkyl optionally substituted with acyl, lower alkenyl optionally substituted with acyl, lower alkoxy optionally substituted with acyl, or amino optionally substituted with acyl(lower)alkyl, R3 is hydrogen, an N-protective group, or lower alkyl optionally substituted with lower alkylthio, n is an integer of 0 to 3, and a heavy solid line means a single bond or a double bond, provided that when n is 1, then 1) R1 is a condensed aromatic hydrocarbon group or a heterocyclic group, each of which may be substituted with halogen, etc., and the like, and pharmaceutically acceptable salts thereof to processes for the preparation thereof and to a pharmaceutical composition comprising the same.
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- Inexpensive Reagents for the Synthesis of Amides from Esters and for Regioselective Opening of Epoxides
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Lithium aluminum amides , 6a-6d, easily prepared in Et2O or THF from 1 equiv of LiAlH4 and 5 equiv of amine, proved to be efficient reagents for the synthesis of secondary amides from esters (ca. 100 percent with unhindered amines and 92 percent with t-BuNH2).They also open aryl epoxides with very high regioselectivity to give 97-98 percent of the β-amino-α-arylethanols (corresponding to the SN2 mechanism).
- Solladie-Cavallo, A.,Bencheqroun, M.
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p. 5831 - 5834
(2007/10/02)
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- A Convenient Strategy for Homologation of p-Oxygenated Benzaldehydes
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It is shown that p-oxygenated benzaldehydes can be conveniently obtained by pyrolysis of the corresponding oxiranes.
- Haridas, K.,Dev, Sukh
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p. 1018 - 1020
(2007/10/02)
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- ALDEHYDES AND KETONES EPOXIDATION WITH TRIMETHYLSULFONIUM BROMIDE IN A SLIGHTLY HYDRATED SOLID-LIQUID MEDIUM
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Trimethylsulfonium bromide used in low hydrated solid-liquid phase transfer conditions is a very efficient agent for aldehyde and ketone epoxidation.
- Bouda, H.,Borredon, M. E.,Delmas, M.,Gaset A.
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p. 503 - 514
(2007/10/02)
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