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Hashem Sharghi - One of the best experts on this subject based on the ideXlab platform.
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A facile conversion of epoxides to halohydrins with Elemental Halogen using isonicotinic hydrazide (isoniazide) as a new catalyst
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Hashem Sharghi, Mohammad Mehdi Eskandari, Raoof GhavamiAbstract:Abstract The regioselective ring opening Halogenation of some epoxides using Elemental iodine and bromine in the presence of a series of pyridine-containing groups has been studied. The epoxides were subject to cleavage by Elemental Halogen (I2 and Br2) in the presence of isonicotinic hydrazide (isoniazide) under mild reaction conditions in various solvents. In this study, reagents and conditions have been discovered with which the individual halohydrins can be synthesized in high yield and with more than 95% regioselectivity.
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Conversion of epoxides into halohydrins with Elemental Halogen catalyzed by thiourea
Tetrahedron, 2003Co-Authors: Hashem Sharghi, Mohammad Mehdi EskandariAbstract:Abstract A highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins by the direct ring opening of epoxides with Elemental Halogen in the presence of thiourea is described. This method occurs under neutral and mild conditions with high yields in various solvents even when sensitive functional groups are present.
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Conversion of Epoxides to Halohydrins with Elemental Halogen Catalyzed by Phenylhydrazine
Synthesis, 2002Co-Authors: Hashem Sharghi, Mohammad Mehdi EskandariAbstract:The highly regioselective method for the synthesis of β-iodohydrins and β-hromohydrins by the direct ring opening of 1,2-epoxides with Elemental Halogen in the presence of phenylhydrazine is described. This method occurs under neutral and mild conditions with high yields in various aprotic solvents even when sensitive functional groups are present.
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schiff base complexes of metal ii as new catalysts in the high regioselective conversion of epoxides to halo alcohols by means of Elemental Halogen
Bulletin of the Chemical Society of Japan, 1999Co-Authors: Hashem Sharghi, Hossein NaeimiAbstract:The ring opening of epoxides with Elemental iodine and bromine in the presence of some Schiff-base complexes of the first-row transition metal(II) as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
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Crown Ethers as New Catalysts in the Highly Regioselective Halogenative Cleavage of Epoxides with Elemental Halogen
The Journal of Organic Chemistry, 1998Co-Authors: Hashem Sharghi, Ahmad Reza Massah, Hossein Eshghi, Khodabakhsh NiknamAbstract:The regioselective ring opening Halogenation of some epoxides using Elemental iodine and bromine in the presence of a series of new synthetic macrocycle diamides and also dibenzo-18-crown -6, 18-crown-6, and aza-18-crown-6 has been studied. The epoxides were subject to cleavage by Elemental Halogen (I2 and Br2) in the presence of these catalysts under mild reaction conditions in various aprotic solvents. In this study, reagents and conditions have been discovered with which the individual halohydrins can be synthesized in high yield and with more than 95% regioselectivity. The results can be discussed in terms of a four-step mechanism: (1) formation of a charge-transfer complex between catalyst and Halogen, (2) release of Halogen nucleophile from the complex, (3) reaction of the active nucleophile at the less sterically-hindered site in the epoxide, and (4) regeneration of catalyst. The major advantages of this method are high regioselectivity, simple regeneration of catalyst and its reuse through severa...
Hossein Naeimi - One of the best experts on this subject based on the ideXlab platform.
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Convenient, Easy and Highly Regioselective Preparation of Haloalcohols from the Reaction of Epoxides with Elemental Halogen Catalyzed by Hexamethylenetetramine (HMTA)
Journal of the Chinese Chemical Society, 2008Co-Authors: Hossein NaeimiAbstract:The highly regioselective cleavage of epoxides into corresponding vicinal haloalcohols with Elemental Halogen has been catalyzed by hexamethylenetetramine (HMTA). This method occurred under neutral and mild conditions with high yields and short reaction times in various aprotic solvents even when sensitive functional groups were present.
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Alumina-supported metal(II) Schiff base complexes as heterogeneous catalysts in the high-regioselective cleavage of epoxides to halohydrins by using Elemental Halogen
Polyhedron, 2008Co-Authors: Hossein Naeimi, Mohsen MoradianAbstract:Abstract A highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins through direct ring opening of epoxides with Elemental Halogen in the presence of alumina-supported Schiff base complexes of Mn(II), Co(II), Ni(II) and Cu(II) as new catalysts is described. This method is regioselective under mild conditions in various aprotic solvents with high yields, even when sensitive functional groups are present. The catalysts are easily recovered and can be reused several times.
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schiff base complexes of metal ii as new catalysts in the high regioselective conversion of epoxides to halo alcohols by means of Elemental Halogen
Bulletin of the Chemical Society of Japan, 1999Co-Authors: Hashem Sharghi, Hossein NaeimiAbstract:The ring opening of epoxides with Elemental iodine and bromine in the presence of some Schiff-base complexes of the first-row transition metal(II) as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
Waldemar Goldeman - One of the best experts on this subject based on the ideXlab platform.
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comments on a facile conversion of epoxides to halohydrins with Elemental Halogen using isonicotinic hydrazide isoniazide as a new catalyst a reinvestigation
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Miroslaw Soroka, Waldemar GoldemanAbstract:Abstract The reaction of epoxides with bromine or iodine in the presence of isonicotinic hydrazide gives in fact the corresponding 2-halohydrins with reasonable yields, but contrary to the literature statement [H. Sharghi, M.M. Eskandari, R. Ghovami, J. Mol. Catal. A: Chem. 215 (2004) 55–62] the isonicotinic hydrazide is not a catalyst—it is just a stoichiometric reagent which reacts with 2 mol of Halogene to give quantitatively the nitrogen, and to generate the hydrogen Halogenide, which is a real epoxide ring opening compound.
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Comments on a facile conversion of epoxides to halohydrins with Elemental Halogen using isonicotinic hydrazide (isoniazide) as a new catalyst—a reinvestigation
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Mirosław Soroka, Waldemar GoldemanAbstract:Abstract The reaction of epoxides with bromine or iodine in the presence of isonicotinic hydrazide gives in fact the corresponding 2-halohydrins with reasonable yields, but contrary to the literature statement [H. Sharghi, M.M. Eskandari, R. Ghovami, J. Mol. Catal. A: Chem. 215 (2004) 55–62] the isonicotinic hydrazide is not a catalyst—it is just a stoichiometric reagent which reacts with 2 mol of Halogene to give quantitatively the nitrogen, and to generate the hydrogen Halogenide, which is a real epoxide ring opening compound.
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Reinvestigation of the conversion of epoxides into halohydrins with Elemental Halogen catalysed by thiourea
Tetrahedron, 2005Co-Authors: Mirosław Soroka, Waldemar GoldemanAbstract:In contrast to a previous literature report, thiourea is not a catalyst in the ring opening reaction of epoxides by means of bromine or iodine. Instead, thiourea reacts with the Halogen to give a complex mixture of products, among them hydrogen Halogenides, which are in fact the real epoxide ring opening reactants. The presence of water is crucial in this reaction.
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Comments on a Conversion of Epoxides to Halohydrins with Elemental Halogen Catalyzed by Phenylhydrazine: Tandem Electrophilic Halogenation of Aromatic Compounds and Epoxide Ring Opening to Halohydrins
Synthesis, 2003Co-Authors: Mirosław Soroka, Waldemar Goldeman, Piotr Maysa, Monika StochajAbstract:The Halogenation of aromatic compounds by bromine or chlorine in the presence of an epoxide gives the corresponding Halogenated aromatics and 2-halohydrins, both with good yields.
Mohammad Mehdi Eskandari - One of the best experts on this subject based on the ideXlab platform.
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A facile conversion of epoxides to halohydrins with Elemental Halogen using isonicotinic hydrazide (isoniazide) as a new catalyst
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Hashem Sharghi, Mohammad Mehdi Eskandari, Raoof GhavamiAbstract:Abstract The regioselective ring opening Halogenation of some epoxides using Elemental iodine and bromine in the presence of a series of pyridine-containing groups has been studied. The epoxides were subject to cleavage by Elemental Halogen (I2 and Br2) in the presence of isonicotinic hydrazide (isoniazide) under mild reaction conditions in various solvents. In this study, reagents and conditions have been discovered with which the individual halohydrins can be synthesized in high yield and with more than 95% regioselectivity.
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Conversion of epoxides into halohydrins with Elemental Halogen catalyzed by thiourea
Tetrahedron, 2003Co-Authors: Hashem Sharghi, Mohammad Mehdi EskandariAbstract:Abstract A highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins by the direct ring opening of epoxides with Elemental Halogen in the presence of thiourea is described. This method occurs under neutral and mild conditions with high yields in various solvents even when sensitive functional groups are present.
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Conversion of Epoxides to Halohydrins with Elemental Halogen Catalyzed by Phenylhydrazine
Synthesis, 2002Co-Authors: Hashem Sharghi, Mohammad Mehdi EskandariAbstract:The highly regioselective method for the synthesis of β-iodohydrins and β-hromohydrins by the direct ring opening of 1,2-epoxides with Elemental Halogen in the presence of phenylhydrazine is described. This method occurs under neutral and mild conditions with high yields in various aprotic solvents even when sensitive functional groups are present.
Mohsen Moradian - One of the best experts on this subject based on the ideXlab platform.
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Alumina-supported metal(II) Schiff base complexes as heterogeneous catalysts in the high-regioselective cleavage of epoxides to halohydrins by using Elemental Halogen
Polyhedron, 2008Co-Authors: Hossein Naeimi, Mohsen MoradianAbstract:Abstract A highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins through direct ring opening of epoxides with Elemental Halogen in the presence of alumina-supported Schiff base complexes of Mn(II), Co(II), Ni(II) and Cu(II) as new catalysts is described. This method is regioselective under mild conditions in various aprotic solvents with high yields, even when sensitive functional groups are present. The catalysts are easily recovered and can be reused several times.