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Kana M. Sureshan - One of the best experts on this subject based on the ideXlab platform.
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Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives.
Carbohydrate Research, 2002Co-Authors: Kana M. Sureshan, Thoniyot Praveen, Mysore S. Shashidhar, Rajesh G. Gonnade, Mohan M BhadbhadeAbstract:Abstract The regioselectivity of sulfonylation of myo-inositol orthoesters was controlled by the use of different bases to obtain the desired sulfonate. Monosulfonylation of myo-inositol orthoesters in the presence of one equivalent of Sodium Hydride or triethylamine resulted in the sulfonylation of the 4-hydroxyl group. The use of pyridine as a base for the same reaction resulted in sulfonylation of the 2-hydroxyl group. Disulfonylation of these orthoesters in the presence of excess Sodium Hydride yielded the 4,6-di-O-sulfonylated orthoesters. However, the use of triethylamine or pyridine instead of Sodium Hydride yielded the 2,4-di-O-sulfonylated orthoester. Sulfonylated derivatives of myo-inositol orthoesters were stable to conditions of O-alkylation but were cleaved using magnesium/methanol or Sodium methoxide in methanol to regenerate the corresponding myo-inositol orthoester derivative. These new methods of protection–deprotection have been used: (i) for the efficient synthesis of enantiomers of 2,4-di-O-benzyl-myo-inositol, which are precursors for the synthesis of d - and l -myo-inositol 1,3,4,5-tetrakisphosphate; (ii) for the preparation of 2-O-benzyl-myo-inositol which is a precursor for the preparation of myo-inositol 1,3,4,5,6-pentakisphosphate.
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sulfonate protecting groups regioselective o sulfonylation of myo inositol orthoesters
Tetrahedron Letters, 2001Co-Authors: Kana M. Sureshan, Mysore S. ShashidharAbstract:Abstract Sulfonylation of myo -inositol 1,3,5-orthoesters with alkyl or aryl sulfonyl chlorides in the presence of Sodium Hydride gives the corresponding 4,6-di- O -sulfonates in good yields. These sulfonates can be cleaved with magnesium in methanol to generate the free myo -inositol derivative. This methodology was used for the preparation of racemic 2,4-di- O -benzyl- myo -inositol and 2- O -benzyl- myo -inositol, which are precursors for some phosphoinositols.
Mysore S. Shashidhar - One of the best experts on this subject based on the ideXlab platform.
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Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives.
Carbohydrate Research, 2002Co-Authors: Kana M. Sureshan, Thoniyot Praveen, Mysore S. Shashidhar, Rajesh G. Gonnade, Mohan M BhadbhadeAbstract:Abstract The regioselectivity of sulfonylation of myo-inositol orthoesters was controlled by the use of different bases to obtain the desired sulfonate. Monosulfonylation of myo-inositol orthoesters in the presence of one equivalent of Sodium Hydride or triethylamine resulted in the sulfonylation of the 4-hydroxyl group. The use of pyridine as a base for the same reaction resulted in sulfonylation of the 2-hydroxyl group. Disulfonylation of these orthoesters in the presence of excess Sodium Hydride yielded the 4,6-di-O-sulfonylated orthoesters. However, the use of triethylamine or pyridine instead of Sodium Hydride yielded the 2,4-di-O-sulfonylated orthoester. Sulfonylated derivatives of myo-inositol orthoesters were stable to conditions of O-alkylation but were cleaved using magnesium/methanol or Sodium methoxide in methanol to regenerate the corresponding myo-inositol orthoester derivative. These new methods of protection–deprotection have been used: (i) for the efficient synthesis of enantiomers of 2,4-di-O-benzyl-myo-inositol, which are precursors for the synthesis of d - and l -myo-inositol 1,3,4,5-tetrakisphosphate; (ii) for the preparation of 2-O-benzyl-myo-inositol which is a precursor for the preparation of myo-inositol 1,3,4,5,6-pentakisphosphate.
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sulfonate protecting groups regioselective o sulfonylation of myo inositol orthoesters
Tetrahedron Letters, 2001Co-Authors: Kana M. Sureshan, Mysore S. ShashidharAbstract:Abstract Sulfonylation of myo -inositol 1,3,5-orthoesters with alkyl or aryl sulfonyl chlorides in the presence of Sodium Hydride gives the corresponding 4,6-di- O -sulfonates in good yields. These sulfonates can be cleaved with magnesium in methanol to generate the free myo -inositol derivative. This methodology was used for the preparation of racemic 2,4-di- O -benzyl- myo -inositol and 2- O -benzyl- myo -inositol, which are precursors for some phosphoinositols.
Kazuhiro Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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one pot synthesis of 2 sulfanyl 3 sulfinyl or sulfonyl 1h indoles via cyclization of 1 isothiocyanato 2 sulfinyl or sulfonyl methyl benzenes with Sodium Hydride
Tetrahedron, 2013Co-Authors: Kazuhiro Kobayashi, Akihiro Kobayashi, Kosuke EzakiAbstract:An efficient one-pot method for the synthesis of 2-sulfanyl-3-sulfinyl(or sulfonyl)-1H-indoles from 1-isothiocyanato-2-[sulfinyl(or sulfonyl)methyl]benzenes, derived from N-[2-(chloromethyl)phenyl]formamide by an easy four-step sequence, has been developed. The products are formed via cyclization of the precursor isothiocyanates using 2 equiv of Sodium Hydride followed by S- and/or N-alkylation of the resulting 1-sodio-2-sodiosulfanyl-1H-indole intermediates.
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synthesis of 2 thioxo 2 3 dihydropyrido 3 2 e 1 3 thiazin 4 ones by the reaction of n alkyl 2 chloropyridine 3 carboxamides with carbon disulfide
Heterocycles, 2009Co-Authors: Kazuhiro Kobayashi, Toshihide Komatsu, Hisatoshi KonishiAbstract:A facile method for the preparation of 2-thioxo-2,3-dihydropyrido[3,2-e]-1,3-thiazin-4-ones by the reaction of N-alkyl-2-chloropyridine-3-carboxamides with carbon disulfide in the presence of Sodium Hydride as a base has been developed.
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one pot synthesis of 2 arylimino 2 3 dihydropyrido 3 2 e 1 3 thiazin 4 ones by the reaction of secondary 2 chloropyridine 3 carboxamides with aryl isothiocyanates
Heterocycles, 2009Co-Authors: Kazuhiro Kobayashi, Toshihide Komatsu, Daizo Nakamura, Hisatoshi KonishiAbstract:A very facile method for the synthesis of 2-arylimino-2,3-dihydropyrido[3,2-e]-1,3-thiazin-4-ones has been developed. Thus, secondary 2-chloropyridine-3-carboxamides undergo addition to aromatic isothiocyanates in the presence of Sodium Hydride, followed by attack of the sulfur atom of the resulting adducts on the 2-position of the pyridine ring, to give the desired products in fair to good yields.
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a new synthesis of 4h 1 4 benzothiazine derivatives based on ring closure of ewg stabilized 2 isocyanophenylthio methyl anions
Synthesis, 2006Co-Authors: Kazuhiro Kobayashi, Kazutaka Hayashi, Daisuke Iitsuka, Osamu Morikawa, Hisatoshi KonishiAbstract:2-Cyano(phenylsulfinyl-, p-nitrophenyl-, or o-nitrophenyl-)methylthiophenyl isocyanides were synthesized from 2-aminobenzenethiols and were shown to undergo ring closure to 2,4-disubstituted 4H-1,4-benzothiazine derivatives by deprotonation of the hydrogen adjacent to the sulfur atom with Sodium Hydride or potassium tert-butoxide, followed by trapping with various electrophiles.
Mohan M Bhadbhade - One of the best experts on this subject based on the ideXlab platform.
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Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives.
Carbohydrate Research, 2002Co-Authors: Kana M. Sureshan, Thoniyot Praveen, Mysore S. Shashidhar, Rajesh G. Gonnade, Mohan M BhadbhadeAbstract:Abstract The regioselectivity of sulfonylation of myo-inositol orthoesters was controlled by the use of different bases to obtain the desired sulfonate. Monosulfonylation of myo-inositol orthoesters in the presence of one equivalent of Sodium Hydride or triethylamine resulted in the sulfonylation of the 4-hydroxyl group. The use of pyridine as a base for the same reaction resulted in sulfonylation of the 2-hydroxyl group. Disulfonylation of these orthoesters in the presence of excess Sodium Hydride yielded the 4,6-di-O-sulfonylated orthoesters. However, the use of triethylamine or pyridine instead of Sodium Hydride yielded the 2,4-di-O-sulfonylated orthoester. Sulfonylated derivatives of myo-inositol orthoesters were stable to conditions of O-alkylation but were cleaved using magnesium/methanol or Sodium methoxide in methanol to regenerate the corresponding myo-inositol orthoester derivative. These new methods of protection–deprotection have been used: (i) for the efficient synthesis of enantiomers of 2,4-di-O-benzyl-myo-inositol, which are precursors for the synthesis of d - and l -myo-inositol 1,3,4,5-tetrakisphosphate; (ii) for the preparation of 2-O-benzyl-myo-inositol which is a precursor for the preparation of myo-inositol 1,3,4,5,6-pentakisphosphate.
Hisatoshi Konishi - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 2 thioxo 2 3 dihydropyrido 3 2 e 1 3 thiazin 4 ones by the reaction of n alkyl 2 chloropyridine 3 carboxamides with carbon disulfide
Heterocycles, 2009Co-Authors: Kazuhiro Kobayashi, Toshihide Komatsu, Hisatoshi KonishiAbstract:A facile method for the preparation of 2-thioxo-2,3-dihydropyrido[3,2-e]-1,3-thiazin-4-ones by the reaction of N-alkyl-2-chloropyridine-3-carboxamides with carbon disulfide in the presence of Sodium Hydride as a base has been developed.
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one pot synthesis of 2 arylimino 2 3 dihydropyrido 3 2 e 1 3 thiazin 4 ones by the reaction of secondary 2 chloropyridine 3 carboxamides with aryl isothiocyanates
Heterocycles, 2009Co-Authors: Kazuhiro Kobayashi, Toshihide Komatsu, Daizo Nakamura, Hisatoshi KonishiAbstract:A very facile method for the synthesis of 2-arylimino-2,3-dihydropyrido[3,2-e]-1,3-thiazin-4-ones has been developed. Thus, secondary 2-chloropyridine-3-carboxamides undergo addition to aromatic isothiocyanates in the presence of Sodium Hydride, followed by attack of the sulfur atom of the resulting adducts on the 2-position of the pyridine ring, to give the desired products in fair to good yields.
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a new synthesis of 4h 1 4 benzothiazine derivatives based on ring closure of ewg stabilized 2 isocyanophenylthio methyl anions
Synthesis, 2006Co-Authors: Kazuhiro Kobayashi, Kazutaka Hayashi, Daisuke Iitsuka, Osamu Morikawa, Hisatoshi KonishiAbstract:2-Cyano(phenylsulfinyl-, p-nitrophenyl-, or o-nitrophenyl-)methylthiophenyl isocyanides were synthesized from 2-aminobenzenethiols and were shown to undergo ring closure to 2,4-disubstituted 4H-1,4-benzothiazine derivatives by deprotonation of the hydrogen adjacent to the sulfur atom with Sodium Hydride or potassium tert-butoxide, followed by trapping with various electrophiles.