- Enantioselective α-tosyloxylation of ketones catalyzed by spirobiindane scaffold-based chiral iodoarenes
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Enantiomerically pure iodoarene (S)-2 and its derivatives (S)-3 to (S)-18 with a spirobiindane scaffold have been synthesized. The evaluation of these new chiral iodoarenes as catalysts in the enantioselective α-tosyloxylation of ketones was performed using m-CPBA as a stoichiometric oxidant, and the synthetically useful α-tosyloxylated ketones were obtained in up to 58% enantiomeric excess (ee).
- Yu, Jun,Cui, Jian,Hou, Xue-Sen,Liu, Shan-Shan,Gao, Wen-Chao,Jiang, Shan,Tian, Jun,Zhang, Chi
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p. 2039 - 2055
(2012/03/11)
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- Studies on angiotensin converting enzyme inhibitors. VI. Synthesis and angiotensin converting enzyme inhibitory activities of the dicarboxylic acid derivative of imidapril and its diastereoisomers
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All possible diastereoisomers of the dicarboxylic acid (10a), the biologically active form of imidapril (1), were synthesized, and their inhibitory activity against angiotensin converting enzyme (ACE) was examined. The in vitro ACE inhibitory activity of these compounds greatly depended on the configurations of the three asymmetric carbons in each molecule. The (S,S,S) isomer (10a) showed much more potent activity than the others.
- Kubota,Nunami,Hayashi,Hashimoto,Ogiku,Matsuoka,Ishida
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p. 1619 - 1622
(2007/10/02)
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- Concise Synthesis of Optically Active Oxirane Precursors for the Preparation of Triazole Antifungals Using the Friedel-Crafts Reaction of (S)-2-Tosyloxypropionyl Chloride
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Optically active epoxide (2R,3S)-4, a key intermediate for the preparation of triazole antifungal agents (4R,5R)-1 and (2R,3R)-2 (X = 2,4-F2), was synthesized.The Friedel-Crafts reaction between the (S)-lactic acid derivative (S)-10 and m-difluorobenzene gave the (R)-2-chloropropiophenone derivative (R)-11, which was converted into (2R,3R)-18 via Peterson olefination, stereoselective osmium(VIII) oxide oxidation, and mesylation.Treatment of (2R,3R)-18 with sodium triazolide gave (2R,3S)-4.Similarly, the 4-chlorophenyl analog (2R,3S)-4' was prepared.
- Konosu, Toshiyuki,Tajima, Yawara,Miyaoka, Takeo,Oida, Sadao
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p. 7545 - 7548
(2007/10/02)
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- Preparation of α-arylalkanoic acids
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Pharmaceutically useful optically active α-arylalkanoic acids or esters, ortho esters, or amides thereof are stereoselectively prepared by contacting an aryl magnesium Grignard reagent with an optically active α-substituted acyl halide to form the optically active aryl α-substituted alkyl ketone, which is ketalized and rearranged to the desired optically active α-arylalkanoic acid or the corresponding ester, ortho ester or amide. In an alternate embodiment, the aryl α-substituted alkyl ketone is reduced to the corresponding alkanol, which is rearranged to the α-arylalkanal. The alkanal so produced is converted to the desired optically active α-arylalkanoic acid by conventional methods.
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- Results of Process Research. I. Synthesis of O-propionyl>-acetone oxime
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Efficient and simple procedures for the preparation of O--propionyl>-oxime derivatives 7b-e have been developed.The alkylation of 4-phenol (11) with 7d, the final step of a technical synthesis of 1, has been studied in detail.
- Imfeld, Marquard,Suchy, Milos,Vogt, Peter,Lukac, Teodor,Schlageter, Markus,Widmer, Erich
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p. 1233 - 1241
(2007/10/02)
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