- Asymmetric hydrogenation of 2-substituted N-protected-indoles catalyzed by rhodium complexes of BINOL-derived phosphoramidites
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The rhodium-catalyzed asymmetric hydrogenation of 2-substituted N-protected-indoles using monodentate phosphoramidites as ligands was examined. Full conversion and 74% ee, were obtained with a catalyst based on PipPhos. The use of a catalytic amount of base is necessary for activity; best results were obtained with Cs2CO3.
- Mrsic, Natasa,Jerphagnon, Thomas,Minnaard, Adriaan J.,Feringa, Ben L.,de Vries, Johannes G.
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- Direct Optical Resolution of Carboxylic Acids by Chyral HPLC on Tris(3,5-dimethylphenylcarbamate)s of Cellulose and Amylose
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A variety of racemic carboxylic acids have been for the first time directly resolved by normal-phase, high-performance liquid chromatography using a hexane-2-propanol eluting system containing a small amount (ca. 1percent) of a strong carboxylic acid, like formic acid, trichloroacetic acid, and trifluoroacetic acid.
- Okamoto, Yoshio,Aburatani, Ryo,Kaida, Yuriko,Hatada, Koichi
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p. 1125 - 1128
(2007/10/02)
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- Application of Microbes and Microbial Esterases to the Preparation of Optically Active N-Acetylindoline-2-Carboxylic Acid
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Methylotrophic bacteria, isolated from soil samples or from sewage sludge, proved to be useful sources of esterases for catalyzing the enantioselective hydrolysis of racemic N-acetyl-indoline-2-carboxylic acid methyl ester (7) to the corresponding (2S) or (2R)-N-acetyl amino acid (6) with high optical yields.From the DMF-utilizer Pseudomonas DMF 5/8 and the methanol-utilizer Isolate EE 210, the corresponding esterases were isolated.Reactions with whole cells as well as with the purified enzymes are described.
- Ramos Tombo, Gerardo M.,Schaer, Hans-Peter,Ghisalba, Oreste
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p. 1833 - 1838
(2007/10/02)
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- Angiotensin converting enzyme inhibitors: N-substituted monocyclic and bicyclic amino acid derivatives
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The synthesis of N-(3-mercaptopropionyl)-N-arylglycines (14a-x), -N-arylalanines (15a,b), -N-cycloalkylglycines (16a-k), and -1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids (17a-d), -1,2,3,4-tetrahydroquinoline-2-carboxylic acids (18a-f), and -indoline-2-carboxylic acids (19a-k) is described. In vitro inhibition of angiotensin converting enzyme (ACE) is reported for each compound, and the structure-activity relationship for each series is discussed. The in vivo inhibition of ACE and antihypertensive effects of representative compounds from each series are discussed. The most potent compound, 19d, had an in vitro ACE IC50 of 2.6 x 10-9 M and lowered blood pressure in spontaneous hypertensive rats 85 mm at a dose of 10 mg/kg po.
- Stanton,Gruenfeld,Babiarz,Ackerman,Friedmann,Yuan,Macchia
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p. 1267 - 1277
(2007/10/02)
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