- Effect of substituents on enantioselectivity in chiral oxazaborolidine mediated asymmetric ketone reduction reaction
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Various new chiral ligands have been synthesized by the condensation of different esters of L-Valine with different substituted salicylaldehydes in order to find the most effective catalyst for the enantioselctive ketone reduction. Chiral amine synthesized from L-Valine methyl ester and 5-chloro salicylaldehyde is found to catalyse the enantioselective reduction of prochiral ketone with high yield (99%) and enantiomeric excess (91%) with 20 mol% of the catalyst using borane dimethylsulphide as a stoichiometric reducutant. Different subsituted prochiral ketones have also been reduced in high yield upto 90% and the corresponding secondary alcohols are formed with good enantiomeric excess upto 99%. The mechanism of this reduction can be very well explained by considering a plausible mechanism for the CBS catalyst.
- Balakrishnan,Ananthi,Velmathi
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experimental part
p. 1157 - 1164
(2011/10/13)
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- Nitric oxide enhancing angiotensin II antagonist compounds, compositions and methods of use
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The invention describes compositions and kits comprising at least one nitric oxide enhancing angiotensin II antagonist compound, or pharmaceutically acceptable salts thereof, and novel compositions comprising at least one nitric oxide enhancing angiotensin II antagonist compound, and, optionally, at least one nitric oxide enhancing compound and/or at least one therapeutic agent. The invention also provides methods for (a) treating cardiovascular diseases; (b) treating renovascular diseases; (c) treating diabetes; (d) treating diseases resulting from oxidative stress; (e) treating endothelial dysfunctions; (f) treating diseases caused by endothelial dysfunctions; (g) treating cirrhosis; (h) treating pre-eclampsia; (j) treating osteoporosis; (k) treating nephropathy; (l) treating peripheral vascular diseases; (m) treating portal hypertension (o) treating central nervous system disorders; (p) treating metabolic syndrome; and (q) treating hyperlipidemia. The nitric oxide enhancing angiotensin II antagonist compounds comprise at least one nitric oxide enhancing group linked to the angiotensin II antagonist compound through one or more sites such as carbon, oxygen and/or nitrogen via a bond or moiety that cannot be hydrolyzed.
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Page/Page column 35
(2008/06/13)
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- N-cyclopentyl modulators of chemokine receptor activity
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The present invention is directed to compounds of the formula I: (wherein R1, R3, R4, R5, R6, R7, R8, X, n, x and y are defined herein) which are useful as modulators of chemokin
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- STUDIES ON AMINO ACIDS AND PEPTIDES X. HPLC-MEDIATED TEST OF 2,4-BIS(4-METHOXYPHENYL)-1,3,2,4-DITHIADIPHOSPHETANE 2,4-DISULFIDE (LAWESSONS'S REAGENT) AS A RACEMIZATIONFREE COUPLING REAGENT IN PEPTIDE SYNTHESIS
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The easily available 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson's Reagent), 1, has been tested as a coupling reagent for racemization in peptide synthesis.The assay procedure is separation of stereomeric products by HPLC.Z-S-Pro-S-Val-S-Pro-OtBu and Z-S-Leu-S-Phe-S-Val-OtBu have been used as test peptides in 2+1 segment couplings, and only a small amount of epimerization (0.5 and 0.1percent, respectively) has been observed.
- Thorsen, M.,Andersen, T. P.,Pedersen, U.,Yde, B.,Lawesson, S.-O.,Hansen. H. F.
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p. 5633 - 5636
(2007/10/02)
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