62281-72-5Relevant articles and documents
Boron-Catalyzed O-H Bond Insertion of α-Aryl α-Diazoesters in Water
San, Htet Htet,Wang, Shi-Jun,Jiang, Min,Tang, Xiang-Ying
supporting information, p. 4672 - 4676 (2018/08/09)
A catalytic, metal-free O-H bond insertion of α-diazoesters in water in the presence of B(C6F5)3·nH2O (2 mol %) was developed, affording a series of α-hydroxyesters in good to excellent yields. The reaction features easy operation and wide substrate scope, and importantly, no metal is needed as compared with the conventional methods. Significantly, this approach further expands the applications of B(C6F5)3 under water-tolerant conditions.
Simple and efficient synthesis of racemic substituted mandelic acid esters from nonactivated arenes and ethyl glyoxylate
Kwiatkowski, Jacek,Majer, Jakub,Kwiatkowski, Piotr,Jurczak, Janusz
experimental part, p. 3237 - 3244 (2009/05/26)
Direct synthesis of racemic aromatic α-hydroxyacetic acid esters via Friedel-Crafts reaction of nonactivated, simple arenes with ethyl glyoxylate promoted by SnCl4 or AlCl3 is described. The use of SnCl4 opens a fast access to various alkyl- and aryl-substituted mandelic acids esters at room temperature within two hours in good yield (>80%) and with high regioselectivity. The procedure was successfully employed also for the alkylation of compounds with condensed aromatic rings. Alternative hydroxyalkylations with AlCl3 require longer reaction time and higher temperature to get a good yield.
CeCl3·7H2O: An effective additive in ru-catalyzed enantioselective hydrogenation of aromatic α-ketoesters
Meng, Qinghua,Sun, Yanhui,Ratovelomanana-Vidal, Virginie,Genet, Jean Pierre,Zhang, Zhaoguo
, p. 3842 - 3847 (2008/09/21)
(Chemical Equation Presented) In the presence of catalytic amounts of CeCl3·7H2O, [RuCl(benzene)(S)-SunPhos]Cl is a highly effective catalyst for the asymmetric hydrogenation of aromatic α-ketoesters. A variety of ethyl α-hydroxy-α-arylacetates have been prepared in up to 98.3% ee with a TON up to 10 000. Challenging aromatic α-ketoesters with ortho substituents are also hydrogenated with high enantioselectivities. The addition of CeCl3·7H2O not only improves the enantioselectivity but also enhances the stability of the catalyst. The ratio of CeCl3·7H2O to [RuCl(benzene)(S)-SunPhos]Cl plays an important role in the hydrogenation reaction with a large substrate/catalyst ratio.
Mechanism and scope of salen bifunctional catalysts in asymmetric aldehyde and α-ketoester alkylation
Fennie, Michael W.,DiMauro, Erin F.,O'Brien, Erin M.,Annamalai, Venkatachalam,Kozlowski, Marisa C.
, p. 6249 - 6265 (2007/10/03)
Metal complexes of C2-symmetric Lewis acid/Lewis base salen ligands provide bifunctional activation resulting in rapid rates in the enantioselective addition of diethylzinc to aldehydes (up to 92% ee). Further experiments probed the reactivity of the individual Lewis acid and Lewis base components of the catalyst and established that both moieties are essential for asymmetric catalysis. These catalysts are also effective in the asymmetric addition of diethylzinc to α-ketoesters. This finding is significant because α-ketoesters alone serve as their own ligands to accelerate racemic 1,2-carbonyl addition of Et2Zn and racemic carbonyl reduction. The latter proceeds via a metalloene pathway, and often accounts for the predominant product. Singular Lewis acid catalysts do not accelerate enantioselective 1,2-addition over these two competing paths. The bifunctional amino salen catalysts, however, rapidly provide enantioenriched 1,2-addition products in excellent yield, complete chemoselectivity, and good enantioselectivity (up to 88% ee). A library of the bifunctional amino salens was synthesized and evaluated in this reaction. The utility of the α-ketoester method has been demonstrated in the synthesis of an opiate antagonist.
Development of bifunctional salen catalysts: Rapid, chemoselective alkylations of α-ketoesters
DiMauro, Erin F.,Kozlowski, Marisa C.
, p. 12668 - 12669 (2007/10/03)
Lewis acid-Lewis base salen complexes have been identified as highly efficient catalysts for the addition of dialkylzincs to α-ketoesters. In contrast to aldehydes or ketones, the reaction between diethylzinc and α-ketoesters is significant in the absence of catalyst. In the presence of catalyst, the reaction rate is increased over 100-fold relative to the background. Furthermore, the reduction product, which is a major coproduct with other catalysts, is not observed with these bifunctional salens. As a result, high yields of the addition products can be obtained (57-99%). Both the Lewis acid and Lewis base portions of the catalyst are critical to the reactivity and selectivity. The two separate portions of the catalyst have been shown to function in a cooperative manner. Copyright
Non-Peptide Angiotensin II Receptor Antagonists. 2. Design, Synthesis, and Biological Activity of N-Substituted (Phenylamino)phenylacetic Acids and Acyl Sulfonamides
Dhanoa, Daljit S.,Bagley, Scott W.,Chang, Raymond S. L.,Lotti, Victor J.,Chen, Tsing-Bau,et al.
, p. 4239 - 4249 (2007/10/02)
The design, synthesis, and biological activity of a new class of highly potent non-peptide AII receptor antagonists derived from N-substituted (phenylamino)phenylacetic acids and acyl sulfonamides which exhibit a high selectivity for the AT1 receptor are described.A series of N-substituted (phenylamino)phenylacetic acids (9) and acyl sulfonamides (16) and a tetrazole derivative (19) were synthesized and evaluated in the in vitro AT1 (rabbit aorta) and AT2 (rat midbrain) binding assay.The (phenylamino)phenylacetic acids 9c (AT1 IC50=4 nM, AT2 IC50=0.74 μM), 9d (AT1 IC50=5.3 nM, AT2 IC50=0.49 μM), and 9e (AT1 IC50=5.3 nM, AT2 IC50=0.56 μM) were found to be the most potent AT1-selective AII antagonists in the acid series.Incorporation of various substituents in the central and bottom phenyl rings led to a decrease in the AT1 and AT2 binding affinity of the resulting compounds.Replacement of the carboxylic acid (CO2H) in 9c, 9d, and 9e with the bioisostere acyl sulfonamide (CONHSO2Ph) resulted in a (5-7)-fold increase in the AT1 potency of 16a (AT1 IC50=0.9 nM, AT2 IC50=0.2 μM), 16b (AT1 IC50=1 nM, AT2 IC50=2.9 μM), and 16c (AT1 IC50=0.8 nM, AT2 IC50=0.42 μM) and yielded acyl sulfonamides with subnanomolar AT1 activity.Incorporation of the acyl sulfonamide (CONHSO2Ph) for the CO2H of 9c not only enhanced the AT1 potency but also effected a marked increase in the AT2 potency of 16a (AT2 IC50=0.74 μM of 9c vs 0.2 μM of 16a) and made it the most potent AT2 antagonist in this study.Replacement of the CO2H of 9b with the bioisostere tetrazole resulted in 19 (AT1 IC50=15 nM) with a 2-fold loss in the AT1 and a complete loss in the AT2 binding affinity. (Phenylamino)phenylacetic acid 9c demonstrated good oral activity in AII-infused conscious normotensive rats at an oral dose of 1.0 mg/kg by inhibiting the pressor response for >6 h.Acyl sulfonamides 16a-c displayed excellent in vivo activity by blocking the AII-induced pressor response for >6 h after oral administration in conscious rats at a 3.0 mg/kg dose level.Both acyl sulfonamides 16a and 16c exhibited superior in vivo activity in rats compared to that of (phenylamino)phenylacetic acid 9c.
ANGIOTENSIN II ANTAGONISTS INCORPORATING A SUBSTITUTED PYRIDOIMIDAZOLYL RING
-
, (2008/06/13)
Substituted heterocycles attached through a methylene bridge to novel substituted phenyl derivatives of the Formula I are useful as angiotensin II antagonists. STR1
