- Synthesis of Analogues of the Carboxyl Protease Inhibitor Pepstatin. Effect of Structure in Subsite P3 on Inhibition of Pepsin
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A series of pepstatin analogues having minimum structural requirements for tight-binding inhibition has been synthesized and tested on porcine pepsin.Subtle changes in the geometry and size of side chains at the valine-1 position of pepstatin were found to dramatically affect inhibitor potency as well as the type of kinetic behavior observed.The inhibitors reported here can be grouped into two categories: the more potent inhibitors are slow-binding inhibitors, i.e., exhibit slow, time-dependent inhibition; the weaker inhibitors, with Ki values greater than 10-8M, are not time-dependent inhibitors.A minimum kinetic mechanism is proposed to account for the observed kinetic behavior.
- Rich, Daniel H.,Bernartowicz, Michael S.
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- Zinc(0)/dimethylformamide-mediated synthesis of symmetrical carboxylic anhydrides from acid chlorides
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The high yielding synthesis of symmetrical carboxylic anhydrides from acid chlorides mediated by zinc dust in the presence of dimethylformamide is presented. A mechanism involving the reductive insertion of zinc(0) into the C-Cl bond of a Vilsmeier-type iminium intermediate as the crucial step is also proposed.
- Serieys, Audrey,Botuha, Candice,Chemla, Fabrice,Ferreira, Franck,Pérez-Luna, Alejandro
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- Isothiourea-Catalysed Regioselective Acylative Kinetic Resolution of Axially Chiral Biaryl Diols
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An operationally simple isothiourea-catalysed acylative kinetic resolution of unprotected 1,1′-biaryl-2,2′-diol derivatives has been developed to allow access to axially chiral compounds in highly enantioenriched form (s values up to 190). Investigation of the reaction scope and limitations provided three key observations: i) the diol motif of the substrate was essential for good conversion and high s values; ii) the use of an α,α-disubstituted mixed anhydride (2,2-diphenylacetic pivalic anhydride) was critical to minimize diacylation and give high selectivity; iii) the presence of substituents in the 3,3′-positions of the diol hindered effective acylation. This final observation was exploited for the highly regioselective acylative kinetic resolution of unsymmetrical biaryl diol substrates bearing a single 3-substituent. Based on the key observations identified, acylation transition state models have been proposed to explain the atropselectivity of this kinetic resolution.
- Qu, Shen,Greenhalgh, Mark D.,Smith, Andrew D.
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supporting information
p. 2816 - 2823
(2019/02/05)
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- Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
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We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
- Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
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p. 1972 - 1978
(2015/02/19)
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- A search for quantitative acylation of α-trinositol (1D-myo-inositol 1,2,6-tris(dihydrogen phosphate) pentasodium salt)
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The acylation of α-trinositol is very sensitive to reaction conditions. Competing condensation reactions may give pyrophosphates and cyclic phosphates. Treatment of a tert-ammonium salt corresponding to α-trinositol with carboxylic acid anhydride and DMAP gives a good yield of the expected esters.
- Malmberg, Mats,Rehnberg, Nicola
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p. 459 - 464
(2007/10/03)
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- Hydroxy protection groups
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The present invention concerns a method for preparing unprotected hydroxy compounds or acylated derivatives thereof by conversion of silyl alkyl-protected hydroxy compounds. The invention also relates to novel intermediates useful in the method and for other purposes.
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