1152-62-1Relevant articles and documents
A Model for the Active Sites of Oxo-Transfer Molybdoenzymes: Reactivity, Kinetics, and Catalysis
Berg, Jeremy M.,Holm, R. H.
, p. 925 - 932 (1985)
Oxidation-reduction reactions of substrates in systems containing the complexes Mo(VI)O2(LNS2) and Mo(IV)O(LNS2)(DMF) (LNS2=2,6-bis(2,2-diphenyl-2-mercaptoethyl)pyridine) in DMF solutions at 23 deg C have been investigated as models for the activities of certain oxo-transfer molybdoenzymes.The MoO1,2S2N coordination units are resonable representations of this class of enzymes.MoO2(LNS2) reacts with Ph3P in a second-order process to yield MoO(LNS2)(DMF) and Ph3O with the rate constant k1=7(1)*10-3 M-1 s-1.MoO(LNS2)(DMF) reduces sulfoxides in a two-stage reaction involving equilibrium formation of the R2SO adduct (K=4.2-16*103) followed by R2S formation (k1=1.36-1.70*10-3 s-1).The small dependence of K and k1 on substrate structure suggests that the adduct is O-ligated to Mo(IV).These reactions exhibit the frequent enzymatic property of substrate saturation kinetics.One substrate is d-biotin d-(S-oxide), the natural substrate of the Mo-dependent enzyme biotin S-oxide reductase from E. coli, indicating the biological significance of the reactions.Evidence concerning this and other physiological sulfoxide reducing activities is summarized.Oxo transfers to and from substrate have been coupled to produce a catalytic system which turns over the reaction Me2SO+Ph3P->Me2S+Ph3PO, in which Me2SO serves as a model substrate.No reaction is observed in the absence of the Mo catalyst.The initial catalytic rate is given by k, with k=6*10-3 M-1 s-1.This rate is limited by the rate of reduction of MoO2(LNS)2 by Ph3P.The sulfoxide reducing system developed here is characterized by substrate saturation kinetics, transformation of a biological substrate, and a well-defined catalytic cycle capable of turnover of hundreds of equivalents of a model substrate without intervention of a physiologically unrealistic μ-oxo-Mo(V) dimer.This system joins others recently devised in a broad development of reactivity models of metalloenzymes.
Enantioselective inclusion of pyrene-1-sulfonate salts of α-amino acids with crystals of α-cyclodextrin
Hattori, Tetsutaro,Kitamoto, Yuichi,Maeda, Tetsuya,Miyoshi, Ikuko,Morohashi, Naoya
supporting information, (2020/04/01)
Enantioselective inclusion of α-amino acids with crystals of α-cyclodextrin (α-CD) has been achieved by converting the amino acids into sulfonate salts with pyrene-1-sulfonic acid (PyS). For example, crystals of α-CD selectively include L-leucine/PyS (1:1) salt in a host/guest ratio of ～1 with 92%ee from a solution of the racemic salt in ethanol/N-methylformamide (91:9) at 40 °C. Under conditions optimized for individual amino acids, the PyS salts of valine, phenylalanine, and methionine are also included with good enantioselectivities (up to 86%ee). Mechanistic studies for the inclusion of leucine/PyS salt reveals that the enantioselectivity originates from the difference in stability between the inclusion complexes of D- and L-leucine/PyS salts with α-CD in crystals.
A kind of amino acid tanshinone phenolic derivative and its preparation method
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Paragraph 0085, (2016/10/09)
The invention relates to amino acid tanshinone phenolic ester derivatives and a preparation method thereof. The derivatives are obtained by reducing tanshinone compounds and performing esterified modification on the reduced tanshinone compounds and an amino acid into prodrugs, wherein the tanshinone compounds are phenanthrenequinone compounds which exist in salvia miltiorrhiza and have an o-quinone structure; the esterified amino acid is alpha-amino acid. The amino acid tanshinone phenolic ester derivatives are compounds having a structure of a general formula (I) or medicinal salts thereof, wherein R1 and R2 represent H or acyl alpha-amino acid and a salt thereof, and R1 and R2 are not H at the same time. The amino acid tanshinone phenolic ester derivatives have the beneficial effects that firstly, the new tanshinone derivatives are provided and the new substances have potential treatment effect on some serious diseases such as tumors, and secondly, amino acid tanshinone phenolic ester derivatives have excellent water solubility and thus can be prepared into injections conveniently in addition to various oral preparations, and therefore, the amino acid tanshinone phenolic ester derivatives are capable of quickly taking effect in disease treatment. As important prodrugs, the amino acid tanshinone phenolic ester derivatives have important application value.
