27159-99-5Relevant articles and documents
Structural effects on the OH--promoted fragmentation of methoxy-substituted 1-arylalkanol radical cations in aqueous solution: The role of oxygen acidity
Baciocchi, Enrico,Bietti, Massimo,Gerini, Maria Francesca,Manduchi, Laura,Salamone, Michela,Steenken, Steen
, p. 1408 - 1416 (2001)
A kinetic and product study of the OH--induced decay in H2O of the radical cations generated from some di- and tri-methoxy-substituted 1-arylalkanols (ArCH(OH)R·+) and 2- and 3-(3,4-dimethoxyphenyl) alkanols has been carried out by using pulse- and γ-radiolysis techniques. In the 1-arylalkanol system, the radical cation 3,4-(MeO)2C6H3CH2OH ·+ decay at a rate more than two orders of magnitude higher than that of its methyl ether; this indicates the key role of the side-chain OH group in the decay process (oxygen acidity). However, quite a large deuterium kinetic isotope effect (3.7) is present for this radical cation compared with its α-dideuterated counterpart. A mechanism is suggested in which a fast OH deprotonation leads to a radical zwitterion which then undergoes a rate-determining 1,2-H shift, coupled to a side-chain-to-ring intramolecular electron transfer (ET) step. This concept also attributes an important role to the energy barrier for this ET, which should depend on the stability of the positive charge in the ring and, hence, on the number and position of methoxy groups. On a similar experimental basis, the same mechanism is suggested for 2,5-(MeO)2C6H3CH2OH ·+ as for 3,4-(MeO)2C6H3CH2OH ·+, in which some contribution from direct C-H deprotonation (carbon acidity) is possible. In fact, the latter process dominates the decay of the trimethoxylated system 2,4,5-(MeO)3C6H2CH2OH ·+, which, accordingly, reacts with OH- at the same rate as that of its methyl ether. Thus, a shift from oxygen to carbon acidity is observed as the positive charge is increasingly stabilized in the ring; this is attributed to a corresponding increase in the energy barrier for the intramolecular ET. When R = tBu, the OH--promoted decay of the radical cation ArCH(OH)R·+ leads to products of C-C bond cleavage. With both Ar = 3,4- and 2,5-dimethoxyphenyl the reactivity is three orders of magnitude higher than that of the corresponding cumyl alcohol radical cations; this suggests a mechanism in which a key role is played by the oxygen acidity as well as by the strength of the scissile C-C bond: a radical zwitterion is formed which undergoes a rate-determining C-C bond cleavage, coupled with the intramolecular ET. Finally, oxygen acidity also determines the reactivity of the radical cations of 2-(3,4-dimethoxyphenyl)ethanol and 3-(3,4-dimethoxyphenyl)propanol. In the former the decay involves C-C bond cleavage, in the latter it leads to 3-(3,4-dimethoxyphenyl) propanal. In both cases no products of C-H deprotonation were observed. Possible mechanisms, again involving the initial formation of a radical zwitterion, are discussed.
BCL-2 INHIBITOR
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, (2021/10/22)
Disclosed herein is a compound of Formula (I) for inhibiting both Bcl-2 wild type and mutated Bcl-2, in particular, Bcl-2 G101V and D103Y, and a method of using the compound disclosed herein for treating dysregulated apoptotic diseases.
Reductive Deuteration of Aromatic Esters for the Synthesis of α,α-Dideuterio Benzyl Alcohols Using D 2O as Deuterium Source
Luo, Shihui,Weng, Chaoqun,Ding, Yuxuan,Ling, Chen,Szostak, Michal,Ma, Xiaodong,An, Jie
supporting information, p. 51 - 56 (2020/11/10)
α,α-Dideuterio benzyl alcohols are important building blocks for the synthesis of deuterium-labeled medicines and agrochemicals. We have developed the first general single-electron transfer reductive deuteration of readily commercially available aromatic
An α, α - dideuterium substituted benzyl alcohol compound. Deuterated drug and method for reducing deuteration of benzoate compound
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Paragraph 0049-0050, (2021/09/08)
The invention relates to a method. Α, α-deuterated benzyl alcohol compound and preparation thereofΑ, αThe method for reducing and deuteration - dideuterium-substituted benzyl alcohol compounds is characterized in that the benzoate compound represented by
Differences in the Mechanisms of MnO2Oxidation between Lignin Model Compounds with the p-Hydroxyphenyl, Guaiacyl, and Syringyl Nuclei
Sun, Shirong,Akiyama, Takuya,Yokoyama, Tomoya,Matsumoto, Yuji
, p. 6819 - 6825 (2020/07/02)
The purpose of this study was to examine how the rate and mechanism of MnO2 oxidation differ between the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) types of simple nonphenolic lignin model compounds as well as the p-ethylphenyl (E) type compounds. The oxidation was conducted using an excess amount of MnO2 in a sulfate buffer solution at a pH value of 1.5 at room temperature. MnO2 oxidized at least the G and S nuclei, although it commonly oxidizes alcohols present at the benzyl position. The oxidation rates of the benzyl alcohol derivatives were in the order of G- > S- ? H- > E-type, which suggests that the rates are determined by the electronic effects of their methoxy and ethyl functional groups on not only their benzyl positions but also their aromatic π-electron systems. The kinetic isotope effect was observed in the MnO2 oxidations of the same derivatives deuterated at their benzyl hydroxymethyl groups. The observed magnitudes were in the order of E- ? H- > G- ? S-type, suggesting that the contribution of oxidation of their aromatic nuclei, which is another reaction mode of the oxidation of their benzyl positions, increases in the reverse order.
Kinetic deuterium isotope effect in the oxidation of veratryl alcohol promoted by lignin peroxidase and chemical oxidants
Baciocchi,Gerini,Harvey,Lanzalunga,Prosperi
, p. 1512 - 1515 (2007/10/03)
The intramolecular kinetic deuterium isotope effects (kH/kD = 4.6-4.9) determined in the H2O2-induced oxidation of the racemic and enantiomeric forms of α-monodeuterated veratryl alcohol catalysed by lignin peroxidase (LiP) are very similar to those determined in the oxidation of racemic α-monodeuterated veratryl alcohol promoted either by a LiP model compound (a water soluble iron porphyrin using m-chloroperbenzoic acid as the oxidant) (kH/kD = 4.2) or by potassium 12-tungstocobalt(III)ate, a genuine one-electron oxidant (kH/kD = 4.5). These results indicate that very likely veratryl alcohol radical cation, once generated by the LiP-H2O2 system, is released from the enzyme and is deprotonated by the medium.
Stereochemical control in microbial reduction. XXVIII. Asymmetric reduction of α,β-unsaturated ketones with Bakers' yeast
Kawai, Yasushi,Saitou, Kentarou,Hida, Kouichi,Dao, Duc Hai,Ohno, Atsuyoshi
, p. 2633 - 2638 (2007/10/03)
Bakers' yeast reduction of α,β-unsaturated ketones affords optically active saturated ketones contaminated by allylic and saturated alcohols as minor components. Stereoselectivity of the reduction of carbon-carbon double bond strongly depends on the structure of β-aryl substituent. The bakers' yeast reduction of β-phenyl enones gives saturated ketones in moderate stereoselectivity. Stereoselectivity is not altered by substitution at the para-position, whereas introduction of a substituent at the ortho- or meta-position drastically improves the stereoselectivity. Deuterium-labeling experiments reveal that the enzymatic reduction of carbon-carbon double bond proceeds with formal trans-addition of hydrogens regardless the efficiency of stereoselectivity. The resulting optically active ketone was converted to the precursor of (S)-iopanoic acid, an inhibitor of thyroxine 5′-deiodinase that is a thyroid hormone-converting enzyme and an oral cholecystographic agent.
