6306-07-6Relevant articles and documents
Imuta,Ziffer
, p. 1351 (1979)
High-efficient metal-free aerobic oxidation of aromatic hydrocarbons by N, N-dihydroxypyromellitimide and 1,4-diamino-2,3-dichloroanthraquinone
Chen, Chen,Lv, Zhenguo,Wang, Huibin,Yang, Yuanyuan,Ye, Yicheng,Zhang, Qiaohong,Zhu, Zhuwei
, (2021/12/30)
Metal-free organic catalytic system combining with N, N-dihydroxypyromellitimide (NDHPI) and 1,4-diamino-2,3-dichloroanthraquinone (DADCAQ) was developed for the selective oxidation of hydrocarbon. Being able to simultaneously show good catalytic activity for the oxidation of hydrocarbon and alcohol, NDHPI/DADCAQ was found to be efficient for the conversion of hydrocarbon to ketone. In addition, due to its specific molecular structure, NDHPI was found to be more stable and could supply a PIDNO (pyromellitimide N, N-dioxyl free radical) during the catalytic process. So, higher catalytic activity could be obtained than the famous NHPI even with only half usage, which resolved the problem of high usage (usually 10 mol%) for the organic N-OH compounds to some extent. With 5 mol% NDHPI and 1.25 mol% DADCAQ being used under the conditions of 110 °C and 0.3 MPa molecular oxygen for 7 h, high conversion of ethylbenzene (89.6%), tetralin (98.8%), indene (96.9%), and inert toluene (50.7%) could be selectively converted to the products of acetophenone (93.4%), α-tetralone (97.3%), 1-indanone (98.9%), and benzoic acid (92.4%), respectively.
Asymmetric Transfer Hydrogenation of (Hetero)arylketones with Tethered Rh(III)-N-(p-Tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine Complexes: Scope and Limitations
Zheng, Long-Sheng,Llopis, Quentin,Echeverria, Pierre-Georges,Férard, Charlène,Guillamot, Gérard,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
, p. 5607 - 5615 (2017/06/07)
A series of new tethered Rh(III)/Cp? complexes containing the N-(p-tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine ligand have been prepared, characterized, and evaluated in the asymmetric transfer hydrogenation (ATH) of a wide range of (hetero)aryl ketones. The reaction was performed under mild conditions with the formic acid/triethylamine (5:2) system as the hydrogen source and provided enantiomerically enriched alcohols with good yields and high to excellent enantioselectivities. Although the nature of the substituents on the phenyl tethering ring did not alter the stereochemical outcome of the reaction, complexes bearing electron-donating groups exhibited a higher catalytic activity than those having electron-withdrawing groups. A scale-up of the ATH of 4-chromanone to the gram scale quantitatively delivered the reduced product with excellent enantioselectivity, demonstrating the potential usefulness of these new complexes.
The Oxidation of Hydrophobic Aromatic Substrates by Using a Variant of the P450 Monooxygenase CYP101B1
Sarkar, Md. Raihan,Lee, Joel H. Z.,Bell, Stephen G.
, p. 2119 - 2128 (2017/10/12)
The cytochrome P450 monooxygenase CYP101B1, from a Novosphingobium bacterium is able to bind and oxidise aromatic substrates but at a lower activity and efficiency than norisoprenoids and monoterpenoid esters. Histidine 85 of CYP101B1 aligns with tyrosine 96 of CYP101A1, which, in the latter enzyme forms the only hydrophilic interaction with its substrate, camphor. The histidine residue of CYP101B1 was mutated to phenylalanine with the aim of improving the activity of the enzyme for hydrophobic substrates. The H85F mutant lowered the binding affinity and activity of the enzyme for β-ionone and altered the oxidation selectivity. This variant also showed enhanced affinity and activity towards alkylbenzenes, styrenes and methylnaphthalenes. For example the rate of product formation for acenaphthene oxidation was improved sixfold to 245 nmol per nmol CYP per min. Certain disubstituted naphthalenes and substrates, such as phenylcyclohexane and biphenyls, were oxidised with lower activity by the H85F variant. Variants at H85 (A and G) designed to introduce additional space into the active site so as to accommodate these larger substrates did not improve the oxidation activity. As the H85F mutant of CYP101B1 improved the oxidation of hydrophobic substrates, this residue is likely to be in the substrate binding pocket or the access channel of the enzyme. The side chain of the histidine might interact with the carbonyl groups of the favoured norisoprenoid substrates of CYP101B1.