1502-05-2Relevant articles and documents
A new catalytic system for the selective aerobic oxidation of large ring cycloalkanes to ketones
Baucherel, Xavier,Arends, Isabel W. C. E.,Ellwood,Sheldon, Roger A.
, p. 426 - 428 (2003)
The combination of cobalt with N-hydroxysaccharin proved to be an effective catalyst for the aerobic oxidation of large ring cycloalkanes to the corresponding ketones.
Synthesis of β-cycloalkylglycosides of Muramyl Dipeptide
Zemlyakov,Tsikalova,Tsikalov
, p. 929 - 932 (2017)
β-Cyclooctyl-, β-cyclodecyl-, and β-cyclopentadecylglycosides of N-acetylmuramyl-L-alanyl-D-isoglutamine were prepared in yields of 39, 18, and 25%, respectively, (calculated for muramic acid) via the reaction of β-cycloalkyl-4,6-O-isopropylidene-N-acetyl-D-muramic acids with the benzyl ester of L-Ala-D-iGln using the HOSu/DCC method followed by deprotection.
Copper-containing SiCN precursor ceramics (Cu@SiCN) as selective hydrocarbon oxidation catalysts using air as an oxidant
Glatz, Germund,Schmalz, Thomas,Kraus, Tobias,Haarmann, Frank,Motz, Guenter,Kempe, Rhett
, p. 4231 - 4238 (2010)
A molecular approach to metal-containing ceramics and their application as selective heterogeneous oxidation catalysts is presented. The aminopyridinato copper complex [Cu2(ApTMS)2] (ApTMSH = (4-methylpyridin2-yl)trimethylsilanylamine) reacts with poly(organosilazanes) via aminopyridine elimination, as shown for the commercially available ceramic precursor HTT 1800. The reaction was studied by 1H and 13C NMR spectroscopy. The liberation of the free, protonated ligand Ap TMSH is indicative of the copper polycarbosilazane binding. Crosslinking of the copper-modified poly(organosilazane) and subsequent pyrolysis lead to the copper-containing ceramics. The copper is reduced to copper metal during the pyrolysis step up to 1000 °C, as observed by solid-state 65Cu NMR spectroscopy, SEM images, and energydispersive spectroscopy (EDS). Powder diffraction experiments verified the presence of crystalline copper. All Cu@SiCN ceramics show catalytic activity towards the oxidation of cycloalkanes using air as oxidant. The selectivity of the reaction increases with increasing copper content. The catalysts are recyclable. This study proves the feasibility of this molecular approach to metal-containing SiCN precursor ceramics by using silylaminopyridinato complexes. Furthermore, the catalytic results confirm the applicability of this new class of metal-containing ceramics as catalysts.
Complementary and selective oxidation of hydrocarbon derivatives by two cytochrome P450 enzymes of the same family
Sarkar, Md. Raihan,Bell, Stephen G.
, p. 5983 - 5995 (2020/10/08)
The cytochrome P450 enzymes CYP101B1 and CYP101C1, which are from the bacterium Novosphingobium aromaticivorans DSM12444, can hydroxylate norisoprenoids with high activity and selectivity. With the goal of expanding and establishing their substrate range with a view to developing applications, the oxidation of a selection of cyclic alkanes, ketones and alcohols was investigated. Cycloalkanes were oxidised, but both enzymes displayed moderate binding affinity and low levels of productive activity. We improved the binding and activity of these substrates with CYP101B1 by making the active site more hydrophobic by switching a histidine residue to a phenylalanine (H85F). The presence of a ketone moiety in the cycloalkane skeleton significantly improved the oxidation activity with both enzymes. CYP101C1 preferably catalysed the oxidation of cycloalkanones at the C-2 position whereas CYP101B1 oxidised these substrates with higher productivity and at positions remote from the carbonyl group. This demonstrates that the binding orientation of the cyclic ketones in the active site of each enzyme must be different. Linear ketones were also oxidised by both enzymes but with lower activity and selectivity. Cyclic substrates with an ester directing group were more efficiently oxidised by CYP101B1 than CYP101C1. Both enzymes catalysed oxidation of these esters with high regioselectively on the ring system remote from the ester directing group. CYP101C1 selectively oxidised certain terpenoid ester substrates, such as α-terpinyl and citronellyl acetate more effectively than CYP101B1. Overall, we establish that the high selectivity and activity of these enzymes could provide new biocatalytic routes to important fine chemicals.
Selective biocatalytic hydroxylation of unactivated methylene C-H bonds in cyclic alkyl substrates
Sarkar, Md Raihan,Dasgupta, Samrat,Pyke, Simon M.,Bell, Stephen G.
supporting information, p. 5029 - 5032 (2019/05/21)
The cytochrome P450 monooxygenase CYP101B1 from Novosphingobium aromaticivorans selectively hydroxylated methylene C-H bonds in cycloalkyl rings. Cycloketones and cycloalkyl esters containing C6, C8, C10 and C12 rings were oxidised with high selectively on the opposite side of the ring to the carbonyl substituent. Cyclodecanone was oxidised to oxabicycloundecanol derivatives in equilibrium with the hydroxycyclodecanones.
Structure-reactivity relationship for alcohol oxidations via hydride transfer to a carbocationic oxidizing agent
Lu, Yun,Bradshaw, Joshua,Zhao, Yu,Kuester, William,Kabotso, Daniel
, p. 1172 - 1178 (2013/01/12)
Second-order rate constants were determined for the oxidation of 27 alcohols (R1R2CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60°C. Alcohols include open-chain alkyl, cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol were determined at three H/D positions of the alcohol (KIEα-D=3.9, KIEβ-D3=1.03, KIE OD=1.10). These KIE results are consistent with those we previously reported for the 2-propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer mechanism that involves a rate-limiting formation of the α-hydroxy carbocation intermediate. Structure-reactivity relationship for alcohol oxidations was deeply discussed on the basis of the observed structural effects on the formation of the carbocationic transition state (Cδ+-OH). Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric hindrance effect and ring strain relief effect win over the electronic effect in determining the rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl alcohols. Strained C7-C11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C5 and C12 alcohols react slower. Aromatic alcohols would be efficiently and selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements. This structure-reactivity relationship for alcohol oxidations via hydride-transfer mechanism is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis. Copyright
Screening of a minimal enriched P450 BM3 mutant library for hydroxylation of cyclic and acyclic alkanes
Weber, Evelyne,Seifert, Alexander,Antonovici, Mihaela,Geinitz, Christopher,Pleiss, Juergen,Urlacher, Vlada B.
scheme or table, p. 944 - 946 (2011/02/25)
A minimal enriched P450 BM3 library was screened for the ability to oxidize inert cyclic and acyclic alkanes. The F87A/A328V mutant was found to effectively hydroxylate cyclooctane, cyclodecane and cyclododecane. F87V/A328F with high activity towards cyclooctane hydroxylated acyclic n-octane to 2-(R)-octanol (46% ee) with high regioselectivity (92%).
Aerobic oxidation of cycloalkanes, alcohols and ethylbenzene catalyzed by the novel carbon radical chain promoter NHS (N-hydroxysaccharin)
Baucherel, Xavier,Gonsalvi, Luca,Arends, Isabel W. C. E.,Ellwood, Simon,Sheldon, Roger A.
, p. 286 - 296 (2007/10/03)
Replacement of Ishii's N-hydroxyphthalimide (NHPI) with the novel carbon radical chain promoter N-hydroxysaccharin (NHS) affords, in combination with metal salts, notably Co, or other additives, selective catalytic autoxidation of hydrocarbons, alcohols and alkylbenzenes under mild conditions (25-100°C, O2 1 atm). The effects of solvent, temperature and the nature of the additives were investigated to give an optimised oxidation protocol for the various systems. The NHS/Co combination was more reactive than NHPI/Co in the autoxidation of cycloalkanes. In contrast, the opposite order of reactivity was observed in the autoxidation of ethylbenzene and alcohols. It is suggested, on the basis of bond dissociation energy (BDE) considerations, that this is a result of a change in the rate-limiting step with the more reactive ethylbenzene and alcohol substrates. In the autoxidation of the model cycloalkane, cyclododecane, the best results (90% selectivity to a 4:1 mixture of alcohol and ketone at 24% conversion) were obtained with NHS/Co(acac)3 in PhCF3 at 80°C. Competition experiments revealed that, in contrast to what is commonly believed, formation of the dicarboxylic acid by ring opening is not a result of further oxidation of the ketone product. It is suggested that ring opened products are a result of β-scission of the cycloalkoxy radical formed via (metal-catalysed) decomposition of the hydroperoxide. This is suppressed in the presence of NHS (or NHPI) which efficiently scavenge the alkoxy radicals.
PROCESS FOR PRODUCTION OF DICARBOXYLIC ACIDS
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Page/Page column 14-15; 19, (2008/06/13)
A process of the present invention produces a corresponding dicarboxylic acid by oxidative cleavage of a cycloalkane with oxygen and performs a reaction in the presence of a catalyst including an imide compound and a metallic compound, the imide compound having a cyclic imide skeleton represented by following Formula (I): wherein X is an oxygen atom or an-OR group, and wherein R is a hydrogen atom or a hydroxyl-protecting group, under conditions of a reaction temperature of 80°C or higher and a concentration of the cycloalkane in a system of 21% by weight or more. The imide compound includes, for example, N-hydroxyphthalimide. The amount of the imide compound is, for example, from about 0.000001 to about 0.01 mole per mole of the cycloalkane. In the production of a corresponding dicarboxylic acid by catalytic oxidation of a cycloalkane with oxygen, the present invention can yield the dicarboxylic acid in a high space time yield even using a small amount of the catalyst.
Acceleration of the reduction of aldehydes and ketones using Mn(dpm)3 catalyst and phenylsilane in the presence of dioxygen
Magnus, Philip,Fielding, Mark R
, p. 6633 - 6636 (2007/10/03)
Saturated ketones and aldehydes are reduced to alcohols by phenylsilane and Mn(dpm)3(cat) in the presence of dioxygen.
