- The Stereoselective Oxidation of para-Substituted Benzenes by a Cytochrome P450 Biocatalyst
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The serine 244 to aspartate (S244D) variant of the cytochrome P450 enzyme CYP199A4 was used to expand its substrate range beyond benzoic acids. Substrates, in which the carboxylate group of the benzoic acid moiety is replaced were oxidised with high activity by the S244D mutant (product formation rates >60 nmol.(nmol-CYP)?1.min?1) and with total turnover numbers of up to 20,000. Ethyl α-hydroxylation was more rapid than methyl oxidation, styrene epoxidation and S-oxidation. The S244D mutant catalysed the ethyl hydroxylation, epoxidation and sulfoxidation reactions with an excess of one stereoisomer (in some instances up to >98 %). The crystal structure of 4-methoxybenzoic acid-bound CYP199A4 S244D showed that the active site architecture and the substrate orientation were similar to that of the WT enzyme. Overall, this work demonstrates that CYP199A4 can catalyse the stereoselective hydroxylation, epoxidation or sulfoxidation of substituted benzene substrates under mild conditions resulting in more sustainable transformations using this heme monooxygenase enzyme.
- Chao, Rebecca R.,Lau, Ian C.-K.,Coleman, Tom,Churchman, Luke R.,Child, Stella A.,Lee, Joel H. Z.,Bruning, John B.,De Voss, James J.,Bell, Stephen G.
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p. 14765 - 14777
(2021/09/14)
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- Regioselective Epoxide Ring Opening for the Stereospecific Scale-Up Synthesis of BMS-960, A Potent and Selective Isoxazole-Containing S1P1 Receptor Agonist
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This article presents a stereospecific scale-up synthesis of (S)-1-((S)-2-hydroxy-2-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)phenyl)ethyl)piperidine-3-carboxylic acid (BMS-960), a potent and selective isoxazole-containing S1P
- Hou, Xiaoping,Zhang, Huiping,Chen, Bang-Chi,Guo, Zhiwei,Singh, Amarjit,Goswami, Animesh,Gilmore, John L.,Sheppeck, James E.,Dyckman, Alaric J.,Carter, Percy H.,Mathur, Arvind
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p. 200 - 207
(2017/02/26)
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- Azidolysis of epoxides catalysed by the halohydrin dehalogenase from Arthrobacter sp. AD2 and a mutant with enhanced enantioselectivity: an (S)-selective HHDH
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Halohydrin dehalogenase from Arthrobacter sp. AD2 catalysed azidolysis of epoxides with high regioselectivity and low to moderate (S)-enantioselectivity (E?=?1–16). Mutation of the asparagine 178 to alanine (N178A) showed increased enantioselectivity towards styrene oxide derivatives and glycidyl ethers. Conversion of aromatic epoxides was catalysed by HheA-N178A with complete enantioselectivity, however the regioselectivity was reduced. As a result of the enzyme-catalysed reaction, enantiomerically pure (S)-β-azido alcohols and (R)-α-azido alcohols (ee???99%) were obtained.
- Mikleu?evi?, Ana,Primo?i?, Ines,Hrenar, Tomica,Salopek-Sondi, Branka,Tang, Lixia,Elenkov, Maja Majeri?
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p. 930 - 935
(2016/09/13)
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- Catalytic Enantioselective Conversion of Epoxides to Thiiranes
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A highly efficient and enantioselective Br?nsted acid catalyzed conversion of epoxides to thiiranes has been developed. The reaction proceeds in a kinetic resolution, furnishing both epoxide and thiirane in high yields and enantiomeric purity. Heterodimer formation between the catalyst and sulfur donor affords an effective way to prevent catalyst decomposition and enables catalyst loadings as low as 0.01 mol %.
- Liao, Saihu,Leutzsch, Markus,Monaco, Mattia Riccardo,List, Benjamin
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supporting information
p. 5230 - 5233
(2016/05/19)
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- Asymmetric epoxidation of alkenes and benzylic hydroxylation with P450tol monooxygenase from Rhodococcus coprophilus TC-2
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P450tol monooxygenase was discovered as a unique and highly enantioselective enzyme for asymmetric epoxidation of some terminal alkenes containing electron-withdrawing groups and benzylic hydroxylation of several ethylbenzenes giving the corresponding useful and valuable products, such as (R)-2- and 3-substituted styrene oxides, (S)-4-substituted styrene oxides, and (S)-benzylic alcohols, in high ee.
- Li, Aitao,Wu, Shuke,Adams, Joseph P.,Snajdrova, Radka,Li, Zhi
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p. 8771 - 8774
(2014/07/22)
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- Engineered P450pyr monooxygenase for asymmetric epoxidation of alkenes with unique and high enantioselectivity
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A triple mutant of P450pyr monooxygenase (P450pyrTM) catalysed the epoxidation of several para-substituted styrenes as the first enzyme showing high (R)-enantioselectivity and high conversion, demonstrated a broad substrate range, and showed high enantioselectivity for the epoxidation of an unconjugated 1,1-disubstituted alkene, 2-methyl-3-phenyl-1-propene, and a cyclic alkene, N-phenoxycarbonyl-1,2,5,6-tetrahydropyridine, respectively.
- Li, Aitao,Liu, Ji,Pham, Son Q.,Li, Zhi
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supporting information
p. 11572 - 11574
(2013/12/04)
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- Mechanistic investigations of cooperative catalysis in the enantioselective fluorination of epoxides
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This report describes mechanistic studies of the (salen)Co- and amine-cocatalyzed enantioselective ring opening of epoxides by fluoride. The kinetics of the reaction, as determined by in situ 19F NMR analysis, are characterized by apparent first-order dependence on (salen)Co. Substituent effects, nonlinear effects, and reactivity with a linked (salen)Co catalyst provide evidence for a rate-limiting, bimetallic ring-opening step. To account for these divergent data, we propose a mechanism wherein the active nucleophilic fluorine species is a cobalt fluoride that forms a resting-state dimer. Axial ligation of the amine cocatalyst to (salen)Co facilitates dimer dissociation and is the origin of the observed cooperativity. On the basis of these studies, we show that significant improvements in the rates, turnover numbers, and substrate scope of the fluoride ring-opening reactions can be realized through the use of a linked salen framework. Application of this catalyst system to a rapid (5 min) fluorination to generate the unlabeled analog of a known PET tracer, F-MISO, is reported.
- Kalow, Julia A.,Doyle, Abigail G.
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p. 16001 - 16012
(2011/11/13)
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- SUBSTITUTED PIPERAZINES AS CB1 ANTAGONISTS
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Compounds of Formula (I) or pharmaceutically acceptable salts, solvates, or esters thereof, are useful in treating diseases or conditions mediated by CB1receptors, such as metabolic syndrome and obesity, neuroinflammatory disorders, cognitive disorders and psychosis, addiction (e.g., smoking cessation), gastrointestinal disorders, and cardiovascular conditions.
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Page/Page column 173
(2009/03/07)
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- Discovery of a novel series of benzoic acid derivatives as potent and selective human β3 adrenergic receptor agonists with good oral bioavailability. 3. Phenylethanolaminotetraline (PEAT) skeleton containing biphenyl or biphenyl ether moiety
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We designed a series of benzoic acid derivatives containing the biphenyl ether or biphenyl template on the RHS and a phenylethanolaminotetraline (PEAT) skeleton, which was prepared by highly stereoselective synthesis, to generate two structurally different lead compounds (10c, 10m) with a good balance of potency, selectivity, and pharmacokinetic profile. Further optimization of the two lead compounds to improve potency led to several potential candidates (i.e., 11f, 11l, 11o, 12b). In particular, biphenyl analogue 12b exhibited an excellent balance of high potency (EC50 = 0.38 nM) for β3, high selectivity over β1 and β2, and good pharmacokinetic properties in rats, dogs, and monkeys.
- Imanishi, Masashi,Nakajima, Yutaka,Tomishima, Yasuyo,Hamashima, Hitoshi,Washizuka, Kenichi,Sakurai, Minora,Matsui, Shigeo,Imamura, Emiko,Ueshima, Koji,Yamamoto, Takao,Yamamoto, Nobuhiro,Ishikawa, Hirofumi,Nakano, Keiko,Unami, Naoko,Hamada, Kaori,Matsumura, Yasuhiro,Takamura, Fujiko,Hattori, Kouji
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experimental part
p. 4804 - 4822
(2009/07/11)
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- Dynamic kinetic resolution of racemic β-haloalcohols: Direct access to enantioenriched epoxides
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The direct chemo-enzymatic DKR of racemic β-haloalcohols is reported, yielding the corresponding optically active epoxides in a single step. The mutant haloalcohol dehalogenase HheC Cys153Ser Trp249Phe is used for the asymmetric ring closure, whereas racemization of the remaining enantiomer of the haloalcohol is achieved using the new iridacycle 3, one of the most effective racemization catalysts to date for β-haloalcohols. Copyright
- Haak, Robert M.,Berthiol, Florian,Jerphagnon, Thomas,Gayet, Arnaud J. A.,Tarabiono, Chiara,Postema, Christiaan P.,Ritleng, Vincent,Pfeffer, Michel,Janssen, Dick B.,Minnaard, Adriaan J.,Feringa, Ben L.,De Vries, Johannes G.
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supporting information; scheme or table
p. 13508 - 13509
(2009/02/06)
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- Effective asymmetric epoxidation of styrenes by chiral dioxirane
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High enantioselectivity (80-92% enantiomeric excess (ee)) has been obtained for the epoxidation of various styrenes using an easily prepared ketone (4) catalyst.
- Goeddel, David,Shu, Lianhe,Yuan, Yi,Wong, O. Andrea,Wang, Bin,Shi, Yian
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p. 1715 - 1717
(2007/10/03)
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