6290-03-5Relevant articles and documents
Introduction of Hindered Electrophiles via C-H Functionalization in a Palladium-Catalyzed Multicomponent Domino Reaction
Qureshi, Zafar,Schlundt, Waldemar,Lautens, Mark
, p. 2446 - 2456 (2015)
A general method for the incorporation of secondary alkyl iodides in a palladium-catalyzed multicomponent domino reaction is reported. With the relatively inexpensive Pd(OAc)2 as the catalyst and norbornene as a mediator, a variety of 1,2,3-trisubstituted aromatic compounds were synthesized. The reaction was shown to be scalable, producing excellent isolated yields on up to 5 mmol scale. Chiral alkyl iodides were also incorporated without any loss of stereochemical information. The developed method offers an expedient and mild C-H functionalization strategy for the synthesis of sterically congested aromatic compounds in a one-pot process.
Chiral tetradentate ligand, chiral ruthenium complex and method for preparing (R)-(-)-1, 3-butanediol
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Paragraph 0088-0089, (2021/03/24)
The invention discloses a chiral tetradentate ligand, a chiral ruthenium complex and a method for preparing (R)-(-)-1, 3-butanediol. The structural formula of the ligand is preferred, and R1 and R2 are H, Br, tert-butyl, phenyl, 3, 5-trifluoromethyl phenyl which are independent of each other. The method overcomes the defects of high cost, large catalyst dosage, difficulty in product separation andthe like in the existing technology for preparing (R)-(-)-1, 3-butanediol, and can perform asymmetric hydrogenation on carbonyl of the substrate methyl acetoacetate and reduce the ester group to obtain (R)-(-)-1, 3-butanediol by using a low-cost and small-dosage catalyst. The reaction operation process is simple, the catalyst is simple to prepare, and the yield and ee value of the target productare 98% or above. Meanwhile, the catalyst can be used for five times, so that the cost is greatly reduced, and the potential of industrial application is achieved.
SYNTHESIS OF 3-HYDROXYBUTYRYL 3-HYDROXYBUTYRATE AND RELATED COMPOUNDS
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Paragraph 0308; 0317; 0325-0327, (2021/04/02)
In various embodiments methods of preparing hydroxybutyryl 3-hydroxybutyrate and related compounds are provided along with methods of use thereof.
Efficient asymmetric synthesis of chiral alcohols using high 2-propanol tolerance alcohol dehydrogenase: Sm ADH2 via an environmentally friendly TBCR system
Yang, Zeyu,Fu, Hengwei,Ye, Wenjie,Xie, Youyu,Liu, Qinghai,Wang, Hualei,Wei, Dongzhi
, p. 70 - 78 (2020/01/21)
Alcohol dehydrogenases (ADHs) together with the economical substrate-coupled cofactor regeneration system play a pivotal role in the asymmetric synthesis of chiral alcohols; however, severe challenges concerning the poor tolerance of enzymes to 2-propanol and the adverse effects of the by-product, acetone, limit its applications, causing this strategy to lapse. Herein, a novel ADH gene smadh2 was identified from Stenotrophomonas maltophilia by traditional genome mining technology. The gene was cloned into Escherichia coli cells and then expressed to yield SmADH2. SmADH2 has a broad substrate spectrum and exhibits excellent tolerance and superb activity to 2-propanol even at 10.5 M (80%, v/v) concentration. Moreover, a new thermostatic bubble column reactor (TBCR) system is successfully designed to alleviate the inhibition of the by-product acetone by gas flow and continuously supplement 2-propanol. The organic waste can be simultaneously recovered for the purpose of green synthesis. In the sustainable system, structurally diverse chiral alcohols are synthesised at a high substrate loading (>150 g L-1) without adding external coenzymes. Among these, about 780 g L-1 (6 M) ethyl acetoacetate is completely converted into ethyl (R)-3-hydroxybutyrate in only 2.5 h with 99.9% ee and 7488 g L-1 d-1 space-time yield. Molecular dynamics simulation results shed light on the high catalytic activity toward the substrate. Therefore, the high 2-propanol tolerance SmADH2 with the TBCR system proves to be a potent biocatalytic strategy for the synthesis of chiral alcohols on an industrial scale.
Rational engineering of 2-deoxyribose-5-phosphate aldolases for the biosynthesis of (R)-1,3-butanediol
Kim, Taeho,Stogios, Peter J.,Khusnutdinova, Anna N.,Nemr, Kayla,Skarina, Tatiana,Flick, Robert,Joo, Jeong Chan,Mahadevan, Radhakrishnan,Savchenko, Alexei,Yakunin, Alexander F.
, p. 597 - 609 (2020/01/21)
Carbon– carbon bond formation is one of the most important reactions in biocatalysis and organic chemistry. In nature, aldolases catalyze the reversible stereoselective aldol addition between two carbonyl compounds, making them attractive catalysts for the synthesis of various chemicals. In this work, we identified several 2-deoxyribose-5-phosphate aldolases (DERAs) having acetaldehyde condensation activity, which can be used for the biosynthesis of (R)-1,3-butanediol (1,3BDO) in combination with aldo-keto reductases (AKRs). Enzymatic screening of 20 purified DERAs revealed the presence of significant acetaldehyde condensation activity in 12 of the enzymes, with the highest activities in BH1352 from Bacillus halodurans, TM1559 from Thermotoga maritima, and DeoC from Escherichia coli. The crystal structures of BH1352 and TM1559 at 1.40 –2.50 ? resolution are the first full-length DERA structures revealing the presence of the C-terminal Tyr (Tyr224 in BH1352). The results from structure-based site-directed mutagenesis of BH1352 indicated a key role for the catalytic Lys155 and other active-site residues in the 2-deoxyribose-5-phosphate cleavage and acetaldehyde condensation reactions. These experiments also revealed a 2.5-fold increase in acetaldehyde transformation to 1,3BDO (in combination with AKR) in the BH1352 F160Y and F160Y/M173I variants. The replacement of the WT BH1352 by the F160Y or F160Y/M173I variants in E. coli cells expressing the DERA + AKR pathway increased the production of 1,3BDO from glucose five and six times, respectively. Thus, our work provides detailed insights into the molecular mechanisms of substrate selectivity and activity of DERAs and identifies two DERA variants with enhanced activity for in vitro and in vivo 1,3BDO biosynthesis.
Conformational Dynamics-Guided Loop Engineering of an Alcohol Dehydrogenase: Capture, Turnover and Enantioselective Transformation of Difficult-to-Reduce Ketones
Liu, Beibei,Qu, Ge,Li, Jun-Kuan,Fan, Wenchao,Ma, Jun-An,Xu, Yan,Nie, Yao,Sun, Zhoutong
, p. 3182 - 3190 (2019/05/15)
Directed evolution of enzymes for the asymmetric reduction of prochiral ketones to produce enantio-pure secondary alcohols is particularly attractive in organic synthesis. Loops located at the active pocket of enzymes often participate in conformational changes required to fine-tune residues for substrate binding and catalysis. It is therefore of great interest to control the substrate specificity and stereochemistry of enzymatic reactions by manipulating the conformational dynamics. Herein, a secondary alcohol dehydrogenase was chosen to enantioselectively catalyze the transformation of difficult-to-reduce bulky ketones, which are not accepted by the wildtype enzyme. Guided by previous work and particularly by structural analysis and molecular dynamics (MD) simulations, two key residues alanine 85 (A85) and isoleucine 86 (I86) situated at the binding pocket were thought to increase the fluctuation of a loop region, thereby yielding a larger volume of the binding pocket to accommodate bulky substrates. Subsequently, site-directed saturation mutagenesis was performed at the two sites. The best mutant, where residue alanine 85 was mutated to glycine and isoleucine 86 to leucine (A85G/I86L), can efficiently reduce bulky ketones to the corresponding pharmaceutically interesting alcohols with high enantioselectivities (～99% ee). Taken together, this study demonstrates that introducing appropriate mutations at key residues can induce a higher flexibility of the active site loop, resulting in the improvement of substrate specificity and enantioselectivity. (Figure presented.).
Efficient synthesis of the ketone body ester (R)-3-hydroxybutyryl-(R)-3-hydroxybutyrate and its (S,S) enantiomer
Budin, Noah,Higgins, Erin,DiBernardo, Anthony,Raab, Cassidy,Li, Chun,Ulrich, Scott
, p. 560 - 564 (2018/07/25)
The ketone body ester (R)-3-hydroxybutyryl-(R)-3-hydroxybutyrate and its (S,S) enantiomer were prepared in a short, operationally simple synthetic sequence from racemic β-butyrolactone. Enantioselective hydrolysis of β-butyrolactone with immobilized Candida antarctica lipase-B (CAL-B) results in (R)-β-butyrolactone and (S)-β-hydroxybutyric acid, which are easily converted to (R) or (S)-ethyl-3-hydroxybutyrate and reduced to (R) or (S)-1,3 butanediol. Either enantiomer of ethyl-3-hydroxybutyrate and 1,3 butanediol are then coupled, again using CAL-B, to produce the ketone body ester product. This is an efficient, scalable, atom-economic, chromatography-free, and low cost synthetic method to produce the ketone body esters.
Enantioselective hydrogenation of ketones over a tartaric acid-modified raney nickel catalyst: Substrate-modifier interaction strength and enantioselectivity
Choliq, Azka Azkiya,Murakami, Eitaro,Yamamoto, Shota,Misaki, Tomonori,Fujita, Morifumi,Okamoto, Yasuaki,Sugimura, Takashi
, p. 1325 - 1332 (2018/09/21)
Chiral (R,R)-tartaric acid and NaBr-doubly modified Raney nickel (TA-MRNi) is a promising heterogeneous catalyst for enantioselective hydrogenation of prochiral β-keto esters. To obtain deeper insights into the factors ruling the enantioselectivity, enantiodifferentiating hydrogenation of substituted ketones was studied over TA-MRNi and NaBr-modified RNi by use of combined individual-competitive hydrogenation techniques. Relative equilibrium adsorption constants of the substrates were estimated to evaluate their relative interaction strength with adsorbed tartaric acid moiety. DFT calculations were also performed to estimate the interaction energy through hydrogen bonding, providing clear support to the kinetic analysis and surface model. It is concluded with the enantioselective hydrogenation of ketones over TA-MRNi that the enantioselectivity increases as the substrate-modifier interaction strength increases: Methyl acetoacetate (MAA) > acetylacetone (AA) ～ 4-hydroxy-2-butanone (HB) > 2-octanone (2O).
Regio- and Enantioselective Sequential Dehalogenation of rac-1,3-Dibromobutane by Haloalkane Dehalogenase LinB
Gross, Johannes,Faber, Kurt,Hall, Mélanie,Prokop, Zbyněk,Janssen, Dick
, p. 1437 - 1441 (2016/12/24)
The hydrolytic dehalogenation of rac-1,3-dibromobutane catalyzed by the haloalkane dehalogenase LinB from Sphingobium japonicum UT26 proceeds in a sequential fashion: initial formation of intermediate haloalcohols followed by a second hydrolytic step to produce the final diol. Detailed investigation of the course of the reaction revealed favored nucleophilic displacement of the sec-halogen in the first hydrolytic event with pronounced R enantioselectivity. The second hydrolysis step proceeded with a regioselectivity switch at the primary position, with preference for the S enantiomer. Because of complex competition between all eight possible reactions, intermediate haloalcohols formed with moderate to good ee ((S)-4-bromobutan-2-ol: up to 87 %). Similarly, (S)-butane-1,3-diol was formed at a maximum ee of 35 % before full hydrolysis furnished the racemic diol product.
METHOD FOR PRODUCING 3-BUTENE-2-OL
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Paragraph 0030, (2016/11/07)
PROBLEM TO BE SOLVED: To provide a method for efficiently producing racemic 3-butene-2-ol having an (S)- or (R)-configuration. SOLUTION: There is provided a method for producing racemic 3-butene-2-ol, wherein an ammonium salt compound represented by the following general formula (1) (wherein, R1, R2 or R3 represents an alkyl group, an aryl group or an aralkyl group; X- represents OH-, HCO3-, CO32-, R4O-, R5CO2-, R6SO3- (R4, R5 or R6 represents an alkyl group, an aryl group or an aralkyl group) and a halide ion; n represents 0.5 when X- is CO32- and n represents 1 when X- is other than CO32-; the carbon atom marked with * is an asymmetric carbon atom) is subjected to Hofmann elimination. COPYRIGHT: (C)2016,JPOandINPIT
