945-89-1Relevant academic research and scientific papers
Resolution of (R,S)-1-(4-methoxyphenyl)ethanol by lipase-catalyzed stereoselective transesterification and the process optimization
He, Bingbing,Tang, Fengci,Sun, Chenrui,Su, Jiahao,Wu, Bingcheng,Chen, Yan,Xiao, Yuquan,Zhang, Panliang,Tang, Kewen
, p. 438 - 445 (2021/12/17)
An efficient lipase-catalyzed stereoselective transesterification reaction system was established for resolution of 1-(4-methoxyphenyl)ethanol (MOPE) enantiomers. A series of lipases were tested and compared. The immobilized lipase Novozym 40086 is selected as the best choice. The effects of organic solvent, acyl donor, time and temperature on substrate conversion (c), and optical purity of the remaining substrate (eeS) were investigated. Response surface methodology and central composite design were employed to evaluate the effect of some important factors and to optimize the process. Under the optimized conditions including solvent of n-hexane, acyl donor of vinyl acetate, temperature of 35°C, substrate molar ratio of 1:6, enzyme dosage of 20 mg, and reaction time of 2.5 h, eeS of 99.87% with c of 56.71% is achieved. The use of alkane solvent and immobilized enzyme, the mild reaction conditions, and the reduced reaction time make the system promising in industrial application.
PQXdpap: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
Murakami, Ryo,Suginome, Michinori,Yamamoto, Takeshi
supporting information, p. 8711 - 8716 (2021/11/24)
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and 1,1,2-trichloroethane enabled the preparation of either compound of a pair of enantiomerically pure alcohols (>99% ee) from a single catalyst.
Activity and specificity studies of the new thermostable esterase EstDZ2
Myrtollari, Kamela,Katsoulakis, Nikolaos,Zarafeta, Dimitra,Pavlidis, Ioannis V.,Skretas, Georgios,Smonou, Ioulia
, (2020/09/16)
In this paper, we study the activity and specificity of EstDZ2, a new thermostable carboxyl esterase of unknown function, which was isolated from a metagenome library from a Russian hot spring. The biocatalytic reaction employing EstDZ2 proved to be an efficient method for the hydrolysis of aryl p-, o- or m-substituted esters of butyric acid and esters of secondary alcohols. Docking studies revealed structural features of the enzyme that led to activity differences among the different substrates.
Continuous-Flow Dynamic Kinetic Resolution of Racemic Alcohols by Lipase–Oxovanadium Cocatalysis
Adebar, Niklas,Akai, Shuji,Gr?ger, Harald,Higashio, Koichi,Kühn, Franziska,Katsuragi, Satoko,Kundu, Dhiman,Plass, Carmen
supporting information, p. 1961 - 1967 (2020/04/09)
A continuous-flow dynamic kinetic resolution of racemic secondary alcohols was carried out using a single column reactor packed with a mixture of immobilized lipase and an immobilized oxovanadium species, VMPS4. As a result, optically pure esters were produced in 88–92 % yields. Problems encountered in this study were overcome by using fillers that efficiently maintained the initial distribution of the catalysts in the reactor and by using a packing method in which the mixing ratio of the two catalysts was varied in a stepwise fashion. The flow process led to an increased turnover number of each catalyst compared to those of batch reactions.
LipG9-mediated enzymatic kinetic resolution of racemates: Expanding the substrate-scope for a metagenomic lipase
Thomas, Juliana Christina,Alnoch, Robson Carlos,Costa, Allen Carolina dos Santos,Bandeira, Pamela Taisline,Burich, Martha Daniela,Campos, Suelem Kluconski,de Oliveira, Alfredo Ricardo Marques,de Souza, Emanuel Maltempi,Pedrosa, Fabio de Oliveira,Krieger, Nadia,Piovan, Leandro
, (2019/05/22)
Enzymes are the main biocatalysts of biological systems and nowadays they play an important role in asymmetric organic synthesis. Microorganisms are the main source for enzymes, however, just a very small portion of them are culturable at lab conditions and, as an alternative, metagenomics approaches allow new enzymes to be accessed from so-called “non-culturable” microorganisms. Several classes of metagenomic enzymes have been described in literature. Nevertheless, studies about their potential for asymmetric biotransformation are underexploited. Therefore, we present our recent efforts to establish the substrate-scope of LipG9, a metagenomic lipase, in enzymatic kinetic resolution (EKR) of chiral substances. LipG9 was previously isolated, immobilized and successfully applied in EKR of aliphatic alcohols. In this study, a series of resolvable chiral substances were assayed with LipG9, and secondary benzyl alcohols/esters were preferentially resolved in a much superior enantioselectivity (E > 200) than those described for aliphatic alcohols (E from 4 to 63). In an opposite way, Im-LipG9 did not present activity for tertiary alcohols, amines and lactones. When compared to commercial lipases, Im-LipG9 enantioselectivity was superior to Candida rugosa lipase and equivalent to Candida antarctica lipase B. Thus, the chemo and enantioselectivity of LipG9 in EKR reactions were identified and its potential for asymmetric synthetic approaches was demonstrated.
Base-Free Dynamic Kinetic Resolution of Secondary Alcohols with a Ruthenium-Lipase Couple
Yun, Inyeol,Park, Jin Yong,Park, Jaiwook,Kim, Mahn-Joo
, p. 16293 - 16298 (2019/12/27)
We report the dynamic kinetic resolution (DKR) of various secondary alcohols by the combination of a ruthenium catalyst and an anionic surfactant-activated lipoprotein lipase. The DKR reactions performed under totally base-free conditions at room temperature provided the products of excellent enantiopurities (91-99% ee or greater) in high yields (92-99%). More importantly, the DKR of α-arylallyl alcohols was achieved for the first time with high yields (87-91%).
Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system
Dohi, Toshifumi,Iwasaki, Kosuke,Kita, Yasuyuki,Morimoto, Koji,Tsunoda, Yusuke,Ueda, Shohei
, p. 1087 - 1094 (2020/05/06)
An oxidation system comprising phenyliodine(III) diacetate (PIDA) and iodosobenzene with inorganic bromide, i.e., sodium bromide, in an organic solvent led to the direct introduction of carboxylic acids into benzylic C–H bonds under mild conditions. The unique radical species, generated by the homolytic cleavage of the labile I(III)–Br bond of the in situ-formed bromo-λ3-iodane, initiated benzylic carboxylation with a high degree of selectivity for the secondary benzylic position.
Base-catalyzed selective esterification of alcohols with unactivated esters
Zhang, Chunyan,Zhang, Guoying,Luo, Shizhong,Wang, Chunfu,Li, Huiping
supporting information, p. 8467 - 8471 (2018/12/01)
A practical and efficient base-catalyzed esterification has been developed for the facile synthesis of a broad range of esters from simple alcohols with unactivated tert-butyl esters. This protocol could be conducted at mild conditions, providing esters in high to excellent yields with good functional tolerance. Mechanistic studies provided evidence of an exchange of the tert-butyl alkoxide metal with the alcohol, producing a new alkoxide to participate in the transesterification reaction.
Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
Jereb, Marjan,Vra?i?, Dejan
, p. 747 - 762 (2018/01/17)
Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
Dynamic kinetic resolution of aromatic: Sec -alcohols by using a heterogeneous palladium racemization catalyst and lipase
Xu, Yuanfeng,Wang, Meng,Feng, Bo,Li, Ziyang,Li, Yuanhua,Li, Hexing,Li, Hui
, p. 5838 - 5842 (2017/12/26)
Microwave-assisted one-pot dynamic kinetic resolution of aromatic secondary alcohols is successfully conducted by using a recyclable chemoenzymatic catalyst combination. This design concept will attract more attention in the foreseeable future for the synthesis of chiral drugs and their building blocks.
