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Stereoselective synthesis of optical isomers of ethyl 4-chloro-3-hydroxybutyrate in a microfluidic chip reactor.
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SYSNO ASEP 0507667 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Stereoselective synthesis of optical isomers of ethyl 4-chloro-3-hydroxybutyrate in a microfluidic chip reactor. Tvůrce(i) Klusoň, Petr (UCHP-M) RID, ORCID, SAI
Stavárek, Petr (UCHP-M) RID, ORCID, SAI
Pěnkavová, Věra (UCHP-M) RID, ORCID, SAI
Vychodilová, Hana (UCHP-M) RID, SAI
Hejda, Stanislav (UCHP-M) RID, ORCID, SAI
Jaklová, N. (CZ)
Cuřínová, Petra (UCHP-M) RID, SAI, ORCIDZdroj.dok. Journal of Flow Chemistry - ISSN 2062-249X
Roč. 9, č. 4 (2019), s. 221-230Poč.str. 10 s. Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova l-carnitine ; microfluidic chip reactor ; optical purity Vědní obor RIV CI - Průmyslová chemie a chemické inženýrství Obor OECD Chemical process engineering CEP GA15-04790S GA ČR - Grantová agentura ČR Způsob publikování Omezený přístup Institucionální podpora UCHP-M - RVO:67985858 UT WOS 000517126800003 EID SCOPUS 85069674188 DOI 10.1007/s41981-019-00043-y Anotace Ethyl (R)-4-chloro-3-hydroxybutyrate ((R)-CHBE) is a versatile fine chemistry intermediate. It is used as a precursor in the synthesis of several pharmacologically valuable products, including L-carnitine. It is usually produced by means of stereoselective biotechnology methods in enzymatic reactions. An alternative preparation strategy towards ethyl (R)-4-chloro-3-hydroxybutyrate is based on the asymmetric hydrogenation of ethyl 4-chloro-acetoacetate (ECAA) to the optically pure product ((R)-CHBE) over ((S)-Ru-BINAP) catalytic complex. The reaction conditions were optimised first using (R)-Ru-BINAP yielding the (S)-CHBE isomer. All reactions were performed under continuous regime in a microfluidic chip reactor. Three different solvent phases were employed. The methanol/water phase, the ethanol/water phase, and the [N8,222][Tf2N]/methanol/water phase. The attained conversions were total in all cases already at 408 K. The parameter of enantioselectivity ee was 99.4% towards the (S)-CHBE for the system in which (R)-Ru-BINAP was accommodated in [N8,222][Tf2N]/methanol/water phase. In the case of methanol/water experiment the ee parameter reached 92.5%. For ethanol/water ee was 91.8%. The (R)-CHBE isomer over (S)-Ru-BINAP was obtained with ee = 99.3% in the [N8,222][Tf2N]/methanol/water phase at 408 K. For the reactions leading to (S)-CHBE apparent activation energies were evaluated. They were similar for MeOH/water and EtOH/water (110.5 and 110.7 kJ.mol−1). The apparent activation energies corresponding with the [N8,222][Tf2N]/MeOH/water system were much higher (of about 90 kJ.mol−1) reaching the level of 200 kJ.mol−1. The impact of the molecular structure of the main reactant was negligible as appeared from the comparison with hydrogenation of methylacetoacetate (MAA, ~ 200 kJ.mol−1). The effect of the presence of the [N8,222][Tf2N] ionic liquid on the sum of the activation energy dominated. The effectiveness of the enantioselective synthesis was additionally assessed by nuclear magnetic resonance employing the method of enantioselective complexation of the chiral compound with a chiral solvating agent. Pracoviště Ústav chemických procesů Kontakt Eva Jirsová, jirsova@icpf.cas.cz, Tel.: 220 390 227 Rok sběru 2020 Elektronická adresa http://hdl.handle.net/11104/0303716
Počet záznamů: 1