Emprego de lipases na resolução cinética do rac-1-[tris(isopropil)silil]penta-1,4-diin-3-ol, um importante intermediário para síntese de alquinil carbinóis lipídios

• Ano de defesa: 2022
• Autor(a) principal: Davi, Dalila Maria Barbosa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Biocatálise; Dialquinilcarbinol; Lipase; Resolução Cinética
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/65299

This work aimed to investigate the enzymatic kinetic resolution (EKR) of the dialkinyl carbinol rac-1-[tris(isopropyl)silyl]penta-1,4-diin-3-ol (rac-1), via lipase catalyzed acylation reaction, to produce the enantiomerically pure or enriched dialkinylcarbinols (R-1 and S-1). Initially, ten commercial lipases with enzymatic potential for the kinetic resolution of rac-1 were screened. Among them, the enzymes Candida antarctica B immobilized on acrylic resin (CAL-B), Thermomyces lanuginous immobilized on immobead-150 (TLL), Amano PS from Burkholderia cepacia immobilized on diatomaceous earth (PS-IM) and the free enzyme Amano lipase from Pseudomonas fluorescens were selected for presenting results of enantiomeric excess (eep and ees) >99%, conversion (c) of 50% and enantioselectivity (E) >200. The influence of the solvent on the EKR catalyzed by these enzymes was investigated, performing the reaction in heptane, hexane, cyclohexane, toluene, ethyl ether, tetrahydrofuran (THF) and acetonitrile (ACN). Among these, heptane and hexane were the solvents that resulted in eep and ees >99%, c=50% and E >200 for all tested enzymes. In the case of lipases CAL-B and PS-IM, five of the seven solvents tested (except THF and ACN) produced optimal EKR results. Subsequently, studies with the CAL-B enzyme and the heptane solvent were carried out to evaluate the influence of temperature, time, enzyme:substrate ratio and enzyme reuse in the reaction. The studies resulted in the optimization of the RCE of rac-1 (eep and ees > 99%, c = 50% and E = 200) with the reaction being carried out under the following conditions: CAL-B, heptane, 40°C, 2 h and enzyme ratio:substrate (0.5:1). Study on the lipase under these conditions was carried out, resulting, already in the second cycle, in a reduction of the conversion value (c = 40%) and enantiomeric excesses of both the substrate and the product (eep > 99% and ees > 66%), although maintaining E > 200.