Regioselectivity control in biocatalysis: lipase catalyzed synthesis of biomaterials derived from ethyl acrylate

L.EANDRO N. MONSALVE; PAULA G. QUINTANA; ALICIA BALDESSARI

Berna, Suiza

Simposio; 9th International Symposium on Biocatalysis and Biotransformation; 2009

European Federation of Biotechnology

Regioselectivity control in biocatalysis: Lipase-catalyzedsynthesis of biomaterials derived from ethyl acrylateLeandro N. Monsalve, Paula G. Quintana, Alicia Baldessari*Departamento de Química Orgánica y UMYMFOR. Facultad de CienciasExactas y Naturales. Universidad de Buenos Aires. Ciudad Universitaria.Pab. II. Piso 3. C1428EGA. Buenos Aires. ArgentinaEnzymes can catalyze many and very diverse chemical transformations.This is a well known and widespread phenomenon called catalyticpromiscuity, and it is utilized in numerous synthetic applications Here wereport new examples carried out by lipases. The use of various substratesand reaction conditions made it possible to efficiently catalyze severalreactions such as aminolysis, hydrolysis, Michael addition and evenpolymerization. This enzymatic behavior allowed us to obtain us a varietyproducts (1-5) from ethyl acrylate and alkanolamines or diamines as startingmaterials.The reaction with alkanolamines afforded hydroxyalkylacrylamides (1) andacrylic co- and terpolymers containing, at random, sequences of ethylpolyacrylate, acrylic acid and poly(N-(2-hydroxyethyl)acrylamide)(2).1Inthe presence of ethanolamine, the enzyme not only catalyzes the chainpolymerization of ethyl acrylate but also the hydrolysis and aminolysis ofthe pendant ester groups. With diamines we obtained a Michael adduct (3)and N-(4-aza-5-methylhexyl)acrylamide (4). The enzymatic reactions werehighly regioselective: aminolysis occurred exclusively on the primary aminogroup in the diamine while the secondary amino group was the nucleophilein the Michael addition. In addition, CAL B lipase allowed us to obtainpolyamidoamine (5), a monodisperse and highly regular polymeric materialthat could not obtained following traditional synthetic methods. It isinteresting to point out that, although both polymeric materials 2 and 6 comefrom ethyl acrylate and CAL B catalysis, the reaction with an alkanolamineafforded a series of hydrophobically modified polyacrylamides withpotential use in tissue engineering while a polyamidoamine, useful assolubility drug enhancer, was obtained by reaction with a diamine.[1] E. Rustoy, Y. Sato, H. Nonami, R. Erra-Balsells, A. Baldessari, Polymer 2007,48,1517