Unreported methylated catechin and epicatechin derivatives 5 and 6 were synthesized by an oxa-Pictet- Spengler reaction. Catechin 5 shows the B and C rings coplanar because of the formation of a trans junction between the C ring and the newly generated six-term cycle D, in turn condensed to ring B. In contrast, epicatechin 6 presents a bent geometry due to the establishment of a cis junction between the C ring and the newly formed cycle D. The oxidation of compounds 5 and 6 in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system was investigated under aerobic conditions in both a biphasic system and a reverse micelle. The unexpected different chemoselective oxidation at the benzylic position of catechin and epicatechin derivatives 5 and 6 has been rationalized using a molecular modelling approach. These results demonstrate that the Trametes villosa laccase/HBT system represents a useful tool to functionalize the C-2 or C-4 position of phenolic compounds depending on the structural features.
Unexpected different chemoselectivity in the aerobic oxidation of methylated planar catechin and bent epicatechin derivatives catalysed by the Trametes villosa laccase/1-hydroxybenzotriazole system / R., Bernini; Crisante, Fernanda; Gentili, Patrizia; Menta, Sergio; F., Morana; Pierini, Marco. - In: RSC ADVANCES. - ISSN 2046-2069. - 4:(2014), pp. 8183-8190. [10.1039/c3ra47753c]
Unexpected different chemoselectivity in the aerobic oxidation of methylated planar catechin and bent epicatechin derivatives catalysed by the Trametes villosa laccase/1-hydroxybenzotriazole system
CRISANTE, FernandaMembro del Collaboration Group
;GENTILI, Patrizia
Conceptualization
;MENTA, SERGIOMembro del Collaboration Group
;PIERINI, MARCOMembro del Collaboration Group
2014
Abstract
Unreported methylated catechin and epicatechin derivatives 5 and 6 were synthesized by an oxa-Pictet- Spengler reaction. Catechin 5 shows the B and C rings coplanar because of the formation of a trans junction between the C ring and the newly generated six-term cycle D, in turn condensed to ring B. In contrast, epicatechin 6 presents a bent geometry due to the establishment of a cis junction between the C ring and the newly formed cycle D. The oxidation of compounds 5 and 6 in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system was investigated under aerobic conditions in both a biphasic system and a reverse micelle. The unexpected different chemoselective oxidation at the benzylic position of catechin and epicatechin derivatives 5 and 6 has been rationalized using a molecular modelling approach. These results demonstrate that the Trametes villosa laccase/HBT system represents a useful tool to functionalize the C-2 or C-4 position of phenolic compounds depending on the structural features.File | Dimensione | Formato | |
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