6451-72-5Relevant articles and documents
Inverting the regioselectivity of the berberine bridge enzyme by employing customized fluorine-containing substrates
Resch, Verena,Lechner, Horst,Schrittwieser, Joerg H.,Wallner, Silvia,Gruber, Karl,MacHeroux, Peter,Kroutil, Wolfgang
, p. 13173 - 13179 (2013/01/15)
Fluorine is commonly applied in pharmaceuticals to block the degradation of bioactive compounds at a specific site of the molecule. Blocking of the reaction center of the enzyme-catalyzed ring closure of 1,2,3,4- tetrahydrobenzylisoquinolines by a fluoro moiety allowed redirecting the berberine bridge enzyme (BBE)-catalyzed transformation of these compounds to give the formation of an alternative regioisomeric product namely 11-hydroxy-functionalized tetrahydroprotoberberines instead of the commonly formed 9-hydroxy-functionalized products. Alternative strategies to change the regioselectivity of the enzyme, such as protein engineering, were not applicable in this special case due to missing substrate-enzyme interactions. Medium engineering, as another possible strategy, had clear influence on the regioselectivity of the reaction pathway, but did not lead to perfect selectivity. Thus, only substrate tuning by introducing a fluoro moiety at one potential reactive carbon center switched the reaction to the formation of exclusively one regioisomer with perfect enantioselectivity. Custom-made substrates: Employing customized substrates with a fluoro atom at the normally preferred reaction site switched the regioselectivity of the berberine-bridged enzyme. With this strategy, it was possible to get access to (S)-11-hydroxy-functionalized berbines in an asymmetric fashion by using the wild-type enzyme (see scheme). Copyright
Biocatalytic organic synthesis of optically pure (S)-scoulerine and berbine and benzylisoquinoline alkaloids
Schrittwieser, Joerg H.,Resch, Verena,Wallner, Silvia,Lienhart, Wolf-Dieter,Sattler, Johann H.,Resch, Jasmin,MacHeroux, Peter,Kroutil, Wolfgang
experimental part, p. 6703 - 6714 (2011/10/18)
A chemoenzymatic approach for the asymmetric total synthesis of the title compounds is described that employs an enantioselective oxidative C-C bond formation catalyzed by berberine bridge enzyme (BBE) in the asymmetric key step. This unique reaction yielded enantiomerically pure (R)-benzylisoquinoline derivatives and (S)-berbines such as the natural product (S)-scoulerine, a sedative and muscle relaxing agent. The racemic substrates rac-1 required for the biotransformation were prepared in 4-8 linear steps using either a Bischler-Napieralski cyclization or a C1-Cα alkylation approach. The chemoenzymatic synthesis was applied to the preparation of fourteen enantiomerically pure alkaloids, including the natural products (S)-scoulerine and (R)-reticuline, and gave overall yields of up to 20% over 5-9 linear steps.
BIOTRANSFORMATION OF ISOQUINOLINE ALKALOIDS WITH RAT LIVER MICROSOMES
Kametani, Tetsuji,Kanaya, Naoaki,Ohta, Yohko,Ihara, Masataka
, p. 963 - 970 (2007/10/02)
Optically active (+)-reticuline (1) was biotransformed into (-)-coreximine (2), (-)-scoulerine (3), (+)-isoboldine (4) and (-)-pallidine (5) with retention of the chirality by the incubation with rat liver microsomes.On the other hand, the racemate of reticuline formed the racemates of the above alkaloids on the some treatment.The S-adenosylmethionine was partially incorporated into the berberine bridge during the biotransformation of reticuline into the protoberberines.