@article{ScheinerSinkSpatzetal.2021, author = {Scheiner, Matthias and Sink, Alexandra and Spatz, Philipp and Endres, Erik and Decker, Michael}, title = {Photopharmacology on Acetylcholinesterase: Novel Photoswitchable Inhibitors with Improved Pharmacological Profiles}, series = {ChemPhotoChem}, volume = {5}, journal = {ChemPhotoChem}, number = {2}, doi = {10.1002/cptc.202000119}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218445}, pages = {149 -- 159}, year = {2021}, abstract = {Considerable effort has previously been invested in a light-controlled inhibition of the enzyme acetylcholinesterase (AChE). We found that a novel azobenzene-based bistacrine AChE inhibitor switched faster than the known dithienylethene based bistacrine and inverted the photo-controlled interactions of the photoisomers compared to its dithienylethene congener. Furthermore, we have optimized a previously described light-controlled tacrine-based AChE inhibitor. Isomerization upon irradiation with UV light of the novel inhibitor was observed in aqueous medium and showed no fatigue over several cycles. The cis-enriched form showed an 8.4-fold higher inhibition of hAChE compared with its trans-enriched form and was about 30-fold more active than the reference compound tacrine with a single-digit nanomolar inhibition. We went beyond proof-of-concept to discover photoswitchable AChE inhibitors with pharmacologically desirable nanomolar inhibition, "cis-on" effect, and pronounces differences between the photoisomers.}, language = {en} } @article{SawatzkyDrakopoulosRoelzetal.2016, author = {Sawatzky, Edgar and Drakopoulos, Antonios and R{\"o}lz, Martin and Sotriffer, Christoph and Engels, Bernd and Decker, Michael}, title = {Experimental and theoretical investigations into the stability of cyclic aminals}, series = {Beilstein Journal of Organic Chemistry}, volume = {12}, journal = {Beilstein Journal of Organic Chemistry}, doi = {10.3762/bjoc.12.221}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160976}, pages = {2280-2292}, year = {2016}, abstract = {Background: Cyclic aminals are core features of natural products, drug molecules and important synthetic intermediates. Despite their relevance, systematic investigations into their stability towards hydrolysis depending on the pH value are lacking. Results: A set of cyclic aminals was synthesized and their stability quantified by kinetic measurements. Steric and electronic effects were investigated by choosing appropriate groups. Both molecular mechanics (MM) and density functional theory (DFT) based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude of the conformational energy of the ring system and pK a values of the N-3 nitrogen atom. Conclusion: Cyclic aminals are stable compounds when not exposed to acidic media and their stability is mainly dependent on the conformational energy of the ring system. Therefore, for the preparation and work-up of these valuable synthetic intermediates and natural products, appropriate conditions have to be chosen and for application as drug molecules their sensitivity towards hydrolysis has to be taken into account.}, language = {en} }