TY - JOUR A1 - Danneberg, Friederike A1 - Westemeier, Hauke A1 - Horx, Philip A1 - Zellmann, Felix A1 - Dörr, Kathrin A1 - Kalden, Elisabeth A1 - Zeiger, Mirco A1 - Akpinar, Abdullah A1 - Berger, Robert A1 - Göbel, Michael T1 - RNA hydrolysis by heterocyclic amidines and guanidines: parameters affecting reactivity T2 - European journal of organic chemistry N2 - 2-Aminobenzimidazole 10, although a weak catalyst in the monomeric state, is a successful building block for effective artificial ribonucleases. In an effort to identify new building blocks with improved catalytic potential, RNA cleavage by a variety of heterocyclic amidines and guanidines has been studied. In addition to pKa values and steric effects, the energy difference between tautomeric forms seems to be another important parameter for catalysis. This information is available from quantum chemical calculations on higher levels, but semiempirical methods are sufficient to get a first estimate. According to this assumption, imidazoimidazol 18, characterized by isoenergetic tautomeric forms, is superior to 2-aminoimidazol 6, the best candidate among the simple compounds. By far the largest effects are seen with 2-aminoperimidine 24, which rapidly cleaves RNA even in the micromolar concentration range. The impressive reactivity, however, is related to a tendency of compound 24 to form polycationic aggregates which are the actual catalysts. Y1 - 2021 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/64107 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-641077 SN - 1099-0690 N1 - Early View: Online Version before inclusion in an issue N1 - This work is dedicated to the memory of Prof. Klaus Hafner, to whom R.B. is extremely grateful for a welcoming, friendly and open atmosphere, numerous stimulating discussions as well as support and advice whenever needed during his time at TU Darmstadt. We also thank the Center for Scientific Computing (CSC) Frankfurt for computer time. Open Access funding enabled and organized by Projekt DEAL. VL - 2021 IS - online version before inclusion in an issue SP - 1 EP - 10 PB - Wiley VCZ CY - Weinheim ER -