ChemInform Abstract: Synthesis of Novel Pyrazolo[5,1‐b]benzothiazoles: A New Pericyclic Pathway.

Abstract

Benzothiazole derivatives R 0270Synthesis of Novel Pyrazolo[5,1-b]benzothiazoles: A New Pericyclic Pathway. -N-Amination of the benzylbenzothiazoles (I), followed by reaction of the N-amino salts (III) with ethyl orthoformate (IV) afford derivatives (V) of the pyrazolobenzothiazole ring system. The ring closure may proceed via deprotonation of the N-amino salt and subsequent electrocyclization to provide the tricyclic ring system. From a theoretical point of view, the pericyclic nature of the ring-closure step is of importance. -(TEKINER-GULBAS, B.; FILAK, L.; VASKO, G. A.; EGYED, O.; YALCIN, I.; AKI-SENER, E.; RIEDL, Z.; HAJOS*, G.; Heterocycles 75 (2008) 8, 2005-2012; Chem. Res. Cent., Hung. Acad. Sci., H-1025 Budapest, Hung.; Eng.) -H. Hoennerscheid 50-123

Evaluation of inhibitory effects of benzothiazole and 3-amino-benzothiazolium derivatives on DNA topoisomerase II by molecular modeling studies

“…A set of previously synthesized benzothiazole and 3-amino-benzothiazolium derivatives [16] tested for DNA topoisomerase II inhibitory activity were chosen from our previous study [21] as shown in Table 1. The DNA topoisomerase II inhibitory activities of these compounds are represented as IC 50 values in the millimolar, micromolar or nanomolar range [21].…”

“…Our group has been working for many years on the synthesis of some new heterocyclic compounds that were potentially DNA topoisomerase I and II inhibitors, and molecular modelling studies of these compounds [15][16][17][18][19][20][21]. So far some of the compounds exhibited significant topoisomerase II inhibitory activity with IC 50 values differing from 11.4 and 46.8 μM compared with the standard drug etoposide [15,18].…”