TARGET-ORIENTED SYNTHESIS OF FUNCTIONALIZED PYRAZOLO-FUSED MEDIUM-SIZED N,S-HETEROCYCLES <i>VIA</i> FRIEDEL–CRAFTS RING CLOSURE APPROACH

Authors

  • Hassan A. K. Abd El-Aal Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt

DOI:

https://doi.org/10.1007/5331

Keywords:

polycycles, pyrazoles, thiazocinones, thiecinones, Friedel–Crafts cycliacylation.

Abstract

Efficient and concise synthetic protocol to benzo- and pyrazolo-fused medium-sized N,S-heterocycles (e.g,. thiazocinones, thiazoninones, thiazecinones, thiecinones, and thioninones) is developed. The process involves the AlCl3/MeNO2, TfOH or polyphosphoric acid mediated cyclization of pyrazole-based carboxylic acids or esters into tricyclic ketones under mild conditions. The designed protocol offers easy access to biologically and pharmaceutically promising pyrazoles in good yields. The structure elucidation of all new
compounds without stereochemical assignments has been carried out by spectral and elemental analysis.

Published

2020-11-05

Issue

Section

Original Papers