4-Amino-2-butyl-7-methoxycarbonylthiazolo[4,5-c]quinoline

Abstract

4-Amino-imidazo-, oxazolo-, and thiazoloquinolines are key structural scaffolds in the design of nucleoside base analogs for use as therapeutic agents. Current strategies for arriving at diverse substitutions at the C6–C9 positions of the thiazolo- and oxazoloquinolines, however, are limited due to difficulties in arriving at the thiazoloquinoline-5N-oxide intermediate using electron deficient aromatic systems. Here, we demonstrate a synthetic route to obtain substituted thiazoloquinolines with electron-withdrawing groups at the C7 position. The target compound, 4-amino-2-butyl-7-methoxycarbonylthiazolo[4,5-c]quinoline, is obtained in eight steps using a 7-bromo surrogate as a precursor to the successful generation of the N-oxide intermediate, and final transformation via Pd-mediated C7-acylation.