Synthesis of Tetrasubstituted Thieno[3,2‐b]pyridin‐5(4H)‐one Derivatives as a Heterocyclic Scaffold for Multisite‐specific Fluorous Fluorescent Tagging and Fluorous Solid‐Phase Extraction

Abstract

Tetrasubstituted thieno[3,2‐b]pyridin‐5(4H)‐one derivatives were selected as a highly functionalized heterocyclic scaffold for a multisite‐specific tagging process utilizing a previously devised fluorous fluorescent tag system. A suitable synthetic method was established for the 7‐alkoxy‐2,4,6‐trisubstituted‐thieno[3,2‐b]pyridin‐5(4H)‐one derivatives, and incorporating t‐butoxycarbonyl‐functionalized building blocks into the reaction sequence produced precursors that could be used in the tagging process. Fluorous solid‐phase extraction facilitated the purification of the tagged target compounds after a series of reactions, including t‐Bu deprotection/N‐hydroxysuccinimidyl ester formation/amidation.