Synthesis of novel water soluble onium salts and thieno[3,4-c]thiolactones – precursors of conductive materials derived from substituted 2-aminothiophenes

Zita Puterová,Renata Gottasová,Daniel Végh,Zsolt Végh,Joachim Schantl

doi:10.3998/ark.5550190.0006.c04

Abstract

The synthetic utility in the area of synthesis of smart conductive materials of the easily accessible 2-aminothiophenes is described. Simple protection of amino group and subsequent radical bromination leads to brominated intermediates. The novel 4-bromomethylthiophene derivatives easily enter into reaction with tertiary amines and thiourea to give ammonium and thiouronium salts - novel water-soluble thiophenes. Thiouronium salts are predisposed to deliver substituted thieno(3,4-c)thiolactone derivatives, which are attractive from the point of view of their further utilization in the synthesis of thieno(3,4-c)thiophenes. Each of the mentioned compounds showed bioactivity as well as propensity to be polymerized to conductive oligomers and polymers.

Highlights

Functionalized polyheterocycles belong to a class of novel polyconjugated materials possessing unconventional electrical, optical and magnetic properties.[1]
Preparation of 2-aminothiophenes is a very simple, one-step reaction originally published by Gewald.[8]
In the first one we prepared 5unsubstituted 2-aminothiophene derivative 1a by the procedure published in our earlier paper.[9]

Summary

Introduction

Functionalized polyheterocycles belong to a class of novel polyconjugated materials possessing unconventional electrical, optical and magnetic properties.[1]. For bromination of methyl 2-acetylamino-4-methyl-3-thiophene carboxylate (2a) two approaches were tried, one by bromine in acetic acid, the other by N-bromosuccinimide in carbon tetrachloride (Scheme 1). The use of Nbromosuccinimide in CCl4 (with dibenzoylperoxide) means a simple and successful method for brominating the methyl group in a case of 5-acetylamino-3-methylthiophene–2,4-dicarboxylic acid dimethylester (2b) and its 2-tert-butoxycarbonyl analogue (2c) (Scheme 2) to give bromoderivates 3b,c in approximately yield 70%.

Objectives

Results

Conclusion