Synthesis of some alkylaminothiophene derivatives from 3,4-dibromothiophene and their theoretical calculations.

In this study, the copper catalyzed amination reactions of 3,4-dibromothiophene with some primary, cyclic and acyclic secondary amines were investigated to prepare novel electron rich-thiophenes which are expected to be used as novel N-containing donor type monomer candidates for conductive polymers. In order to obtain better yields, this S N Ar type amination reaction was optimized by studying the reaction conditions, such as the copper catalyst, the type of copper source, the presence of a base and the type of the solvent on the model reaction between 3,4-dibromothiophene and n-butylamine. A variety of 3,4-(N,N′-dialkylamino)thiophenes and 3-(N-alkylamino)thiophenes were synthesized in moderate yields under the optimized reaction conditions. In addition, two new heterocyclothiophene derivatives were successfully prepared from the cyclization reaction of 3,4-bis(N-butylamino)thiophene. The characterization of the isolated alkylaminothiophenes was performed by FTIR, 1H and 13C NMR, GCMS and elemental analysis. The theoretical calculations for all alkylaminothiophenes were executed by using the DFT/B3LYP/6-311+G(2d,p) approach. Image 1 • Some alkylaminothiophenes from 3,4-dibromothiophene were synthesized. • Two novel heterocyclothiophenes were prepared from 3,4-bis(N-butylamino)thiophene. • DFT calculations for all alkylaminothiophenes were performed. • The theoretical results were compared with the experimental spectroscopic data. [ABSTRACT FROM AUTHOR]