Synthesis of Thieno[2,3-b]pyrazines via an Acylation - Deacylation Process of 3,4-Dihydro Precursors

Abstract

In the first step 3, 4-dihydrothieno[2,3-h]pyrazines (1, 2 and 4) were N-acylated by the acyl chlorides followed by a deacylation process mediated by triethylamine to give thieno[2,3-b]pyrazines. In a final rection the excess of the appropriate acyl chlorides react with the free hydroxy residue to afford compounds (15, 16 or 17).