Synthesis of functionalized imidazo[4,5- e ]thiazolo[3,2- b ]triazines by condensation of imidazo[4,5- e ]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5- e ]thiazolo[2,3- c ]triazines

Two series of functionalized imidazothiazolotriazine derivatives were synthesized via the condensation of imidazo[4,5- e ]-1,2,4-triazine-3-thiones with acetylenedicarboxylic acid dimethyl and diethyl esters (DMAD and DEAD) and subsequent base-catalyzed rearrangement of the obtained imidazo[4,5- e ]thiazolo[3,2- b ]-1,2,4-triazines into regioisomeric imidazo[4,5- e ]thiazolo[2,3- c ]-1,2,4-triazine derivatives.