Synthesis of novel dispiro[indoline-3,2'-pyrrolidine-3',10”-thiazolo[3',2':1,2]pyrimido[5,4-g]indolizine] derivatives by 1,3-dipolar cycloaddition reaction

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

“…The structures of some of the thiazolidine derivatives and their biological properties are specified in Figure 1. One of the effective approaches to the preparation of heteroannelated thiazolidin-4-one derivatives consists in the condensation of acetylenedicarboxylic acid esters with heterocyclic compounds containing a thiourea fragment, e.g., pyrimidinethiones [18,19], 1,2,4-triazolethiols [20], and 1,2,4-triazinethiones [21,22]. An important feature of the reactions of dialkyl acetylenedicarboxylates with asymmetric substrates is the high regioselectivity of the cyclizations of intermediate Michael adducts at one of several reactive nitrogen atoms.…”