New 3-Alken(yn)ylsulfanyl-9H-indeno[1,2-e][1,2,4]triazin-9-ones and Their Heterocyclization

A one-pot three-component synthesis of previously undescribed 3-alkenyl(propargyl)sulfanyl-indeno[1,2-e][1,2,4]triazin-9-ones was developed for the first time. The direction of cyclization in the reaction of ninhydrin and thiosemicarbazide in the presence of a base and an alkyl halide was-established for the first time by single crystal XRD analysis using the-example of 3-allylsulfanylindeno[1,2-e][1,2,4]triazin-9-one. In some cases, subsequent heterocyclization was also achieved, in particular, for allyl sulfide under the action of bromine, for methallyl sulfide under the action of iodine and bromine, and for butenyl sulfide under the action of iodine.