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Methods for the synthesis of two types of isomeric dispirocompounds based on imidazothiazolotriazine and pyrrolidineoxindole, differing in the structure of imidazothiazolotriazine fragment, namely, linear dispiro[imidazo[4,5- e ]thiazolo[3,2- b ][1,2,4]triazine-6,3'-pyrrolidine- 4',3″-indolines] and angular dispiro[imidazo[4,5- e ]thiazolo[2,3- c ][1,2,4]triazine-7,3'-pyrrolidine-4',3″-indolines] were proposed. The first method relies on a 1,3-dipolar cycloaddition of azomethine ylides generated in situ from paraformaldehyde and N-alkylglycine derivatives to the corresponding oxindolylidene derivatives of imidazothiazolotriazine. The cycloaddition leads to a mixture of two diastereomers resulted from anti - and syn -approaches of azomethine ylide in approximately a 1:1 ratio, which were separated by column chromatography. Another method consists in rearrangement of linear dispiro[imidazo[4,5- e ]thiazolo[3,2- b ][1,2,4]triazine-6,3'-pyrrolidine-4',3″-indolines] into hitherto unavailable angular dispiro[imidazo[4,5- e ]thiazolo[2,3- c ]-[1,2,4]triazine-7,3'-pyrrolidine-4',3″-indolines] upon treatment with KOH. It was found that the anti -diastereomer of linear type underwent rearrangement into the isomeric angular syn -diastereomer, while the rearrangement of the linear syn -diastereomer gave the angular anti -diastereomer.