The synthesis of pyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitriles from (4H-1,2,6-thiadiazin-4-ylidene)malononitriles

3,5-Bis(dialkylamino)-4H-1,2,6-thiadiazin-4-ylidene]propanedinitriles 6a-c, react with sodium methoxide or ethoxide to give the corresponding 6-alkoxy-4-dialkylamino substituted pyrrolo2,3-c]1,2,6]thiadiazine-5-carbonitriles 7a-f in variable yields. These new compounds are fully characterised and two rational mechanisms are proposed for their formation.