Application： 3,6-Bis(methylthio)-1,2,4,5-tetrazine can be used as a versatile building block in the inverse elecron demand hetero Diels-Alder reactions. The Boger Research Group has reported this powerful approach in the synthesis of alkaloids. It can also used to synthesize: Substituted indoles and indolines derivatives by sequential [4+2] cycloaddition reactions. 3-(Methylthio)-6-(4-morpholinyl)-1,2,4,5-tetrazine by aromatic nucleophilic substitution reaction.