Reactions of 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines with indole and 1,3,3-trimethyl-2-methyleneindoline

It has been found that 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5- tetrazines react with indole and 1,3,3-trimethyl-2-methyleneindoline to give pyridazines as (4+2)cycloaddition products. 1,3,3-Trimethyl-2-methyleneindoline has been shown to act as C-nucleophile in the substitution of pyrazolyl group as well as in the reactions of tetrazine ring expansion in