Anticytokinin activity of 4-substituted triazolo[4,5-d]pyrimidines and 4-substituted pyrazolo[3,4-d]pyrimidines

The synthesis and physiological activity of some novel 4-substituted triazolo[4,5-d]pyrimidines and 4-substituted pyrazolo[3,4-d]pyrimidines are described. Most of the compounds possessed high anticytokinin activity towards purine (benzyladenine) and phenylurea (4-PU-30) type cytokinins. 1-Benzyl-4-ethoxycarbonylpiperazinyl-1H-1,2,3-triazolo[4,5-d]pyrimidine almost completely removed cytokinin stimulated effects—betacyanin synthesis in Amaranthus caudatus cotyledons; growth of radish cotyledons and retention of chlorophyll in leaf explants. Some chemical structurephysiological activity relationships have been established.