Phytokinin activity in some new 6-substituted purines

Abstract

New kinetin analogues have been synthesized and assayed in three biological tests. These tests were based on the following physiological responses: the stimulation of the growth of very young wheat coleoptiles, retardation of senescence of wheat leaves and the stimulation of cell division activity in tobacco pith tissue. Using these methods four compounds, 6-($\beta $-ethoxyethyl)aminopurine, 6-($\beta $-propoxyethyl)aminopurine, 6-($\beta $-ethoxy-$\beta $-methylethyl)-aminopurine and 6-($\beta $-butoxyethyl)aminopurine have been found to have activity of the same order as kinetin. No correlation between the oil/water partition coefficient of the compounds and their biological activity was established. The compounds have been shown to act as reducing agents in the photochemical reaction with riboflavin and to be oxidized in this system to adenine. The possibility that the property of phytokinins to behave as reducing agents is related to their biological activity is discussed.