Transformations of the natural cytokinin zeatin in aqueous acidic media

Abstract

The behaviour of the naturally occurring cytokinin zeatin 1 in aqueous acidic conditions has been studied, after it was observed that this compound was relatively more stable than another related cytokinin, 6-(3-methylbut-2-enylamino)purine 2. Zeatin 1 reacted readily in 1 mol dm^–3 aqueous HCl at 100 °C. Three products were characterized, a diol resulting from the hydration of the double bond of the aliphatic chain, and two cyclized products, a hydroxypyrrolidine and a dihydropyrrole. A scheme is proposed to explain the formation of these products. However, zeatin was found to be stable in 0.1 mol dm^–3 aqueous HCl at 100°C and in 1 mol dm^–3 aqueous HCl at 50 °C, conditions which allow the hydrolysis of zeatin riboside.