The synthesis and biological properties of 8-azido-N (6)-benzyladenine, a potential photoaffinity reagent for cytokinin.

A cytokinin photoaffinity reagent, 8-azido-N (6)-benzyladenine (8N3BA), was synthesized from 8-bromoadenosine via azide replacement, benzylation at N-1, rearrangement to the N-6-benzyl derivative and acid hydrolysis. The compound thus obtained was found to have full cytokinin activity in the moss and tobacco cell-suspension bioassays. Photolysis of 8N3BA was accomplished with long and short-wavelength ultraviolet light and produced compounds which had very little or no biological activity in the two bioassays. In-vivo photolysis of 8N3BA caused loss of the cytokinin activity of this compound in moss protonemata. This result was similar to earlier ones where the biological response of moss protonemata to benzyladenine was reversed following removal of the hormone by a short rinse with water.