Alkylation of 8-oxoadenosine (13) with 4-benzyloxy-3,5-dibromobenzyl bromid
e (20), followed by Dimroth rearrangement and acid hydrolysis, provided N-(
3,5-dibromo-4-hydroxybenzyl)-8-oxoadenosine (15). The 2'-deoxy version of t
his reaction sequence accomplished the first synthesis of N-(3,5-dibromo-4-
hydroxybenzyl)-8-oxoadenine (16), which is the correct expression for marin
e ascidian purine aplidiamine.