Efficient approaches toward the solid-phase synthesis of new heterocyclic azoniaspiro ring systems: synthesis of tri- and tetrasubstituted 10-oxo- 3,9-diaza-6-azoniaspiro[5.5]undecanes

Reaction: see text]. An efficient approach for the parallel solid-phase synthesis of novel heterocyclic azoniaspiro ring systems is described. The target compounds, the 1,8,9-trisubstituted 10-oxo-3,9-diaza-6-azoniaspiro5.5]undecanes, were obtained starting from resin-bound reduced dipeptides. The azoniaspiro cation was formed by intramolecular attack of a tertiary nitrogen on pendent alpha-bromocarbonyl. N-3 acylated and N-3 alkylamino carbonyl derivatives of the 1,8,9-trisubstituted 10-oxo-3,9-diaza-6-azoniaspiro5.5]undecanes were obtained following in solution treatment of the N-3 azoniaspiro derivatives with different carboxylic acids and isocyanates.