2 (ω-Piperidinoalkyl) phthalazin-1 (2H)-ones can be prepared from the 2-hydroxyalkyl compounds both via the open-chain 2-bromoalkyl derivatives and via their cyclic isomers. Substitution reactions of bromoalkyl compounds may be assisted by polar solvents and by neighbouring group effect of hydrazinocarbonyl moiety. Nucleophiles attack the condensed oxazolinium ring in tricyclic intermediates at the saturated carbon bonded to the oxygen ...
