Novel heterocyclic spirobenzofurans

Abstract

Novel 1′,3′-dialkyl-1′,2′,3′,4′,5′,6′-hexahydrospiro(benzofuran-2,5′-pyrimidine)-3(2H)-ones and 1′,4′-dialkyl-2′,3′,4′,5′,6′,7′-hexahydrospiro(benzofuran-2,6′-[1,4]diazepine)-3(2H)-ones have been synthesised from benzofuran-3-one by Mannich reactions with primary amines and diamines. The structures have been confirmed by cyclisation of related bis-Mannich bases with oxalyl chloride or phosgene followed by reduction with lithium aluminium hydride to products identical with those obtained by reduction of the heterocyclic spiro-compounds.