Nucleophilic substitution of pyridines and the synthesis of selected benzoxepins and benzazepines.

Abstract

Certain N-functionalised pyridines have been shown to promote specific 4-nucleophilic substitution. The 1-(N-methylacetimido) group has been previously observed to serve such a purpose; this function may be introduced by means of the aminating agent O-mesitylenesulphonylhydroxylamine (MSH) and the resultant 1-amino function is easily modified to the required grouping. The scope and limitations of the MSH reagent for a variety of substituted pyridines and different nucleophiles has been investigated. The possible use of other N-activating, groups, more easily introduced, has also been explored. A search been made for a novel method of synthesis of 7,8-dimethoxy-1-(3,4-dimothoxybenzyl)-2,3,4,5-tetrahydro-1H-3-benzazepine required for electrochemical studies. Many synthetic routes to seven-membered ring formation has ten attempted with varying degrees of success. A convenient method has been developed involving the preparation and subsequent cyclisation of 2,3-bis(3,4-dimethoxyphenyl) propyl-aminoacetaldehyde diethyl acetal. Other routes have been directed towards the synthesis of 2,3,4,5-tetrahydro-1H-3-benzoxepins where the ring O-atom may subsequently be replaced by nitrogen to give the corresponding tetrahydro-benzazepine derivatives.

Date of Award	1980
Original language	English
Awarding Institution	University of Bath