Part I : Synthetic approaches to allohimachalol 2-(gamma-formylbutyl )-2,6,6-trimethylcycloheptanone was synthesised in six steps from tetrahydroeucarvone. Attempts to effect aldol cyclisation to 1,5,5,8-tetromethylbicyclo (4.4.1) undec-7-en-11-one, which has already been related to the naturally occurring sesquiterpene alcohol allohimachalol, were unsuccessful. Other approaches afforded a variety of compounds, in particular, a number of bicyclo (4.3.1) decanes derived from 1,5,5-trimethyl-8-oxabicyclo(5.4.0) undec-6-en-9-one. Part II : Studies in the 3-azabicyclo(3.3.1)nonane system The reported procedure for the syntheses of a small number of 6-substituted 1,5-dinitro-3-raethyl-3-azabicyclo(3.3.1)non-6-enes was extended to provide a wide range of 6- and 7-substituted analogues, the structures of which have been rigorously proved by chemical and spectroscopic methods. Initial difficulty in assigning certain NMR signals of these compounds led to a study of the NMR shifts of protons alpha and beta to the nitrogen atom in simple amines and amine picrates. Some correlation between structure and magnitude of shift was observed. The scope of the reaction sequence leading to these compounds was thoroughly investigated, and a number of 3-unsubstituted, 3-ethyl, and 3-benzyl analogues prepared. In particular, this made available several 3-substituted 1,5-(dinitro-3-azabicyclo(3.3.1)nonan-7-ones, IR studies of which established the absence of interaction between the amine and carbonyl functions. Evidence was presented confirming reported findings of the chair-chair conformation of the 3-azabicyclo(3.3.1)nonane system
