The first chapter of this thesis deals with the synthesis, cyclisation of 2-aminobenzophenones and biomimetic synthesis of acridone alkaloids. The biogenesis of acridone alkaloids produced in tissue culture is described. 2,4,6-Triacetoxy-2'-methylaminobenzophenone was prepared to study its cyclisation to the acridone ring system. 2,4,6-Triacetoxy-2'-methylaminobenzophenone was converted to 1,3-dihydroxy-N-methylacridone. The intermediate 2,4,6-trihydroxy-2'-methylaminobenzophenone was also synthesised and found to be highly reactive, cyclising extremely easily to the acridone thus confirming the probable role of the 2'-aminobenzophenone as a precursor in the biosynthesis of acridone alkaloids in tissue cultures. The second part is concerned with a phytochemical investigation of two species of <i>Ruta</i> namely <i>Ruta montana</i> and <i>Ruta chalepensis</i> from Turkey. This chapter deals with the isolation and identification of coumarins and alkaloids from both species of <i>Ruta</i>. The compounds which are isolated and identified from root extracts of <i>Ruta montana</i> are chalepensin, rutamarin, xanthotoxin and marmesin. From the root extract of <i>Ruta chalepensis</i> the alkaloid skimmianine was isolated together with chalepensin, rutamarin, and bargapten. An as yet, unidentified sugar was isolated. The structures of these natural products were elucidated on the basis of spectroscopic data together with comparisons with published data and authentic samples (wherever possible).