Chemical investigation of Acacia latescens and synthesis of some related compounds

Abstract

From the seeds of the Acacia latescens and the related species, Acacia plectocarpa and Acacia cambagei, a complex mixture of sulfur compounds was extracted and purified using chromatography. These sulfur compounds were highly volatile and rapidly decomposed when left at room temperature. Eight of these sulfur compounds were identified through their fragmentation patterns on GC-MS. The major component, cis-5-dihydro-4H-4,6-dimethyl-1,3,5-dithiazine was isolated and purified by TLC. Its structure was elucidated by ¹H NMR, ¹³C NMR and High Resolution Mass Spectrometery. 

Amino acid analysis of various seed samples was carried out to determine the concentration of djenkolic acid. Djenkolic is considered as the precursor of the sulfur compounds generated by the Acacia species. A modified method for the determination of djenkolic acid suitable for our biological material was developed and used for all the djenkolic acid determinations. 

Investigation into the synthesis of dithiazines using Lawesson's reagent with diacetamide and an aldehyde was unsuccessful as unwanted side products were formed. A new synthetic methodology was developed for the preparation of dithiazine and the synthesis of major compound, cis-5-dihydro-4H-4,6-dimethyl-1,3,5-dithiazine. Benzotriazole mediated syntheses of various dithiazines, 5,6-dihydro-4H- 1,3 ,5-dithiazine, 5 -methyl-5 ,6-dihydro-4H- 1,3,5 -dithiazine, 5 -propyl-5 ,6-dihydro-4H- 1,3,5 -dithiazine, 5 -isopropyl-5 ,6-dihydro-4H- 1,3,5 -dithiazine, 5-benzyl-5,6-dihydro-4H-1,3,5-dithiazine were successfully carried out producing good to moderate yield of the products. The stereoselective synthesis of the component, cis-5 -dihydro-4H-4,6-dimethyl- 1,3,5 -dithiazine, was successfully carried by cyclisation of N.N-bis(ethylbenzotiazol- 1-yl)amine with formaldehyde and sodium sulfide.

Date of Award	Mar 1999
Original language	English
Supervisor	David Fenn (Supervisor)