Alkaloids of the Australian Leguminosae*

Many species of Acacia have been tested by Mr. E. P. White for the presence of alkaloids in plants grown in New Zealand. He identified tryptamine, phenylethylamine, and N-methylphenylethylamine. Acacia kettlewelliae Maiden was found by White1 to oontain about 1.5% base in its leaves and stems, 92% of which was 2-phenylethylamine. A sample of leaves collected at Creswick, Victoria, gave 0.9% base which was identified as N-methyl-2phenylethylamine from consideration of its nuclear magnetic resonance spectrum and the properties of its picrate and oxalate. It is relevant that White2 found that the proportions of these two bases varied between plants of the species A . prominens, and in the one plant a t different times of the year. Acacia adunca A. Cunn. ex G . Don is a valid species though there has been botanical confusion with other species. No record of its alkaloid content has been found. Leaves obtained from Stanthorpe in south-eastern Queensland yielded 2.4% of a base which proved to be N-methyl-2-phenylethylamine. Acacia harpophylla F. Muell. (brigalow) predominates in parts of Queensland to such an extent that these areas have become known as the Brigalow country. Although the tree has been studied by those seeking methods of control, its constituent bases have not previously been examined. It has now been shown that the leaves oontain 2-phenylethylamine and [2-(p-hydroxyphenyl)ethyl]dimethylamine (hordenine) in the proportions of 2 : 3, the crude base amounting to 0.6% of the dry weight of leaf. Poor recoveries resulted when the milled plant was extracted with methanol, but much higher yields of base were obtained by extraction with ammoniacal chloroform. From some experiments a small amount of crystals separated while the chloroform solution of the crude base was being concentrated. These proved to be the chloromethyl bromide of hordenine, presumably formed by reaction of the base with chlorobromomethane present in the chloroform as an impurity. This would support the suggestion of Williams3 that the supposed interaction of chloroform and tertiary bases is due to this impurity. Previously hordenine has been reported only from the families Cactaceae and Gramineae, although its methyl ether was recently found by Badger, Christie, and Rodda4 in a member of the Rutaceae (Teclea simplicifolia).