The occurrence of cyanogenetic glucosides in South African species of Acacia. II. Determination of the chemical constitution of acacipetalin. Its isolation from Acacia stolonifera, Burch

Abstract

1. The cyanogenetic glucoside Acacipetalin has been isolated by an improved method from Acacia stolonifera Burch. 2. Tetra-acetylacacipetalin has been prepared. 3. Pinit, inositol monomethyl ether, has been identified as a constituent of Acacia stolonifera. 4. The constitution of Acacipetalin has been elucidated. It is the glucose ether of dimethylketenecyanhydrin. 5. The facts upon which this conclusion is based are recorded and include the identification of the following breakdown products of the glucoside. On enzymic hydrolysis, hydrogen cyanide, glucose, acetone and acidic substances. On acid hydrolysis, hydrogen cyanide, glucose and isobutyric acid. After alkaline followed by acid hydrolysis, ammonia, glucose and isobutyrylformic acid, isolated as the 2:4 dinitrophenylhydrazone. This latter substance was prepared synthetically and found to have M.P. 190°. The 2:4 dinitrophenylhydrazone of isobutylideneacetone crystallises in orange-red prisms and melts at 163-5⁰. 6. Catalytic hydrogenation using colloidal palladium as catalyst leads to deep-seated changes in the glucoside. Among the reaction products were detected acetone, glucose and amino substances. 7. A comparison with other glucosides containing unsaturated aglycones is made and a suggestion put forward as to the possible mode of origin of Acacipetalin in the plant.