NOVEL O-PRENYLATED FLAVONOIDS FROM 2 VARIETIES OF BORONIA-COERULESCENS

The aerial parts of Boronia coerulescens ssp. spicata Rutaceae yielded nine flavonoids which were identfied on the basis of detailed spectroscopic analysis. Seven appeared to be navel and were identified as (-)-(2R:3R)-3,4',5-trihydroxy-7-(E-3 ,7-dimethylocta-2,6-dienyloxy)flavanone, 5,7-dihydroxy-8-methoxy-3,4'-di(3-methylbut-2-enyloxy) flavone, 5,7-dihydroxy- 3,6-dimethoxy-4'-(3-methylbut-2-enyloxy)flavone, 3,5,7-trihydroxy-8-methoxy-4'-(3-methylbut-2-enyloxy)flavone, 3,5,7-trihydroxy-6-methoxy-4'-(3-methylbut-2-enyloxy)flavone, 4',5-dihydroxy-3,3',8-trimethoxy-7-(3-methylbut-2-enyloxy)flavone and 4',5-dihydroxy-3,3',6-trimethoxy-7-(3-methylbut-2-enyloxy)flavone. The known flavones were ternatin and 4',5,7-trihydroxy-3,3',8-trimethoxyflavone. The sample of B. coerulescens ssp. spinescens also yielded three of the above new flavonoids together with another known flavone, 5,7-dihydroxy-3-methoxy-4'-(3-methylbut-2-enyloxy)flavone and two further novel flavones, 5,7-dihydroxy-3,8-dimethoxy-4'-(3-methylbut-2-enyloxy)flavone and 5,7-dihydroxy-3,3',8-trimethoxy-4'-(3-methylbut-2-enyloxy)flavone. Other novel compounds isolated from ssp. spinescens were the acetophenone 8-acetyl-7-hydroxy-5-methoxy-6-(3-methylbut-2-enyl)-2,2-dimethyl-2H-benzopyran, and the flavanones 5,7-dihydroxy-4'-(E-3,7-dimethylocta-2,6-dienyloxy)-flavanone and 5-hydroxy-7-methoxy-4'-(3-methylbut-2-enyloxy)flavanone.