Natural product chemisrty, 143. Convenient synthesis of isoacronycine and some other new acridone derivatives

Abstract The iodination of 1,3‐dihydroxy‐9‐acridone ( 1 ), 1‐hydroxy‐3‐methoxy‐10‐methyl‐9‐acridone ( 2 ) and 1,3‐dihydroxy‐10‐methyl‐9‐acridone ( 3 ) yields 1,3‐dihydroxy‐2,4‐diiodo‐9‐acridone ( 4 ), 1‐hydroxy‐2‐iodo‐3‐methoxy‐10‐methyl‐9‐acridone ( 5 ) and 1,3‐dihydroxy‐2‐iodo‐10‐methyl‐9‐acridone ( 6 ), respectively. The methylation of 4 and 5 gives 2,4‐diiodo‐1,3‐dimethoxy‐10‐methyl‐9‐acridone ( 7 ) and 2‐iodo‐1,3‐dimethoxy‐10‐methyl‐9‐acridone ( 9 ), respectively. The direct CC coupling of 2‐methyl‐3‐buten‐2‐ol to the compounds 5, 7 and 9 by palladium catalysed Heck condensation method gives three new acridone derivatives 1‐hydroxy‐2‐(3‐hydroxy‐3‐methyl‐1‐butenyl)‐3‐methoxy‐10‐methyl‐9‐acridone ( 10 ), 2,4‐bis(3‐hydroxy‐3‐methyl‐1‐butenyl)‐1,3‐dimethoxy‐10‐methyl‐9‐acridone ( 12 ) and 2‐(3‐hydroxy‐3‐methyl‐1‐butenyl)‐1,3‐dimethoxy‐10‐methyl‐9‐acridone ( 13 ) while compound 6 is converted into isonoracronycine ( 11 ). The methylation of 11 yields isoacronycine ( 14 ).