STUDIES IN FRIES MIGRATION. PART I. THE FRIES MIGRATION OF ESTERS OF 7- HYDROXY 4-METHYLCOUMARIN

Little systematic work has been done on the Fries migration of the hydroxy-esters of the coumarins. The work described in this paper was therefore undertaken and 7-acetoxy-and 7-benzoyl-oxy-4-methylcoumarins have been subjected to the Fries migration with a view to investigating the effect of various factors on the migration. The results show that (i) three mols. of AlCl₃ are necessary to effect the migration, (ii) nitrobenzene as a solvent facilitates the reaction with better yields, (iii) the change in the conditions of the migration fails to effect the direction of the migrating group, which predominantly occupies the '8' position of the coumarin nucleus, and (iv) the benzoyl group requires a higher temperature for migration.