HETEROCYCLIC COMPOUNDS. PART XXX. NEW SYNTHESIS OF 4-METHYLSCOPOLETIN AND 4-METHYLFRAXETIN

Two new methods of the synthesis of 7-hydroxy-6-methoxy-4-methylcoumarin (4-methylscopoletin) have been described. The oxidation of 4-methyl-7-coumarinyl-methanesulphonate by alkaline potassium persulphate (Elb's mothod) furnished 4-methyl-6-hydroxy 7-coumarinyl-methanesulphonate which after methylation and subsequent demesylation afforded 4-methylscopoletin. The preferential monotosylation of 6 : 7-dihydroxy-4-methylcoumarin gave the 7-O-tosyl derivative which on methylation and subsequent detosylation yielded 4-methylscopoletin. The oxidation of 4-methyl-7:8-coumarinyl­-dimethanesulphonate by alkaline potassium persulphate yielded 4-methyl-6-hydroxyl-7 :8-coumarinyl­-dimethanesulphonate which on methylation and subsequent demesylation furnished 4-methyl-6- methoxy-7:8-dihydroxycoumarin (4-methylfraxetin).