Acylation of anthralin (I) either with phenylacetic acid (II) by means of EDC and pyridine in THF or with phenylacetyl chloride (III) by means of pyridine in THF affords compound (IV), which is finally converted into the desired hydroxamate by reaction with N-methyl-N-hydroxylamine and EDC in DMF.
Acid chloride (II) was prepared by treatment of 4-phenylvaleric acid (I) with thionyl chloride. Condensation of acid chloride (II) with dithranol (III) in the presence of pyridine provided the title compound.