The esterification of N-phenylanthranilic acid (I) with methanol and HCl yields the corresponding methyl ester (II), which by a Grignard reaction with methylmagnesium iodide in THF is converted into 2-anilinophenyl dimethyl carbinol (III). The cyclization of (III) with polyphosphoric acid at 170 C affords 9,9-dimethylacridan (IV), which by carbonylation with phosgene in refluxing toluene yields 9,9-dimethylacridan-10-carbonyl chloride (V) (1). Finally this compound is esterified with 2-dimethylaminoethanethiol (VI) by means of NaH in ether