Anthranitic acid (I) is reacted with cyclohexanone (II) to give 5-hydroxy-1,2,3,4-tetrahydroacridine (III). The hydroxy compound (III) is then reacted with phosphorous oxychloride to give 5-chloro-1,2,3,4-tetrahydroacridine (IV). Aminolysis of (IV) with n-butylamine affords centbucridine.