DNA intercalating properties of tetrahydro-9-aminoacridines. Synthesis and 23Na NMR spin-lattice relaxation time measurements.

A series of 9-(arylamino)-1,2,3,4-tetrahydroacridines, including the tetrahydro m-AMSA [N-[4-(acridin-9-yl-amino)-3- methoxyphenyl]methanesulfonamide] derivative, has been synthesized. 23Na NMR spin-lattice relaxation rate (1/T1) measurements have been used to study whether these hydrogenated acridines were capable of intercalative binding to calf thymus DNA. The results have been compared to corresponding measurements for 9-aminoacridine, m-AMSA, and MgCl2. All compounds studied were capable of intercalative binding to DNA. However, it was found that the interaction was strongly influenced by substituents on the 9-arylamino group. Thus, tetrahydro m-AMSA was found to intercalate much more weakly with DNA than m-AMSA. Removal of the 3'-methoxy substituent of the 9-arylamino group resulted in intercalation in DNA that was almost as strong as that for m-AMSA.