23521-00-8 9H-Purin-2-amine, 6, {6'-dithiobis[9-(2-deoxy-.alpha.-D-erythro-pentofuranosyl)-} 9H-Purine, 6, {6'-dithiobis[2-amino-9-(2-deoxy-.alpha.-D-erythro-pentofuranosyl)-} AIDS-126660 AIDS126660 NSC121871