2,7,12,17-Tetrakis(5-chloropentyl)-21,22,23,24-tetraazapentacyclo[16.2.1.1~3,6~.1~8,11~.1~13,16~]tetracosa-1,3,5,7,9,11(23),12,14,16,18(21),19-undecaene AIDS-145659 AIDS145659 NSC670861