4,15,20,31-Tetramethoxy-6,8,11,13,22,24,27,29-octaazaheptacyclo[28.2.2.2~2,5~.2~8,11~.2~14,17~.2~18,21~.2~24,27~]tetratetraconta-1(32),2,4,14,16,18,20,30,33,37,39,43-dodecaene-7,12,23,28-tetrone 6337-91-3 AIDS-124539 AIDS124539 NSC37554