1,7,7-Trimethylbicyclo[2.2.1]hept-2-yl 2,9-dimethyl-3a,4,9,9a-tetrahydrofuro[2,3-b]quinoxaline-3-carboxylate 136471-32-4 AIDS-142909 AIDS142909 Encyclan Isobornyl ester {2,9-dimethyl-3a,4,9,9a-tetrahydrofuro[2,} 3-b\]quinoxaline-3-carbonic acid NSC661582