1 U5A [(2z,3as,4r,6z,10ar)-2,6-diiminooctahydro-1h,8h-pyrrolo[1,2-C]purin-4-yl]methyl carbamate 1.000 2 D82 Beta-saxitoxinol 0.950 3 9SL [(3as,4r,10as)-2,6-diamino-10,10-dihydroxy-3a,4,9,10-tetrahydro-3h,8h-pyrrolo[1,2-C]purin-4-yl]methyl carbamate 0.905