Figure 2.
The SAR analysis of compound 38. (A) The structures and percentages of residual AEP activity of the compound 38 derivatives, in which substitutions were made to the nitrogen in the R7 position. (B) The structures and percentages of residual AEP activity of the compound 38 derivatives, in which substitutions were made to the nitrogens at the R7 and R1 positions. (C) The structures and percentages of residual AEP activity of the compound 38 derivatives, in which substitutions were made at the R7, R1, and R6 positions in the xanthine ring.