“…7-Amino-1,3-diphenylpyrazolo[3,4-b]pyrrolo[3,4-d]pyridine-6,8(3H,7H)-dione ( 2f ) [ 28 ]: White solid; 83% yield; mp 217–219 °C; 1 H NMR (DMSO- d 6 , 400 MHz) δ 4.55 (br, 2H, N H 2 ), 7.42 (t, J = 7.46 Hz, 1H, Ar H ), 7.49–7.55 (m, 3H, Ar H ), 7.60–7.65 (m, 4H, Ar H ), 8.25 (d, J = 8.08 Hz, 2H, Ar H ), 8.82 (s, 1H, Ar H ).…”