passages.id: split_4_test_2935_passage
passages.type: progene_text
passages.text: Interestingly , methoxyethoxy ( IC(50) of 16j is 0.02 microM ; IC(50) of 17h is 0.01 microM ) and ethoxyethoxy ( IC(50) of 17j is 0.02 micro M ) analogues showed the most potent activity , suggesting that the inserted oxygen atom significantly interacts with beta-PDGFR .