TLC ( ethyl acetate / n - hexane = 1 : 20 ) Rf = 0 . 35 , mp : 178 - 180 ℃, HPLC purity : 95 . 8 %; ESI LC / MS : m / z calcd for C 24 H 18 NO [ MH ] + 336 . 14 ; found 336 . 23 . 1 H NMR ( 250 MHz , DMSO - d 6 ) δ 9 . 57 ( s , 1 H , indenopyridine 9 - OH ) , 8 . 20 ( d , J = 8 . 27 Hz , 2 H , 2 - phenyl H - 2 , H - 6 ) , 7 . 91 - 7 . 89 ( m , 3 H , 4 - phenyl H - 2 , H - 6 , indenopyridine H - 3 ) , 7 . 61 - 7 . 44 ( m , 6 H , 4 - phenyl H - 3 , H - 4 , H - 5 , 2 - phenyl H - 3 , H - 4 , H - 5 ) , 7 . 34 ( t , J = 7 . 90 Hz , 1 H , indenopyridine H - 7 ) , 7 . 15 ( d , J = 7 . 42 Hz , 1 H , indenopyridine H - 6 ) , 6 . 91 ( d , J = 8 . 01 Hz , 1 H , indenopyridine H - 8 ) , 4 . 04 ( s , 2 H , indenopyridine H - 5 ) . 13 C NMR ( 62 . 5 MHz , DMSO - d 6 ) δ 161 . 46 , 155 . 26 , 1254 . 07 , 146 . 19 , 145 . 59 , 138 . 45 , 137 . 80 , 132 . 38 , 130 . 82 , 129 . 39 , 129 . 21 ( 2 C ) , 129 . 15 ( 2 C ) , 129 . 11 ( 2 C ) , 128 . 70 , 126 . 99 ( 2 C ) , 124 . 96 , 117 . 21 , 116 . 89 , 113 . 41 , 34 . 70 .