## 2 Materials and Methods
### Synthesis of Chalcone Derivatives
\({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\): 12.86 (s, 1H, OH), 7.91 (dd, \(J_{1}\) = 8.0, \(J_{2}\) = 1.4 Hz, 1H, H2\({}^{\prime}\)), 7.69 (d, \(J\) = 15.1 Hz, 1H, H5), 7.56 (d, \(J\) = 15.1 Hz, 1H, H6), 7.55 (dd, \(J\) = 15.4 Hz, 1H, H6), 7.55 (dd, \(J_{1}\) = 3.4, \(J_{2}\) = 1.3 Hz, 1H, H4), 7.49 (ddd, \(J_{1}\) = 8.5, \(J_{2}\) = 8.5, \(J_{3}\) = 1.5 Hz, 1H, H4\({}^{\prime}\)), 6.94 (ddd, \(J_{1}\) = 8.1, \(J_{2}\) = 8.1, \(J_{3}\) = 1.0 Hz, 1H, H3\({}^{\prime}\)), 6.76 (d, 1H, H2). \({}^{13}\)C NMR (100 MHz, CDCl\({}_{3}\)) \(\delta\): 193.4 (s, C7), 163.7 (s, C6\({}^{\prime}\)), 151.6 (s, C1), 145.5 (d, C4), 136.4 (d, C4\({}^{\prime}\)), 131.2 (d, C2\({}^{\prime}\)), 129.7 (d, C6), 120.2 (d, C3\({}^{\prime}\)), 118.9 (s, C1\({}^{\prime}\)), 1C6), 118.2 (d, C8), 107.7 (d, C3). GC-MS m/z (rel. int.) = 222.12 [M]\({}^{+}\) (19), 221.13 (5), 194.11 (14), 165.11 (7), 120.04 (48), 102.06 (28), 97.07 (15), 92.05 (100). 2-(2-hydroxyphenyl)-4H-chromen-4-one (**3b**): Pale yellow powder (yield 60%). C\({}_{15}\)H\({}_{10}\)O\({}_{3}\). Mp = 254-256 \({}^{\circ}\)C. IR (ATR diamond, cm\({}^{-1}\)) = 3141 (O-H), 3098 (C-H), 1638 (C=O), 1051 (C-O) cm\({}^{-1}\). \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\): 11.02 (s, 1H, OH), 8.17 (dd, 1H, H5), 8.05 (ddd, \(J_{1}\) = 8.6, \(J_{2}\) = 8.6, \(J_{3}\) = 1.1 Hz, H7), 7.843 (ddd, \(J_{1}\) = 7.8, \(J_{2}\) = 8.0, \(J_{3}\) = 1.0 Hz, H6), 7.845 (ddd, \(J_{1}\) = 8.4, \(J_{2}\) = 1.4 Hz, 1H, H8), 7.80 (ddd, \(J_{1}\) = 8.0, \(J_{2}\) = 8.0, \(J_{3}\) = 1.4 Hz, 1H, H4\({}^{\prime}\)), 7.70 (dd, \(J_{1}\) = 8.6, \(J_{2}\) = 2.3 Hz, 1H, H6\({}^{\prime}\)), 7.51 (ddd, \(J_{1}\) = 7.9, \(J_{2}\) = 8.0, \(J_{3}\) = 1.9 Hz, 1H, H5\({}^{\prime}\)), 7.12 (s, H1, H3), 6.92 (dd, 1H, H3\({}^{\prime}\)). \({}^{13}\)C NMR (100 MHz, CDCl\({}_{3}\)) \(\delta\): 177.0 (s, C4), 159.1 (s, C2), 156.7 (s, C9), 156.3 (s, C2\({}^{\prime}\)), 140.6 (d, C7), 136.2 (d, C4\({}^{\prime}\)), 134.1 (d, C6\({}^{\prime}\)), 125.2 (d, C5), 124.64 (s, C10), 124.61 (d, C6), 123.0 (d, C5\({}^{\prime}\)), 120.3 (s, C1\({}^{\prime}\)), 119.5 (d, C3\({}^{\prime}\)), 118.5 (d, C8), 111.4 (s, C3). GC-MS m/z (rel. int.) = 238.23 [M]\({}^{+}\) (10), 210.20 (2), 152.27 (3), 121.15 (17), 120.14 (10), 118.16 (12), 92.14 (61), 90.16 (30), 76.15 (21), 64.14 (59), 63.13 (100). 2-(4-hydroxy-3-methoxyphenyl)-4H-chromen-4-one (**3c**): Yellow powder (yield 40%). C\({}_{16}\)H\({}_{12}\)O\({}_{4}\). Mp = 198-200 \({}^{\circ}\)C. IR (ATR diamond, cm\({}^{-1}\)) = 3295 (O-H), 3092 (C-H), 2935 (C-H), 1624 (C=O) cm\({}^{-1}\). \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\): 8.12 (dd, \(J_{1}\) = 8.0, \(J_{2}\) = 1.6 Hz, 1H, H5), 8.03 (dd, \(J_{2}\) = 2 Hz, 1H, H8), 7.82 (ddd, \(J_{1}\) = 8.8, \(J_{2}\) = 8.4, \(J_{3}\) = 1.6 Hz, 1H, H7), 7.74 (ddd, \(J_{1}\) = 8.4, \(J_{2}\) = 8.4, \(J_{3}\) = 1 Hz, 1H, H6), 7.59 (dd, \(J_{2}\) = 2 Hz, 1H, H6\({}^{\prime}\)), 7.50 (dd, \(J_{1}\) = 8.8, \(J_{2}\) = 1.2 Hz, 1H, H2\({}^{\prime}\)), 6.98 (d, 1H, H3\({}^{\prime}\)), 6.84 (s, 1H, H3), 4.01 (s, 3H, H11). \({}^{13}\)C NMR (100 MHz, CDCl\({}_{3}\)) \(\delta\): 179.5 (s, C4), 163.9 (s, C2), 157.4 (s, C9), 151.5 (s, C4\({}^{\prime}\)), 148.3 (s, C5\({}^{\prime}\)), 135.3 (d, C7), 130.4 (d, C5), 126.5 (s, C10), 126.0 (d, C6), 125.4 (s, C1\({}^{\prime}\)), 124.6 (d, C2\({}^{\prime}\)), 119.4 (d, C3\({}^{\prime}\)), 110.4 (d, C8), 106.8 (d, C6\({}^{\prime}\)), 83.7 (d, C3), 57.0 (q, C11). GC-MS m/z (rel. int.) = 268.24 [M]\({}^{+}\) (20), 197.16 (8), 148.18 (16), 121.13 (27), 105.14 (47), 92.12 (95), 63.13 (100). 2-(2-hydroxy-5-nitrophenyl)-4H-chromen-4-one (**3d**): Pale yellow powder (yield 58%). C\({}_{15}\)H\({}_{9}\)NO\({}_{5}\). Mp = 268-270 \({}^{\circ}\)C. IR (ATR diamond, cm\({}^{-1}\)) = 3298 (O-H), 3024 (C-H), 1652 (C=O), 1342 (N-O) cm\({}^{-1}\). GC-MS m/z (rel. int.) = 282.23 [M]\({}^{+}\) (3), 281.20 (10), 235.18 (3), 179.25 (7), 150.19 (10), 104.12 (9), 92.15 (8), 30.09 (100). 2-(4-methoxyphenyl)-4H-chromen-4-one (**3e**): white powder (yield 50%). C\({}_{16}\)H\({}_{12}\)O\({}_{3}\).