General Procedure for the Synthesis of Chalcones
To a stirred solution of the appropriate 1-azulenecarbaldehyde (10 mmol) in ethanol (10 mL) after the complete dissolution, the appropriate aromatic methyl ketone (10 mmol) and solid KOH (10 mmol) were added. The reaction mixture was then stirred at room temperature overnight. After completion (as been monitored by TLC), the reaction mixture was filtered and washed with cold ethanol. The filtrate, containing besides unreacted raw materials additional chalcone product, was evaporated to dryness, and the crude product was purified by silica gel column chromatography with petroleum ether and ethyl acetate (3:1 v/v) as solvent system. The yields of the condensation reaction for each chalcone are listed in Tables 1 and 2, whereas relevant spectroscopic data are given in Tables 3 and 4.
(E)-1-(2-Hydroxyphenyl)-3-phenylprop-2-en-1-one (1). Synthesized according to the general procedure, using acetophenone and azulene-1-carbaldehyde. Yield: 67%, green solid, m.p. 160.9—162.8 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 8.69 (d, 1H, H-8, 9.9 Hz), 8.54 (d, 1H, H-β, J = 15.2 Hz,), 8.35–8.33 (m, 2H, H-2 and H-4), 8.09 (d, 2H, H-2′and H-6′, 7.3 Hz), 7.70 (t, 1H, H-6, 9.8 Hz), 7.61 (d, 1H, H-α, 15.2 Hz), 7.58 (t, 1H, H-4′, 7.3 Hz), 7.52 (t, 2H, H-3′ and H-5′, 7.3 Hz), 7.46 (d, 1H, H-3, 4.3 Hz), 7.37 (t, 1H, H-7, 9.8 Hz), 7.31 (t, 1H, H-5, 9.7 Hz). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 190.4 (C=O), 144.9 (Cq), 139.8 (Cq), 139.2( Cq), 139.1 (C-6), 137.7 (C-2 or C-4), 136.3 (C-β), 134.7 (C-2 or C-4), 134.3 (C-8), 132.2 (C-4′), 128.5 (C-3′ and C-5′), 128.3 (C-2′ and C-6′), 126.2 (C-5), 125.5 (C-7), 125.2 (Cq), 120.2 (C-3), 118.2 (C-α). MS-ESI positive mode: 259 (M+) (100%), 105 (25%), 152 (46%), 181 (30%) Selected IR data: 3056, 1643 (C=O), 1595 (C=C), 1562, 1398, 1273, 1217, 1182, 1022, 978 (C=C), 780, 692, 640 cm−1.
(E)-3-(Azulen-1-yl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2). Synthesized following the general procedure using p-hydroxyacetophenone and azulen-1-carbaldehyde. Yield 62%, light brown solid, m.p. 218.7–227.9 °C. 1H-NMR (500.13 MHz, DMSO-d6, δ ppm, J Hz): 10.31 (s, 1H, -OH), 8.80 (d, 1H, H-8, 9.9 Hz), 8.65 (d, 1H, H-2, 4.2 Hz), 8.48 (d, 1H, H-4, 9.3. Hz), 8.37 (d, 1H, H-β, 15.0 Hz), 8.09 (d, 2H, H-2′ and H-6′, 8.3 Hz), 7.90 (d, 1H, H-α, 15.0 Hz), 7.82 (t, 1H, H-6, 9.9 Hz), 7.55 (d, 1H, H-3, 4.2 Hz), 7.47–7.37 (m, 2H, H-5 and H-7), 6.91 (d, 2H, H-3′ and H-5′, 8.3 Hz). 13C-NMR (125.77 MHz, DMSO-d6, δ ppm): 186.8 (C=O), 161.7 (Cq), 144.2 (Cq), 139.6 (C-6), 138.8 (Cq), 137.9 (C-4), 135.5 C-2), 134.5, (C-8), 134.4 (C-β), 130.8 (C-2′ and C-8′), 129.8 (Cq), 126.3 (C-5 or C-7), 125.7 (C-5 or C-7), 124.9 (Cq), 120.1 (C-3), 118.2 (C-α), 115.2 (C-3′ and C-5′). MS-ESI positive mode: 275 (M+) (100%), 120.9 (20%). Selected IR data: 3490 (OH), 3016, 2950, 1587 (C=O), 1545 (C=C), 1515, 1402, 1281, 1167.98, 972 (C=C), 824, 774, 705 cm−1.
(E)-1-(4-Aminophenyl)-3-(azulen-1-yl)prop-2-en-1-one (3). Synthesized from p-aminoacetophenone and azulen-1-carbaldehyde. Yield 73%, silver solid, m.p. 219.7–222.9 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 8.79 (d, 1H, H-8, 9.9 Hz), 8.50 (d, 1H, H-β, 15.1 Hz), 8.34 (d, 1H, H-2, 4.3 Hz), 8.32 (d, 1H, H-4, 9.4 Hz), 8.00 (d, 2H, H-2′, H-6′, 8.5 Hz), 7.67 (t, 1H, H-6, 9.8 Hz), 7.63 (d, 1H, H-α, 15.1 Hz), 7.45 (d, 1H, H-3, 4.2 Hz), 7.33 (t, 1H, H-7, 9.8 Hz), 7.29–7.26 (m, 1H, H-5, signal overlapped with CHCl3), 6.73 (d, 2H, H-3′, H-5′, 8.5 Hz). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 188.2 (C=O), 150.6 (Cq), 144.6 (Cq), 139.3 (Cq), 139.0 (C-6), 137.5 (C-4), 134.8 (C-2), 134.6 (C-β), 134.4 (C-8), 130.8 (C-2′, C-6′), 129.5 (Cq), 125.8 (C-5), 125.6 (Cq), 125.1 (C-7), 120.0 (C-3), 118.4 (C-α), 114.0 (C-3′, C-5′). MS-ESI positive mode: 274 (M+) (100%), 181 (60%), 153 (40%), 120 (30%). Selected IR data: 3439 (NH2), 3340, 3229, 1628, 1593 (C=C), 1545, 1438, 1273, 1176, 964 (C=C), 827, 782, 734 cm−1.
(E)-3-(Azulen-1-yl)-1-(naphthalen-1-yl)prop-2-en-1-one (4). Synthesized according to the general procedure using 1-acetylnaphthalene and azulen-1-carbaldehyde. Yield 75%, brown oil, m.p. 89.9–98.9 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 8.50 (d, 1H, H-8, 9.9 Hz), 8.38 (d, 1H, H-8′, 9.2 Hz), 8.33–8.29 (m, 3H, H-2, H-4, H-β), 8.00 (d, 1H, H-2′, 8.2 Hz), 7.93 (d, 1H, H-5′, 9.3 Hz), 7.83 (d, 1H, H-4′, 7.0 Hz), 7.68 (t, 1H, H-6, 9.9 Hz), 7.58–7.54 (m, 3H, H-3′, H-6′, H-7′), 7.44 (d, 1H, H-3, 4.3 Hz), 7.37 (d, 1H, H-α, 15.4 Hz), 7.32–7.28 (m, 2H, H-5, H-7, 9.8 Hz). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 195.8 (C=O), 145.0 (Cq), 139.7 (Cq), 139.1 (C-6), 138.4 (Cq), 137.7 (C-2, C-4 or C- β), 137.3 (C-2, C-4 or C- β), 135.0 (C-2, C-4 or C- β), 134.1 (C-8), 133.9 (Cq), 130.9 (C-2′), 130.6 (Cq), 128.4 (C-5′), 127.1 (C-3′, C-6′ or C-7′), 126.6 (C-5 or C-7), 126.3 (C-4′), 125.9 (C-3′, C-6′ or C-7′), 125.6 (C-8′), 124.8 (C-5 or C-7), 124.7 (C-3′, C-6′ or C-7′), 123.6 (C-α), 120.4 (C-3). MS-ESI positive mode: 309 M+ (100%), 181 (48%), 155 (44%), 308 (24%). Selected IR data: 3434, 3045, 2924, 1678 (C=O), 1557 (C=C), 1397, 1280, 1175, 965 (C=C), 864, 804, 744 cm−1.
(E)-3-(Azulen-1-yl)-1-(naphthalen-2-yl)prop-2-en-1-one (5). Synthesized using 2-acetylnaphthalene and azulen-1-carbaldehyde. Yield 99.99%, brown solid, m.p. 183.9–193.7 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 8.72 (d, 1H, H-8, 9.9 Hz), 8.61–8.59 (m, 2H, H-β, H-1′), 8.43 (d, 1H, H-2, 4.3 Hz), 8.36 (d, 1H, H-4, 9.4 Hz), 8.17 (d, 1H, H-3′, 8.8 Hz), 8.03 (d, 1H, H-8′, 7.9 Hz), 7.97 (d, 1H, H-4′, 8.6 Hz), 7.91 (d, 1H, H-5′, 8.0 Hz), 7.78 (d, 1H, H-α, 15.1 Hz), 7.71 (t, 1H, H-6, 9.9 Hz), 7.62–7.56 (m, 2H, H-6′ and H-7′), 7.48 (d, 1H, H-3, 4.3 Hz), 7.38 (t, 1H, H-7, 9.9 Hz), 7.31 (t, 1H, H-5, 9.8 Hz). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 190.2 (C=O), 145.0 (C-10), 139.9 (C-9), 139.1 (C-6), 137.7 (C-4), 136.5 (C-10′), 136.3 (C-β), 135.30 (C-9′), 134.8 (C-2), 134.4 (C-8), 132.7 (C-2′), 129.5 (C-8′), 129.4 (C-1′), 128.4 (C-4′), 128.0 (C-6′ or C-7′), 127.8 (C-5′), 126.6 (C-6′ or C-7′), 126.2 (C-5), 125.6 (C-7), 125.3 (C-1), 124.7 (C-3′), 120.3 (C-3), 118.3 (C-α). MS-ESI positive mode: 309 (M+) (100%), 181 (50%), 155 (30%). Selected IR data: 3054, 1642 (C=O), 1562 (C=C), 1398, 1216, 1055, 975 (C=C), 898, 759, 742 cm−1.
(E)-1,3-Di(azulen-1-yl)prop-2-en-1-one (6). Similarly to Type I chalcones, equimolar amounts of 1-acetylazulene and azulen-1-carbaldehyde were reacted under the same conditions. Yield 84%, black solid, m.p. 185.4 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 10.08 (d, 1H, H-8′, 9.9 Hz), 8.74 (d, 1H, H-8, 9.9 Hz), 8.56–8.49 (m, 3H, H-2′, H-4′ and H-β), 8.40 (d, 1H, H-2, 4.2 Hz), 8.32 (d, 1H, H-4, 9.3 Hz), 7.85–7.82 (m, 2H, H-6′ or H-α), 7.67 (t, 1H, H-7′, 9.9 Hz), 7.64 (t, 1H, H-6, 9.9 Hz), 7.50–7.46 (m, 2H, H-3′ or H-5′), 7.37 (d, 1H, H-3, 4.1 Hz), 7.34 (t, 1H, H-7, 9.9 Hz), 7.29–7.26 (m, 1H, H-5, overlapped with CHCl3 signal). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 186.8 (C=O), 145.3 (Cq), 144.5 (Cq), 140.9 (Cq), 139.9 (C-2′, C-4′ or C- β), 139.5 (C-8′), 139.48 (C-6′), 139.1 (Cq), 138.9 (C-6 or C-7′), 138.4 (C-2′, C-4′ or C- β), 137.4 (C-4), 134.6 (C-2), 134.2 (C-8), 133.3 (C-2′, C-4′ or C- β), 129.0 (C-6 or C-7′), 127.2 (C-3′ or C-5′), 127.1 (Cq), 125.8 (Cq), 125.6 (C-5), 125.0 (C-7), 122.1 (C-α), 119.9 (C-3′ or C-5′), 117.9 (C-3). MS-ESI positive mode: 309 (M+) (100%), 181 (75%), 157 (46%), 108 (30%). Selected IR data: 2856, 1620 (C=O), 1549, 1396, 1283, 976 (C=C) cm−1.
(E)-1-(Azulen-1-yl)-3-(3-chloroazulen-1-yl)prop-2-en-1-one (7). Synthesized similarly to 6, using 1-acetylazulene and 3-chloroazulene-1-carbaldehyde following the above described general procedure. Yield 78%, dark brown solid, m.p. 229.6–233.2 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 10.07 (d, 1H, H-8′, 9.9 Hz), 8.68 (d, 1H, H-8, 9.9 Hz), 8.52–8.50 (m, 2H, H-2′ and H-4′), 8.64 (d, 1H, H- β, 15.1 Hz), 8.39 (d, 1H, H-4, 9.5 Hz), 8.28 (s, 1H, H-2), 7.85 (t, 1H, H-6′, 9.6 Hz), 7.82 (d, 1H, H-α, 15.3 Hz), 7.71 (t, 1H, H-6, 9.9 Hz), 7.65 (t, 1H, H-7′, 9.9 Hz), 7.50 (t, 1H, H-5′, 9.6 Hz), 7.38 (d, 1H, H-3′, 4.1 Hz), 7.33–7.28 (m, 2H, H-5 and H-7). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 186.4 (C=O), 145.5 (Cq), 141.1 (Cq), 140.4 (C-6), 139.9 (C-8′), 139.6 (C-6′), 139.5 (C-2′ or C-4′), 138.5 (C-2′ or C-4′), 137.9 (Cq), 137.7 (Cq), 135.4 (C-4), 135.1 (C-8), 132.1 (C-2), 131.9 (C-β), 129.2 (C-7′), 128.4 (C-5′), 126.9 (Cq), 125.5 (C-5 or C-7), 125.3 (C-5 or C-7), 123.5 (Cq), 122.8 (C-α), 119.4 (Cq), 118.0 (C-3′). MS-ESI positive mode: 343 (M+) (100%), 215 (75%), 128 (60%), 345 (40%). Selected IR data: 3445, 2918, 1628 (C=O), 1399 (C=C), 1028, 958 (C=C), 867, 741, 615 cm−1.
(E)-1-(Azulen-1-yl)-3-(3-bromoazulen-1-yl)prop-2-en-1-one (8). Synthesized following the above described general procedure using equimolar amounts of 1-acetylazulene and 3-bromoazulene-1-carbaldehyde. Yield 74%, black solid, m.p. 206.7–213.3 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 10.07 (d, 1H, H-8’, 9.9 Hz), 8.68 (d, 1H, H-8, 9.9 Hz), 8.51–8.49 (m, 2H, H-2′ and H-4′), 8.46 (d, 1H, H-β, 15.1 Hz), 8.37–8.35 (m, 2H, H-2 and H-4), 7.85 (t, 1H, H-6′, 9.8 Hz), 7.79 (d, 1H, H-α, 15.1 Hz), 7.71 (t, 1H, H-6, 9.8 Hz), 7.65 (t, 1H, H-7′, 9.9 Hz), 7.50 (t, 1H, H-5′, 9.7 Hz), 7.37–7.33 (m, 3H, H-3′, H-5 and H-7). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 186.3 (C=O), 145.5 (Cq), 141.1 (Cq), 140.3 (C-6), 139.9 (C-8′), 139.6 (C-2′ or C-4′), 139.56 (Cq), 139.5 (C-6′), 138.6 (Cq), 138.4 (C-2′ or C-4′), 137.1 (C-2 or C-4), 135.3 (C-2 or C-4), 134.8 (C-8), 131.8 (C-β), 129.2 (C-7′), 127.4 (C-5′), 126.8 (Cq), 125.8 (C-3′, C-5 or C-7), 125.6 (C-3′, C-5 or C-7), 124.8 (Cq), 122.8 (C-α), 118.1 (C-3′, C-5 or C-7), 107.2 (Cq). MS-ESI positive mode: 387 (M+) (100%), 258.9 (80%), 389 (75%), 260.9 (50%). Selected IR data: 1626 (C=O), 1567 (C=C), 1383, 1304, 1112, 957 (C=O), 809, 739 cm−1.
(E)-1-(Azulen-1-yl)-3-(3-methylazulen-1-yl)prop-2-en-1-one (9). Synthesized by general condensation reaction protocol from 1-acetylazulene and 3-methylazulene-1-carbaldehyde. Yield 63%, brown solid, m.p. 97.2–103.9 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 10.07 (d, 1H, H-8′, 9.8 Hz), 8.63 (d, 1H, H-8, 9.8 Hz), 8.53–8.49 (m, 3H, H-2′, H-4′ and H-β), 8.22 (s, 1H, H-2), 8.19 (d, 1H, H-4, 9.4 Hz), 7.83 (d, 1H, H-6′, 9.8 Hz), 7.79 (d, 1H, H-α, 15.0 Hz), 7.65–7.58 (m, 2H, H-6 and H-7′), 7.47 (t, 1H, H-5′, 9.6 Hz), 7.36 (d, 1H, H-3′, 4.1 Hz), 7.23–7.17 (m, 2H, H-5 and H-7), 2.69 (s, 3H, H-11). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 186.9 (C=O), 145.2 (Cq), 141.6 (Cq), 140.9 (Cq), 139.9 (C-8′), 139.5 (Cq), 139.47 (C-6′), 139.4 (C-2′, C-4′ or C-β), 138.8 (C-6 or C-7′), 138.3 (C-2′, C-4′ or C-β), 135.1 (C-2), 134.3 (C-4), 133.8 (C-8), 133.0 (C-2′, C-4′ or C-β), 128.9 (C-6 or C-7′), 128.1 (Cq), 127.2 (Cq), 127.1 (C-5′), 124.3 (C-5 or C-7), 124 (Cq), 121.7 (C-α), 117.9 (C-3′), 12.8 (C-11). MS-ESI positive mode: 323 (M+) (100%), 195 (75%), 154 (26%), 324 (23%). Selected IR data: 3413, 2923, 2852, 1621 (C=O), 1551 (C=C), 1396, 963 (C=C), 741 cm−1.
(E)-3-(Azulen-1-yl)-1-(3-methylazulen-1-yl)prop-2-en-1-one (10). Synthesized following the above described general procedure using 1-(3-methylazulen-1-yl)ethanone and azulen-1-carbaldehyde described above. Yield 57%, brown solid, m.p. 158.2–168.7 °C. 1H-NMR (500.13 MHz, CDCl3, δ ppm, J Hz): 9.99 (d, 1H, H-8′, 9.8 Hz), 8.71 (d, 1H, H-8, 9.9 Hz), 8.54 (d, 1H, H-β, 15.1 Hz), 8.39 (d, 1H, H-2, 4.2 Hz), 8.36–8.34 (m, 2H, H-2′ and H-4′), 8.29 (d, 1H, H-4, 9.4 Hz), 7.79 (d, 1H, H-α, 15.1 Hz), 7.75 (t, 1H, H-6′, 9.8 Hz), 7.64 (t, 1H, H-6, 9.9 Hz), 7.53 (t, 1H, H-7′, 9.8 Hz), 7.45 (d, 1H, H-3, 4.2 Hz), 7.39 (t, 1H, H-5′, 9.7 Hz), 7.30 (t, 1H, H-7, 9.8 Hz), 7.23 (t, 1H, H-5, 9.8 Hz), 2.67 (s, 3H, H-11′). 13C-NMR (125.77 MHz, CDCl3, δ ppm): 186.4 (C=O), 144.4 (Cq), 142.0 (Cq), 141.3 (Cq), 140.2 (C-2′ or C-4′), 139.19 (C-8′), 139.18 (C-6′), 139.0 (Cq), 138.8 (C-6), 137.3 (C-4), 135.2 (C-2′ or C-4′), 134.6 (C-2), 134.3 (C-8), 133.0 (C- β), 128.4 (C-7’), 125.9 (C-5′), 125.8 (Cq), 125.7 (Cq), 125.5 (C-5), 125.2 (Cq), 124.8 (C-7), 122.2 (C-α), 119.9 (C-3), 12.67 (C-11′). MS-ESI positive mode: 323 (M+) (90%), 181 (100%), 367(30%). Selected IR data: 3065, 2919, 1616 (C=O), 1573 (C=C), 1543, 1425, 1395, 1287, 1193, 966 (C=C), 860, 743 cm−1.