3.2. Intermediates and Derivatives
3.2.1. 3-acetyl-2,4-dihydroxy-6-methoxy-5-methylbenzaldehyde (6 and 7)
Compound 5 (631.1 mg, 3.2 mmol) was dissolved in 5 mL of dry dichloromethane, and then TiCl4 (16 mL, 16 mmol, dissolved in 16 mL of dry CH2Cl2 and Cl2CHOCH3 (2.7 mL, 30.4 mmol) was added at −40 °C. After sufficient dissolution, the reaction device was transferred to a room-temperature environment and stirred overnight. The next day, the reaction was quenched by slowly adding an appropriate amount of ice water dropwise to the reaction solution at 0 °C, and the reaction was stopped after stirring for one hour. After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once with NaCl (aq) and desiccated with anhydrous Na2SO4. Compounds 6 and 7 were purified via column chromatography (eluent, EtOAc/PE = 1/12 to 1/8) after vacuum concentration (513.5 mg, 71.2% yield, white solid). TLC: Rf = 0.3 (EtOAc/PE = 1/10). Compound 6: 1H NMR (400 MHz, CDCl3) δ 2.07 (s, 3H), 2.74 (s, 3H), 3.89 (s, 3H), 9.98 (s, 1H), 14.09 (s, 1H), 15.02 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 8.08, 33.19, 63.03, 106.58, 107.29, 111.07, 166.66, 167.58, 172.57, 192.74, 204.76; HRMS (ESI) calcd for C11H11O5[M-H]−: 223.0606, found 223.0602. TLC: Rf = 0.3 (EtOAc/PE = 1/6); Compound 7:1H NMR (400 MHz, CDCl3) δ 2.04 (s, 3H), 2.72 (s, 3H), 3.96 (s, 3H), 10.07 (s, 1H), 12.56 (s, 1H), 14.03 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 6.78, 31.48, 66.82, 108.23, 108.47, 109.62, 166.07, 167.95, 168.96, 192.51, 203.37; HRMS(ESI) calcd for C11H11O5[M-H]−: 223.0606, found 223.0606.
3.2.2. 2-acetyl-4-formyl-5-methoxy-6-methyl-1,3-phenylene dibenzoate (9)
The 4Å-type molecular sieve was activated and loaded into a reaction flask. Compounds 6 and 7 (448 mg, 2.0 mmol) were added and dissolved in 5 mL of Py, DMAP (48.9 mg, 0.4 mmol) was added, and then BzCl (0.7 mL, 4.0 mmol) was added slowly, dropwise. The reaction was carried out at 60 °C for 12 h under nitrogen protection. After the reaction, the molecular sieve was removed via filtration, using diatomaceous earth; the reaction solution was diluted with dichloromethane; and then Py was removed via extraction with 1 N HCl. The organic phase was collected and washed once with NaCl (aq), and the desiccant was anhydrous Na2SO4. The purification was carried out via column chromatography after concentration under reduced pressure (eluent, EtOAc/PE = 1/8 to 1/6) to give compound 8 (94.5 mg, 14.4% yield, white solid) and compound 9 (635.1 mg, 73.5% yield, white solid). TLC: Rf = 0.3 (EtOAc/PE = 1/5); 1H NMR (400 MHz, CDCl3) δ 2.20–2.25 (s, 3H), 2.40–2.47 (s, 3H), 3.94–4.00 (s, 3H), 7.49–7.57 (q, J = 7.5 Hz, 4H), 7.62–7.71 (m, 2H), 8.13–8.21 (d, J = 6.6 Hz, 4H), 10.28–10.37 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 197.67, 187.41, 164.61, 164.09, 163.78, 151.59, 146.18, 134.53, 134.16, 130.61, 130.57, 129.03, 128.87, 128.76, 128.13, 127.09, 125.17, 120.44, 63.91, 31.52, 9.80; HRMS(ESI) calcd for C25H21O7[M+H]+: 433.1282, found 433.1267.
3.2.3. 2-acetyl-3-hydroxyphenyl 4-chlorobenzoate (10) and 2-acetyl-1,3-phenylene bis(4-chlorobenzoate) (12)
2,6-dihydroxy acetophenone (500 mg, 3.29 mmol) was dissolved in 5 mL of dry dichloromethane, and 4-chlorobenzoyl chloride (0.5 mL, 4 mmol), Et3N (0.5 mL, 4 mmol) was added slowly, dropwise, at room temperature (30 °C). The reaction was terminated after 4 h. After that, we added dichloromethane and distilled water to both phases and extracted three times. The organic phase was collected and washed once with NaCl (aq), desiccated with anhydrous Na2SO4, concentrated under vacuum, and purified via column chromatography (eluent, EtOAc/PE = 1/20 to 1/15) to give compound 10 (458.1 mg, 48.0% yield, yellow solid) and compound 12 (312.8 mg, 22.2% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/16); compound 10: 1H NMR (400 MHz, CDCl3) δ 2.54–2.57 (s, 3H), 6.64–6.70 (d, J = 8.0 Hz, 1H), 6.91–6.98 (d, J = 8.5 Hz, 1H), 7.44–7.50 (t, J = 7.6 Hz, 1H), 7.52–7.57 (d, J = 8.5 Hz, 2H), 8.12–8.20 (d, J = 8.4 Hz, 2H), 12.69–12.72 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 203.13, 164.20, 164.15, 151.50, 141.20, 135.69, 131.82, 129.54, 127.38, 116.84, 114.82, 114.12, 32.52; HRMS(ESI) calcd for C15H10ClO4[M-H]−: 289.0268, found 289.0269.TLC: Rf = 0.3 (EtOAc/PE = 1/12); compound 12: 1H NMR (400 MHz, CDCl3) δ 2.41–2.50 (s, 3H), 7.19–7.25 (d, J = 8.3 Hz, 2H), 7.46–7.57 (m, 5H), 8.05–8.15 (d, J = 7.0 Hz, 4H); 13C NMR (101 MHz, CDCl3) δ 198.19, 163.87, 148.02, 140.89, 131.80, 131.15, 129.32, 128.38, 127.22, 120.86, 31.47; HRMS(ESI) calcd for C22H15Cl2O5[M+H]+: 429.0291, found 429.0261.
3.2.4. 1-(4-chlorophenyl)-3-(2,6-dihydroxyphenyl)propane-1,3-dione (11)
Compound 10 (145 mg, 0.5 mmol) was dissolved in 2 mL of dry DMSO, then t-BuOK (112.2 mg, 1 mmol) was added, and the reaction was carried out at room temperature (26 °C) for 12 h. After the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4, concentrated under reduced pressure, and purified via column chromatography (eluent, EtOAc/PE = 1/15) to give compound 11 (56.7 mg, 39.1% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/12); 1H NMR (400 MHz, CDCl3) δ 2.99–3.09 (s, 2H), 6.49–6.56 (d, J = 8.1 Hz, 1H), 6.57–6.62 (d, J = 8.4 Hz, 1H), 7.37–7.46 (t, J = 8.4 Hz, 3H), 7.60–7.66 (d, J = 8.4 Hz, 2H), 11.47–11.57 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 196.26, 161.83, 157.82, 140.41, 138.44, 135.63, 129.11, 126.74, 110.62, 108.21, 101.34, 48.90; HRMS(ESI) calcd for C15H10ClO4[M-H]−: 289.0268, found 289.0251.
3.2.5. 2-(4-chlorophenyl)-5-hydroxy-4H-chromen-4-one (13)
Compound 12 (214 mg, 0.5 mmol) was dissolved in 3 mL of dry DMF, then t-BuOK (112.2 mg, 1 mmol) was added, and the reaction was carried out at room temperature (16 °C) for 12 h. After the reaction, ethyl acetate and distilled water were added to both phases. After three extractions, the organic phase was collected and washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4, concentrated under reduced pressure, and purified via column chromatography (eluent, EtOAc/PE = 1/12). The crude product was obtained as 46.8 mg, and the pure compound 13 was obtained after recrystallization in methanol (23 mg, 16.9% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/10); 1H NMR (400 MHz, CDCl3) δ 6.65–6.73 (s, 1H), 6.77–6.85 (d, J = 8.2 Hz, 1H), 6.93–7.02 (d, J = 8.4 Hz, 1H), 7.46–7.59 (m, 3H), 7.78–7.89 (d, J = 8.2 Hz, 2H), 12.38–12.56 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 183.55, 163.48, 160.94, 156.46, 138.54, 135.68, 129.78, 129.61, 127.79, 111.78, 110.95, 107.15, 106.28; HRMS(ESI) calcd for C15H10ClO3[M+H]+: 273.0313, found 273.0252.
3.2.6. 2,4-diacetyl-3,5-dihydroxy-6-methylphenyl benzoate (14); 2,6-diacetyl-3,5-dihydroxy-4-methylphenyl benzoate (15); 2,4-diacetyl-6-methylbenzene-1,3,5-triyl tribenzoate (16)
Compound 4 (249 mg, 1.11 mmol) was placed in 3 mL of dichloromethane, with thorough stirring, and BzCl (0.14 mL, 1.22 mmol) and Et3N (0.17 mL, 1.22 mmol) were added under an ice bath. The reaction was allowed to continue at room temperature for 4 h. After the reaction was completed, dichloromethane and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq), and the desiccant was used as anhydrous Na2SO4 and purified via column chromatography after vacuum concentration (eluent, EtOAc/PE = 1/35 to 1/30 to 1/20) to give compound 14 (79.7 mg, 21.9% yield, yellow solid), compound 15 (70.1 mg, 19.3% yield, yellow solid), and compound 16 (113.1 mg, 19.0% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/30). Compound 14: 1H NMR (400 MHz, CDCl3) δ 1.92–2.02 (s, 3H), 2.48–2.60 (s, 3H), 2.75–2.86 (s, 3H), 7.55–7.62 (t, J = 7.6 Hz, 2H), 7.67–7.76 (t, J = 6.9 Hz, 1H), 8.19–8.29 (d, J = 6.3 Hz, 2H), 14.86–15.21 (s, 1H), 15.45–15.77 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 205.65, 202.23, 169.98, 168.59, 163.70, 155.47, 134.75, 130.57, 129.24, 128.28, 111.98, 108.46, 107.45, 33.66, 31.97, 8.73; HRMS(ESI) calcd for C18H15O6[M-H]−: 327.0869, found 327.0868. TLC: Rf = 0.3 (EtOAc/PE = 1/25). Compound 15: 1H NMR (400 MHz, CDCl3) δ 2.11–2.18 (s, 3H), 2.47–2.57 (s, 6H), 7.57–7.65 (t, J = 7.8 Hz, 2H), 7.72–7.80 (t, J = 7.5 Hz, 1H), 8.21–8.30 (d, J = 8.3 Hz, 2H), 13.59–13.80 (s, 2H); 13C NMR (101 MHz, CDCl3) δ 202.36, 166.37, 164.76, 154.09, 135.20, 130.66, 129.56, 128.39, 111.96, 109.38, 32.65, 7.55; HRMS(ESI) calcd for C18H15O6[M-H]−: 327.0869, found 327.0869. TLC: Rf = 0.3 (EtOAc/PE = 1/15). Compound 16: 1H NMR (400 MHz, CDCl3) δ 2.07–2.17 (s, 3H), 2.43–2.54 (d, J = 1.5 Hz, 6H), 7.47–7.60 (dt, J = 7.3, 13.8 Hz, 6H), 7.62–7.73 (m, 3H), 8.09–8.26 (m, 6H); 13C NMR (101 MHz, CDCl3) δ 197.58, 164.35, 163.82, 147.87, 142.82, 134.50, 130.58, 129.03, 128.99, 128.16, 127.96, 124.75, 31.24, 10.69; HRMS(ESI) calcd for C32H28NO8[M+NH4]+: 554.1815, found 554.1793.
3.2.7. 1-(3-acetyl-2,4,6-trihydroxy-5-methylphenyl)-3-phenylpropane-1,3-dione (17)
Compound 14 (100 mg, 0.3 mmol) was dissolved in 2 mL of dry DMSO, followed by NaOH (24.4 mg, 0.61 mmol), and reacted for 12 h at room temperature (21 °C). After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4 and concentrated under reduced pressure via column chromatography (eluent, EtOAc/PE = 1/30) to give compound 17 (36.9 mg, 37.5% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/25); 1H NMR (400 MHz, CDCl3) δ 2.04–2.09 (s, 3H), 2.68–2.75 (s, 3H), 3.05–3.13 (s, 2H), 7.42–7.51 (d, J = 6.9 Hz, 3H), 7.64–7.71 (d, J = 7.3 Hz, 2H), 13.95–14.04 (s, 1H), 14.88–14.97 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 204.09, 194.62, 171.00, 166.08, 159.99, 141.27, 129.39, 128.74, 124.72, 105.21, 104.73, 101.36, 100.44, 47.77, 32.71, 7.11; HRMS(ESI) calcd for C18H17O6[M+H]+: 329.1020, found 329.1016.
3.2.8. 1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)ethan-1-one (18)
Compound 3 (364 mg, 2 mmol) was dissolved in 6 mL of ethyl acetate, 0.6 mL of methanol was added, and then TMSCHN2 (2.95 mL, 20 mmol, dissolved in 2.95 mL of ether) was added under an ice bath. Then, the reaction device was moved to a room-temperature environment, and the reaction was allowed to continue for 24 h. After the reaction was completed, the reaction was quenched by the addition of acetic acid, dropwise. After adding ethyl acetate and distilled water in both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq); dried using anhydrous Na2SO4; and purified via column chromatography (eluent, EtOAc/PE = 1/10 to 1/4) after vacuum concentration to yield compound 18 (242.3 mg, 57.7% yield, white solid) and compound 5 (99.6 mg, 25.4% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/8); 1H NMR (400 MHz, CD3OD) δ 1.91–1.97 (s, 3H), 2.55–2.61 (s, 3H), 3.86–3.97 (d, J = 8.5 Hz, 6H), 6.13–6.19 (s, 1H); 13C NMR (101 MHz, CD3OD) δ 204.79, 165.34, 164.44, 163.37, 106.58, 106.03, 87.32, 56.13, 56.05, 33.29, 7.26; HRMS(ESI) calcd for C11H15O4[M+H]+: 211.0965, found 211.0956.
3.2.9. 2-acetyl-3,5-dimethoxy-6-methylphenyl benzoate (19)
Compound 18 (63.1 mg, 0.3 mmol) was dissolved in 1 mL of dry dichloromethane, and then BzCl (0.07 mL, 0.6 mmol) and Et3N (0.09 mL, 0.6 mmol) were added slowly, dropwise, under an ice bath. After that, the reaction was moved to room temperature (16 °C) and ended after 4 h. After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to yield compound 19 (69.2 mg, 73.4% yield, white solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.93–2.04 (s, 3H), 2.43–2.53 (s, 3H), 3.83–3.95 (s, 6H), 6.37–6.42 (s, 1H), 7.45–7.53 (t, J = 7.1 Hz, 2H), 7.58–7.65 (t, J = 8.1 Hz, 1H), 8.13–8.20 (d, J = 8.3 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.91, 164.81, 160.35, 157.05, 147.57, 133.69, 130.41, 129.29, 128.68, 116.97, 112.68, 92.88, 56.11, 55.90, 32.12, 8.79; HRMS(ESI) calcd for C18H19O5[M+H]+: 315.1227, found 315.1217.
3.2.10. (Z)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)-3-phenylprop-2-en-1-one and 1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)-3-phenylpropane-1,3-dione (20)
Compound 19 (39.8 mg, 0.13 mmol) was dissolved in 1 mL of dry DMF, then t-BuOK (29.2 m, 0.26 mmol) was added, and the reaction was carried out at room temperature (16 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4, concentrated under reduced pressure, and purified via column chromatography (eluent, EtOAc/PE = 1/10) to yield compound 20 (37 mg, 93.0% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 2:3. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 1.99–2.08 (d, J = 10.1 Hz, 3H), 3.46–3.99 (m, 6H), 4.55 [s, 1.2H, C(O)CH2C(O) for 1,3-diketo form], 5.85 (s, 0.6H, ArH for 1,3-diketo form), 6.01 (s, 0.4H, ArH for enol form), 7.34 (s, 0.4H, olefin for enol form), 7.41–7.66 (m, 3H), 7.83–8.05 (dd, J = 8.1, 32.0 Hz, 2H), 13.34 (s, 0.4H, ArOH for enol form), 13.68 (s, 0.6H, ArOH for 1,3-diketo form), 15.55 (s, 0.4H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 198.87, 194.88, 194.27, 175.64, 164.16, 164.13, 163.24, 163.13, 160.77, 160.45, 136.86, 134.63, 133.42, 131.78, 128.88, 128.75, 128.25, 126.76, 106.45, 106.26, 105.54, 104.68, 98.54, 86.73, 85.86, 55.99, 55.62, 55.48, 55.35, 55.05, 7.47, 7.27; HRMS(ESI) calcd for C18H19O5[M+H]+: 315.1227, found 315.1217.
3.2.11. 2-acetyl-3,5-dimethoxy-6-methylphenyl 4-chlorobenzoate (21)
Compound 18 (400 mg, 1.9 mmol) was dissolved in 3 mL of dry dichloromethane and 4-chlorobenzoyl chloride (0.27 mL, 2.1 mmol), and then Et3N (0.3 mL, 2.1 mmol) was added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (27 °C). After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 21 (619.54 mg, 93.7% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.94–2.00 (s, 3H), 2.43–2.50 (s, 3H), 3.85–3.94 (s, 6H), 6.36–6.43 (s, 1H), 7.42–7.50 (d, J = 8.6 Hz, 2H), 8.03–8.14 (d, J = 8.6 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.70, 164.02, 160.49, 157.31, 147.54, 140.21, 131.79, 129.06, 127.82, 116.64, 112.68, 92.95, 56.11, 55.91, 32.15, 8.76; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0823.
3.2.12. (Z)-3-(4-chlorophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(4-chlorophenyl)-3-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)propane-1,3-dione (22)
Compound 21 (367.5 mg, 1.06 mmol) was dissolved in 3 mL of DMF, and then t-BuOK (235.6 mg, 2.1 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 22 (295.1 mg, 80.3% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol-form:diketonic) of 1:1. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 2.01–2.03 (d, J = 9.5 Hz, 3H), 3.51–3.98 (m, 6H), 4.51 [s, 1H, C(O)CH2C(O) for 1,3-diketo form], 5.86 (s, 0.5H, ArH for 1,3-diketo form), 6.01 (s, 0.5H, ArH for enol form), 7.30 (s, 0.5H, olefin for enol form), 7.40–7.50 (dd, J = 7.9, 21.0 Hz, 2H), 7.77–7.95 (dd, J = 8.5, 38.4 Hz, 2H), 13.27 (s, 0.5H, ArOH for enol form), 13.60 (s, 0.5H, ArOH for 1,3-diketo form), 15.50 (s, 0.5H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 198.41, 194.31, 193.72, 174.17, 164.26, 164.14, 163.30, 160.74, 160.49, 139.89, 137.86, 135.21, 133.13, 131.05, 129.69, 129.24, 129.04, 128.05, 106.55, 106.40, 105.49, 104.67, 98.59, 86.75, 85.90, 65.71, 56.02, 55.66, 55.42, 54.97, 7.47, 7.28; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0813.
3.2.13. 2-acetyl-3,5-dimethoxy-6-methylphenyl 2-chlorobenzoate (23)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane, and 2-chlorobenzoyl chloride (0.19 mL, 1.5 mmol), Et3N (0.21 mL, 1.5 mmol) was added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane, and distilled water to both phases and extracting three times, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 23 (278.9 mg, 80.1% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 2.01–2.09 (s, 3H), 2.46–2.56 (s, 3H), 3.84–3.97 (s, 6H), 6.36–6.44 (s, 1H), 7.34–7.42 (t, J = 7.2 Hz, 1H), 7.42–7.52 (d, J = 7.8 Hz, 2H), 8.02–8.11 (d, J = 7.8 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 199.97, 163.61, 160.55, 157.34, 147.38, 134.14, 133.06, 132.11, 131.14, 129.47, 126.91, 116.58, 112.77, 93.00, 56.11, 55.93, 32.22, 8.89; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0801.
3.2.14. (Z)-3-(2-chlorophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(2-chlorophenyl)-3-(2-hydroxy-4,6-dimethoxy-3-methylphenyl) propane-1,3-dione (24)
Compound 23 (115.0 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 24 (94 mg, 81.7% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 3:2. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 2.00–2.03 (d, J = 8.8 Hz, 3H), 3.62–4.62 (m, 6H), 4.62 [s, 0.8H, C(O)CH2C(O) for 1,3-diketo form], 5.88 (s, 0.4H, ArH for 1,3-diketo form), 5.98 (s, 0.6H, ArH for enol form), 7.28 (s, 0.6H, olefin for enol form), 7.35–7.72 (m, 4H), 13.24 (s, 0.6H, ArOH for enol form), 13.61 (s, 0.4H, ArOH for 1,3-diketo form), 15.35 (s, 0.6H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 197.77, 194.47, 173.95, 163.39, 160.70, 132.47, 131.20, 131.05, 130.81, 130.46, 130.34, 126.94, 106.24, 103.94, 86.53, 85.68, 58.70, 55.79, 55.53, 55.34, 7.33, 7.15; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0805.
3.2.15. 2-acetyl-3,5-dimethoxy-6-methylphenyl 3-chlorobenzoate (25)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane and 3-chlorobenzoyl chloride (0.19 mL, 1.5 mmol), and then Et3N (0.21 mL, 1.5 mmol) was added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 25 (307.6 mg, 88.4% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.96–2.03 (s, 3H), 2.44–2.52 (s, 3H), 3.86–3.97 (s, 6H), 6.35–6.49 (s, 1H), 7.40–7.46 (t, J = 7.9 Hz, 1H), 7.55–7.61 (d, J = 8.0 Hz, 1H), 8.02–8.08 (d, J = 7.9 Hz, 1H), 8.11–8.17 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 199.69, 163.72, 160.54, 157.39, 147.52, 134.85, 133.70, 131.10, 130.39, 130.03, 128.53, 116.52, 112.65, 92.99, 56.11, 55.91, 32.18, 8.75; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0806.
3.2.16. (Z)-3-(3-chlorophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(3-chlorophenyl)-3-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)propane-1,3-dione (26)
Compound 25 (115.0 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 26 (95.4 mg, 83.0% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 1:1. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 1.97–2.11 (d, J = 8.8 Hz, 3H), 3.50–4.00 (m, 6H), 4.51 [s, 1.00H, C(O)CH2C(O) for 1,3-diketo form], 6.01 (s, 0.50H, ArH for 1,3-diketo form), 5.86 (s, 0.50H, ArH for enol form), 7.30 (s, 0.44H, olefin for enol form), 7.35–7.97 (m, 4H), δ13.25 (s, 0.50H, ArOH for enol form), δ 13.59 (s, 0.50H, ArOH for 1,3-diketo form), δ 15.42 (s, 0.50H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 198.22, 194.45, 193.65, 173.56, 164.29, 164.13, 163.41, 163.35, 160.72, 160.56, 138.40, 136.53, 135.27, 134.90, 133.38, 131.55, 130.25, 129.99, 128.30, 126.86, 126.38, 124.78, 106.52, 106.39, 105.45, 104.65, 99.01, 86.74, 85.91, 56.03, 55.65, 55.45, 55.00, 7.45, 7.27; HRMS(ESI) calcd for C18H18ClO5[M+H]+: 349.0837, found 349.0806.
3.2.17. 2-acetyl-3,5-dimethoxy-6-methylphenyl 3,5-dichlorobenzoate (27)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane and 2,4-dichlorobenzoyl chloride (0.19 mL, 1.5 mmol); Et3N (0.21 mL, 1.5 mmol) was added slowly, dropwise, under an ice bath; and the reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane and distilled water in both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq); the desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 27 (354.1 mg, 92.7% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.91–2.03 (s, 3H), 2.41–2.55 (s, 3H), 3.82–4.01 (s, 6H), 6.35–6.47 (s, 1H), 7.53–7.65 (s, 1H), 7.96–8.12 (s, 2H); 13C NMR (101 MHz, CDCl3) δ 199.39, 162.69, 160.68, 157.69, 147.50, 135.61, 133.46, 132.24, 128.73, 116.05, 112.59, 93.06, 56.11, 55.93, 32.25, 8.71; HRMS(ESI) calcd for C18H17Cl2O5[M+H]+: 383.0448, found 383.0386.
3.2.18. (Z)-3-(3,5-dichlorophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(3,5-dichlorophenyl)-3-(2-hydroxy-4,6-dimethoxy -3-methylphenyl)propane-1,3-dione (28)
Compound 27 (126.0 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 28 (110.0 mg, 87.3% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 4:1. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 2.01–2.05 (d, J = 9.4 Hz, 3H), 3.78–4.06 (m, 6H), 4.31 [s, 0.34H, C(O)CH2C(O) for 1,3-diketo form], 5.96 (s, 0.17H, ArH for 1,3-diketo form), 6.02 (s, 0.76H, ArH for enol form), 7.28 (s, 0.76H, olefin for enol form), 7.47–7.72 (m, 3H), δ 13.16 (s, 0.76H, ArOH for enol form), δ 13.96 (s, 0.17H, ArOH for 1,3-diketo form), δ 15.33 (s, 0.76H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 197.88, 195.98, 194.59, 174.07, 164.25, 164.17, 163.50, 163.39, 160.82, 160.70, 137.81, 134.57, 132.59, 132.33, 132.01, 131.31, 131.16, 130.92, 130.58, 130.47, 127.05, 106.36, 105.48, 104.65, 104.06, 86.64, 85.78, 58.84, 55.91, 55.65, 55.63, 55.46, 7.45, 7.27; HRMS(ESI) calcd for C18H15Cl2O5[M-H]−: 381.0297, found 381.0244.
3.2.19. 2-acetyl-3,5-dimethoxy-6-methylphenyl 4-fluorobenzoate (29)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane and 4-fluoro benzoyl chloride (0.19 mL, 1.5 mmol), and then Et3N (0.21 mL, 1.5 mmol) was added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq); the desiccant was used as anhydrous Na2SO4, and it was purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 29 (318.4 mg, 95.9% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.92–2.06 (s, 3H), 2.39–2.56 (s, 3H), 3.82–3.98 (s, 6H), 6.32–6.46 (s, 1H), 7.07–7.23 (t, J = 8.6 Hz, 2H), 8.09–8.28 (t, J = 7.1 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.80, 167.57, 165.03, 163.86, 160.45, 157.24, 147.54, 133.09, 132.99, 125.62, 125.59, 116.77, 116.00, 115.79, 112.70, 92.93, 56.11, 55.91, 32.14, 8.77; HRMS(ESI) calcd for C18H18FO5[M+H]+: 333.1133, found 333.1076.
3.2.20. (Z)-3-(4-fluorophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(4-fluorophenyl)-3-(2-hydroxy-4,6-dimethoxy-3 -methylphenyl)propane-1,3-dione (30)
Compound 29 (109.6 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 30 (83.5 mg, 76.2% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 2:3. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 2.11–2.25 (d, J = 9.9 Hz, 3H), 3.64–4.15 (m, 6H), 4.66 [s, 1.20H, C(O)CH2C(O) for 1,3-diketo form], 6.01 (s, 0.60H, ArH for 1,3-diketo form), 6.16 (s, 0.40H, ArH for enol form), 7.28 (s, 0.40H, olefin for enol form), 7.29–7.47 (m, 2H), 7.95–8.33 (m, 2H), 13.42 (s, 0.40H, ArOH for enol form), 13.77 (s, 0.60H, ArOH for 1,3-diketo form), 15.75 (s, 0.40H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 198.55, 194.15, 193.36, 174.59, 167.21, 164.68, 164.23, 164.14, 163.24, 163.20, 160.77, 160.44, 133.33, 130.96, 130.86, 129.05, 128.96, 116.14, 115.99, 115.92, 115.77, 106.53, 106.37, 105.52, 104.62, 98.23, 86.75, 85.90, 56.02, 55.65, 55.41, 54.96, 32.06, 29.84, 22.83, 14.26, 7.47, 7.28; HRMS(ESI) calcd for C18H18FO5[M+H]+: 333.1133, found 333.1082.
3.2.21. 2-acetyl-3,5-dimethoxy-6-methylphenyl 4-bromobenzoate (31)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane and 4-bromobenzoyl chloride (0.19 mL, 1.5 mmol), and then Et3N (0.21 mL, 1.5 mmol) was added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane, and distilled water to both phases and extracting three times, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 31 (381.8 mg, 97.4% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.89–2.07 (s, 3H), 2.37–2.56 (s, 3H), 3.80–3.98 (s, 6H), 6.32–6.46 (s, 1H), 7.52–7.73 (d, J = 8.8 Hz, 2H), 7.94–8.10 (d, J = 8.8 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.69, 164.18, 160.49, 157.32, 147.53, 132.07, 131.90, 128.93, 128.28, 116.62, 112.68, 92.96, 56.12, 55.92, 32.16, 8.76; HRMS(ESI) calcd for C18H18BrO5[M+H]+: 393.0332, found 393.0267.
3.2.22. (Z)-3-(4-bromophenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(4-bromophenyl)-3-(2-hydroxy-4,6-dimethoxy -3-methylphenyl)propane-1,3-dione (32)
Compound 31 (129.4 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 32 (107.2 mg, 82.8% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 2:3. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 1.97–2.07 (d, J = 9.4 Hz, 3H), 3.47–4.05 (m, 6H), 4.51 [s, 1.20H, C(O)CH2C(O) for 1,3-diketo form], 5.86 (s, 0.60H, ArH for 1,3-diketo form), 6.01 (s, 0.40H, ArH for enol form),7.30 (s, 0.40H, olefin for enol form), 7.52–7.89 (m, 4H), 13.27 (s, 0.40H, ArOH for enol form), 13.60 (s, 0.60H, ArOH for 1,3-diketo form), 15.48 (s, 0.40H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 198.38, 194.33, 193.92, 174.19, 164.26, 164.13, 163.31, 160.73, 160.49, 135.60, 133.59, 132.24, 132.01, 129.79, 128.62, 128.21, 126.35, 106.54, 106.40, 105.48, 104.66, 98.61, 86.75, 85.90, 56.02, 55.66, 55.43, 54.94, 29.84, 22.83, 14.26, 7.47, 7.28; HRMS(ESI) calcd for C18H16BrO5[M-H]−: 391.0181, found 391.0122.
3.2.23. 2-acetyl-3,5-dimethoxy-6-methylphenyl 4-methylbenzoate (33)
Compound 18 (210 mg, 1 mmol) was dissolved in 3 mL of dry dichloromethane, and p-Toluoyl chloride (0.19 mL, 1.5 mmol) and Et3N (0.21 mL, 1.5 mmol) were added slowly, dropwise, under an ice bath. The reaction was terminated after 4 h at room temperature (29 °C). After adding dichloromethane and distilled water to both phases and extracting three times, the organic phase was collected and washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration to give compound 33 (294.2.4 mg, 89.7% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.93–2.02 (s, 3H), 2.43 (s, 3H), 2.48 (s, 3H), 3.83–3.96 (s, 6H), 6.34–6.44 (s, 1H), 7.26–7.34 (d, J = 7.9 Hz, 2H), 7.98–8.11 (d, J = 8.1 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.95, 164.82, 160.29, 156.93, 147.59, 144.52, 130.46, 129.40, 126.54, 117.17, 112.72, 92.87, 56.11, 55.88, 32.08, 21.86, 8.79; HRMS(ESI) calcd for C19H21O5[M+H]+: 329.1384, found 329.1332.
3.2.24. (Z)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)-3-(p-tolyl)prop-2-en-1-one and 1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)-3-(p-tolyl) propane-1,3-dione (34)
Compound 33 (108.0 mg, 0.33 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (74.8 mg, 0.66 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was collected and washed once with NaCl (aq). The desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 34 (82.1 mg, 76.0% yield, yellow solid) as a reciprocal isomer with a molar ratio (enol: diketonic) of 3:7. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 1.97–2.11 (d, J = 10.3 Hz, 3H), 2.37–2.55 (d, J = 6.4 Hz, 3H), 3.49–3.98 (m, 6H), 4.53 [s, 1.40H, C(O)CH2C(O) for 1,3-diketo form], 5.86 (s, 0.70H, ArH for 1,3-diketo form), 6.02 (s, 0.30H, ArH for enol form),7.27 (s, 0.30H, olefin for enol form), 7.28–7.36 (m, 2H), 7.75–7.94 (dd, J = 8.3, 31.1 Hz, 2H), 13.36 (s, 0.30H, ArOH for enol form), 13.71 (s, 0.70H, ArOH for 1,3-diketo form), 15.63 (s, 0.30H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 199.10, 194.54, 194.01, 176.06, 164.11, 163.16, 162.99, 160.81, 160.37, 144.24, 142.47, 134.41, 131.79, 129.55, 129.48, 128.38, 126.77, 106.43, 106.21, 105.59, 104.69, 98.01, 86.74, 85.87, 55.99, 55.61, 55.36, 55.01, 29.83, 21.81, 21.72, 7.48, 7.27; HRMS(ESI) calcd for C19H21O5[M+H]+: 329.1384, found 329.1334.
3.2.25. 2-acetyl-3,5-dimethoxy-6-methylphenyl 4-ethylbenzoate (35)
Compound 18 (100 mg, 0.48 mmol) was dissolved in dry dichloromethane, and 4-ethylbenzoyl chloride (76 μL, 0.52 mmol) was added slowly, dropwise, under an ice bath, followed by Et3N (72 μL, 0.52 mmol), and the reaction was terminated by thorough stirring for 4 h. After adding dichloromethane, adding distilled water in both phases, and extracting three times, the organic phase was collected and washed once, using NaCl (aq); the desiccant was used as anhydrous Na2SO4 and purified via column chromatography (eluent, EtOAc/PE = 1/8) after vacuum concentration, yielding compound 35 (105.6 mg, 64.3% yield, yellow solid). TLC: Rf = 0.3 (EtOAc/PE = 1/6); 1H NMR (400 MHz, CDCl3) δ 1.92–2.02 (s, 3H), 2.42–2.50 (s, 3H), 2.67–2.78 (q, J = 7.7 Hz, 2H), 3.81–3.96 (s, 6H), 6.34–6.42 (s, 1H), 7.27–7.35 (d, J = 8.1 Hz, 2H), 8.01–8.14 (d, J = 8.3 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 199.98, 164.83, 160.30, 156.94, 150.70, 147.62, 130.59, 128.25, 126.74, 117.18, 112.76, 92.88, 56.13, 55.90, 32.10, 29.20, 15.40, 8.80; HRMS(ESI) calcd for C20H23O5[M+H]+: 343.1540, found 343.1522.
3.2.26. (Z)-3-(4-ethylphenyl)-3-hydroxy-1-(2-hydroxy-4,6-dimethoxy-3-methylphenyl)prop-2-en-1-one and 1-(4-ethylphenyl)-3-(2-hydroxy-4,6-dimethoxy-3 -methylphenyl)propane-1,3-dione (36)
Compound 35 (24 mg, 0.07 mmol) was dissolved in 2 mL of dry DMF, and t-BuOK (15.71 mg, 0.14 mmol) was added. The reaction was carried out at room temperature (27 °C) for 12 h. After the completion of the reaction, ethyl acetate and distilled water were added to both phases, and after three extractions, the organic phase was washed once, using NaCl (aq). The desiccant was used as anhydrous Na2SO4, and it was purified via column chromatography (eluent, EtOAc/PE = 1/10) after vacuum concentration to yield compound 36 (14.6 mg, 60.8% yield, yellow solid) as a reciprocal isomer with a molar ratio (enolic: diketonic) of 1:4. TLC: Rf = 0.3 (EtOAc/PE = 1/9); 1H NMR (400 MHz, CDCl3) δ 1.27–1.36 (d, J = 9.9 Hz, 3H), 1.99–2.07 (d, J = 9.9 Hz, 3H), 2.67–2.80 (q, J = 7.6 Hz, 2H), 3.50–3.97 (m, 6H), 4.53 [s, 1.56H, C(O)CH2C(O) for 1,3-diketo form], 5.86 (s, 0.77H, ArH for 1,3-diketo form), 6.02 (s, 0.22H, ArH for enol form), 7.28 (s, 0.22H, olefin for enol form), 7.31–7.33 (m, 2H), 7.80–7.90 (m, 2H), 13.36 (s, 0.22H, ArOH for enol form), 13.71 (s, 0.77H, ArOH for 1,3-diketo form), 15.62 (s, 0.22H, OH for enol form); 13C NMR (101 MHz, CDCl3) δ 199.13, 194.59, 194.02, 176.09, 164.11, 163.16, 162.96, 160.82, 160.36, 150.39, 148.72, 134.60, 132.03, 128.49, 128.36, 128.31, 126.90, 106.43, 106.22, 105.60, 104.69, 98.07, 86.71, 85.85, 56.00, 55.63, 55.39, 55.05, 29.09, 29.04, 15.45, 15.29, 7.49, 7.29; HRMS(ESI) calcd for C20H23O5[M+H]+: 343.1540, found 343.1514.