Methylation of Q by CH I (1:5) in DMSO was carried out in the same manner as above. Two principal fractions
3
were isolated and crystallized from EtOH. The mp, TLC, and NMR spectra of the first fraction agreed with those of
tetra-O-methyl ether 3 (0.15 g, 42% yield). The second fraction was identified as tri-O-methyl ether 4 (0.02 g, 6% yield).
Methylation of Q by CH I (1:7) in DMF was carried out in the same manner as above. The obtained yellowish-
3
green precipitate was filtered off, rinsed with H O, dried, and chromatographed over a column of SG with elution by
2
C H –EtOH (200:1, 100:1, 100:2, 100:3, v/v). The principal fraction was isolated and identified as tri-O-methyl ether 4
6
6
(
0.15 g, 44% yield). The other fractions contained inseparable product mixtures.
Alkylation of Q by Butylbromide (1:7) in DMF. The obtained product was rinsed with H O by decantation, dried,
2
and chromatographed over a column of SG with elution by C H –MeOH (300:1, 200:1, 100:1, 50:1, v/v). Fractions that were
6
6
homogeneous according to TLC were combined and evaporated. The principal fraction was isolated and identified as
3,4ꢀ,7-tri-O-butyl ether 6 (0.2 g, 43% yield).
Quercetin 3,5,7,3ꢀ,4ꢀ-penta-O-methyl ether (2), mp 152–154°C, lit. 151–152°C (EtOH) [9], 151°C (EtOH) [12].
–
1
IR spectrum (ꢄ , cm ): 1645, 1632, 1609, 1580, 1520, 1271, 1250. UV spectrum (EtOH, ꢅmax, nm) (log ꢆ): 250 (5.7), 340
max
1
(
6
5.6). Í NMR spectrum (300 MHz, ÑDÑl , ꢁ, ppm, J/Hz): 3.95, 3.99, 4.04, 4.04, 4.23 (15Í, all s, 5ÎÑÍ ), 6.70 (1Í, s, Í-8),
.98 (1Í, s, Í-6), 7.25 (1Í, d, J = 9, Í-5ꢀ), 8.06 (1Í, d, J = 9, Í-6ꢀ), 8.72 (1Í, s, Í-2ꢀ). C NMR spectrum (75.5 MHz, CDCl3,
, ppm): 173.2 (Ñ-4), 164.2 (Ñ-7), 161.1 (Ñ-8à), 158.9 (Ñ-5), 152.5 (Ñ-2), 151.5 (Ñ-4), 148.2 (Ñ-3ꢀ), 141.4 (Ñ-3), 123.6
3
3
1
3
ꢁ
(
Ñ-1ꢀ), 122.0 (Ñ-6ꢀ), 111.9 (Ñ-2ꢀ), 111.6 (Ñ-5ꢀ), 109.7 (Ñ-4à), 96.1(Ñ-6), 93.1 (Ñ-8); 5ÎÑÍ : 55.6, 55.7, 55.8, 56.0, 59.6;
3
+
MS: m/z 373, [M + H] . C H O . [Ì] 372.4.
2
0 20 7
Quercetin 3,7,3ꢀ,4ꢀ-tetra-O-methyl ether (3), mp 157–159°C (MeOH–Et O) (yellow needles), lit. 159–160°C (anhydr.
2
–1
EtOH) [9], 159°C (EtOH) [10]. IR spectrum (ꢄ , cm ): 3215 (ÎÍ), 1650, 1603, 1589, 1512. UV spectrum (EtOH, ꢅmax, nm)
log ꢆ): 254 (5.5), 353 (5.5). Í NMR spectrum (500 MHz, ÑDCl , ꢁ, ppm): 3.85, 3.86, 3.95, 3.96 (12H, all s, 4OCH ), 6.33
1H, s, H-8), 6.43 (1H, s, H-6), 6.97 (1Í, d, J = 8.5, Í-5ꢀ), 7.67 (1Í, s, Í-2ꢀ), 7.73 (1Í, d, J = 8.5, Í-6ꢀ), 12.63 (1Í, s, ÎÍ).
C NMR spectrum (125 MHz, CDCl , ꢁ, ppm): 178.8 (Ñ-4), 165.4 (Ñ-7), 162.0 (Ñ-8à), 156.7 (Ñ-5), 155.8 (Ñ-2), 151.4
max
1
(
(
3
3
1
3
3
(
4
Ñ-4ꢀ), 148.7 (Ñ-3ꢀ), 139.0 (Ñ-3), 122.9 (Ñ-1ꢀ), 122.2 (Ñ-6ꢀ), 111.3 (Ñ-2ꢀ), 110.8 (Ñ-5ꢀ), 106.0 (Ñ-4à), 97.8 (Ñ-6), 92.2 (Ñ-8);
+
–
ÎÑÍ : 55.8, 55.9, 56.0, 60.2. MS: m/z 359, [M + H] , 357 [M – H] . C H O . [Ì] 358.4.
3 19 22 7
Quercetin 3,7,4ꢀ-tri-O-methyl ether (4), mp 168–170°C (EtOH) (yellow needles), lit. 169°C (Me CO–MeOH) [8].
2
–
1
IR spectrum (ꢄmax, cm ): 3398 (ÎÍ), 1651, 1625, 1517. UV spectrum (EtOH, ꢅmax, nm) (log ꢆ): 256 (5.4), 357 (5.3).
UV spectrum (0.01% NaOAc, ꢅmax, nm) (log ꢆ): 257 (5.5), 356 (5.4). UV spectrum (0.01% NaOEt, ꢅmax, nm) (log ꢆ): 273
1
(
6
5.4), 383 (5.0). Í NMR spectrum (500 MHz, DMSO-d , ꢁ, ppm): 3.78, 3.80, 3.85 (15Í, all s, 3ÎÑÍ ), 6.36 (1Í, s, Í-8),
6
3
1
3
.72 (1Í, s, Í-6), 7.56 (1Í, s, Í-2ꢀ), 7.09 (1Í, d, J = 8.9, Í-5ꢀ), 7.57 (1Í, d, J = 8.9, Í-6ꢀ), 8.29. C NMR spectrum
(
125 MHz, DMSO-d , ꢁ, ppm): 178.6 (Ñ-4), 165.6 (Ñ-7), 161.4 (Ñ-9), 156.1 (Ñ-2), 156.8 (Ñ-5), 150.8 (Ñ-4ꢀ), 146.8 (Ñ-3ꢀ),
6
1
6
38.7 (Ñ-3), 122.6 (Ñ-1ꢀ), 120.9 (Ñ-6ꢀ), 115.5 (Ñ-2ꢀ), 112.4 (Ñ-5ꢀ), 105.7 (Ñ-10), 98.3 (Ñ-6), 92.8 (Ñ-8); 3ÎÑÍ : 56.1, 56.5,
3
+
–
0.2. MS: m/z 345, [M + H] , 343 [M – H] . C Í Î . [Ì] 344.3.
1
8 16 7
–1
Quercetin 3,4ꢀ,7-tri-O-butyl ether (5), amorphous compound. IR spectrum (ꢄmax, cm ): 3406, 1732, 1605, 1510.
Í NMR spectrum (300MHz, CDCl , ꢁ, ppm, J/Hz): 1.03–2.19 (9Í, m, 3ÑÍ ÑÍ ÑÍ ÑÍ ), 3.99–4.16 (18Í, m, 3ÑÍ ÑÍ ÑÍ ÑÍ ),
1
3
3
2
2
2
3
2
2
2
13
5.75 (1Í, s, Í-8), 6.35 (1Í, s, Í-6), 6.97 (1Í, d, J = 9, Í-5ꢀ), 7.28 (1Í, s, Í-2ꢀ), 7.71 (1Í, d, J = 9, Í-6ꢀ). C NMR spectrum
(
75.5 MHz, CDCl , ꢁ, ppm): 179.0 (Ñ-4), 165.0 (Ñ-7), 161.9 (Ñ-9), 156.8 (Ñ-5), 155.8 (Ñ-2), 148.1 (Ñ-4ꢀ), 145.5 (Ñ-3ꢀ), 138.3
3
(
Ñ-3), 123.6 (Ñ-1ꢀ), 121.6 (Ñ-6ꢀ), 114.4 (Ñ-2ꢀ), 110.9 (Ñ-5ꢀ), 105.9 (Ñ-4à), 98.2 (Ñ-8), 92.5 (Ñ-6); 3ÑÍ Î, 3ÑÍ , 3ÑÍ : 72.7, 68.8,
2
2
3
6
8.4, 32.1, 31.1, 31.0, 19.2, 18.9, 13.8. C H O . [Ì] 470.5.
27 34 7
Quercetin 3,3ꢀ,4ꢀ,5,7-Penta-O-benzoate (6) [9]. Compound 1 (0.30 g, 1 mmol) was dissolved in anhydrous Py (20 mL),
treated with benzoylchloride (1.15 mL, 10 mmol), refluxed for 4 h, left overnight at 22–24°C, and diluted on the following day
with cold H O. The resulting precipitate (0.92 g) was filtered off, dried, and recrystallized from CHCl –MeOH. Yield 0.76 g
2
3
–
1
1
(
92%), mp 170–172°C. IR spectrum (ꢄmax, cm ): 3472, 1742, 1582, 1506. Í NMR spectrum (300 MHz, CDCl , ꢁ, ppm):
.18–7.54 (17H, m, 3Ñ Í CO, Í-8, 6), 7.88–8.15 (13H, m, 2Ñ Í CO, Í-6ꢀ, 5ꢀ, 2ꢀ). C NMR spectrum (75.5 MHz, CDCl3,
6 5 6 5
, ppm): 169.8 (Ñ-4), 164.9 (Ñ-7), 163.8, 163.4, 157.0, 154.5, 153.6, 150.7, 145.0, 142.8, 134.4, 134.2, 133.8, 133.5, 130.7,
30.4, 130.2, 129.2, 128.8, 128.5, 128.0, 126.7, 124.0, 123.7, 115.3, 114.4, 109.4. MS: m/z 823 [M + H] . Ñ Í Î . [Ì] 822.8.
3
13
7
ꢁ
1
+
50 30 12
Determination of Antioxidant Activity. The effect of the compounds on in vitro FRO was assessed using model
systems generating AOS and promoting LPO and chemiluminescence on a KhLM-003 instrument (Russia). CL of the model
systems was characterized by spontaneous emission, rapid luminescence, and then slow luminescence. The principal and
most informative CL characteristics were the emission light sum, which was determined from the emission intensity, and
the maximum emission amplitude.
854