EXPERIMENTAL
General Comments. UV spectra were measured on a Lambda-16 spectrophotometer (Perkin Elmer). Melting
points were determined on a Boetius heating stage. IR spectra were taken (KBr) on a Model 2000 Fourier spectrometer
13
(Perkin Elmer). PMR and C NMR spectra were recorded from DMSO-d solutions with DMSO-d as an internal standard
6
6
(ꢅ 2.50, ꢅ 39.51) on a VNMRS 400 spectrometer (Varian) at operating frequency 400 MHz. TLC used Silufol UV 254
H
C
plates with detection by I and NH vapors, UV light at 254 and 365 nm, and vanillin solution (1%) in conc. H SO . Paper
2
3
2
4
chromatography (PC) was performed on Filtrak No. 11 paper using n-BuOH:AcOH:H O (4:1:5, system 1) and
2
n-BuOH:Py:H O (6:4:3, system 2). Free monosaccharides were detected on PC by spraying with anilinium phthalate.
2
Extraction and Isolation of Flavonoid from theAerial Part of A. pseudalhagi. Air-dried ground plant raw material
(2000 g) was extracted at room temperature with EtOH (40%, 6 ꢆ 5 L). The combined extracts were vacuum distilled. The
condensed residue (220 g) was diluted with H O (1:1) and worked up successively with hexane (4 ꢆ 0.5 L), CHCl (5 ꢆ 0.5 L),
2
3
EtOAc (5 ꢆ 0.5 L), and n-BuOH (5 ꢆ 0.5 L). The solvents were distilled off to afford hexane (11.5 g), CHCl (9.63 g), EtOAc
3
(7.9 g), and BuOH (17.4 g) fractions.
The BuOH fraction (10 g) was chromatographed over a column (3.5 ꢆ 130 cm) of silica gel (250 g) using gradient
elution by CHCl :MeOH (CHCl ; CHCl :MeOH 25:1–1:1).
3
3
3
Alhaoside (1) was isolated by elution of the column with CHCl :MeOH (2:1) as yellowish crystals, C H O ,
3
41 54 25
–1
mp 194–196°C (MeOH). UV spectrum (MeOH, ꢄ , nm): 207, 256, 359. IR spectrum ( , cm ): 3382 (OH), 2969 (CH),
max
2900 (CH), 1655 (C=O), 1604, 1502, 1456 (C=C), 1430, 1354 (CH), 1290, 1205, 1138, 1058 (C–O), 983, 923, 875, 811, 688
(CH), 654.
13
Table 1 presents PMR and C NMR spectral data.
Acid Hydrolysis. Alhaoside (1, 20 mg) was hydrolyzed in an aqueous MeOH solution of HCl (15 mL, 5%) for 2 h
on a boiling-water bath. The resulting precipitate of the aglycon was filtered off and recrystallized from Me CO to afford
2
dillenetin (3ꢀ,4ꢀ-di-O-methylquercetin) (6 mg). The carbohydrate part of the hydrolysate was neutralized by BaCO and
3
evaporated. PC of the residue using system 2 identified D-glucose, D-galactose, and L-rhamnose.
3ꢀ,4ꢀ-Di-O-methylquercetin. C H O , mp 290–292°C, R 0.25 (TLC, CHCl :EtOAc, 2:1). UV spectrum (MeOH,
17 14
–1
7
f
3
ꢄ
, nm): 255, 267, 366. IR spectrum ( , cm ): 3430 (OH), 2997 (CH), 2975 (CH), 1656 (C=O), 1617, 1561, 1509 (C=C),
max
1359, 1315 (CH), 1279, 1243, 1210, 1167, 1121, 1094, 1033 (C–O), 920, 863, 834, 791, 740, 705 (CH), 638, 601.
Partial Hydrolysis. Glycoside 1 (20 mg) was treated with HCl solution (20 mL, 0.1 N) and heated on a water bath
for ~2 h. The reaction was monitored every 5 min using TLC and PC. Rutinose was observed in the first 10 min and then
L-rhamnose and D-glucose after 20 min; D-galactose, after 30 min.
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