486 J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 3
Ferte´ et al.
1
ClCH2CO2Et (13 mL, 120 mmol) was added. After 3 h under
the same conditions, the reaction mixture was cooled, filtered,
and evaporated to dryness. A solution of the dried residue in
aqueous 11 N HCl (150 mL) was stirred between 50 and 55
°C until crystallization occurred (0.75-1 h). After 2 h at room
temperature, the crystals were filtered, washed several times
with water, and then dried with P2O5 under vacuum to yield
a crude residue of 3′-O-(carboxymethyl)diosmetin (7 g). In the
next step, this dried residue was stirred under reflux for 5 h
in anhydrous ethanol (100 mL) in the presence of TsOH (0.35
g). Concentration of the mixture gave 6.8 g of the ester which
yielded pure 11 (4.4 g, 46% from diosmin) as pale-yellow
crystals after recrystallization from THF-MeOH: mp 226-
227 °C; 1H NMR (DMSO-d6) δ 1.20 (t, J ) 7.5 Hz, 3H), 3.85 (s,
3H), 4.15 (q, J ) 7.5 Hz, 2H), 4.90 (s, 2H), 6.21 (d, J ) 2 Hz,
1H), 6.48 (d, J ) 2 Hz, 1H), 6.95 (s, 1H), 7.14 (d, J ) 8.5 Hz,
1H), 7.52 (d, J ) 2 Hz, 1H), 7.68 (dd, J ) 8.5 and 2 Hz, 1H),
10.8 (br s, 1H, OH), 12.9 (s, 1H, chelated OH).
crystals: mp 194-195 °C; H NMR (DMSO-d6) δ 1.21 (t, J )
7.5 Hz, 3H), 3.90 (s, 3H), 4.20 (q, J ) 7.5 Hz, 2H), 4.93 (s,
2H), 6.40 (d, J ) 2 Hz, 1H), 6.75 (d, J ) 2 Hz, 1H), 6.82 (s,
1H), 7.10 (d, J ) 8.5 Hz, 1H), 7.45 (d, J ) 2 Hz, 1H), 7.55 (dd,
J ) 8.5 and 2 Hz, 1H), 9.5 (s, 1H, OH), 12.95 (s, 1H, chelated
OH).
3′-[4-(2-Ch lor op h en yl)m eth yl]p ip er a zin yl-1-ylca r bon -
ylm et h oxy]-7-(et h oxyca r b on ylm et h oxy)-5-h yd r oxy-4′-
m eth oxyfla von e (15). Alkylation of 8 (0.39 g, 1 mmol) with
4b was carried out according to the 11 f 25 procedure.
Crystallization of the dried residue from EtOH and then
purification of the crude crystals by flash chromatography
(SiO2, CH2Cl2-MeOH, 96/4) yielded pure 15 (0.44 g, 69%) as
white-yellowish crystals: 1H NMR (CDCl3) similar to that of
25 except for one fewer proton signal at δ 7.15-7.3; 13C NMR
(CDCl3) δ 14.1 (CH3), 42.1 (CH2), 45.2 (CH2), 52.6 (CH2), 53.0
(CH2), 56.0 (OCH3), 59.0 (CH2), 61.6 (CH2), 65.2 (CH2), 68.5
(CH2), 93.4 (CH), 98.3 (CH), 104.7 (CH), 106.0 (C), 111.8 (CH),
112.2 (CH), 121.3 (CH), 123.6 (C), 126.6 (CH), 128.4 (CH),
129.5 (CH), 130.7 (CH), 134.3 (C), 135.1 (C), 147.6 (C), 152.8
(C), 157.4 (C), 162.2 (C), 163.3 (C), 163.7 (C), 165.7 (C), 167.8
(C), 182.2 (C); FABMS (thioglycerol-glycerol matrix) in posi-
tive mode m/z 637-635 (M + H)+; IR see 25.
(b) F r om Diosm in (6). 7-[[6-O-6-Deoxy-r-L-m a n n op y-
r a n osyl)-â-D-glu cop yr a n osyl]oxy]-5-h yd r oxy-4′-m eth oxy-
3′-[4-[(2,3,4-tr im eth oxyp h en yl)m eth yl]p ip er a zin -1-ylca r -
bon ylm eth oxy]fla von e (22). A mixture of diosmin (11.9 g,
19.5 mmol) and KHCO3 (2.5 g, 25 mmol) in DMF (80 mL) was
stirred for 3 min at 115 °C under nitrogen, and 4f (8.67 g, 25
mmol) in solution in DMF (20 mL) was added. After 3 h under
the same conditions, the mixture was cooled, filtered, diluted
with water (200 mL), and thoroughly extracted first with
AcOEt and then with n-butanol. The collected n-butanol layers
were concentrated under vacuum until crystallization started
and then left at room temperature for 12 h. Crude crystals
were recrystallized in the same manner to provide pure 22
(11.6 g, 65%) as pale-brown crystals: 13C NMR (DMSO-d6)
(sugar carbons) δ 17.7, 66.2, 68.3, 69.8, 70.4, 70.9, 72.2, 73.2,
75.9, 76.5, 100.2, 100.6; (benzylpiperazinylcarbonylmethyl
chain carbons) δ 41.6, 44.6, 52.3, 52.7, 55.8, 55.9, 60.2, 60.9,
67.1, 107.8, 123.3, 124.8, 142.0, 152.0, 152.6, 165.6; (flavone
moiety carbons) δ 55.9, 95.1, 99.7, 104.1, 105.6, 111.7, 112.6,
120.9, 122.7, 147.7, 152.6, 156.9, 161.3, 163.0, 163.8, 182.0;
FABMS (glycerol matrix) in positive mode m/z 915 (M + H)+.
3′-(Eth oxyca r bon ylm eth oxy)-5-h yd r oxy-4′-m eth oxy-7-
[4-(p h en ylm et h yl)p ip er a zin -1-ylca r b on ylm et h oxy]fla -
von e (25). A mixture of 11 (0.39 g, 1 mmol) and KHCO3 (0.15
g, 1.5 mmol) was stirred for 3 min in DMF (5 mL) at 115 °C
under nitrogen; 4a (0.3 g, 1.2 mmol) in DMF (3 mL) was added.
After 2.5 h under the same conditions, the reaction mixture
was cooled, diluted with CH2Cl2 (15 mL), filtered, and evapo-
rated to dryness. The dried residue yielded pure 25 (0.46 g,
76%) as light-yellow crystals after flash chromatography (SiO2,
CH2Cl2-acetone, 4/1) and crystallization from MeOH: 1H
NMR (CDCl3) (benzylpiperazinylcarbonylmethyl and ethoxy-
carbonylmethyl chains) δ 1.30 (t, J ) 7.5 Hz, 3H), 2.4 (m, 4H),
3.48 (s, 2H), 3.5-3.6 (m, 4H), 4.28 (q, J ) 7.5 Hz, 2H), 4.80 (s,
4H), 7.3 (m, 5H); (flavone moiety) δ 3.90 (s, 3H), 6.35 (d, J )
2 Hz, 1H), 6.50 (s + d, J ) 2 Hz, 2H), 6.96 (d, J ) 8.5 Hz, 1H),
7.3 (m, 1H), 7.52 (dd, J ) 8.5 and 2 Hz, 1H), 12.8 (s, 1H,
chelated OH); 13C NMR (CDCl3) δ 14.1 (CH3), 42.1 (CH2), 45.2
(CH2), 52.5 (CH2), 52.3 (CH2), 56.0 (OCH3), 61.4 (CH2), 62.7
(CH2), 66.6 (CH2), 67.3 (CH2), 93.1 (CH), 98.6 (CH), 104.7 (CH),
106.0 (C), 111.9 (CH), 112.5 (CH), 121.3 (CH), 123.5 (C), 127.3
(CH), 128.3 (2CH), 134.0 (2CH), 137.3 (C), 147.5 (C), 152.9 (C),
157.5 (C), 162.1 (C), 163.5 (C), 163.7 (C), 165.1 (C), 168.4 (C),
182.2 (C); FABMS (thioglycerol-glycerol matrix) in positive
mode m/z 603 (M + H)+; IR (Nujol) 3400-2600 (OH), 1750
(ester), 1660 (amide, cetone), 1610 (CdC) cm-1
.
(c) F r om Hesp er et in (7). 5,3′-Dih yd r oxy-4′-m et h oxy-
7-[4-[(2,3,4-tr im eth oxyp h en yl)m eth yl]p ip er a zin -1-ylca r -
bon ylm et h oxy]fla va n on e (33). Alkylation with 4f was
carried out from hesperetin (3.6 g, 12 mmol) under the same
conditions as the 5 f 13 procedure. The dried residue was
purified by flash chromatography (SiO2, CH2Cl2-MeOH, 97.5/
2.5) and provided pure 33 (3.6 g, 49%) as a light-yellow
amorphous compound: 1H NMR (CDCl3) (benzylpiperazinyl-
carbonylmethyl chain) δ 2.47 (m, 4H), 3.52 (s, 2H), 3.5-3.6
(m, 4H), 3.90 (3s, 9H), 4.67 (s, 2H), 6.88 (d, J ) 8.5 Hz, 1H),
6.98 (d, J ) 8.5 Hz, 1H); (flavanone moiety) δ 2.81 (dd, J )
12.7 and 2.5 Hz, 1H), 3.08 (dd, J ) 16.5 and 12.7 Hz, 1H),
3.90 (s, 3H), 5.32 (dd, J ) 12.7 and 2.5 Hz, 1H), 6.08 (s, 2H),
6.65 (d, J ) 8.5 Hz, 1H), 6.92 (dd, J ) 8.5 and 2 Hz, 1H), 7.04
(d, J ) 2 Hz, 1H), 12.0 (s, 1H, chelated OH); 13C NMR (CDCl3)
δ 42.1 (CH2), 43.1 (CH2), 45.1 (CH2), 52.3 (CH3), 52.7 (CH2),
55.9 (2OCH3), 56.3 (CH2), 60.7 (OCH3), 61.1 (OCH3), 66.9
(CH2), 78.9 (CH), 94.3 (CH), 95.7 (CH), 103.5 (C), 106.9 (CH),
110.6 (CH), 112.7 (CH), 118.1 (CH), 123.1 (C), 125.0 (CH),
131.3 (C), 142.3 (C), 145.9 (C), 147.0 (C), 152.6 (C), 153.1 (C),
162.8 (C), 163.9. (C), 164.9 (C), 165.9 (C), 196.1 (C); CIMS
(NH3) m/z 609 (M + 1)+; IR (CH2Cl2) 3500-2500 (OH), 1660
(amide, cetone).
7-(â-D-Glu cop yr a n osyloxy)-5-h yd r oxy-4′-m eth oxy-3′-[4-
[(2,3,4-tr im eth oxyp h en yl)m eth yl]p ip er a zin -1-ylca r bon -
ylm eth oxy]fla von e (23). A solution of 22, hemitartrate (4 g,
3.9 mmol) in water (100 mL) was set at pH 4 by addition of
0.5 N aqueous HCl and heated at 40 °C. Naringinase (1.2 g;
Sigma N 1385) was added, and the reaction was stirred at 40
°C for 2 h. The cloudy mixture was diluted with DMF (20 mL),
neutralized with 10% aqueous NaHCO3, and extracted with
n-butanol. After evaporation of the organic layer, the dried
residue was crystallized twice from MeOH to yield pure 23
(2.4 g, 80%) as pale-brown crystals: 1H NMR (DMSO-d6) (â-
glucose) δ 3.2-3.5 (m, 6H), 4.6-5.4 (4H, OH), 5.04 (d, J ) 7
Hz, 1H); (benzylpiperazinylcarbonylmethyl chain) δ 2.40 (m,
4H), 3.30 (s, 2H), 3.2-3.5 (m, 2H), 3.7 (m, 2H), 3.73-3.77 (3s,
9H), 4.93 (s, 2H), 6.76 (d, J ) 8.5 Hz, 1H), 7.16 (d, J ) 8.5 Hz,
1H); (flavone moiety) δ 3.87 (s, 3H), 6.46 (d, J ) 2 Hz, 1H),
6.84 (d, J ) 2 Hz, 1H), 6.99 (s + d, J ) 8.5 Hz, 2H), 7.54 (d, J
) 2 Hz, 1H), 7.72 (dd, J ) 8.5 and 2 Hz, 1H), 12.9 (s, 1H,
chelated OH); FABMS (glycerol matrix) in positive mode m/z
769 (M + 1)+.
7,5-Dih yd r oxy-4′-m eth oxy-3′-[4-[(2,3,4-tr im eth oxyp h e-
n yl)m eth yl]p ip er a zin -1-ylca r bon ylm eth oxy]fla von e (24).
To a solution of 23 (1.54 g, 2 mmol) in water (40 mL) adjusted
to pH 3.95 with 1 N aqueous H3PO4 and heated at 37 °C was
added â-glucosidase (0.055 g; Sigma type II G8625). Then the
reaction was stirred for 48 h at the same temperature. A
similar workup to that in the 22 f 23 procedure yielded a
dried residue (1.17 g) which was purified by crystallization
from MeOH followed by flash chromatography (SiO2, CH2Cl2-
acetone, 1/1) to provide pure 24 (0.94 g, 77%) as pale-yellow
Gen er a l P r oced u r e for th e Alk yla tion of th e 3′-P h en ol
Gr ou p by 4. (a ) F r om Diosm etin (5). 5,3′-Dih yd r oxy-7-
(eth oxyca r bon ylm eth oxy)-4′-m eth oxyfla von e (8). Alky-
lation of diosmetin (6 g, 20 mmol) with ClCH2CO2Et was
carried out under the same conditions as described for diosmin.
Two successive crystallizations of the dried residue from THF-
MeOH and then CH2Cl2-acetone systems provided pure 7-O-
(carboxymethyl)diosmetin (8) (4 g, 52%) as bright-yellow