Chen DQ et al
npg
671
(d, 1H, J=3.9 Hz), 5.86 (d, 1H, J=7.5 Hz), 4.57 (m, 1H), 4.20 (m, 13R,14S,17R)-3,7,12-trihydroxy-10,13-dimethylhexadecahydro-
2H), 4.07 (m, 1H), 4.01 (m, 1H), 3.94 (brs, 1H), 3.78 (d, 1H, J=2.8 1H-cyclopenta[a]phenanthren-17-yl)pentanamido)propanoate
Hz), 3.37 (m, 1H), 2.50–2.15 (m, 4H), 2.05–1.10 (m, 20H), 1.0 (d, (12)
3H, J=6.5 Hz), 0.9 (s, 3H), 0.65 (s, 3H).
Cytarabine (324 mg, 1.33 mmol) was dissolved in dry DMF
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13C NMR (100 MHz, CD3OD) δ 176.2, 168.0, 158.6, 145.3, 95.3, (12 mL) and heated to 60 C. Compound 11 (0.96 g, 2 mmol),
89.2, 84.8, 78.9, 76.8, 74.5, 73.3, 69.5, 65.3, 48.6, 48.0, 43.7, 43.5, DCC (453 mg, 2.2 mmol) and DMAP (24.4 mg, 0.2 mmol) were
41.4, 41.0, 37.0, 36.4, 32.8, 32.6, 31.7, 30.1, 29.2, 28.4, 24.7, 23.7, then added. The mixture was cooled to rt and stirred for
18.0, 13.4.
2 d. Another addition of 11 (0.96 g, 2 mmol), DCC (453 mg,
MS (ESI): m/z 634 (M+H)+; HRMS calcd for C33H51N3O9Na: 2.2 mmol) and DMAP (24.4 mg, 0.2 mmol) was made. The
656.3523 (M+Na)+; Found: 656.3531.
mixture continued to stir for 2 d and was then filtered. The
filtration was concentrated, and the residue was subjected to
Ethyl 3-((4R)-4-((3R,5S,7R,9S,10S,12S,13R,14S,17R)-3,7,12-tri- silica gel chromatography (dichloromethane/methanol, 15:1)
hydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenan- to yield 12 as a white solid 200 mg (15%).
thren-17-yl)pentanamido)propanoate (10)
Thionyl chloride (20 mL) was added dropwise to anhydrous
ethanol (80 mL), and the temperature did not exceed 25 C. (d, 1H, J=3.5 Hz), 5.87 (d, 1H, J=7.6 Hz), 4.51 (m, 1H), 4.27 (m,
β-Alanine (9 g, 0.1 mol) was then added. After stirring at 50 oC 1H), 4.18 (m, 1H), 4.08 (m, 1H), 4.02 (m, 1H), 3.93 (brs, 1H),
for 3 h, β-Alanine dissolved. The mixture was stirred at rt 3.78 (m, 1H), 3.44 (t, 2H, J=6.9 Hz), 2.58 (t, 2H, J=6.3 Hz), 2.4–
overnight. The solvent was evaporated and ether was added 1.1 (m, 25H), 0.99 (d, 3H, J=6.4 Hz), 0.90 (s, 3H), 0.69 (s, 3H).
mp 174–176 oC.
1H-NMR (CD3OD, 300 MHz): δ 7.72 (d, 1H, J=7.4 Hz), 6.20
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to the residue. A white solid was formed, filtered and then
13C NMR (100 MHz, CD3OD) δ 177.5, 173.6, 168.0, 158.6,
dried (Na2SO4) to yield 16 g 9 (100%). Cholic acid (5.57 g, 13.6 145.0, 95.3, 89.2, 84.6, 79.0, 76.8, 74.5, 73.3, 69.5, 65.6, 55.3, 48.4,
mmol) and triethylamine (TEA, 1.92 mL, 15 mmol) were dis- 47.9, 43.6, 43.4, 41.5, 40.9, 37.3, 36.9, 36.8, 36.4, 36.3, 35.4, 34.5,
solved in dry DMF (45 mL). The mixture was cooled to -15 oC, 33.7, 31.6, 30.0, 29.2, 28.3, 24.7, 23.7, 18.2, 13.5.
and isobutyl chloroformate (1.78 mL, 17 mmol) was added.
MS (ESI): m/z 705 (M+H)+; HRMS calcd for C36H56N4O10Na:
After stirring for 5 min, 9 (2.3 g, 20 mmol) and TEA (3.84 mL, 727.3894 (M+Na)+; Found: 727.3913.
30 mmol) were combined with 10 mL DMF, which was added
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dropwise. The reaction mixture was stirred at -15 C for 1 h tert-butyl 3-(1-((3S,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetra-
and at rt overnight. The mixture was filtered, and the filtra- hydrofuran-2-yl)-2-oxo-1,2-dihydropyrimidin-4-ylamino)-3-oxopro-
tion was concentrated. The residue was dissolved in ethyl pylcarbamate (14)
acetate and washed with water 4 times (water/ethyl acetate, Boc-β-Ala-OH (945 mg, 5 mmol) and triethylamine (0.6 mL, 5
1:2). The organic layer was combined and washed with 0.5 mmol) were dissolved in dry DMF (30 mL). The mixture was
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mol/L NaOH, 0.5 mol/L HCl and brine; it was then dried and cooled to -15 C, and ethyl chloroformate (0.48 mL, 5 mmol)
concentrated to yield 10 as a white solid 5.67 g (87%).
was added. After stirring for 30 min, cytarabine (1.22 g, 5
1H-NMR (CD3OD, 300 MHz): δ 4.12 (m, 2H), 3.94 (brs, 1H), mmol) in 10 mL DMF was added dropwise to the mixture.
3.78 (brs, 1H), 3.4 (m, 3H), 2.5 (t, 2H, J=6.6 Hz), 2.4–1.2 (m, The reaction mixture was stirred at -15 oC for 30 min and then
24H), 1.24 (t, 3H, J=7.2 Hz), 1.0 (d, 3H, J=6.4 Hz), 0.9 (s, 3H), at rt overnight. The reaction mixture was filtered, and the
0.7 (s, 3H).
filtration was concentrated and subjected to silica gel chroma-
tography (dichloromethane/methanol, 20:1) to yield 14 as a
white solid (1.7 g, 82%).
MS (ESI): m/z 1015 (2M+H)+.
3-((4R)-4-((3R,5S,7R,9S,10S,12S,13R,14S,17R)-3,7,12-tri-
1H-NMR (CD3OD, 300 MHz): δ 8.24 (d, 1H, J=7.5 Hz), 7.42
hydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenan- (d, 1H, J=7.5 Hz), 6.19 (d, 1H, J=3.9 Hz), 4.25 (m, 1H), 4.08 (t,
thren-17-yl)pentanamido)propanoic acid (11)
1H, J=2.4 Hz), 4.01 (m, 1H), 3.81 (d, 2H, J=4.8 Hz), 3.36 (t, 2H,
Compound 10 (3.9 g, 7.7 mmol) was dissolved in ethanol (30 J=6.6 Hz), 2.62 (t, 2H, J=6.3 Hz), 1.41 (s, 9H).
mL) and added to a solution of 10% NaOH (30 mL). The reac-
tion mixture was stirred at rt overnight and then poured
MS (ESI): m/z 415 (M+H)+.
into ice water and acidified with 1 mol/L HCl, which was (4R)-N-(3-(1-((3S,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetra-
extracted with ethyl acetate 3 times. The organic layer was hydrofuran-2-yl)-2-oxo-1,2-dihydropyrimidin-4-ylamino)-3-oxopro-
combined and washed with brine, dried (Na2SO4) and concen- pyl)-4-((3R,5S,7R,9S,10S,12S,13R,14S,17R)-3,7,12-trihydroxy-
trated to yield 11 as a white solid 3.2 g (87%).
10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-
1H-NMR (CD3OD, 300 MHz): δ 3.95 (brs, 1H), 3.8 (brs, 1H), yl)pentanamide (16)
3.4 (t, 3H, J=7 Hz), 2.5 (t, 2H, J=6.8 Hz), 2.4–1.05 (m, 24H), 1.0 Compound 14 (700 mg, 1.7 mmol) was dissolved in saturated
(d, 3H, J=6.1 Hz), 0.9 (s, 3H), 0.7 (s, 3H).
HCl in ethanol (5 mL) and stirred at rt overnight. The
solvent was evaporated and methanol (10 mL) was added to
the residue then stirred for 1 h. The solid was filtered and
MS (ESI): m/z 959 (2M+H)+.
((2R,3S,4S)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-3,4-dihydroxy- washed with methanol. The white solid was dried, and the
tetrahydrofuran-2-yl)methyl- 3-((4R)-4-((3R,5S,7R,9S,10S,12S, crude product 15 (400 mg) was obtained, which was used in
Acta Pharmacologica Sinica