H. Cheng et al. / Bioorg. Med. Chem. 13 (2005) 3593–3599
3597
1022 cmÀ1; MALDI-FTHRMS (DHB) m/z 303.1320
MeOH (1.58 mL) was treated with guanidine hydrochlo-
ride (0.143 g, 1.5 mmol, 1.2 equiv) at ambient tempera-
ture. After the reaction mixture was stirred at ambient
temperature for 30 min, 9 (0.57 g, 1.25 mmol) in freshly
distilled DMF (1.58 mL) was added. The reaction mix-
ture was warmed to 75 ꢁC and stirred for 16 h. The reac-
tion mixture was cooled and quenched by addition of
acetic acid (79.7 lL, 1.5 mmol, 1.1 equiv). Column chro-
matography (SiO2, 8–25% MeOH–CHCl3) afforded 10
(0.32 g, 58%) as a light yellow solid: 1H NMR (CD3OD,
400 MHz) d 7.67 (d, J = 8.2 Hz, 2H), 7.09 (d, J = 8.2 Hz,
2H), 3.63 (s, 3H), 3.56–3.52 (m, 1H), 2.75 and 2.66 (AB
in ABX system, J = 7.0, 13.8 Hz, 2H), 2.12 (s, 6H), 2.10–
1.97 (m, 2H), 1.48–1.37 (m, 2H), 1.24–1.16 (m, 2H); IR
(neat) mmax 3330, 3180, 2941, 1709, 1604, 1492, 1440,
(M+H+, C14H17F3N2O2 requires 303.1315).
7.3. Methyl 4-[5-chloro-2-(2,2,2-trifluoro-1-dimethylhydr-
azonoethyl)pentyl]benzoate (8)
A solution of sodium bis(trimethylsilyl)amide (1.0 M in
THF, 1.88 mL, 1.88 mmol, 1.05 equiv) was treated with
a solution of 7 (0.54 g, 1.79 mmol) in freshly distilled
THF (8.1 mL) at À78 ꢁC, and 1-chloro-3-iodopropane
(1.92 mL, 17.9 mmol, 10 equiv) was added quickly to
the reaction mixture. The cooling bath was removed,
and the reaction mixture was stirred at 25 ꢁC for 1 h be-
fore being quenched by addition of saturated aqueous
NH4Cl (100 mL). The resulting aqueous solution was
extracted with EtOAc (5 · 30 mL). The combined or-
ganic layers were washed with saturated aqueous NaCl
(60 mL), dried (Na2SO4), filtered, and concentrated.
Column chromatography (SiO2, 7–25% EtOAc–hex-
anes) afforded 8 mixed with 7 as a yellow oil, which
was used directly in the next reaction. For 8: MALDI-
1328, 1275, 1178, 1126, 1014, 753 cmÀ1
; MAL-
DIÀFTHRMS (DHB) m/z 469.2155 (M+H+,
C21H27F3N6O3 requires 469.2169).
7.6. 4-[5-(2,4-Diamino-6-oxo-1,6-dihydropyrimidin-5-yl)-
2-(2,2,2-trifluoroacetyl)pentyl]benzoic acid (11)
FTHRMS
C17H22ClF3N2O2 requires 379.1395).
(DHB)
m/z
379.1398
(M+H+,
A solution of 10 (30 mg, 64.0 lmol) in MeOH (0.87 mL)
was treated with LiOH monohydrate (8.1 mg,
0.192 mmol, 3 equiv) in water (0.30 mL), and the reaction
solution was stirred at ambient temperature for 24 h. The
reaction solution was diluted with water (10 mL), washed
with EtOAc (2 · 10 mL), acidified to pH 1 by addition of
1 N aqueous HCl, stirred for 30 min, and concentrated.
Removal of traces of water by treatment of the residue
with benzene (3 · 5 mL) provided 11 (26.4 mg, 100%) as
a white solid: 1H NMR (D2O, 400 MHz) d 7.68 (d,
J = 8.2 Hz, 2H), 7.13 (d, J = 8.2 Hz, 2H), 2.98–2.93 (m,
1H), 2.37 (t, J = 12.3 Hz, 1H), 2.04–2.00 (m, 1H), 1.90–
1.84 (m, 2H), 1.36–1.26 (m, 2H), 1.08–1.02 (m, 1H),
0.87–0.79 (m, 1H); ESITOF-HRMS m/z 413.1436
(M+H+, C18H19F3N4O4 requires 413.1431).
7.4. Methyl 4-[6-cyano-6-ethoxycarbonyl-2-(2,2,2-triflu-
oro-1-dimethylhydrazonoethyl)hexyl]benzoate (9)
A suspension of sodium hydride (60% dispersion,
85.9 mg, 2.15 mmol, 1.2 equiv) in freshly distilled
DMF (1.69 mL) was treated with ethyl cyanoacetate
(0.248 mL, 2.33 mmol, 1.3 equiv) at 0 ꢁC. The reaction
mixture was stirred at 0 ꢁC for 30 min, forming the so-
dium salt as a clear solution. A solution of 8 (8,
0.68 g, 1.79 mmol, mixed with 7) in freshly distilled
DMF (1.69 mL) was added at 0 ꢁC. The reaction mix-
ture was allowed to warm to 50 ꢁC, and stirred for 9 h
before being quenched by addition of saturated aqueous
NH4Cl (50 mL). The resulting aqueous solution was ex-
tracted with EtOAc (5 · 15 mL). The combined organic
layers were washed with saturated aqueous NaCl
(50 mL), dried (Na2SO4), filtered, and concentrated.
Column chromatography (SiO2, 8–33% EtOAc–hex-
anes) afforded 9 (0.57 g, 19% from 7) as a yellow oil:
1H NMR (CDCl3, 400 MHz) d 7.97 (d, J = 7.9 Hz,
2H), 7.27 (d, J = 7.9 Hz, 2H), 4.24 (q, J = 7.0 Hz, 2H),
3.91 (s, 3H), 3.82–3.74 (m, 1H), 3.46–3.40 (m, 1H),
2.98–2.90 (m, 2H), 2.43 (s, 3H), 2.42 (s, 3H), 1.97–1.87
(m, 1H), 1.75–1.69 (m, 1H), 1.68–1.55 (m, 3H), 1.49–
1.43 (m, 1H), 1.30 (t, J = 7.0 Hz, 3H); 13C NMR
(CDCl3, 100 MHz) d 166.8, 165.8, 163.0, 144.2, 129.8,
129.0, 128.6, 121.1 (q, J = 278 Hz), 116.3, 113.1, 62.9,
62.8, 52.0, 47.5, 40.2, 38.1, 37.3, 30.4, 29.5, 25.1, 24.9,
24.7, 13.9; IR (neat) mmax 2941, 2868, 1745, 1715, 1678,
1611, 1434, 1282, 1178, 1105, 1014 cmÀ1; MALDI-
FTHRMS (DHB) m/z 456.2107 (M+H+, C22H28F3N3O4
requires 456.2105).
7.7. Di-tert-butyl N-{4-[5-(2,4-diamino-6-oxo-1,6-dihy-
dropyrimidin-5-yl)-2-(2,2,2-trifluoroacetyl)pentyl]ben-
zoyl}-L-glutamate (12)
A solution of 11 (26.4 mg, 64.0 lmol), di-tert-butyl L-
glutamate hydrochloride (28.4 mg, 0.096 mmol,
1.5 equiv) and NaHCO3 (16.1 mg, 0.19 mmol, 3 equiv)
in DMF (0.62 mL) was treated with EDCI (36.8 mg,
0.19 mmol, 3 equiv) at 0 ꢁC. The reaction mixture was
stirred at ambient temperature overnight before the
addition of CHCl3 (10 mL). The resulting solution was
washed with saturated aqueous NaHCO3 (2 · 10 mL),
dried (Na2SO4), filtered, and concentrated. PCTLC
(SiO2, 1 mm plate, 14% MeOH–CHCl3) afforded 12
(18.4 mg, 44%) as a light yellow solid: 1H NMR
(CD3OD, 400 MHz) d 7.50 (d, J = 7.6 Hz, 1H), 7.44
(d, J = 7.6 Hz, 1H), 7.02 (d, J = 7.6 Hz, 2H), 4.28–4.22
(m, 1H), 3.41–3.38 (m, 0.5H), 3.19–3.15 (m, 0.5H),
2.94–2.88 (m, 0.5H), 2.81–2.75 (m, 0.5H), 2.68–2.61
(m, 0.5H), 2.50–2.48 (m, 0.5H), 2.17–2.01 (m, 2H),
1.99–1.78 (m, 2H), 1.48–1.36 (m, 2H), 1.24 (s, 9H),
1.19 (s, 9H), 1.08–1.04 (m, 2H), 0.72–0.60 (m, 2H); IR
(neat) mmax 3340, 3215, 2921, 1724, 1616, 1446, 1355,
1151 cmÀ1; ESITOF-HRMS m/z 654.3109 (M+H+,
C31H42F3N5O7 requires 654.3109).
7.5. Methyl 4-[5-(2,4-diamino-6-oxo-1,6-dihydropyrim-
idin-5-yl)-2-(2,2,2-trifluoro-1-dimethylhydrazono-
ethyl)pentyl]benzoate (10)
A solution of sodium methoxide prepared by dissolving
sodium (60.4 mg, 2.63 mmol, 2.1 equiv) in anhydrous