5060 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 16
Deng et al.
(d, 2 H, C6H4, J ) 4.0 Hz), 7.95 (d, 2 H, C6H4, J ) 4.0 Hz). HRMS
calcd for C15H19BrO3 326.0518, found 326.0524.
2 H, C6H4, J ) 4.0 Hz), 7.84 (d, 2 H, C6H4, J ) 4.0 Hz), 10.12 (s,
1 H, 3-NH), 10.80 (s, 1H, 7-NH). Anal. (C18H20N4O3 ·0.75CH3OH)
C, H, N.
Methyl 4-(8-Bromo-7-oxooctyl)benzoate (10c). Compound 10c
was synthesized as described for 10a: yield 85% as yellow crystals,
mp 47-48 °C, Rf ) 0.53 (hexane/EtOAc, 3:1). 1H NMR (CDCl3)
δ 1.30-1.39 (m, 4 H, 2 CH2), 1.60-1.71 (m, 4 H, 2 CH2),
2.58-2.69 (m, 4 H, 2 CH2), 3.87 (s, 2H, CH2Br), 3.90 (s, 3 H,
OCH3), 7.23 (d, 2 H, C6H4, J ) 4.0 Hz), 7.95 (d, 2 H, C6H4, J )
4.0 Hz). HRMS calcd for C16H21BrO3 340.0674, found 340.0683.
4-[6-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-
yl)hexyl]benzoic Acid (12c). Compound 12c was synthesized as
described for 12a: yield 98% as a brown powder, mp >276 °C
(dec), Rf ) 0.18 (CHCl3/MeOH, 5:1). 1H NMR (DMSO-d6) δ
1.24-1.35 (m, 4 H, 2 CH2), 1.48-1.64 (m, 4 H, 2 CH2), 2.49-2.66
(m, 4 H, 2 CH2), 5.84 (s, 1 H, CH), 5.97 (s, 2 H, 2-NH2), 7.29 (d,
2 H, C6H4, J ) 4.0 Hz), 7.84 (d, 2 H, C6H4, J ) 4.0 Hz), 10.13 (s,
1 H, 3-NH), 10.77 (s, 1H, 7-NH). Anal. (C19H22N4O3 ·1.4H2O) C,
H, N.
Methyl 4-[4-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]py-
rimidin-6-yl)butyl]benzoate (11a). To a suspension of 2,4-diamino-
6-hydroxypyrimidine (1.53 g, 12.2 mmol) in anhydrous DMF (40
mL) was added 10a (3.82 g, 12.2 mmol). The resulting mixture
was stirred under N2 at room temperature for 3 days. TLC showed
the disappearance of starting materials and the formation of one
major spot at Rf ) 0.28 (CHCl3/MeOH, 6:1). After evaporation of
solvent, CH3OH (20 mL) was added followed by silica gel (5 g).
Evaporation of the solvent afforded a plug, which was loaded onto
a silica gel column (3.5 cm × 15 cm) and eluted initially with
CHCl3 followed by 10% MeOH in CHCl3 and then 15% MeOH in
CHCl3. Fractions showing Rf ) 0.28 were pooled and evaporated,
and the resulting solid was recrystallized from MeOH to afford
1.53 g (37%) of 11a as yellow crystals: mp 240-241 °C (lit.23 mp
241.9-243.7 °C). This compound was identical in all respects to
that reported in the literature.23 1H NMR (DMSO-d6) δ 1.52-1.62
(m, 4 H, 2 CH2), 2.49-2.71 (m, 4 H, 2 CH2), 3.83 (s, 3 H, OCH3),
5.84 (s, 1 H, CH), 5.95 (s, 2 H, 2-NH2), 7.34 (d, 2 H, C6H4, J )
4.0 Hz), 7.87 (d, 2 H, C6H4, J ) 4.0 Hz) 10.12 (s, 1 H, 3-NH),
10.80 (s, 1H, 7-NH).
Diethyl N-{4-[4-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-
d]pyrimidin-6-yl)butyl]benzoyl}-L-glutamate (13). To a solution of
12a (290 mg, 0.89 mmol) in anhydrous DMF (40 mL) was added
6-chloro-2,4-dimethoxy-1,3,5-triazine (180 mg, 1.07 mmol) and
N-methylmorpholine (105 mg, 1.07 mmol). After the mixture was
stirred at room temperature for 2 h, N-methylmorpholine (105 mg,
1.07 mmol) and dimethyl L-glutamate hydrochloride (423 mg, 1.78
mmol) were added all at once. The mixture was stirred at room
temperature for 4 h. TLC showed the formation of one major spot
at Rf ) 0.55 (CHCl3/MeOH, 5:1). The reaction mixture was
evaporated to dryness under reduced pressure. The residue was
dissolved in a minimum amount of CHCl3/MeOH, 5:1, and
chromatographed on a silica gel column (2 cm × 15 cm) with 4%
MeOH in CHCl3 as the eluent. Fractions that showed the desired
single spot at Rf ) 0.55 were pooled and evaporated to dryness to
afford 13a, 307 mg, yield 68% as a yellow syrup, which was used
directly for the next step. 1H NMR (DMSO-d6) δ 1.08-1.28 (m, 6
H, 2 CH3), 1.52-1.68 (m, 4 H, 2 CH2), 1.88-2.15 (m, 2 H, CH2),
2.40-2.68 (m, 6 H, 3 CH2), 3.98-4.12 (m, 4 H, 2 CH2), 4.36-4.46
(m, 1 H, CH), 5.84 (s, 1 H, CH), 5.94 (s, 2 H, 2-NH2), 7.28 (d, 2
H, C6H4, J ) 4.0 Hz), 7.78 (d, 2 H, C6H4, J ) 4.0 Hz), 8.63 (d, 1
H, CONH, J ) 4.4 Hz), 10.11 (s, 1 H, 3-NH), 10.78 (s, 1H, 7-NH).
Diethyl N-{4-[5-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-
d]pyrimidin-6-yl)pentyl]benzoyl}-L-glutamate (13b). Compound
13b was synthesized as described for 13a: yield 88% as a yellow
syrup, Rf ) 0.57 (CHCl3/MeOH, 5:1). 1H NMR (DMSO-d6) δ
1.14-1.23 (m, 6 H, 2 CH3), 1.28-1.38 (m, 2 H, CH2), 1.55-1.67
(m, 4 H, 2 CH2), 1.90-2.20 (m, 2 H, CH2), 2.40-2.68 (m, 6 H, 3
CH2), 4.02-4.12 (m, 4 H, 2 CH2), 4.38-4.46 (m, 1 H, CH), 5.85
(s, 1 H, CH), 5.96 (s, 2 H, 2-NH2), 7.30 (d, 2 H, C6H4, J ) 4.0
Hz), 7.79 (d, 2 H, C6H4, J ) 4.0 Hz), 8.64 (d, 1 H, CONH, J )
4.4 Hz), 10.12 (s, 1 H, 3-NH), 10.80 (s, 1H, 7-NH). Anal.
(C27H35N5O6 ·0.75H2O) C, H, N.
Diethyl N-{4-[6-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-
d]pyrimidin-6-yl)hexyl]benzoyl}-L-glutamate (13c). Compound 13c
was synthesized as described for 13a: 77% yield as a yellow syrup,
Rf ) 0.60 (CHCl3/MeOH, 5:1). 1H NMR (DMSO-d6) δ 1.11-1.21
(m, 6 H, 2 CH3), 1.25-1.34 (m, 4 H, 2 CH2), 1.48-1.64 (m, 4 H,
2 CH2), 1.92-2.16 (m, 2 H, CH2), 2.39-2.46 (m, 2 H, CH2),
2.49-2.66 (m, 4 H, 2 CH2), 4.01-4.14 (m, 4 H, 2 CH2), 4.37-4.47
(m, 1 H, CH), 5.82 (s, 1 H, CH), 5.94 (s, 2 H, 2-NH2), 7.28 (d, 2
H, C6H4, J ) 4.0 Hz), 7.78 (d, 2 H, C6H4, J ) 4.0 Hz), 8.63 (d, 1
H, CONH, J ) 3.8 Hz), 10.10 (s, 1 H, 3-NH), 10.77 (s, 1H, 7-NH).
Anal. (C28H37N5O6 ·1.0H2O) C, H, N.
N-{4-[4-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimi-
din-6-yl)butyl]benzoyl}-L-glutamic Acid (3). To a solution of the
diester (13a) (580 mg, 1.14mmol) was added 1 N NaOH (15 mL),
and the mixture was stirred under N2 at room temperature for 1 h.
TLC showed the disappearance of the starting material (Rf ) 0.55)
and formation of one major spot at the origin (CHCl3/MeOH, 5:1).
The reaction mixture was evaporated to dryness under reduced
pressure. The residue was dissolved in water (10 mL), the resulting
solution was cooled in an ice bath, and the pH was adjusted to
3-4 with dropwise addition of 1 N HCl. The resulting suspension
was frozen in a dry ice/acetone bath, thawed in a refrigerator to
4-5 °C, and filtered. The residue was washed with a small amount
of cold water and ethyl acetate and dried in vacuo using P2O5 to
afford 380 mg (73%) 3 as a yellow powder: mp 172-173 °C (lit.23
mp 171-173 °C), Rf ) 0.05 (CHCl3/MeOH, 5:1). 1H NMR
Methyl 4-[5-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]py-
rimidin-6-yl)pentyl]benzoate (11b). Compound 11b was synthesized
as described for 11a: yield 35% as yellow crystals, mp 229-230
°C, Rf ) 0.31 (CHCl3/MeOH, 6:1). 1H NMR (DMSO-d6) δ
1.26-1.36 (m, 2 H, CH2), 1.52-1.66 (m, 4 H, 2 CH2), 2.48-2.68
(m, 4 H, 2 CH2), 3.82 (s, 3 H, OCH3), 5.84 (s, 1 H, CH), 5.95 (s,
2 H, 2-NH2), 7.33 (d, 2 H, C6H4, J ) 4.0 Hz), 7.86 (d, 2 H, C6H4,
J ) 4.0 Hz) 10.12 (s, 1 H, 3-NH), 10.79 (s, 1H, 7-NH). Anal.
(C19H22N4O3 ·0.2H2O) C, H, N.
Methyl 4-[6-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]py-
rimidin-6-yl)hexyl]benzoate (11c). Compound 11c was synthesized
as described for 11a: yield 35% as yellow crystals, mp 219-221
°C, Rf ) 0.35 (CHCl3/MeOH, 6:1). 1H NMR (DMSO-d6) δ
1.25-1.35 (m, 4 H, 2 CH2), 1.47-1.65 (m, 4 H, 2 CH2), 2.49-2.67
(m, 4 H, 2 CH2), 3.82 (s, 3 H, OCH3), 5.83 (s, 1 H, CH), 5.95 (s,
2 H, 2-NH2), 7.33 (d, 2 H, C6H4, J ) 4.0 Hz), 7.86 (d, 2 H, C6H4,
J ) 4.0 Hz) 10.11 (s, 1 H, 3-NH), 10.76 (s, 1H, 7-NH). Anal.
(C20H24 N4O3 ·0.67H2O) C, H, N.
4-[4-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-
yl)butyl]benzoic Acid (12a). To a suspension of 11a (178 mg, 0.5
mmol) in 10 mL of CH3OH was added 3 N NaOH (10 mL). The
resulting mixture was stirred under N2 at 40-50 °C for 24 h. TLC
indicated the disappearance of starting material and the formation
of one major spot at the origin. The resulting solution was passed
through Celite and washed with a minimum amount of CH3OH.
The combined filtrate was evaporated under reduced pressure to
dryness. To this residue was added distilled water (10 mL). The
solution was cooled in an ice bath, and the pH was adjusted to
3-4 using 3 N HCl. The resulting suspension was chilled in a dry
ice/acetone bath and thawed to 4 °C overnight in a refrigerator.
The precipitate was filtered, washed with cold water, and dried in
a desiccator under reduced pressure using P2O5 to afford 120 mg
(74%) of 12a as a brown powder: mp >262 °C (dec) (lit.23 mp
>266 °C), Rf ) 0.20 (CHCl3/MeOH, 5:1). This compound was
identical in all respects to that reported in the literature.23
4-[5-(2-Amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-
yl)pentyl]benzoic Acid (12b). Compound 12b was synthesized as
described for 12a: yield 90% as a brown powder, mp >271 °C
(dec), Rf ) 0.18 (CHCl3/MeOH, 5:1). 1H NMR (DMSO-d6) δ
1.26-1.36 (m, 2 H, CH2), 1.55-1.67 (m, 4 H, 2 CH2), 2.48-2.69
(m, 4 H, 2 CH2), 5.85 (s, 1 H, CH), 5.96 (s, 2 H, 2-NH2), 7.31 (d,