2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as potential inhibitors of thymidylate synthase [1]

Article abstract of DOI:10.1002/jhet.5570390433

Classical, antifolate inhibitors of thymidylate synthase often suffer from a number of potential disadvantages when used as antitumor agents. These include impaired uptake due to an alteration of the active transport system required for cellular uptake, a

Full text of DOI:10.1002/jhet.5570390433

Jul-Aug 2002
2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as Potential
Inhibitors of Thymidylate Synthase [1]
833
Aleem Gangjee* [a], Jianming Yu [a] and Roy L. Kisliuk [b]
[a] Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences,
Duquesne University, Pittsburgh, PA 15282
[b] Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111
Received January 14, 2002
Classical, antifolate inhibitors of thymidylate synthase often suffer from a number of potential disadvan-
tages when used as antitumor agents. These include impaired uptake due to an alteration of the active trans-
port system required for cellular uptake, as well as the formation of long acting, non-effluxing polygluta-
mates via folypolyglutamate synthetase, which are responsible for toxicity to normal cells. To overcome
some of the disadvantages of classical thymidylate synthase inhibitors, there has been considerable interest
in the synthesis and evaluation of nonclassical inhibitors, which could enter cells via passive diffusion and
are not substrates for folypolyglutamate synthetase. A series of eight nonclassical 6-substituted 2-amino-4-
oxo-pyrrolo[2,3-d]pyrimidines 2a-2h were designed as potential inhibitors of thymidylate synthase. The
synthesis of the target compounds 2a-2h was achieved via regioselective iodination at the 6-position of 5,
palladium-catalyzed coupling with the appropriate phenylacetylenes, reduction of the C8-C9 triple bond fol-
lowed by saponification. Preliminary biological results indicated that none of the target compounds showed
inhibitory activities against thymidylate synthase from Escherichia coli, Lactobacillus casei, rat or human
thymidylate synthase at the concentrations tested. None of the target compounds showed inhibitory activity
-5
against dihydrofolate reductase from Escherichia coli, Lactobacillus casei, rat or human at 3.0 x 10 M.
However, 50% inhibition of dihydrofolate reductase from Pneumocystis carinii and from Toxoplasma gondii
-5
was achieved with compound 2d and with compound 2g at 3.0 x 10 M.
J. Heterocyclic Chem., 39, 833 (2002).
Thymidylate synthase catalyzes a two-step conversion of
deoxyuridylate (dUMP) to deoxythymidylate (dTMP) utiliz-
ing 5,10-methylenetetrahydrofolate (5,10-CH -FH ) as the
promising clinical activity [8-10]. However, its develop-
ment was abandoned because of sporadic and unpredictable
nephrotoxicity and myelotoxocity. A successor of CB3717,
ZD1694, a clinically used antitumor agent in Europe
2
4
cofactor [2]. This enzyme is unique among those which uti-
lize tetrahydrofolate cofactors in that 5,10-methylenetetra-
hydrofolate serves the dual function of both a one-carbon
donor and reductant, by concomitant transfer of its methyl-
ene group and the 6-hydrogen atom to form the methyl group
at the 5-position of deoxythymidylate. In the process, the
cofactor is oxidized to 7,8-dihydrofolate. Tetrahydrofolate is
regenerated from 7,8-dihydrofolate by dihydrofolate reduc-
tase in a NADPH-dependent reaction. The conversion of 7,8-
dihydrofolate to deoxythymidylate catalyzed by thymidylate
synthase represents the sole de novo source of
deoxythymidylate, and hence thymidylate synthase plays a
pivotal role in DNA biosynthesis and cell replication. In the
absence of an exogenous supply of thymidine, inhibition of
thymidylate synthase leads to "thymineless cell death" [3,4].
Thus inhibition of thymidylate synthase is an attractive target
for the development of antitumor agents.
TM
(Tomudex ), [11] has been shown to be non-nephrotoxic
[12] and is currently used for the treatment of metastatic col-
orectal cancer. LY231514, also a thymidylate synthase
inhibitor, has entered clinical trials and is currently in Phase
III as an antitumor agent.
Thymidylate synthase inhibitors that are clinically used as
antitumor agents include 5-fluorouracil,[5] a deoxyuridylate
substrate analogue which is rapidly metabolized within the
cell to a number of fluorinated nucleotides. One of these
metabolites, 5-fluorodeoxyuridine monophosphate
(FdUMP) is a potent inhibitor of thymidylate synthase [6].
5-Fluorouracil also has other biochemical sites of action
which result from nucleotide metabolites of 5-fluorouracil
being incorporated into RNA [7]. Among the folate-based
thymidylate synthase inhibitors that were synthesized and
entered clinical trials the first was CB3717, which displayed

834
A. Gangjee, J. Yu and R. L. Kisliuk
Vol. 39
All of the folate-based classical antifolates contain a
inhibitors, independent of the folate transport system(s) [23-
27]. Nolatrexate dihydrochloride (Thymitaq , AG337), a
lipophilic inhibitor of thymidylate synthase, was designed
using X-ray crystallographic structures and molecular mod-
TM
terminal glutamate moiety. A major drawback of these
classical antifolates is that they enter cells via the reduced
folate uptake system, which when impaired can lead to
drug resistance [13-16]. In addition the antitumor activi-
ties of classical thymidylate synthase inhibitors are, in
part, determined by their ability to function as substrates
of the enzyme folypolyglutamate synthetase (FPGS)
[17,18]. Although polyglutamylation is necessary for the
cytotoxicity to tumor cells, it has also been implicated as
a possible cause of detrimental side effects, such as renal
and hepatic toxicities in the host. These toxicities arise
because of their polyionic nature which allows retention
in normal cells [19]. The problem of tumor resistance of
classical antifolates which is, in part, a result of low or
defective folypolyglutamate synthetase activity is also a
potential limitation of these classical antifolates that
depend on polyglutamylation for their antitumor effects
[20-22].
eling, and is the first potent lipophilic thymidylate synthase
-7
inhibitor (human thymidylate synthase IC = 3.4 x 10 M)
50
currently in clinical trials [23].
Molecular modeling of the 6-5 ring-fused analogues
superimposed on 6-6 ring-fused analogues indicated that
the 5-substituents are closely positioned in both ring sys-
tems and the 6-substituent of the 6-5 system lies in
between the 6- and 7- substituent of the 6-6 system
(Figure 1) [28]. Examples of potent thymidylate synthase
inhibitors in the 5-substituted 6-6 system, include AG337
[23] and in 5-substituted 6-5 systems, LY231514 [29]. The
To circumvent these disadvantages associated with classi-
cal antifolates, there has recently been considerable interest
in lipophilic, nonclassical antifolates as thymidylate synthase
inhibitors which lack the L-glutamic acid side chain found in
classical antifolates thus allowing for passive uptake of these

Jul-Aug 2002
2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as Potential Inhibitors
835
chloroacetaldehyde in sodium acetate-water solution. The
cyclocondensation was regiospecific and afforded 4 in
82% yield. Due to the poor solubility of 4 in organic sol-
vent, the 2-amino group was pivaloyated using pivaloyl
chloride in the presence of pyridine, which resulted in the
formation of 5. Chloromercuration of 5 was carried out by
adding mercuric acetate in glacial acetic acid, followed by
the addition of saturated sodium chloride solution. The
precipitated white solid was filtered and washed thor-
oughly with water to give a 10:1 mixture of the
6-chloromercuri derivative 6a and 5-chloromercuri deriva-
tive 6b in 50% overall yield. The resulting mixture of
chloromercuri derivatives was treated with iodine in
dichloromethane to afford the corresponding iodo deriva-
tives 7a and 7b from which the desired 6-iodo compound
7a was readily separated by column chromatography in
64% yield.
6-6 fused systems that have been found to be potent
inhibitors of thymidylate synthase are usually 6-substi-
tuted [30]. A recent report by Gangjee et al.[27] showed
that a series of 5-substituted nonclassical analogues 1 were
inactive against thymidylate synthase and were also poor
inhibitors of Pneumocystis carinii dihydrofolate reductase
and rat liver dihydrofolate reductase. It was therefore of
interest to synthesize 6-substituted analogues in the 6-5
fused system to mimic the 6-substituted 6-6 fused system
as inhibitors of thymidylate synthase. With these objec-
tives in mind, we synthesized analogues 2a-2h.
The next step was the Sonogashira coupling reaction
[33] of 7a with an appropriately substituted phenylacety-
lene. Of the desired phenylacetylenes necessary for the
Sonogashira reaction, only phenylacetylene 8a, p-methyl-
phenylacetylene 8b, p-methoxyphenylacetylene 8c,
o-chlorophenylacetylene 8d and 2-ethynylpyridine 8e
were commercially available. 1-Ethynylnaphthalene 8f,
2-ethynylnaphthalene 8g and (2,5-dimethyoxyphenyl)-
ethyne 8h were synthesized. Compounds 8f and 8g were
synthesized using the method reported by Guzman et al.
[34] using a palladium charcoal-catalyzed coupling reac-
tion which was the most convenient and economical for
large-scale synthesis of the various available methods.
Thus 2-bromonaphthalene 11 was coupled with trimethysi-
lylacetylene in the presence of palladium charcoal, triph-
enylphosphine and copper(I) iodide to afford 12 in 63%
yield (Scheme 2). Intermediate 12 was readily desilylated
by stirring with a 1 M solution of a tetra-n-butylammo-
nium fluoride to afford the terminal acetylene 8h in almost
quantitative yield. Compound 8f was also prepared in a
similar method. An alternate method [35] from commer-
cially available (2,5-dimethoxyphenyl)acetone 13 which
reacted with phosphorous pentachloride followed by treat-
The syntheses of analogues of 2a-2h were envisioned
through the formation of the key intermediate 7a which
was initially reported by Taylor et al. [31] (Scheme 1).
Using a method similar to that reported by Secrist and Liu,
[32] intermediate 4 was synthesized from commercially
available 2,4-diamino-6-hydroxypyrimidine 3 and

836
A. Gangjee, J. Yu and R. L. Kisliuk
Vol. 39
EXPERIMENTAL
ment with potassium hydroxide afforded 8h in 65% yield
(over two steps).
All evaporations were carried out in vacuo with a rotary evap-
orator. Analytical samples were dried in vacuo (0.2 mmHg) in an
With both 7a and 8a-8h in hand, intermediates 9a-9h
were synthesized via palladium-catalyzed coupling reac-
tions in the presence of tetrakis(triphenylphosphine)-
palladium(0), copper(I) iodide and triethylamine. The
desired products 9a-9h were separated and isolated by
carefully increasing the polarity of the mobile phase
during flash chromatography. Reduction of the C8-C9
triple bonds of 9a-9h were accomplished by hydrogena-
tion at 50 psi using 5% palladium on charcoal as catalyst,
along with 3-4 drops of concentrated ammonium hydrox-
ide to prevent reduction of the pyrrole ring [36]. Finally,
the depivaloylation of the 2-amino group of 10a-10h were
accomplished with 1 N sodium hydroxide to afford 2a-2h
in yields ranging from 44-80%.
Abderhalden drying apparatus over P O and refluxing ethanol.
2
5
Thin layer chromatography (TLC) was performed on silica gel
plates with fluorescent indicator. Spots were visualized by UV
light (254 and 365 nm). All analytical samples were homoge-
neous on TLC in at least two different solvent systems.
Purification by column and flash chromatography was carried out
using Merck silica gel 60 (200-400 mesh). The amount (weight)
of silica gel for column chromatography was in the range of 50-
100 times the amount (weight) of the crude compounds being
separated. Columns were dry packed unless specified otherwise.
Solvent systems are reported as volume percent mixture. Melting
points were determined on a Mel-Temp II melting point appara-
1
tus with a digital thermometer and are uncorrected. H nmr spec-
tra were recorded on a Bruker WH-300 (300 MHz) nmr spec-
trometer. The chemical shift (δ) values are reported as parts per
million (ppm) relative to tetramethylsilane as internal standard;
s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, bs =
Compounds 2a-2h were evaluated as inhibitors against
thymidylate synthase from Escherichia coli, Lactobacillus
casei, rat and human [37]. None of the target compounds
inhibited any of the thymidylate synthase at the concentra-
broad singlet, exch = protons exchangeable by addition of D O.
2
Elemental analyses were performed by Atlantic Microlab, Inc.,
Norcross, GA. Elemental compositions were within ± 0.4% of
the calculated values. Fractional moles of water or organic sol-
vents frequently found in some analytical samples of antifolates
could not be removed despite 24 hours of drying in vacuo and
-5
tions tested (>1.0 x 10 M). These results along with
observations reported for analogues of general structure 1
suggest that nonclassical analogues with a two-atom side
chain substituent at the 5- or 6-position of 2-amino-4-oxo-
pyrrolo[2,3-d]pyrimidine systems are not conducive to
thymidylate synthase inhibitory activity. However, 50%
inhibition of dihydrofolate reductase from Pneumocystis
carinii and from Toxoplasma gondii was achieved with 2d
and with 2g as well as with Escherichia coli (2c) and with
Toxoplasma gondii (2a) (Table 1). None of the target com-
1
were confirmed, where possible, by their presence in the H nmr
spectrum. All solvents and chemicals were purchased from
Aldrich Chemical Co. and Fisher Scientific and were used as
received except anhydrous solvents, which were freshly dried in
the laboratory.
2-(Naphthyl)trimethylsilylacetylene (12).
A mixture of 2-bromonaphthalene 11 (2.07 g, 10.0 mmol),
trimethylsilylacetylene (1.03 g, 10.5 mmol), 10% palladium on
charcoal (0.43 g, 0.4 mmol), triphenylphosphine (0.42 g, 1.6
mmol), copper iodide (0.08 g, 1.6 mmol) and triethylamine (25
pounds reached the IC level with human dihydrofolate
50
reductase (Table 1).
Table 1
Inhibition of Dihydrofolate Reductases from Escherichia coli, Pneumocystis carinii, Toxoplasma gondii and Human by Compounds 2a-2h.
IC
M
50
Compound
E. coli [a]
P. carinii [b]
T. gondii [c]
Human [d]
-5
-5
-5
-5
2a
2b
2c
2d
2e
2f
> 3.9 x 10 (0) [e]
> 1.9 x 10 (20)
3.9 x 10
> 3.9 x 10 (0)
-5
-5
-5
-5
> 3.7 x 10 (0)
> 1.8 x 10 (24)
> 3.7 x 10 (23)
> 3.7 x 10 (0)
-5
-5
-5
-5
3.7 x 10
> 1.8 x 10 (16)
> 3.7 x 10 (0)
> 3.7 x 10 (0)
-5
-5
-5
-5
> 3.4 x 10 (0)
2.0 x 10
3.4 x 10
> 3.4 x 10 (0)
-5
-5
-5
-5
> 3.8 x 10 (0)
> 1.9 x 10 (17)
> 3.8 x 10 (0)
> 3.8 x 10 (20)
-5
-5
-5
-5
> 3.3 x 10 (0)
> 1.7 x 10 (17)
> 3.3 x 10 (26)
> 3.3 x 10 (16)
-5
-5
-5
-5
2g
2h
> 3.3 x 10 (0)
> 1.7 x 10
3.3 x 10
> 3.3 x 10 (31)
-5
-5
-5
-5
> 3.0 x 10 (0)
> 1.5 x 10 (0)
> 3.0 x 10 (21)
> 3.0 x 10 (19)
-8
-5
-6
-4
Trimethoprim
Methotrexate
Trimetrexate
2.0 x 10
6.0 x 10
7.0 x 10
1.5 x 10
3.4 x 10
2.2 x 10
5.1 x 10
3.4 x 10
2.2 x 10
1.8 x 10
-9
-9
-8
-8
1.1 x 10
-9
-8
-9
-8
1.0 x 10
[a] Kindly provided by Dr. R. L. Blakley, St. Jude Children’s Hospital, Memphis, TN. [b] Kindly provided by Dr. D. Borhani, Southern Research
Institute, Birmingham, AL. [c] Kindly provided by Dr. D. V. Santi, University of California, San Francisco, CA. [d] Kindly provided by Dr. J. H.
Freisheim, Medical College of Ohio, Toledo, OH. [e] Numbers in parenthese indicate the % inhibition at the given concentration.

Jul-Aug 2002
2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as Potential Inhibitors
837
mL) in dry acetonitrile (15 mL) were heated at reflux under nitro-
gen for 24 hours. After cooling, the reaction mixture was filtered
through a celite pad and the solid washed with methylene chlo-
ride. Silica gel (10 g) was added to the filtrate, and the solvent
evaporated to afford a plug. The silica gel plug obtained was
loaded onto a silica gel column and eluted with hexanes followed
(0.01 g, 0.07 mmol), tetrakis(triphenyl phosphine)palladium (0)
(0.04 g, 0.03 mmol) and triethylamine (0.5 mL) afforded 0.05 g
(45%) of 9a as a white solid: mp >310 °C (dec); H nmr (DMSO-
1
d ): δ 1.25 (s, 9 H, C(CH ) ), 6.79 (s, 1 H, 5-H), 7.55 (m, 5 H,
6
3 3
C H ), 10.99 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.96 (s, 1 H, 2-
6
5
NHPiv or 3-NH, exch), 12.25 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O •0.3H O: C, 67.16; H, 5.52; N,
by crystallization from hexanes to afford 1.40 g (63%) of 12 as a
H
19 18
4
2
2
1
pale yellow solid: H nmr (CDCl ): δ 0.29 (s, 9 H, Si(CH ) ),
16.49. Found: C, 67.23; H, 5.49; N, 16.40.
3
3 3
7.49 (m, 3 H, C H ), 7.77 (m, 3 H, C H ), 7.99 (s, 1 H, C H ).
10
7
10
7
10 7
2-Pivaloylamino-4-oxo-6-[(p-methylphenyl)ethynyl]pyrrolo-
[2,3-d]pyrimidine (9b).
2-Ethynylnaphthalene (8g).
To a solution of 12 (2.2 g, 10.0 mmol) in THF (15 mL) was
added a 1 M solution of tetrabutylammonium fluoride in THF (3
mL, 3.0 mmol), and the solution was stirred under nitrogen at room
temperature for 2 hours. Silica gel (10 g) was added, and the sol-
vent evaporated to afford a plug which was loaded onto a silica gel
column and eluted with hexanes. Fractions containing the product
(TLC) were pooled and the solvent evaporated to afford 1.2 g
Using the general procedure described above, 7a (0.12 g, 0.33
mmol), p-methylphenylacetylene 8b (0.17 g, 1.5 mmol), cop-
per(I) iodide (0.04 g, 0.20 mmol), tetrakis(triphenyl
phosphine)palladium (0) (0.01 g, 0.07 mmol) and triethylamine
(0.5 mL) afforded 0.06 g (52%) of 9b as a white solid: mp >250
1
°C (dec); H nmr (DMSO-d ): δ 1.24 (s, 9 H, C(CH ) ), 2.34 (s,
6
3 3
3 H, 4'-CH ), 6.76 (s, 1 H, 5-H), 7.24 (d, 2 H, J = 8.0 Hz, C H ),
3
6 4
(81%) of 8f as a white solid: mp 39-40.5 °C (lit.,[34] no mp
7.44 (d, 2 H, J = 8.0 Hz, C H ), 10.97 (s, 1 H, 2-NHPiv or 3-NH,
exch), 11.95 (s, 1 H, 2-NHPiv or 3-NH, exch), 12.20 (bs, 1 H, 7-
6 4
1
reported); H nmr (DMSO-d ): δ 4.29 (s, 1 H, CH), 7.51-7.57 (m,
6
3 H, C H ), 7.91-7.94 (m, 3 H, C H ), 8.11 (s, 1 H, C H ).
NH, exch).
10
7
10
7
10 7
Anal. Calcd. For C
Found: C, 68.73; H, 5.63; N, 15.79.
H N O : C, 68.95; H, 5.79; N, 16.08.
20 20 4 2
(2,5-Dimethoxyphenyl)ethyne (8h).
A solution of 13 (6.25 g, 35.0 mmol) in dry benzene (5 mL) was
added dropwise with stirring to phosphorous pentachloride (3.98 g,
18.5 mmol) in dry benzene (15 mL) and the initial exothermic
reaction was allowed to subside. The mixture was then heated to
reflux for 5 hours to complete the reaction. The reaction mixture
was cooled and poured into water (40 mL). The organic material
was extracted into ether and the ether extracts were thoroughly
2-Pivaloylamino-4-oxo-6-[(p-methoxyphenyl)ethynyl]pyrrolo-
[2,3-d]pyrimidine (9c).
Using the general procedure described above, 7a (0.36 g, 1.0
mmol), p-methoxyphenylacetylene 8c (0.26 g, 2 mmol), cop-
per(I) iodide (0.04 g, 0.10 mmol), tetrakis(triphenyl phosphine)-
palladium (0) (0.12 g, 0.10 mmol) and triethylamine (0.5 mL)
1
washed with brine, separated and dried over MgSO . Evaporation
afforded 0.05 g (17%) of 9c as a gray solid: mp >300 °C (dec); H
4
and chromatography with 1:4 methylene chloride/hexanes on silica
gel afforded 5.60 g (80%) of 14 (1-chloro-1-(2,5-dimethoxy-
phenyl)ethane) which was used without further purification. To 14
(5.60 g, 28.2 mmol) was added a solution of potassium hydroxide
(2.30 g, 39.0 mmol) in ethanol (25 mL) and the resulting solution
was refluxed for 48 hours and then cooled. After dilution with
water (40 mL), the product was extracted into ether and the ether
nmr (DMSO-d ): δ 1.24 (s, 9 H, C(CH ) ), 3.79 (s, 3 H, 4'-
6 3 3
OCH ), 6.73 (s, 1 H, 5-H), 7.00 (d, 2 H, J = 8.4 Hz, C H ), 7.49
3
6 4
(d, 2 H, J = 8.4 Hz, C H ), 10.95 (s, 1 H, 2-NHPiv or 3-NH,
6
4
exch), 11.95 (s, 1 H, 2-NHPiv or 3-NH, exch), 12.17 (bs, 1 H, 7-
NH, exch).
Anal. Calcd. For C
H N O •0.5H O: C, 64.33; H, 5.67; N,
20 20 4 2 2
15.00. Found: C, 64.42; H, 5.56; N, 14.64.
extracts dried over MgSO . Silica gel (10 g) was added to the
4
2-Pivaloylamino-4-oxo-6-[(2'-chlorophenyl)ethynyl]pyrrolo[2,3-
d]pyrimidine (9d).
organic solvent, and the solvent evaporated to afford a plug, which
was loaded onto a silica gel column and eluted with 1:4 methylene
chloride/hexanes. Fractions containing the product (TLC) were
pooled and the solvent evaporated to afford 3.28 g (81%) of 8h as
Using the general procedure described above, 7a (0.12 g, 0.33
mmol), o-chlorophenylacetylene 8d (0.07 g, 0.50 mmol), cop-
per(I) iodide (0.01 g, 0.03 mmol), tetrakis(triphenyl
phosphine)palladium (0) (0.02 g, 0.02 mmol) and triethylamine
1
a brown solid: mp 38-40 °C (lit., [35] mp 39-40 °C); H nmr
(CDCl ): δ 3.30 (s, 1 H, CH), 3.78 (s, 3 H, OCH ), 3.86 (s, 3 H,
3
3
(0.5 mL) afforded 0.12 g (93%) of 9d as a pale yellow solid: mp
OCH ), 6.78-7.02 (m, 3 H, C H ).
3
6 3
1
>250 °C (dec); H nmr (DMSO-d ): δ 1.24 (s, 9 H, C(CH ) ),
6
3 3
General Procedure for the Synthesis of Compounds 9a-9h.
6.84 (s, 1 H, 5-H), 7.40-7.68 (m, 4 H, C H ), 10.97 (s, 1 H, 2-
6
4
To a 50-mL round-bottom flask covered with aluminum foil
were added 7a, the appropriate (substituted)phenylacetylene 8a-
8h, copper(I) iodide and tetrakis(triphenyl phosphine)palladium
(0) dissolved in anhydrous DMF, followed by the addition of tri-
ethylamine. The dark brown solution was stirred at room temper-
ature under nitrogen for 3 days. The solvents were removed in
vacuo and the crude residue was flash chromatographed on silica
NHPiv or 3-NH, exch), 11.97 (s, 1 H, 2-NHPiv or 3-NH, exch),
12.29 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C
H N O Cl: C, 61.57; H, 4.71; N, 15.12;
19 17 4 2
Cl: 9.57. Found: C, 61.41; H, 4.86; N, 15.35, Cl: 9.53.
2-Pivaloylamino-4-oxo-6-[(2'-pyridin)ethynyl]pyrrolo[2,3-d]-
pyrimidine (9e).
Using the general procedure described above, 7a (0.36 g, 1.0
mmol), 2-ethynylpyridine 8e (0.16 g, 1.5 mmol), copper(I) iodide
(0.04 g, 0.20 mmol), tetrakis(triphenyl phosphine)palladium (0)
(0.12 g, 0.10 mmol) and triethylamine (0.5 mL) afforded 0.17 g
gel and eluted with 1.5% MeOH in CHCl to afford the product.
3
2-Pivaloylamino-4-oxo-6-phenylethynylpyrrolo[2,3-d]pyrimi-
dine (9a).
1
Using the general procedure described above, 7a (0.12 g, 0.33
mmol), phenylacetylene 8a (0.05 g, 0.50 mmol), copper(I) iodide
(49%) of 9e as a grey solid: mp >270 °C (dec); H nmr (DMSO-
d ): δ 1.25 (s, 9 H, C(CH ) ), 6.90 (s, 1 H, 5-H), 7.41 (d, 1 H, C
6
3 3
5-

838
A. Gangjee, J. Yu and R. L. Kisliuk
Vol. 39
H ), 7.61 (d, 1 H, C H ), 7.85 (t, 1 H, C H ), 8.61 (d, 1 H, C H ),
10.99 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.98 (s, 1 H, 2-NHPiv or
2-Pivaloylamino-4-oxo-6-(2-phenethyl)pyrrolo[2,3-d]pyrimi-
dine (10a).
4
5
4
5
4
5 4
3-NH, exch), 12.37 (bs, 1 H, 7-NH, exch).
Compound 10a was obtained from 9a (0.16 g, 0.50 mmol)
Anal. Calcd. For C
H N O •0.3H O: C, 63.44; H, 5.21; N,
18 17 5 2 2
using the general procedure described above to afford 0.16 g
20.55. Found: C, 63.29; H, 5.12; N, 20.58.
1
(97%) of 10a as a white solid: mp 250-251.5 °C; H nmr
(DMSO-d ): δ 1.24 (s, 9 H, C(CH ) ), 2.91 (m, 4 H, CH CH ),
Pivaloylamino-4-oxo-6-[(1'-naphthlene)ethynyl]pyrrolo[2,3-d]-
pyrimidine (9f).
6
3 3
2
2
6.09 (s, 1 H, 5-H), 7.24 (m, 5 H, C H ), 10.76 (s, 1 H, 2-NHPiv
6
5
or 3-NH, exch), 11.42 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.79
(bs, 1 H, 7-NH, exch).
Using the general procedure described above, 7a (0.36 g, 1.0
mmol), 1-ethynylnaphthalene 8f (0.18 g, 1.2 mmol), copper(I)
iodide (0.04 g, 0.20 mmol), tetrakis(triphenyl phosphine)palla-
dium (0) (0.07 g, 0.06 mmol) and triethylamine (1.0 mL)
Anal. Calcd. For C
H N O •0.2C H : C, 68.22; H, 7.03; N,
19 22 4 2 6 14
15.75. Found: C, 68.21; H, 6.79; N, 16.11.
afforded 0.34 g (89%) of 9f as a pale-yellow solid: mp >280 °C
2-Pivaloylamino-4-oxo-6-[2-(p-methylphenyl)ethyl]pyrrolo[2,3-
d]pyrimidine (10b).
1
dec; H nmr (DMSO-d ): δ 1.26 (s, 9 H, C(CH ) ), 6.94 (s, 1 H,
6
3 3
5-H), 7.54-7.67 (m, 3 H, C H ), 7.80 (d, 1 H, J = 6.9 Hz,
10
7
Compound 10b was obtained from 9b (0.24 g, 0.69 mmol)
C
H ), 8.02 (dd, 2 H, J = 7.8 Hz & 3.0 Hz, C H ), 8.40 (d, 1 H,
10
7 10 7
using the general procedure described above to afford 0.20 g
J = 8.2 Hz, C H ), 10.96 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.99
10
7
1
(80%) of 10b as a white solid: mp 255-257 °C; H nmr (DMSO-
(s, 1 H, 2-NHPiv or 3-NH, exch), 11.34 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O •0.3H O: C, 70.86; H, 5.33; N,
d ): δ 1.24 (s, 9 H, C(CH ) ), 2.25 (s, 3 H, 4'-CH ), 2.88 (m, 4 H,
6
3 3
3
H
23 20
4
2
2
CH CH ), 6.07 (s, 1 H, 5-H), 7.09 (s, 4 H, C H ), 10.72 (s, 1 H,
2
2
6 4
14.37. Found: C, 70.70; H, 5.22; N, 14.45.
2-NHPiv or 3-NH, exch), 11.38 (s, 1 H, 2-NHPiv or 3-NH, exch),
11.78 (bs, 1 H, 7-NH, exch).
2-Pivaloylamino-4-oxo-6-[(2'-naphthlene)ethynyl]pyrrolo[2,3-d]-
pyrimidine (9g).
Anal. Calcd. For C
H N O : C, 68.16; H, 6.86; N, 15.90.
20 24 4 2
Found: C, 68.19; H, 6.89; N, 15.85.
Using the general procedure described above, 7a (0.36 g, 1.0
mmol), 2-ethynylnaphthalene 8g (0.18 g, 1.2 mmol), copper(I)
iodide (0.04 g, 0.20 mmol), tetrakis(triphenyl phosphine)palla-
dium (0) (0.07 g, 0.06 mmol) and triethylamine (1.0 mL)
2-Pivaloylamino-4-oxo-6-[2-(p-methoxyphenyl)ethyl]pyrrolo-
[2,3-d]pyrimidine (9c).
Compound 10c was obtained from 9c (0.16 g, 0.43 mmol)
using the general procedure described above to afford 0.12 g
(74%) of 10c as a off-white solid: mp 232-233 °C; H nmr
1
afforded 0.12 g (31%) of 9g as a brown solid: mp 195-197 °C; H
nmr (DMSO-d ): δ 1.25 (s, 9 H, C(CH ) ), 6.84 (s, 1 H, 5-H),
6
3 3
1
7.56-7.99 (m, 6 H, C H ), 8.17 (s, 1 H, C H ), 10.99 (s, 1 H, 2-
10
7
10 7
(DMSO-d ): δ 1.24 (s, 9 H, C(CH ) ), 2.87 (s, 4 H, CH CH ),
6
3 3
2
2
NHPiv or 3-NH, exch), 11.97 (s, 1 H, 2-NHPiv or 3-NH, exch),
12.29 (bs, 1 H, 7-NH, exch).
3.71 (s, 3 H, OCH ), 6.08 (s, 1 H, 5-H), 6.85 (d, 2 H, J = Hz,
3
C H ), 7.13 (d, 2 H, J = Hz, C H ), 10.73 (s, 1 H, 2-NHPiv or
6
4
6 4
Anal. Calcd. For C
H N O •0.2H O: C, 71.19; H, 5.30; N,
23 20 4 2 2
3-NH, exch), 11.39 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.79 (bs, 1
H, 7-NH, exch).
14.44. Found: C, 71.04; H, 5.18; N, 14.68.
Anal. Calcd. For C
H N O : C, 65.20; H, 6.57; N, 15.20.
20 24 4 3
2-Pivaloylamino-4-oxo-6-[(2',5'-dimethoxyphenyl)ethynyl]-
Found: C, 64.98; H, 6.51; N, 15.07.
pyrrolo[2,3-d]pyrimidine (9h).
Using the general procedure described above, 7a (0.12 g, 0.33
mmol), (2,5-dimethoxyphenyl)ethyne 8h (0.08 g, 0.50 mmol),
copper(I) iodide (0.02 g, 0.10 mmol), tetrakis(triphenyl phos-
phine)palladium (0) (0.02 g, 0.02 mmol) and triethylamine (1.0
2-Pivaloylamino-4-oxo-6-[2-(2'-chlorophenyl)ethyl]pyrrolo[2,3-
d]-pyrimidine (10d).
Compound 10d was obtained from 9d (0.10 g, 0.27 mmol)
using the general procedure described above to afford 0.07 g
mL) afforded 0.13 g (36%) of 9h as a off-white solid: mp >250
1
(64%) of 10d as a white solid: mp 215-218 °C; H nmr (DMSO-
1
°C (dec); H nmr (DMSO-d ): δ 1.25 (s, 9 H, C(CH ) ), 3.73 (s,
6
3 3
d ): δ 1.24 (s, 9 H, C(CH ) ), 2.90 (t, 2 H, CH CH ), 3.06 (t, 2 H,
6
3 3
2
2
3 H, OCH ), 3.80 (s, 3 H, OCH ), 6.75 (s, 1 H, 5-H), 6.95-7.05
3
3
CH CH ), 6.10 (s, 1 H, 5-H), 7.21-7.43 (m, 4 H, C H ), 10.74 (s,
2
2
6 4
(m, 3 H, C H ), 10.98 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.95 (s,
6
3
1 H, 2-NHPiv or 3-NH, exch), 11.44 (s, 1 H, 2-NHPiv or 3-NH,
exch), 11.74 (bs, 1 H, 7-NH, exch).
1 H, 2-NHPiv or 3-NH, exch), 12.22 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O •0.5H O: C, 62.52; H, 5.75; N,
H
21 22
4
4
2
Anal. Calcd. For C
H N O Cl: C, 61.21; H, 5.68; N, 15.03;
19 21 4 2
13.89. Found: C, 62.84; H, 5.63; N, 13.58.
Cl, 9.51. Found: C, 61.58; H, 5.42; N, 15.31; Cl, 9.27.
General Procedure for the Synthesis of Compounds 10a-10h.
2-Pivaloylamino-4-oxo-6-[2-(2'-pyridin)ethyl]pyrrolo[2,3-d]-
pyrimidine (10e).
To a Parr hydrogenation bottle was added 9a-9h dissolved in a
mixture of DMF and THF followed by the addition of 5% Pd/C
(same as the weight of 9) and 3-4 drops of concentrated ammo-
nium hydroxide. The reaction mixture was then shaken at 50 psi
for 20 hours, filtered through a celite pad, and washed with hot
THF (15 mL x 2). Silica gel (10 g) was added to the filtrate and
the solvent evaporated to form a plug which was dried, loaded on
Compound 10e was obtained from 9e (0.16 g, 0.48 mmol)
using the general procedure described above to afford 0.14 g
1
(87%) of 10e as a off-white solid: mp 217-218 °C; H nmr
(DMSO-d ): δ 1.22 (s, 9 H, C(CH ) ), 3.04 (m, 4 H, CH CH ),
6
3 3
2
2
6.08 (s, 1 H, 5-H), 7.21 (m, 1 H, C H ), 7.27 (d, 1 H, C H ), 7.68
5
4
5 4
(t, 1 H, J = 4.8 Hz, C H ), 8.49 (d, 1 H, J = 4.8 Hz, C H ), 10.77
5
4
5 4
top of a silica gel column and eluted with 1.5% MeOH in CHCl .
(s, 1 H, 2-NHPiv or 3-NH, exch), 11.44 (s, 1 H, 2-NHPiv or 3-
3
Fractions containing the product (TLC) were pooled, and the sol-
vent evaporated to afford the solid, which was further washed
with hexanes to afford the pure product.
NH, exch), 11.79 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For: C
H N O •0.2H O: C, 63.03; H, 6.29; N,
18 21 5 2 2
20.42. Found: C, 63.00; H, 6.27; N, 20.30.

Jul-Aug 2002
2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as Potential Inhibitors
839
2-Pivaloylamino-4-oxo-6-[2-(1'-naphthlene)ethyl]pyrrolo[2,3-d]-
pyrimidine (10f).
CH CH ), 2.85 (t, 2 H, J = 6.6 Hz, CH CH ), 5.83 (s, 1 H, 5-H),
2 2 2 2
5.98 (s, 2 H, 2-NH , exch), 7.08 (m, 4 H, C H ), 10.14 (s, 1 H,
2
6 4
3-NH, exch), 10.88 (bs, 1 H, 7-NH, exch).
Compound 10f was obtained from 9f (0.88 g, 2.3 mmol) using
Anal. Calcd. For C
H N O •0.1H O: C, 66.70; H, 6.05; N,
15 16 4 2 2
the general procedure described above to afford 0.65 g (73%) of
20.74. Found: C, 66.68; H, 6.09; N, 20.51.
1
10f as a pale yellow solid: mp 228-230 °C; H nmr (DMSO-d ):
6
δ 1.18 (s, 9 H, CH ), 3.00 (t, 2 H, J = 9.0 Hz, CH CH ), 3.41 (t, 2
2-Amino-4-oxo-6-[2-(p-methoxyphenyl)ethyl]pyrrolo[2,3-
d]pyrimidine (2c).
3
2
2
H, J = 9.0 Hz, CH CH ), 6.20 (s, 1 H, 5-H), 7.39-7.60 (m, 4 H,
2
2
C
C
H ), 7.80 (d, 1 H, J = 3.0 Hz, C H ), 7.95 (d, 1 H, J = 8.1 Hz,
10
7 10 7
Compound 2c was obtained from 10c (0.09 g, 0.24 mmol)
H ), 8.21 (d, 1 H, J = 7.1 Hz, C H ), 10.74 (s, 1 H, 2-NH,
10
7
10 7
using the general procedure described above to afford 0.04 g
exch), 11.50 (s, 1 H, 3-NH, exch), 11.81 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O : C, 70.40; H, 6.28; N, 14.28.
Found: C, 70.40; H, 6.24; N, 14.27.
1
(62%) of 2c as a pale yellow solid: mp 278.5-280 °C; H nmr
H
23 24
4 2
(DMSO-d ): δ 2.76 (t, 2 H, J = 7.5 Hz, CH CH ), 2.82 (t, 2 H, J =
6
2
2
7.5 Hz, CH CH ), 3.70 (s, 3 H, OCH ), 5.83 (s, 1 H, 5-H), 5.98
2
2
3
2-Pivaloylamino-4-oxo-6-[2-(2'-naphthlene)ethyl]pyrrolo[2,3-
(s, 2 H, 2-NH , exch), 6.82 (d, 2 H, J = 8.4 Hz, C H ), 7.12 (d, 2
2 6 4
d]pyrimidine (10g).
H, J = 8.4 Hz, C H ), 10.14 (s, 1 H, 3-NH, exch), 10.87 (bs, 1 H,
6 4
7-NH, exch).
Anal. Calcd. For C
Found: C, 63.26; H, 5.78; N, 19.56.
Compound 10g was obtained from 9g (0.28 g, 0.73 mmol) using
H
N O: C, 63.37; H, 5.67; N, 19.71.
4
15 16
the general procedure described above to afford 0.20 g (71%) of
1
10g as a white solid: mp 248.5-249.5 °C; H nmr (DMSO-d ): δ
6
1.23 (s, 9 H, C(CH ) ), 2.99 (t, 2 H, J = 7.5 Hz, CH CH ), 3.1 (t, 2
2-Amino-4-oxo-6-[2-(2'-chlorophenyl)ethyl]pyrrolo[2,3-d]-
pyrimidine (2d).
3 3
2
2
H, J = 7.5 Hz, CH CH ), 6.12 (s, 1 H, 5-H), 7.40-7.87 (m, 7 H,
2
2
C H ), 10.75 (s, 1 H, 2-NHPiv or 3-NH, exch), 11.45 (s, 1 H, 2-
10
7
Compound 2d was obtained from 10d (0.06 g, 0.15 mmol)
NHPiv or 3-NH, exch), 11.79 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O •0.1CHCl : C, 69.29; H, 6.07;
using the general procedure described above to afford 0.03 g
H
23 24
4
2
3
1
(79%) of 2d as a white solid: mp 264-266 °C; H nmr (DMSO-
N, 13.99. Found: C, 69.23; H, 6.01; N, 14.11.
d ): δ 2.78 (t, 2 H, J = 7.0 Hz, CH CH ), 3.00 (t, 2 H, J = 7.0 Hz,
6
2
2
2-Pivaloylamino-4-oxo-6-[2-(2',5'-dimethoxyphenyl)ethyl]-
CH CH ), 5.80 (s, 1 H, 5-H), 5.98 (s, 2 H, 2-NH , exch), 7.22-
2
2
2
pyrrolo[2,3-d]pyrimidine (10h).
7.42 (m, 4 H, C H ), 10.14 (s, 1 H, 3-NH, exch), 10.92 (bs, 1 H,
6 4
7-NH, exch).
Anal. Calcd. For C
19.16; Cl 12.13. Found: C, 57.82; H, 4.98; N, 18.80; Cl, 12.29.
Compound 10h was obtained from 9h (0.35 g, 0.89 mmol)
H
N OCl•0.2H O: C, 57.52; H, 4.62; N,
4 2
14 13
using the general procedure described above to afford 0.33 g
1
(93%) of 10h as a pale yellow solid: mp 195-197 °C; H nmr
(DMSO-d ): δ 1.23 (s, 9 H, C(CH ) ), 2.85 (s, 4 H, CH CH ),
2-Amino-4-oxo-6-[2-(2'-pyridin)ethyl]pyrrolo[2,3-d]pyrimidine
(2e).
6
3 3
2
2
3.67 (s, 3 H, OCH ), 3.75 (s, 3 H, OCH ), 6.09 (s, 1 H, 5-H), 6.74
3
3
(m, 2 H, C H ), 6.86 (d, 1 H, J = 8.2 Hz, C H ), 10.74 (s, 1 H, 2-
NHPiv or 3-NH, exch), 11.38 (s, 1 H, 2-NHPiv or 3-NH, exch),
11.79 (bs, 1 H, 7-NH, exch).
6
3
6 3
Compound 2e was obtained from 10e (0.09 g, 0.27 mmol)
using the general procedure described above to afford 0.03 g
1
(44%) of 2e as a white solid: mp >265 °C dec; H nmr (DMSO-
Anal. Calcd. For C
H N O : C, 63.30; H, 6.58; N, 14.04.
21 26 4 4
d ): δ 2.89 (t, 2 H, J = 6.9 Hz, CH CH ), 3.04 (t, 2 H, J = 6.9 Hz,
6
2
2
Found: C, 63.34; H, 6.66; N, 13.82.
CH CH ), 5.83 (s, 1 H, 5-H), 5.98 (s, 2 H, 2-NH , exch), 7.22 (m,
2
2
2
General Procedure for the Synthesis of Compounds 2a-2h.
2 H, C H ), 7.67 (t, 1 H, J = 7.5 Hz, C H ), 8.48 (d, 1 H, J = 4.5
5 4 5 4
Hz, C H ), 10.14 (s, 1 H, 3-NH, exch), 10.90 (bs, 1 H, 7-NH,
5
4
To a 25-mL round-bottomed flask was added 10a-10h dis-
solved in THF (10 mL) followed by the addition of 1 N NaOH (3
mL). The mixture was refluxed at 70 °C for 24 hours. The solvent
evaporated and the residue was flash chromatographed on silica
exch).
Anal. Calcd. For C
H
N O•0.5H O: C, 59.04; H, 5.34; N,
5 2
13 13
26.56. Found: C, 59.35; H, 5.52; N, 26.45.
gel and eluted with 1:19 MeOH/CHCl to afford the product.
2-Amino-4-oxo-6-[2-(1'-naphthlene)ethyl]pyrrolo[2,3-d]pyrimi-
dine (2f).
3
2-Amino-4-oxo-6-(2-phenethyl)pyrrolo[2,3-d]pyrimidine (2a).
Compound 2a was obtained from 10a (0.10 g, 0.29 mmol) using
Compound 2f was obtained from 10f (0.11 g, 0.28 mmol)
using the general procedure described above to afford 0.05 g
the general procedure described above to afford 0.06 g (80%) of 2a
1
(57%) of 2f as a yellow solid: mp >220 °C dec; H nmr (DMSO-
1
as a white solid: mp >280 °C (dec); H nmr (DMSO-d ): δ 2.76 (t,
6
d ): δ 2.88 (t, 2 H, J = 9.0 Hz, CH CH ), 3.35 (t, 2 H, J = 9.0 Hz,
6
2
2
2 H, J = 6.9 Hz, CH CH ), 2.91 (t, 2 H, J = 6.9 Hz, CH CH ), 5.85
2
2
2
2
CH CH ), 5.95 (s, 1 H, 5-H), 5.98 (s, 2 H, NH , exch), 7.40-7.57
2
2
2
(s, 1 H, 5-H), 5.98 (s, 2 H, 2-NH , exch), 7.24 (m, 5 H, C H ),
2
6 5
(m, 4 H, C H ), 7.78 (d, 1 H, J = 9.0 Hz, C H ), 7.93 (d, 1 H,
10
7
10 7
10.14 (s, 1H, 3-NH, exch), 10.90 (bs, 1H, 7-NH, exch).
J = 6.0 Hz, C H ), 8.20 (d, 1 H, J = 9.0 Hz, C H ), 10.15 (s, 1
10
7
10 7
Anal. Calcd. For C
H N O: C, 66.13; H, 5.55; N, 22.03.
14 14 4
H, 3-NH, exch), 11.02 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O•0.8H O: C, 68.21; H, 5.53; N,
Found: C, 66.51; H, 5.72; N, 22.08.
H
18 16
4
2
2-Amino-4-oxo-6-[2-(p-methylphenyl)ethyl]pyrrolo[2,3-d]-
pyrimidine (2b).
17.16. Found: C, 67.99; H, 5.57; N, 17.32.
2-Amino-4-oxo-6-[2-(2'-naphthlene)ethyl]pyrrolo[2,3-d]pyrimi-
dine (2g).
Compound 2b was obtained from 10b (0.08 g, 0.23 mmol)
using the general procedure described above to afford 0.04 g
1
(62%) of 2b as a pale yellow solid: mp >290 °C (dec); H NMR
Compound 2g was obtained from 10g (0.07 g, 0.18 mmol)
(DMSO-d ): δ 2.25 (s, 3 H, CH ), 2.76 (t, 2 H, J = 6.6 Hz,
using the general procedure described above to afford 0.08 g
6
3

840
A. Gangjee, J. Yu and R. L. Kisliuk
Vol. 39
[12] D. I. Jodrell, D. R, Newell, S. E. Morgan, S. Clinton, J. P.
Bensted, L. R. Hughes and A. H. Calvert, Br. J. Cancer, 64, 833 (1991).
[13] M. G. Nair, J. Galivan, F. Maley, R. L. Kisliuk and R. Ferone,
Proc. Am. Assoc. Cancer Res. 30, 476 (1990).
[14] D. W. Fry and R. C. Jackson, Cancer Surv., 5, 47 (1986).
[15] J. H. Schornagel, M. F. Pinard, G. R. Westerhof, I. Kathmann,
C. F. M. Molthoff, J. Jolivet and G. Jansen, Proc. Am. Assoc. Cancer Res.,
35, 302 (1994).
1
(55%) of 2g as a yellow solid: mp 165-168 °C; H nmr (DMSO-
d ): δ 2.96 (t, 2 H, J = 7.5 Hz, CH CH ), 3.06 (t, 2 H, J = 7.5 Hz,
6
2
2
CH CH ), 5.88 (s, 1 H, 5-H), 5.99 (s, 2 H, NH , exch), 7.43 (m, 3
H, C H ), 7.72 (s, 1 H, C H ), 7.98 (m, 3 H, C H ), 10.16 (s,
1 H, 3-NH, exch), 10.94 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C N O: C, 71.04; H, 5.30; N, 18.41.
2
2
2
10
7
10
7
10 7
H
18 16
4
Found: C, 71.29; H, 5.63; N, 18.28.
[16] A. L. Jackman, W. Gibson, M. Brown, R. Kimbell and F. T.
Boyle, Adv. Exp. Med. Biol., 339, 265 (1993).
[17] J. J. McGuire, P. Hsieh, J. K. Coward and J. R. Bertino, J.
Biol. Chem., 255, 5776 (1980).
2-Amino-4-oxo-6-[2-(2',5'-dimethoxyphenyl)ethyl]pyrrolo[2,3-d]-
pyrimidine (2h).
Compound 2h was obtained from 10h (0.11 g, 0.27 mmol)
[18] D. E. McCloskey, J. J. McGuire, C. A. Russell, B. G. Rowan,
J. R. Bertino, G. Pizzorno and E. Mini, J. Biol. Chem., 266, 6181 (1991).
[19] G. M. F. Bisset, V. Bavetsias, T. J. Thornton, K. Pawelczak, A.
H. Calvert, L. R. Hughes and A. L. Jackman, J. Med. Chem., 37, 3294
(1994).
[20] A. L. Jackman, L. R. Kelland, M. Brown, W. Gibson, R.
Kimbell, W. Aherne and I. R. Judson, Proc. Am. Assoc. Cancer Res., 33,
406 (1992).
[21] R. R. Barakat, W. W. Li, C. Lovelace and J. R. Bertino,
Gynecol. Oncol. 51, 54 (1993).
[22] B. J. Braakhuis, G. Jansen, P. Noordhius, A. Kegel and G. J.
Peters, Biochem. Pharmacol. 46, 2155 (1990).
[23] S. E. Webber, T. M. Bleckman, J. Attard, V. Kathardekar, K.
M. Welsh, S. Webber, C. A. Janson, D. A. Matthews, W. W. Smith, S. T.
Freer, S. R. Jordan, R. J. Bacquet, E. F. Howland, C. L. J. Booth, R. W.
Ward, J. White, C. A. Morse, J. A. Hilliard and C. A. Baretlett, J. Med.
Chem. 36, 733 (1993).
using the general procedure described above to afford 0.05 g
(52%) of 2h as a yellow solid: mp 225-227 °C; H nmr (DMSO-
1
d ): δ 2.71 (t, 2 H, J = 6.0 Hz, CH CH ), 2.80 (t, 2 H, J = 6.0 Hz,
6
2
2
CH CH ), 3.68 (s, 3 H, OCH ), 3.72 (s, 3 H, OCH ), 5.84 (s, 1 H,
2
2
3
3
5-H), 5.97 (s, 2 H, NH , exch), 6.80 (m, 3 H, C H ), 10.14 (s, 1
2
6 3
H, 3-NH, exch), 10.86 (bs, 1 H, 7-NH, exch).
Anal. Calcd. For C
H N O •0.5MeOH: C, 59.99; H, 6.10;
16 18 4 3
N, 16.96. Found: C, 60.38; H, 6.29; N, 16.70.
Acknowledgement.
This work was supported in part by grants from the National
Institutes of Health, National Institute of Allergy and Infectious
Diseases AI41743 (AG) and AI44661 (AG), and from the
National Cancer Institute CA10914 (RLK).
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