Synthesis of N-aryl-2-amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6- carboxamides

Article abstract of DOI:10.1002/jhet.5570420709

Synthetic routes for the preparation of methyl 2-amino-4-methoxythieno[2,3- d]pyrimidine-6-carboxylate (4) - useful intermediate for lipophilic and classical antifolates from 2-amino-4,6-dichloropyrimidine-5-carbaldehyde (1) have been studied. It has been

Full text of DOI:10.1002/jhet.5570420709

Nov-Dec 2005
1305
Synthesis of N-Aryl-2-amino-4-oxo-
3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides
S. Tumkevicius* and M. Dailide
Department of Organic Chemistry, Faculty of Chemistry,
Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
e-mail: sigitas.tumkevicius@chf.vu.lt
Received April 4, 2005
Synthetic routes for the preparation of methyl 2-amino-4-methoxythieno[2,3-d]pyrimidine-6-carboxylate
(4) - useful intermediate for lipophilic and classical antifolates from 2-amino-4,6-dichloropyrimidine-5-car-
baldehyde (1) have been studied. It has been shown that more efficient synthesis of compound 4 includes the
preparation of 4-methoxy derivative 7 and subsequent tandem substitution/annulation reaction with methyl
mercaptoethanoate in dimethylformamide in the presence of potassium carbonate and molecular sieves 4 Å.
Compound 4 was used for the synthesis of N-aryl 2-amino-4-oxo-3,4-dihydrothieno[2,3-d]-pyrimidine-6-
carboxamides 10a-c, including an analog of folic acid with amide bridge - N-(4-{[(2-amino-4-oxo-3,4-
dihydrothieno[2,3-d]pyrimidin-6-yl)carbonyl]amino}-benzoyl)-L-glutamic acid (10c).
J. Heterocyclic Chem., 42, 1305 (2005).
Thymidylate synthase, which mediates the reductive
porating the pyrimidine ring [11-15] we report herein
results on a synthesis of N-aryl 2-amino-4-oxo-3,4-dihy-
drothieno[2,3-d]pyrimidine-6-carboxamides as novel
potential antifolates. The title compounds contain a new
type of bridge and, therefore, could have a considerable
interest in structure-activity relationship studies. They
were also expected to undergo reduction reaction into
derivatives with the natural methyleneamino bridge
between hetaryl and aryl moieties.
For the synthesis of derivatives of 2-amino-4-substi-
tuted-thieno[2,3-d]pyrimidine-6-carboxylic acids the cor-
responding esters are of considerable interest. According
to the retrosynthetic analysis they could be produced from
2-amino-4,6-dichloropyrimidine-5-carbaldehyde (1) by
synthetic routes I and II, differing in sequence of the thio-
phene ring formation and functionalisation of the position
4 of the pyrimidine ring (Figure 2).
methylation of 2'-deoxyuridine-5'-monophosphate to give
2'-deoxythymidine-5'-monophosphate utilising the cofac-
tor 5,10-methylenetetrahydrofolate and is thus essential
for de novo DNA biosynthesis, has long been recognised
as a prime objective for the development of antitumor
agents. Numerous folate cofactor analogues have been
synthesised and several of them have found use in the
clinic as antitumor, antibacterial, and antiprotozoan agents
[1]. Derivatives of 6/5-fused heterocycles, such as pyrrolo-
, thieno- and furo[2,3-d]pyrimidines have a considerable
interest since the discovery of multitargeted antifolate
(Figure 1) [2].
In search of more potent and selective lipophilic and
classical antifolates structural modifications concerning
the bridge and aromatic part of molecules have been made
in position 5 of the mentioned heterocycles [3-8].
However, to the best of our knowledge, there are only a
few reports on the synthesis of potent dihydrofolate reduc-
tase inhibitors - 2,4-diaminothieno[2,3-d]pyrimidines,
bearing arylalkyl substituents in the position 6 of the hete-
rocycle [5,6,9,10] and no work has been done on the syn-
thesis of the corresponding 6-substituted 2-amino-4-oxoth-
ieno[2,3-d]pyrimidines. In this connection and as a part of
our program designed towards fused heterosystems incor-
Firstly, synthesis of 2-amino-4-substituted-thieno[2,3-
d]pyrimidine-6-carboxylates according to route I has been
investigated. Reaction of carbaldehyde 1 with methyl mer-
captoethanoate in anhydrous methanol in the presence of

1306
S. Tumkevicius and M. Dailide
Vol. 42
triethylamine at room temperature gave a mixture of 2 and
3 in a ratio 1:0.7, as judged by H-NMR. Performing the
reaction of 1 with methyl mercaptoethanoate in a mixture
of methanol and water resulted in the formation of 2 as the
only reaction product (Scheme 1).
synthesis by route II. 2-Amino-4,6-dichloropyrimidine-5-
carbaldehyde (1) was allowed to react with sodium
methoxide in methanol. It was noticed that already at room
temperature a mixture of monomethoxy 7 and dimethoxy
derivatives 8 in a ratio 6:1 was formed (Scheme 2).
1
Reflux of 2 with triethylamine in methanol for 18 hours
(Method A) or heating at 60 °C with potassium carbonate
in dimethylformamide in the presence of molecular sieves
4 Å for 1 hour (Method B) afforded 4-chlorothienopyrimi-
dine 3 (Scheme 1). Compound 3 reacted with sodium
methoxide to give methyl 2-amino-4-methoxythieno[2,3-
d]pyrimidine-6-carboxylate (4) as the sole reaction prod-
uct. Attempt to shorten the reaction pathway, i.e. to synthe-
sise 4 by tandem substitution/annulation reaction of 2 with
an excess of sodium methoxide in methanol led to a mix-
ture of ester 4 and acid 5 in 34% and 33% yields, respec-
tively. Ester 4 when heated with sodium hydroxide in
aqueous methanol afforded 2-amino-4-methoxythieno[2,3-
d]pyrimidine-6-carboxylic acid (5), whereas acidic hydrol-
ysis of 4 using concentrated hydrochloric acid gave 2-
amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-car-
boxylic acid (6). Thus, synthesis of ester 4 – a key interme-
diate for the preparation of 2-amino-4-oxothieno[2,3-d]-
pyrimidines bearing various functional groups in the posi-
tion 6 by route I could be performed by three-step proce-
dure in overall 26% yield. Taking into account that overall
yield of 4 is not high it was of interest to investigate its
Nevertheless we have found that the desired compound 7
can be synthesised in a reasonable yield by reflux of 1 in
methanol in the presence of triethylamine.
2-Amino-6-chloro-4-methoxypyrimidine-5-carbalde-
hyde (7) reacted with methyl mercaptoethanoate in the
presence of bases to give the thienopyrimidine 4. Data pre-
sented in Table 1 indicate that the duration of the reaction
and the yields of ester 4 depend on a solvent and base.
Table 1
Data of synthesis of methyl 2-amino-4-methoxythieno[2,3-d]pyrimidine-
a
6-carboxylate (4) from compound 7 and methyl mercaptoethanoate.
Entry Reaction conditions
Reaction
time, h
Isolated
yield, %
1
2
3
4
5
2.2 equiv. Et N, pyridine, reflux
23
50
27
3
30
63
47
59
93
3
2.2 equiv. Et N, MeOH, reflux
3
2.2 equiv. Et N, DMF, 80 ºC
3
5 equiv. K CO , DMF, 60 ºC
2
3
5 equiv. K CO , DMF, MS 4 Å, 60 ºC
3
2
3
a
in all experiments 1.1 equivalent of HSCH CO Me was used.
2
2

Nov-Dec 2005 Synthesis of N-Aryl-2-amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides
1307
Almost quantitative conversion of 7 into 4 was achieved
when the reaction was carried out in dimethylformamide at
60 °C in the presence of potassium carbonate and molecu-
lar sieves 4 Å (entry 5). Comparing results obtained in the
synthesis of ester 4 from 2-amino-4,6-dichloropyrimidine-
5-carbonitrile (1) by routes I and II one can envisage that
route II is more efficient: compound 4 is produced by two-
step procedure with overall 66% yield.
Although ester group in 4 was able to undergo alkaline or
acidic hydrolysis (Scheme 1) it appeared to be rather inert
towards anilines. We did not succeed to obtain the corre-
sponding amide by performing reaction of 4 with 4-
methoxyaniline in different conditions including pro-
longed heating of reagents without solvent. Similar inert-
ness of the ester group was also observed in a series of ethyl
4-dialkylamino-2-methylthiothieno[2,3-d]pyrimidine-6-
carboxylates [15]. Therefore, arylamides of 2-amino-4-
methoxythieno[2,3-d]pyrimidine-6-carboxylic acid (9a,b)
were obtained by the reaction of acid 5 with the corre-
sponding anilines in the presence of auxiliary reagents -
dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotria-
zole (HOBt) (Scheme 3). 4-Methoxy derivatives 9a,b were
converted into the corresponding 4-oxo derivatives 10a,b
by reflux in concentrated hydrochloric acid.
The thienopyrimidine analog of folic acid bearing amide
bridge - N-(4-{[(2-amino-4-oxo-3,4-dihydrothieno[2,3-d]-

1308
S. Tumkevicius and M. Dailide
Vol. 42
Anal. Calcd. for C H ClN O S: C, 36.72; H, 3.08; N, 16.06.
Found: C, 36.35; H, 2.84; N, 16.29.
pyrimidin-6-yl)carbonyl]amino}benzoyl)-L-glutamic acid
(10c) was synthesised by one-pot procedure according to
the method applied for the synthesis of amides 9a,b by the
reaction of 6 with diethyl N-(aminobenzoyl)-L-glutamate
and following alkaline hydrolysis of the ester groups
(Scheme 3).
8
8
3 3
Methyl 2-Amino-4-chlorothieno[2,3-d]pyrimidine-6-carboxylate
(3).
Method A.
To a stirred suspension of compound 2 (1.00 g, 3.8 mmol) in
methanol (30 ml) was added triethylamine (0.43 g, 4.2 mmol).
The reaction mixture was refluxed while stirring for 18 hours and
cooled to room temperature. The precipitate was collected by fil-
tration, washed with water, dried and recrystallised from a mix-
ture of dimethylformamide and water to give 0.66 g (71%) of 3 as
In order to obtain lipophilic antifolates with CH NH
2
bridge between the thienopyrimidine and aryl fragments
attempts to reduce amides 9,10 using B H or LiAlH
2
6
4
were made. However, only compound 9b in the reaction
with LiAlH furnished 2-amino-4-methoxy-6-{[(3,4,5-
4
a yellow solid, mp 246-249°; ir (Nujol): 3405, 3328 (NH ), 1714
2
trimethoxyphenyl)amino]methyl}thieno[2,3-d]pyrimidine
(11) in 26% yield.
In conclusion, we synthesised and characterised some
N-aryl 2-amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimi-
dine-6-carboxamides (10a-c) which could represent novel
potential antifolates with amide bridge. It was also shown
-1
1
(CO) cm ; H nmr (dimethylsulfoxide-d ): 3.89 (s, 3H, CH ),
6
3
7.52 (br.s, 2H, NH ), 7.81 (s, 1H, C5-H).
2
Anal. Calcd. for C H ClN O S: C, 39.43; H, 2.48. Found: C,
8
6
3 2
39.54; H, 2.56.
Method B.
To a stirred solution of compound 2 (0.70 g, 2.7 mmol) in
dimethylformamide (17 ml) were added molecular sieves 4 Å
(0.70 g) and potassium carbonate (1.87 g, 13.5 mmol). The reac-
tion mixture was stirred at 60° for 1 hour, cooled to room temper-
ature and poured into water (ca. 200 ml). The precipitate was col-
lected by filtration, washed with water, dried and recrystallised
from a mixture of dimethylformamide and water to give 0.46 g
(71%) of 3 as a yellow solid, whose properties are identical to
those of the product obtained in method A.
that reduction of amides 9a,b and 10a,b with LiAlH is not
4
applicable method for the synthesis of the corresponding
methyleneamino derivatives. Investigation of biological
properties of compounds 10, 11 as well as study on the
synthesis of the corresponding compounds with CH NH
2
bridge is under progress and will be reported elsewhere.
EXPERIMENTAL
Methyl 2-Amino-4-methoxythieno[2,3-d]pyrimidine-6-carboxy-
late (4) and 2-Amino-4-methoxythieno[2,3-d]pyrimidine-6-car-
boxylic Acid (5).
Melting points were determined in open capillaries and are
uncorrected. IR spectra were run on a Perkin-Elmer FT-IR spec-
trophotometer Spectrum BX II. NMR spectra were recorded on a
Varian INOVA spectrometer (300 MHz). Chemical shifts are
reported in parts per million (ppm) relative to tetramethylsilane
as internal standard. Optical rotation of 10c was measured using a
polarimeter Polamat-A. Enantiomeric excess was determined
with a P/ACE 2100 apparatus (Beckman Instruments Inc.) using
fused silica capillary (length - 50 cm till detector, internal diame-
ter - 75 µm), electrolyte - 50 mM Na B O solution in water,
To a solution of sodium methoxide in methanol prepared from
sodium (4.8 g, 20.9 mmoles) and methanol (45 ml) compound 2
(1.80 g, 6.9 mmoles) was added portionwise. The reaction mixture
was refluxed for 9 hours. After cooling to room temperature the
precipitate was collected by filtration, washed with water, dried
and recrystallised from a mixture of dimethylformamide and
water to give 0.56 g (34%) of 4 as a yellowish solid, mp 235-238°.
The filtrate was acidified with 5% hydrochloric acid until pH 5.
The precipitate was collected by filtration, rinsed with cold water,
dried and recrystallised from a mixture of dimethylformamide and
water to give 0.51 g (33%) of 5 as a colorless solid, mp > 300°.
2
4 7
selector - β-cyclodextrine (5 mM), voltage +25 kV, and UV
detector (λ = 254 nm). Elemental analyses were performed at the
Elemental Analysis Laboratory of the Department of Organic
Chemistry of Vilnius University. TLC was performed with silica
-1
Compound 4: ir (Nujol): 3424, 3312 (NH ), 1702 (CO) cm ;
2
1
H nmr (dimethylsulfoxide-d ): 3.83 (s, 3H, CO CH ); 3.99 (s,
gel plates 60 F (Merck).
6
2
3
254
3H, C4-OCH ), 7.25 (br.s, 2H, NH ), 7.73 (s, 1H, C5-H).
2-Amino-4,6-dichloropyrimidine-5-carbaldehyde (1) was pre-
pared following the literature procedure [16].
3
2
Anal. Calcd. for C H N O S: C, 45.18; H, 3.79; N, 17.56.
9
9 3 3
Found: C, 45.38; H, 3.79; N, 17.59.
Methyl [(2-Amino-4-chloro-5-formyl-6-pyrimidinyl)thio]-
ethanoate (2).
Compound 5: ir (Nujol): 3508, 3475, 3297, 3178 (NH , NH,
2
-1
1
OH), 1629 (CO) cm ; H nmr (dimethylsulfoxide-d ): 3.96 (s,
6
3H, CH ), 6.64 (br.s, 2H, NH ), 7.23 (s, 1H, C5-H).
To a stirred suspension of 2-amino-4,6-dichloropyrimidine-5-
carbaldehyde (1) (0.2 g, 1.0 mmol) in methanol (6.3 ml) and
water (0.3 ml) was added triethylamine (0.11 g, 1.1 mmol) and
methyl mercaptoethanoate (0.12 g, 1.1 mmol). The reaction mix-
ture was stirred at room temperature for 1.5 hours. The precipi-
tate was collected by filtration, washed with water, dried in air
and recrystallised from 2-propanol to give 0.18 g (66%) of 2 as a
3
2
Anal. Calcd. for C H N O S: C, 42.66; H, 3.13; N, 18.66.
8
7 3 3
Found: C, 42.32; H, 3.25; N, 18.30.
Methyl 2-Amino-4-methoxythieno[2,3-d]pyrimidine-6-carbox-
ylate (4).
Method A.
yellow needles, mp 174-179°; ir (Nujol): 3416, 3299 (NH ),
To a solution of sodium methoxide in methanol prepared from
sodium (0.02 g, 0.9 mmol) and methanol (10 ml) compound 3
(0.2 g, 0.8 mmol) was added portionwise. The reaction mixture
was refluxed for 9 hours. The precipitate was collected by filtra-
2
-1
1
1720, 1646 (CO) cm ; H nmr (dimethylsulfoxide-d ): 3.68 (s,
6
3H, CH ), 4.01 (s, 2H, CH ), 7.99 (br.s, 1H, NH), 8.25 (br.s, 1H,
3
2
NH), 10.09 (s, 1H, CHO).

Nov-Dec 2005 Synthesis of N-Aryl-2-amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides
1309
tion, washed with water, dried and recrystallised from a mixture
of dimethylformamide and water to give 0.11 g (55%) of 4 as a
yellowish solid, whose properties are identical to those of the
product obtained from compound 2.
(10 ml), 4-methoxyaniline (0.18 g, 1.5 mmol), N,N'-dicyclo-
hexylcarbodiimide (0.31 g, 1.5 mmol) and 1H-1,2,3-benzotria-
zol-1-ol (0.2 g, 1.5 mmol). The reaction mixture was stirred
under argon at room temperature for 24 hours. Water (0.5 ml)
was added and the precipitate was collected filtration after 1 hour.
The filtrate was poured into water (ca. 100 ml). The precipitate
was collected by filtration, dried and recrystallised from a mix-
ture of dimethylformamide and water to give 0.19 g (56%) of 9a
as a colorless solid, mp 236-239° (dec.); ir (Nujol): 3442, 3308,
Method B.
To a stirred solution of compound 7 (0.2 g, 1.1 mmol) in
dimethylformamide (5 ml) were added molecular sieves 4 Å (0.3
g), methyl mercaptoethanoate (0.13 g, 1.2 mmoles) and potas-
sium carbonate (0.76 g, 5.5 mmol). Mixture was heated while
stirring at 60° for 3 hours, cooled to room temperature and
poured into water (ca. 70 ml). The precipitate was collected by
filtration, washed with water and dried to give 0.24 g (93%) of 4
as a yellowish solid, whose properties are identical to those of the
product obtained from compound 2. The substance was pure
enough to use further without purification.
-1
1
3164 (NH , NH), 1636 (CO) cm ; H nmr (dimethylsulfoxide-
2
d ): 3.76 (s, 3H, C4'-OCH ), 4.03 (s, 3H, C4-OCH ), 6.89 (br.s,
6
3
3
2H, NH ), 7.05 (d, J = 8.0 Hz, 2H, C3',5'-H), 7.66 (d, J = 8.0 Hz,
2
2H, C2',6'-H), 8.18 (s, 1H, C5-H), 10.18 (br.s, 1H, CONH).
Anal. Calcd. for C
H N O S: C, 54.54; H, 4.27; N, 16.96.
15 14 4 3
Found: C, 54.25; H, 4.64; N, 17.18.
N-(3,4,5-Trimethoxyphenyl)amide of 2-Amino-4-methoxy-
thieno[2,3-d]pyrimidine-6-carboxylic Acid (9b).
2-Amino-4-methoxythieno[2,3-d]pyrimidine-6-carboxylic Acid
(5).
This compound was prepared analogously to 9a from com-
pound 5 (0.45 g, 2.0 mmol). Yield 0.38 g (49%), colorless solid
(2-propanol), mp 189-191° (dec.); ir (Nujol): 3450, 3334, 3216
To a stirred suspension of compound 4 (0.56 g, 2.3 mmol) in
methanol (15 ml) was added a solution of sodium hydroxide (0.23
g, 5.7 mmol) in water (3 ml). The reaction mixture was refluxed
while stirring for 2 hours. After removal of the solvent under
reduced pressure, the residue was dissolved in a minimal amount
of water and acidified with 5% hydrochloric acid to pH 5. The pre-
cipitate was collected by filtration, rinsed with cold water, dried
and recrystallised from a mixture of dimethylformamide and water
to give 0.40 g (76%) of 5 as a colorless solid, whose properties are
identical to those of the product obtained from compound 2.
-1
1
(NH , NH), 1626 (CO) cm ; H nmr (dimethylsulfoxide-d ):
2
6
3.65 (s, 3H, C4'-OCH ), 3.79 (s, 6H, C3',5'-OCH ), 4.03 (s, 3H,
3
3
C4-OCH ), 7.11 (br.s, 2H, NH ), 7.19 (s, 2H, C2',6'-H), 8.20 (s,
3
2
13
1H, C5-H), 10.16 (br.s, 1H, CONH); C nmr (dimethylsulfox-
ide-d ): 54.3, 56.4, 60.8, 98.3, 111.5, 121.7, 130.3, 134.3, 135.6,
6
153.4, 160.6, 162.4, 165.8, 172.4.
Anal. Calcd. for C
H N O S: C, 52.30; H, 4.65; N, 14.35.
17 18 4 5
Found: C, 52.51; H, 4.85; N, 14.17.
2-Amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-car-
boxylic Acid (6).
N-(4-methoxyphenyl)amide of 2-Amino-4-oxo-3,4-dihydroth-
ieno[2,3-d]pyrimidine-6-carboxylic Acid (10a).
A mixture of compound 4 (0.20 g, 0.84 mmoles) and concen-
trated hydrochloric acid (10 ml) was refluxed for 8 hours. After
cooling to room temperature the precipitate was collected by filtra-
tion, washed with water (3 x 10 ml), dried and recrystallised from a
mixture of dimethylformamide and water to give 0.13 g (74%) of 6
as a colorless solid, mp > 300°; ir (potassium bromide): 3310, 3131
A mixture of compound 9a (0.10 g, 0.30 mmol) and concen-
trated hydrochloric acid (5 ml) was refluxed while stirring for 4
hours. After cooling to room temperature, the precipitate was col-
lected by filtration, washed with water (3 x 5 ml), dried and
recrystallised from a mixture of dimethylformamide and water to
give 0.07 g (73%) of 10a as a colorless solid, mp > 300° (dec); ir
-1
1
(NH , NH, OH), 1722, 1717 (CO) cm ; H nmr (dimethylsulfox-
2
-1 1
(Nujol): 3541, 3342, 3187 (NH , NH), 1671, 1636 (CO) cm ; H
2
ide-d ): 6.92 (br.s, 2H, NH ), 7.68 (s, 1H, C5-H), 11.17 (br.s, 1H,
6
2
nmr (dimethylsulfoxide-d ): 3.75 (s, 3H, C4'-OCH ), 6.92 (d, J =
6
3
13
CONH), 12.97 (br.s, 1H, CO H); C nmr (dimethylsulfoxide-d ):
2
6
9,3 Hz, 2H, C3',5'-H), 7.29 (br.s, 2H, NH ), 7.64 (d, J = 9,3 Hz,
2
116.8, 123.4, 128.6, 155.3, 158.9, 163.8, 172.2.
2H, C2',6'-H), 8.22 (s, 1H, C5-H), 10.17 (br.s, 1H, CONH), 11.48
Anal. Calcd. for C H N O S: C, 39.81; H, 2.39; N, 19.90.
7
5 3 3
13
(br.s, 1H, CONH); C nmr (dimethylsulfoxide-d ): 55.9, 114.5,
6
Found: C, 40.17; H, 2.53; N, 19.75.
117.3, 122.3, 124.5, 130.0, 132.6, 154.7, 156.2, 158.6, 160.3,
168.6.
2-Amino-6-chloro-4-methoxypyrimidine-5-carbaldehyde (7).
Anal. Calcd. for C
Found: C, 53.24; H, 3.92; N, 17.49.
H N O S: C, 53.16; H, 3.82; N, 17.71.
14 12 4 3
To a stirred suspension of compound 1 (0.5 g, 2.6 mmol) in
methanol (20 ml) was added triethylamine (1.32 g, 13.0 mmol).
The reaction mixture was refluxed while stirring for 8.5 hours.
The solvent was removed under reduced pressure. The solid was
washed several times with water, dried and recrystallised from 2-
propanol to give 0.347 g (71%) of 7 as a yellowish solid, mp 192-
N-(3,4,5-trimethoxyphenyl)amide of 2-Amino-4-oxo-3,4-dihy-
drothieno[2,3-d]pyrimidine-6-carboxylic Acid (10b).
This compound was prepared analogously to 10a from com-
pound 9b (0.10 g, 0.26 mmole). Yield 0.068 g (71%), colorless
solid (dimethylformamide-water), mp>300° (dec.); ir (potassium
bromide): 3272, 3200 (NH , NH), 1704, 1669 (CO) cm . H nmr
(dimethylsulfoxide-d ): 3.65 (s, 3H, C4'-OCH ), 3.78 (s, 6H,
-1
1
195°; ir (Nujol): 3288, 3112 (NH ), 1692 (CO) cm ; H nmr
2
(dimethylsulfoxide-d ): 3.94 (s, 3H, OCH ), 8.08 (br.s, 2H,
6
3
-1 1
2
NH ), 10.00 (s, 1H, CHO).
2
6
3
Anal. Calcd. for C H ClN O : C, 38.42; H, 3.22; N, 22.40.
6
6
3 2
C3',5'-OCH ), 6.92 (br.s, 2H, NH ), 7.18 (s, 2H, C2',6'-H), 8.21
3
2
Found: C, 38.60; H, 3.29; N, 22.00.
(s, 1H, C5-H), 10.11 (br.s, 1H, CONH), 11.12 (br.s, 1H, CONH);
C nmr (dimethylsulfoxide-d ): 56.4, 60.8, 98.2, 117.1, 124.7,
129.1, 134.3, 135.7, 153.3, 155.0, 159.1, 160.6, 171.4.
N-(4-Methoxyphenyl)amide of 2-Amino-4-methoxythieno[2,3-d]-
pyrimidine-6-carboxylic Acid (9a).
13
6
Anal. Calcd. for C
H N O S: C, 51.06; H, 4.28; N, 14.89.
The reaction vessel was charged with argon and subsequently
16 16 4 5
Found: C, 51.08; H, 4.57; N, 15.11.
loaded with compound 5 (0.23 g, 1 mmol), dimethylformamide

1310
S. Tumkevicius and M. Dailide
Vol. 42
N-(4-{[(2-Amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidin-6-
yl)carbonyl]amino}benzoyl)-L-glutamic Acid (10c).
(s, 3H, C4-OCH ), 4.07 (t, 1H, J = 4.8 Hz, NH), 4.48 (d, 2H, J =
3
4.8 Hz, CH ), 4.99 (br.s, 2H, NH ), 5.96 (s, 2H, C2',6'-H), 7.08
2
2
13
(s, 1H, C5-H); C nmr (chloroform-d): 44.9, 53.9, 56.2, 61.3,
91.2, 112.3, 116.0, 131.0, 135.9, 144.4, 154.2, 160.1, 164.6,
170.7.
The reaction vessel was charged with argon and subsequently
loaded with compound 6 (0.5 g, 2.4 mmol), dimethylformamide
(25 ml), N-(4-aminobenzoyl)-L-glutamic acid diethyl ester (0.92
g, 2.85 mmol), N,N'-dicyclohexylcarbodiimide (0.98 g, 4.75
mmol), and 1H-1,2,3-benzotriazol-1-ol (0.49 g, 3.6 mmol). The
reaction mixture was stirred under argon at room temperature for
7 days. Water (1.5 ml) was added and the reaction mixture was
stirred for an additional 1 hour. The precipitate was collected by
filtration, the filtrate was poured into water (ca. 250 ml). The pre-
cipitate was collected by filtration and suspended in 1 M sodium
hydroxide solution (ca. 7 ml). The mixture was stirred at room
temperature for 15 min and filtered. The filtrate was roughly
acidified with concentrated hydrochloric acid to pH 7 and then
adjusted to pH 4 with 5% hydrochloric acid. The precipitate that
formed was collected by filtration, washed with water (3 x 5 ml),
dried and recrystallised from a mixture of dimethylformamide
and water to give 0.47 g (43%) of 10c as a colorless solid, mp
Anal. Calcd. for C
H N O S: C, 54.24; H, 5.36; N, 14.08.
17 20 4 4
Found: C, 54.45; H, 5.60; N, 14.16.
Acknowledgements.
We express our gratitude to Mrs. E. Kersuliene and Mrs. M.
Gavrilova for the elmental analyses, to Mrs. M. Kreneviciene and
Mrs. A. Karosiene for the recording of NMR and IR spectra, and
to prof. A. Padarauskas for the performing of the electrophoresis
measurements.
REFERENCES AND NOTES
[1] I. M. Kompis, K. Islam, and R. L. Then, Chem. Rev., 105, 593
(2005).
[2] E. C. Taylor, D. Kuhnt, C. Shih, S. M. Rinzel, G. B. Grindey,
J. Barredo, M. Jannatipour, and R. G. Moran, J. Med. Chem., 35, 4450
(1992).
255° (dec); [α] = +8 (c = 2, DMF); ee 95%; ir (Nujol): 3409,
546
-1
1
3316, 3201, 3102 (NH , NH, OH), 1645 (CO) cm ; H nmr
2
(dimethylsulfoxide-d ): 1.90-2.16 (m, 2H, CH ), 2.37 (t, J = 7.4
6
2
[3] A. Gangjee, F. Mavandadi, S. F. Queener, and J. J. McGuire,
J. Med. Chem., 38, 2158 (1995).
Hz, 2H, CH ), 4.36-4.44 (m, 1H, CH), 7.01 (br.s, 2H, NH ), 7.84
(d, J = 9.0 Hz, 2H, Ar-H), 7.89 (d, J = 9.0 Hz, 2H, Ar-H), 8.28 (s,
2
2
[4] A. Gangjee, A. Vidwans, E. Elzein, J. J. McGuire, S. F.
Queener, and R. L. Kisliuk, J. Med. Chem., 44, 1993 (2001).
[5] A. Rosowsky, C. E. Mota, and S. F. Queener, J. Heterocyclic
Chem., 33, 1959 (1996).
[6] A. Rosowsky, A. T. Papoulis, and S. F. Queener, J. Med.
Chem., 40, 3694 (1997).
[7] A. Gangjee, R. Devraj, J. J. McGuire, R. L. Kisliuk, S. F.
Queener, L. R. Barrows, J. Med. Chem., 37, 1169 (1994).
[8] A. Gangjee, X. Guo, S. F. Queener, V. Cody, N. Galitsky, J. R.
Luft, and W. Pangborn, J. Med. Chem., 41, 1263 (1998).
[9] A. Rosowsky, C. E. Mota, J. E. Wright, J. H. Freisheim, J. J.
Heusner, J. J. McCormack, and S. F. Queener, J. Med. Chem., 36, 3103
(1993).
[10] I. O. Donkor, H. Li, and S. F. Queener, Eur. J. Med. Chem., 33,
605 (2003).
[11] S. Tumkevicius, Z. Sarakauskaite, and V. Masevicius,
Synthesis, 1377 (2003).
[12] S. Tumkevicius, Liebigs Ann. Chem., 1703 (1995).
[13] I. Susvilo, A. Brukstus, and S. Tumkevicius, Synlett, 1151
(2003).
[14] S. Tumkevicius and V. Masevicius, Synlett, 2327 (2004).
[15] S. Tumkevicius, A. Kaminskas, V. Bucinskaite, and L.
Labanauskas, Heterocycl. Commun., 9, 89 (2003).
[16] L. Bell, H. M. McGuire, and G. A. Freeman, J. Heterocyclic
Chem., 20, 41 (1983).
1H, C5-H), 8.51 (d, J = 7.5 Hz, 1H, CONH), 10.42 (br.s, 1H,
13
CONH), 11.25 (br.s, 1H, CONH), 12.46 (br.s, 2H, CO H);
C
2
nmr (dimethylsulfoxide-d ): 26.7, 31.2, 52.7, 117.1, 119.7, 125.5,
6
128.6, 129.0, 129.3, 142.4, 155.2, 159.1, 161.0, 166.7, 171.7,
174.2, 174.6.
Anal. Calcd. for C
H N O S: C, 49.67; H, 3.73; N, 15.24.
19 17 5 7
Found: C, 49.77; H, 3.71; N, 15.16.
2-Amino-4-methoxy-6-{[(3,4,5-trimethoxyphenyl)amino]-
methyl}thieno[2,3-d]pyrimidine (11).
The reaction vessel was charged with argon and loaded with
anhydrous tetrahydrofurane (15 ml) and lithium aluminium
hydride (0.36 g, 9.2 mmoles). Compound 9b (0.36 g, 0.92
mmoles) was added in portions and the reaction mixture was
stirred under argon at ambient temperature for 96 hours. Water
was added dropwise while stirring until evolution of hydrogen
ceased. The solid was collected by filtration and washed with
methanol (3 x 15 ml). The solvent from the filtrate was removed
under reduced pressure and the crude product was recrystallised
from a mixture of acetonitrile and water to give 0.09 g (26%) of
11 as a colorless solid, mp 136-137°; ir (potassium bromide):
-1
1
3471, 3357, 3331 cm (NH , NH). H nmr (deuterated chloro-
2
form): 3.79 (s, 3H, C4'-OCH ), 3.83 (s, 6H, C3',5'-OCH ), 4.03
3
3