A convenient synthesis of novel derivatives of pyrido[2,3-d][1,2,4] triazolo[4,3-a]pyrimidine-5,6-dione

Article abstract of DOI:10.1007/s00706-002-0469-8

Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl (Z)2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl (Z)-2-benzoylamino-3-([1,2,4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence of sodium ethoxide to afford novel derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-(1H, 8H)-diones.

Full text of DOI:10.1007/s00706-002-0469-8

Monatshefte fur Chemie 133, 1297±1304 ꢀ2002)
DOI 10.1007/s00706-002-0469-8
A Convenient Synthesis of Novel
Derivatives of Pyrido[2,3-d][1,2,4]
triazolo[4,3-a]pyrimidine-5,6-dione
Ã
Mosselhi A. N. Mosselhi
Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
Received February 8, 2002; accepted ꢀrevised) March 18, 2002
Published online August 14, 2002 # Springer-Verlag 2002
Summary. Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-
amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl ꢀZ)-
2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl ꢀZ)-2-benzoylamino-3-ꢀ[1,2,
4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence
of sodium ethoxide to afford novel derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-
ꢀ1H,8H)-diones.
Keywords. Pyrimidines; Synthetic methods; 1,2,4-Triazolopyrimidinone; Propenoate ester; Pyrido-
1,2,4-triazolo-pyrimidinedione.
Introduction
Triazolopyrimidines have been reported to exhibit in vivo leishmanicidal activity
against the amastigate stage of Leishmania donovani [1, 2] and cardiovascular
activity [3, 4]. They are cardiotonics, coronary vasadilators, and they have anti-
hypertensive properties [5]. They act against Aspergillus and Pencicillium species
[6] and have been tested as microbicidal and bioregulator agents [7]. Literature
protocols, applicable to the synthesis of 1,2,4-triazolo[4,3-a]pyrimidines have so far
been con®ned in general to the condensation of 2-hydrazinopyrimidin-4ꢀ3H)-ones
with carboxylic acids or their derivatives [1] or the oxidative cyclization of 2-aryl-
methylene hydrazinopyrimidin-4ꢀ3H)-ones with ferric chloride [8]. The 2-hydra-
zinopyrimidin-4ꢀ3H)-ones are usually prepared via two steps from 2-thiouracil [8].
In this paper a facile one-pot synthesis for some new derivatives of [1,2,4]tri-
azolo[4,3-a]pyrimidines is disclosed. Furthermore, we report the use of some of the
latter for the synthesis of novel derivatives of pyrido[2,3-d]-1,2,4-triazolo[4,3-a]py-
rimidine-5,6-ꢀ1H,8H)-diones. So far, only one example of pyrido[1,2,4]triazolo-
pyrimidines has been reported in the literature [9].
Ã
E-mail: mosselhi@chem-sci.cairo.eun.eg

1298
M. A. N. Mosselhi
Results and Discussion
L. Grubert [10] has reported that heating of nitrilimines with 1-methyl-4-phenyl-
pyrimidine-2-thione in benzene and triethylamine afforded spiro[pyrimidine-
2ꢀ1H),20ꢀ3H0)[1,3,4]thiadiazole]. When investigating the reaction of nitrilimines
3, which were generated in situ from hydrazonoyl halides 2 and triethylamine with
Scheme 1. R=Ar: a, C6H5=C6H5; b, CH3CO=C6H5; c, EtOCO=C6H5; d, C6H5NHCO=C6H5;
e, C6H5CO=C6H5; f, CH3CO=C6H4-4-CH3; g, C6H5NHCO=C6H4-4-CH3

Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-diones
1299
6-amino-2-thiouracil ꢀ1) in re¯uxing dioxane or sodium ethoxide in ethanol at
room temperature, a single product of a regioselective reaction was isolated. The
compound was characterized as 7-amino-1,3-disubstituted-[1,2,4]triazolo- [4,3-
a]pyrimidin-5ꢀ1H)-one ꢀ8) ꢀScheme 1).
The reaction pathway accounting for the formation of 8 from 1 and 3 is out-
lined in Scheme 1. It is proposed that the reaction involves an initial 1,3-addition
to give thiohydrazonate esters 4 which undergo a Smiles rearrangement to the
thiohydrazides 6 via intermediates 5. The latter then cyclize with concurrent elim-
ination of hydrogen sul®de to give the ®nal product. As outlined in Scheme 1,
there are two possible routes ꢀA and B) for the cyclization of 6 that will lead to 8
and 10.
The actual structure of the products was found to resemble that of 8 by their
1
analytical and spectroscopic data ꢀIR, H, 13C NMR and MS). For example, the
carbonyl stretching frequencies of 8 ꢀ1680±1700 cmÀ 1) were found to be similar
to those of pyrimidines of structure 15 ꢀ1680±1690 cmÀ 1) and not 16 ꢀ1640±
1660 cmÀ 1) [11, 12]. Furthermore, the carbonyl resonance of the products was
found at 164±165 ppm similar to that of 15 [12] ꢀFig. 1). On the basis of these
evidences, the products were assigned structure 8, and structure 10 was discarded.
Next, the reaction of the 7-amino-[1,2,4]triazolo[4,3-a]pyrimidin-5ꢀ1H)-ones 8
with methyl ꢀZ)-2-benzoylamino-3-dimethylamino propenoate ꢀ11) in re¯uxing
acetic acid was examined. It was found to afford the hitherto unreported methyl
ꢀZ)-2-benzoylamino-3-ꢀ[1,2,4]triazolo[4,3-a]-pyrimidin-7-yl)-aminopropenoate 12
and not isomer 13 ꢀScheme 2). The assignment of structures 12 were based on
their elemental analyses and spectral data. Their 1H NMR spectra showed a signal
at 3.7±3.8 ppm for the COOCH3 group and a resonance at 5.68±6.10 ppm for CH-6
of the pyrimidine ring, but gave no indication for an amino group.
Cyclization of 12 to the respective pyrido[2,3-d][1,2,4]triazolo-[4,3-a]pyrimi-
dine-5,6-ꢀ1H,8H)-diones 14 was carried out by sodium ethoxide in ethanol at room
temperature ꢀScheme 2). The structures of 14 were con®rmed by their elemental
1
analyses and spectroscopic data; their H NMR spectra revealed the absence of a
signal for the COOCH3 group. Furthermore, the assignment of the structure 14
is also substantiated by the chemical shift values of the carbonyl carbon of the
pyridinone ring ꢀC6, ꢀ,ꢁ-unsaturated ketone) in 14a and 14b ꢀ169 and 170 ppm)
which are similar to that of 16 ꢀ170±175 ppm, Fig. 1).
Fig. 1. 13C NMR shifts of strategic carbon atoms

1300
M. A. N. Mosselhi
Scheme 2
Experimental
Melting points were measured on a Gallenkamp apparatus and are uncorrected. Infrared spectra were
recorded in KBr using a Pye Unicam SP-300 instrument. 1H and 13C NMR spectra were measured in

DMSO-d6 on a Bruker AC 250 spectrometer at the Fachbereich Chemie, Universitat Rostock,
Germany, mass spectra on a GCMS-QP 100 EX facility. Elemental analyses were carried out at the
Microanalytical Laboratory at Cairo University, Giza, Egypt, and the at Fachbereich Chemie, Uni-

versitat Rostock, Germany; the results agreed favourably ꢀ Æ0.3) with the calculated values. The
starting 6-aminouracil-2-thione ꢀ1) [13], the hydrazonoyl halides 2 [14±17], and methyl ꢀZ)-2-benzoyl-
amino-3-dimethylamino propenoate ꢀ11) [18] were prepared as described in the literature.
Reaction of 1 with hydrazonoyl halides 2; general procedure
Method A. To a mixture of 1.43 g of thione 1 ꢀ0.01 mol) and the appropiate hydrazonoyl halide 2
ꢀ0.01 mol) in 40 cm3 dioxane ꢀand 10 cm3 DMF if necessary for solubility reasons), 1.4 cm3 ꢀ0.01 mol)
of triethylamine were added, and the mixture was heated under re¯ux until H2S evolution ceased

Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-diones
1301
ꢀ10±15h). Then the solvent was distilled off, and the residue was cooled. The solid formed was
®ltered, washed with MeOH, and crystallized from ethanol:dioxaneˆ 3:1 to give 8.
Method B. To a stirred ethanolic solution of NaOEt prepared from 0.023g ꢀ0.01 mol) Na and
20cm3 absolute EtOH, 1.43 g ꢀ0.01 mol) of 1 were added. After 10min, 0.01mol of the appropriate
hydrazonoyl halides 2 were added to the resulting solution, and the mixture was stirred at room
temperature for 24h. During this period the educts dissolved, and a new product precipitated. The
latter was ®ltered, washed with H2O, dried, and ®nally crystallized from ethanol:dioxane ˆ 3:1 to give
8. The products proved to be identical in all respects with those obtained by method A.
7-Amino-1,3-diphenyl[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one ꢀ8a; C17H13N5O)
Yield: 70%; m.p.: 250ꢀC; IR: ꢂ ˆ 3485, 3300, 1683cmÀ 1; 1H NMR ꢀDMSO-d6, ꢃ, 250 MHz): 4.9 ꢀs,
CH), 6.9 ꢀs, NH2), 7.39±8.20 ꢀm, 10 Ar±H) ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9 MHz): 76, 121, 122,
‡
126, 127, 128, 130, 131, 137, 144, 149, 157, 164ppm; MS: m=z ꢀ%) ˆ 303 ꢀM , 80), 193 ꢀ5), 160
ꢀ17), 91 ꢀ100), 77 ꢀ24).
7-Amino-3-acetyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one ꢀ8b; C13H11N5O2)
1
Yield: 65%; m.p.: 185ꢀC; IR: ꢂ ˆ 3480, 3310, 1700, 1690cmÀ 1; H NMR ꢀDMSO-d6, ꢃ, 250MHz):
2.7 ꢀs, CH3CO), 5.00 ꢀs, CH), 6.80 ꢀs, NH2), 7.20±8.20 ꢀm, 5 Ar±H) ppm; 13C NMR ꢀDMSO-d6, ꢃ,
‡
62.9MHz): 21, 77, 120, 121, 123, 128, 129, 130, 142, 164, 192ppm; MS: m=z ꢀ%) ˆ 269 ꢀM , 100),
194 ꢀ7), 159 ꢀ9), 91 ꢀ61), 77 ꢀ79).
7-Amino-3-ethoxycarbonyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one
ꢀ8c; C14H13N5O3)
Yield: 75%; m.p.: 215ꢀC; IR: ꢂ ˆ 3480, 33150, 1750, 1695cmÀ 1; 1H NMR ꢀDMSO-d6, ꢃ, 250MHz):
1.39 ꢀt, J ˆ 7.2 Hz, CH3), 4.5 ꢀq, J ˆ 7.2 Hz, CH2), 4.92 ꢀs, CH), 7.00 ꢀs, NH2), 7.40±8.00 ꢀm, 5 Ar±H)
ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9 MHz): 13, 63, 77, 121, 127, 129, 135, 136, 147, 154, 160, 165 ppm;
‡
MS: m=z ꢀ%) ˆ 299 ꢀM , 90), 194 ꢀ10), 159 ꢀ9), 91 ꢀ61), 77 ꢀ100).
7-Amino-3-phenylcarbamoyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one
ꢀ8d; C18H14N6O2)
1
Yield: 80%; m.p.: 235ꢀC; IR: ꢂ ˆ 3485, 3326, 1694, 1650cmÀ 1; H NMR ꢀDMSO-d6, ꢃ, 250MHz):
5.00 ꢀs, CH), 7.10 ꢀs, NH2), 7.50±8.10 ꢀm, 10 Ar±H), 13.00 ꢀs, NH) ppm; 13C NMR ꢀDMSO-d6, ꢃ,
62.9MHz): 65, 120, 122, 127, 128, 129, 130, 137, 139, 142, 152, 156, 162, 165 ppm; MS: m=z
‡
ꢀ%) ˆ 346 ꢀM , 80), 226 ꢀ33), 199 ꢀ13), 160 ꢀ12), 91 ꢀ77), 77 ꢀ89).
7-Amino-3-benzoyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one ꢀ8e; C18H13N5O2)
1
Yield: 80%; m.p.: 242ꢀC; IR: ꢂ ˆ 3485, 3326, 1690, 1660cmÀ 1; H NMR ꢀDMSO-d6, ꢃ, 250MHz):
‡
5.00 ꢀs, CH), 6.88 ꢀs, NH2), 7.30±8.10 ꢀm, 10 Ar±H) ppm; MS: m=z ꢀ%) ˆ 331 ꢀM , 80), 222 ꢀ30),
105 ꢀ100), 77 ꢀ90).
7-Amino-3-acetyl-1-0p-methylphenyl)-[1,2,4]triazolo[4,3-a]pyrimidin-501H)-one
ꢀ8f; C14H13N5O2)
1
Yield: 73%; m.p.: 165ꢀC; IR: ꢂ ˆ 3485, 3300, 1700, 1685cmÀ 1; H NMR ꢀDMSO-d6, ꢃ, 250MHz):
2.3 ꢀs, CH3), 2.7 ꢀs, CH3CO), 4.98 ꢀs, CH), 6.90 ꢀs, NH2), 7.30±8.10 ꢀm, 4 Ar±H) ppm; MS: m=z
‡
ꢀ%) ˆ 283 ꢀM , 100), 192 ꢀ7), 160 ꢀ10), 91 ꢀ60), 77 ꢀ89).

1302
M. A. N. Mosselhi
7-Amino-3-phenylcarbamoyl-1-0p-methylphenyl)-[1,2,4]triazolo[4,3-a]pyrimidin-
501H)-one ꢀ8g; C19H16N6O2)
1
Yield: 82%; m.p.: 225ꢀC; IR: ꢂ ˆ 3485, 3320, 1690, 1650cmÀ 1; H NMR ꢀDMSO-d6, ꢃ, 250MHz):
2.30 ꢀs, CH3), 5.00 ꢀs, CH), 7.10 ꢀs, NH2), 7.3±8.0 ꢀm, 9 Ar±H), 11.80 ꢀs, NH) ppm; MS: m=z
‡
ꢀ%) ˆ 360 ꢀM , 100), 220 ꢀ50), 180 ꢀ40), 149 ꢀ11), 91 ꢀ100), 77 ꢀ63).
Reaction of 8 with methyl 0Z)-2-benzoylamino-3-dimethylamino propenoate 11;
general procedure
To a boiling solution of 0.01mol of compound 8 in 50cm3 glacial acetic acid, 0.01mol of methyl ꢀZ)-
2-benzoylamino-3-dimethylamino propenoate ꢀ11) were added, and the mixture was re¯uxed for
6±10 h ꢀTLC monitoring). The solvent was evaporated in vacuo, and the residue was recrystallized
from dioxane:ethanol ˆ 1:1 to give 12.
Methyl 0Z)-2-benzoylamino-3-01,3-diphenyl[1,2,4]triazolo[4,3-a]pyrimidin-7-yl)-amino
propenoate ꢀ12a; C28H22N6O4)
Yield: 86%; m.p.: 180±182ꢀC; IR: ꢂ ˆ 3435, 1710, 1680, 1660cmÀ 1
;
1H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 3.71 ꢀs, COOCH3), 6.10 ꢀs, 60-CH) 7.3±8.20 ꢀm, 15 Ar±H), 8.85 ꢀd, J ˆ 12 Hz, 3-CH),
9.60 ꢀs, NH), 10.20 ꢀd, J ˆ 12 Hz, 3-NH) ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9MHz): 51, 68, 83, 107,
121, 121, 124, 127, 128, 129, 130, 132, 133, 134, 136, 138, 139, 147, 152, 157, 162, 165 ppm; MS:
‡
m=z ˆ 506 ꢀM , 80), 475 ꢀ25), 385 ꢀ25), 265 ꢀ10), 105 ꢀ100), 91 ꢀ50), 77 ꢀ75).
Methyl 0Z)-2-benzoylamino-3-03-acetyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-7-yl)-amino
propenoate ꢀ12b; C28H22N6O4)
1
Yield: 75%; m.p.: 232±234ꢀC; IR: ꢂ ˆ 3455, 1725, 1700, 1675, 1660 cmÀ 1; H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 2.70 ꢀs, COCH3), 3.80 ꢀs, COOCH3), 6.00 ꢀs, 60-CH), 7.2±8.10 ꢀm, 10 Ar±H), 8.50 ꢀd,
‡
J ˆ 12, 3-CH), 9.10 ꢀs, 1H, NH), 10.30 ꢀd, J ˆ 12 Hz, 3-NH) ppm; MS: m=z ˆ 472 ꢀM , 65), 440 ꢀ20),
384 ꢀ20), 265 ꢀ5), 105 ꢀ100), 91 ꢀ40), 77 ꢀ70).
Methyl 0Z)-2-benzoylamino-3-03-ethoxycarbonyl-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-7-yl)-
amino propenoate ꢀ12c; C25H22N6O6)
1
Yield: 68%; m.p.: 191±192ꢀC; IR: ꢂ ˆ 3430, 1750, 1710, 1675, 1655cmÀ 1; H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 1.39 ꢀt, J ˆ 7.1 Hz, CH3), 3.72 ꢀs, 3H, H), COOCH3), 4.5 ꢀq, J ˆ 7.1 Hz, CH2), 5.99 ꢀs,
60-CH) 7.30±8.10 ꢀm, 5 Ar±H), 8.50 ꢀd, J ˆ 12Hz, 3-CH), 8.80 ꢀs, NH), 9.25 ꢀd, J ˆ 12Hz, 3-NH),
‡
10.50 ꢀs, NH) ppm; MS: m=z ˆ 502 ꢀM , 80), 470 ꢀ25), 385 ꢀ20), 265 ꢀ10), 105 ꢀ90), 91 ꢀ50),
77 ꢀ100).
Methyl 0Z)-2-benzoylamino-3-03-phenylcarbamoyl-1-phenyl[1,2,4]
triazolo[4,3-a]pyrimidin-7-yl)-amino propenoate ꢀ12d; C29H23N7O5)
Yield: 76%; m.p.: 250±251ꢀC; IR: ꢂ ˆ 3448, 1708, 1660, 1638cmÀ 1
;
1H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 3.72 ꢀs, COOCH3), 5.68 ꢀs, 60-CH) 7.15±8.18 ꢀm, 15 Ar±H), 8.40 ꢀd, J ˆ 12Hz, 3-CH),
8.77 ꢀs, NH), 9.30 ꢀd, 12Hz, 3-NH), 12.10 ꢀs, 1H, NH) ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9MHz): 52,
67, 83, 107, 120, 122, 125, 128.2, 128.5, 129, 130, 132, 133, 134, 136, 138, 139, 148, 153, 157, 159,
‡
165, 166 ppm; MS: m=z ˆ 549 ꢀM , 50), 517 ꢀ20), 384 ꢀ20), 265 ꢀ15), 237 ꢀ15), 119 ꢀ100), 91 ꢀ80),
77 ꢀ20).

Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-diones
Cyclization of 12; general procedure
1303
To a stirred ethanolic NaOEt solution prepared from 0.46g ꢀ20 mmol) Na and 40cm3 of absolute
EtOH, 0.01 mol of 12 were added, and the mixture was stirred at room temperature overnight. The
excess slovent was evaporated in vacuo, and 20 cm3 H2O were added. The solid formed was ®ltered,
dried, and crystallized from dioxane to afford 14.
7-Benzoylamino-1,3-diphenyl-pyrido[2,3-d][1,2,4]triazolo
[4,3-a]pyrimidin-5,6-01H,8H)-dione ꢀ14a; C27H18N6O3)
Yield: 78%; m.p.: 272±273ꢀC; IR: ꢂ ˆ 3350, 1680, 1658, 1645cmÀ 1
;
1H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 7.15±8.18 ꢀm, 15 Ar±H), 8.30 ꢀd, J ˆ 2 Hz, 3-CH), 8.90 ꢀs, NH), 9.35 ꢀd, J ˆ 2 Hz, 3-
NH) ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9 MHz): 70, 85, 110, 121, 122, 125, 127, 128, 129, 130, 131,
‡
132, 134, 136, 138, 139, 147, 152, 157, 164, 169 ppm; MS: m=z ꢀ%) ˆ 474 ꢀM , 50), 397 ꢀ20), 369
ꢀ30), 265 ꢀ15), 105 ꢀ100), 77 ꢀ80).
7-Benzoylamino-3-acetyl-1-phenyl-pyrido[2,3-d][1,2,4]triazolo
[4,3-a]pyrimidin-5,6-01H,8H)-dione ꢀ14b; C23H16N6O4)
Yield: 62%; m.p.: 275±276ꢀC; IR: ꢂ ˆ 3345, ꢀNH), 1720, 1680, 1660, 1650cmÀ 1; 1H NMR ꢀDMSO-
d6, ꢃ, 250 MHz): 2.6 ꢀs, COCH3), 7.30±8.00 ꢀm, 10 Ar±H), 8.50 ꢀd, J ˆ 2 Hz, 3-CH), 9.10 ꢀs, NH), 9.43
‡
ꢀd, J ˆ 2 Hz, 3-NH) ppm; MS: m=z ꢀ%) ˆ 440 ꢀM , 40), 363 ꢀ10), 320 ꢀ30), 265 ꢀ15), 105 ꢀ50), 77
ꢀ90).
7-Benzoylamino-3-ethoxycarbonyl-1-phenyl-pyrido[2,3-d][1,2,4]
triazolo[4,3-a]pyrimidin-5,6-01H,8H)-dione ꢀ14c; C24H18N6O5)
1
Yield: 75%; m.p.: 264±265ꢀC; IR: ꢂ ˆ 3350, 1740, 1675, 1660, 1645 cmÀ 1; H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 1.38 ꢀt, J ˆ 7.1 Hz, CH3), 4.4 ꢀq, J ˆ 7.1 Hz, CH2), 7.15±8.20 ꢀm, 10 Ar±H)), 8.40 ꢀd,
‡
J ˆ 2 Hz, 3-CH), 8.95 ꢀs, 1H, NH), 10.10 ꢀd, J ˆ 2 Hz, 3-NH) ppm; MS: m=z ꢀ%) ˆ 470 ꢀM , 20), 393
ꢀ50), 365 ꢀ30), 350 ꢀ15), 105 ꢀ40), 77 ꢀ100).
7-Benzoylamino-3-phenylcarbamoyl-1-phenyl-pyrido[2,3-d][1,2,4]
triazolo[4,3-a]pyrimidin-5,6-01H,8H)-dione ꢀ14d; C28H19N7O4)
Yield: 78%; m.p.: 287±289ꢀC; IR: ꢂ ˆ 3300, 1680, 1660, 1630cmÀ 1
;
1H NMR ꢀDMSO-d6, ꢃ,
250 MHz): 7.20±8.20 ꢀm, 15 Ar±H), 8.50 ꢀd, J ˆ 2 Hz, 3-CH), 8.90 ꢀs, NH), 9.40 ꢀd, J ˆ 2 Hz, 3-
NH) ppm; 13C NMR ꢀDMSO-d6, ꢃ, 62.9 MHz): 69, 84, 110, 121, 123, 125, 127, 128, 129, 130, 131,
‡
132, 133, 135, 138, 139, 146, 152, 157, 159, 165, 170ppm; MS: m=z ˆ 417 ꢀM , 65), 440 ꢀ25), 412
ꢀ30), 397 ꢀ15), 105 ꢀ30), 77 ꢀ100).
Acknowledgments

The author thanks Prof. Dr. K. Peseke, Fachbereich Chemie, Universitat Rostock, Germany, for
measuring the NMR spectra and for elemental analyses of some of the products.
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1304
M. A. N. Mosselhi: Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-diones
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