Novel Pentaheterocycles. First General Synthesis Entry to Functionalized Derivatives of Pyrido[2,3-f:6,5-f′]di[1,2,4]triazolo[4,3-a] pyrimidin-5(1H)-ones

Article abstract of DOI:10.1007/s00706-003-0113-2

Thirteen derivatives of the novel title ring system were synthesized via a two-step procedure that utilizes hydrazonoyl chlorides and pyridodipyrimidinones as starting materials. The mechanism and regiochemistry of the reactions studied are discussed and

Full text of DOI:10.1007/s00706-003-0113-2

Monatshefte f€ur Chemie 135, 211–222 (2004)
DOI 10.1007/s00706-003-0113-2
Novel Pentaheterocycles.
First General Synthesis Entry
to Functionalized Derivatives
of Pyrido[2,3-f:6,5-f0]di[1,2,4]triazolo[4,3-a]
pyrimidin-5(1H)-ones
Mosselhi A. N. Mosselhi, Magda A. Abdallah,
ꢀ
Thoraya A. Farghaly, and Ahmad S. Shawali
Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
Received July 18, 2003; accepted (revised) August 28, 2003
Published online November 27, 2003 # Springer-Verlag 2003
Summary. Thirteen derivatives of the novel title ring system were synthesized via a two-step proce-
dure that utilizes hydrazonoyl chlorides and pyridodipyrimidinones as starting materials. The mecha-
nism and regiochemistry of the reactions studied are discussed and the compounds prepared were
1
characterized by alternate synthesis, spectra (mass, IR, H and 13C NMR), and elemental analyses.
Keywords. Hydrazonoyl chlorides; Regiochemistry; Hydrazonothioates; Heterocycles.
Introduction
As a continuation of our studies of hydrazonic acid derivatives [1–4], it was
decided to synthesize a series of novel bis(hydrazonothioate) esters of type 2
derived from the corresponding heterocyclic dithiones 1 (Formulae 1) and explore
their utility in the synthesis of novel annelated triazoles with bridgehead nitrogen
atoms. Alkyl, aryl, and heteroaryl-hydrazonate esters and their thio analogs were
proved to be useful precursors for the synthesis of a variety of acyclic and hetero-
cyclic compounds [3–7].
Recently, Shawali et al. reported also that such esters are useful synthons for
fused heterocycles such as [1,2,4]triazolo[4,3-b][1,2,4]triazin-7(1H)-ones [8],
[1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-ones [9], pyrimido[1,2-b][1,2,4,5]tetrazines
[10], and [1,2,4]triazino[4,3-b][1,2,4,5]tetrazines [11]. In this paper we report
the first synthesis of thirteen derivatives of the novel title ring system, namely
pyrido[2,3-f:6,5-f0]di[1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one 3. The heart of
ꢀ
Corresponding author. E-mail: as_shawali@mail.com

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M. A. N. Mosselhi et al.
Formulae 1
our plan was the preparation of the hitherto unreported bis(hydrazonothioate) esters
6 (Formulae 1) from 5-pheny1-1,3,7,9-tetrahydro-2,8-dithioxopyrido[2,3-d:6,5-d0]-
dipyrimidine-4,6(3H,9H)-dione 4 and the respective hydrazonoyl chlorides 5.
Results and Discussion
The starting material, 5-phenyl-1,3,7,9-tetrahydro-2,8-dithioxopyrido[2,3-d:6,5-d0]
dipyrimidine-4,6(1H,9H)-dione (4) [12] was prepared in one step by reaction of 6-
amino-2-thiouracil [13] with benzaldehyde in acetic acid under reflux as previously
described. Reaction of 4 with hydrazonoyl chlorides 5 in ethanol in the presence of
sodium ethoxide at room temperature was found to give products that were identified
as the bis(hydrazonothioate) esters 6 (Scheme 1). The structures of the latter prod-
ucts were established from their microanalyses and mass, IR, and 1H NMR spectra
which showed the expected signals. For example, like other aryl and heteroaryl
hydrazonothioate esters [14], loss of elements of the corresponding thiol 4 from
the molecular ions was a characteristic feature of the mass spectra of 6.
Next, we examined the Smiles rearrangement of the esters 6 in an attempt to get
the respective bis(thiohydrazides) 7. When each of 6 was refluxed in ethanol in the

Novel Pentaheterocycles
213
Scheme 1
presence of sodium ethoxide, a single product was obtained in each case as evi-
denced by tlc analysis of the crude products. Surprisingly however, the microanal-
yses and mass spectral data of the isolated products showed that they were free of
sulfur and such data were consistent with either one of the two isomeric structures
8 and 9 (Scheme 1). An immediate distinction between these structures was
reached by comparison of the 13C NMR and IR spectra of the products with those
of related isomeric annelated pyrimidinones. Literature reports have shown that in
the 4-pyrimidinone ring structure, the chemical shift of the carbonyl carbon is
markedly affected by the nature of the adjacent nitrogen (pyrrole type in structure

214
M. A. N. Mosselhi et al.
Formulae 2
8 and pyridine type in structure 9). The chemical shift values of the annelated
pyrimidinones A and B are shown in Formulae 2 [15–17, 22]. Since the values
found for the isolated products are similar to those of A and not B, the products
were assigned structure 8. Furthermore, the assignment of structure 8 to the prod-
ucts isolated is also substantiated by the similarity of their carbonyl stretching
frequencies (ꢀꢀ¼ 1670–1700 cmꢁ1) with those of pyrimidinone derivatives A. For
example, pyrimidinone derivatives A exhibit their CO bands in the region
ꢀꢀ¼ 1680–1690 cmꢁ1 whereas pyrimidinones B exhibit their CO absorption bands
in the region ꢀꢀ¼ 1640–1660 cmꢁ1 [17].
The direct formation of the products 8 from compounds 6 indicated that the
intermediate thiohydrazides 7 underwent in situ cyclization as soon as they are
formed (Scheme 1). To account for this transformation, we thought of an alternate
synthesis of the products 8. The synthesis strategy employed in this work for the
preparation of the latter compounds is based on application of Japp-Klingemann
reaction [18] and Smiles rearrangement [19, 20]. Thus, treatment of the dithione 4
with two molar equivalents of ethyl 2-chloro-3-oxobutanoate in ethanol in the
presence of potassium hydroxide at room temperature yielded the substitution
product 10 (Scheme 2). The formation of the latter derivative is analogous to S-
alkylation reaction reported to be exhibited by 2-thiouracils [21]. The structure of
the latter product was evidenced by its microanalysis and spectroscopic (mass, IR,
1
1H NMR) data. Its H NMR spectrum showed two characteristic singlet signals
near ꢁ ¼ 2.40 and 5.37 ppm assignable to the CH3CO and –SCH(R)-protons in
addition to the characteristic signals of the –COOCH2CH3 groups. Treatment of
10 with p-chlorobenzenediazonium chloride in ethanol in the presence of sodium
acetate at low temperature (0–5ꢂC) yielded a product identical in all respects (mp,
mixed mp, IR) with that one 6k isolated from reaction of 5k with 4 above

Novel Pentaheterocycles
215
Scheme 2
(Scheme 1). In our hands, attempts to get the bis(thiohydrazide) 7k by refluxing the
bis(hydrazonothioate) 6k were found to give 8k directly as end product.
The final structure proof was completed by alternate synthesis of 8m, as a
typical example of the series, from 7-amino-1,3-diphenyl-[1,2,4]triazolo[4,3-a]py-
rimidin-5(1H)-one (11) which was reported recently from our laboratory [23].
Thus, refluxing an equimolar mixture of 11 and benzaldehyde in glacial acetic
acid and work up of the reaction mixture, yielded 8m in 70% yield and proved
to be identical in all respects with that one obtained from base catalyzed cycliza-
tion of the bis(hydrazonothioate) ester 6m.

216
M. A. N. Mosselhi et al.
Scheme 3
Experimental
All melting points were determined on an electrothermal Gallenkamp apparatus. The IR spectra were
1
measured on a Pye-Unicam SP300 instrument in KBr discs. The H and 13C NMR spectra were
recorded on a Varian Mercury VXR-300 spectrometer (300 MHz for 1H and 75MHz for 13C) in CDCl3
or DMSO-d6 and the chemical shifts were related to that of the solvent. The mass spectra were
recorded on a GCMS-Q1000-EX spectrometer, the ionizing voltage was 70eV. Elemental analyses
were carried out by the Microanalytical Center of Cairo University, Giza, Egypt. The identification of
compounds from different experiments were secured by mixed mps and superimposable IR spectra.
The reagents 4-amino-2-thiouracil [13], 5-pheny1-1,3,7,9-tetrahydro-2,8-dithioxopyrido[2,3-d:6,5-
d0]dipyrimidine-4,6(1H,9H)-dione 4 [12] and the hydrazonoyl chlorides 5 [6] were prepared as pre-
viously described.
General Procedures for the Synthesis of 5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidine-
4,6(3H,7H)-dione-2,8-diyl bis(N-arylalkanehydrazonothioates) 6
Method A: To an ethanolic EtONa solution, prepared from 0.115g of Na (5mmol) and 30cm3 of
absolute EtOH, 0.9 g of dithione 4 (2.5mmol) were added with stirring. To the resulting solution
5 mmol of the appropriate hydrazonoyl chloride 5 were added and the mixture was stirred at room
temperature for 24 h. The precipitated solid was filtered off, washed with H2O, dried, and finally
crystallized from the appropriate solvent to give the respective bis(hydrazonothioate) ester 6.
Reaction of 4 with 5e, when it was carried out as above, gave the cyclized product 8e directly.
However, when the reaction mixture was stirred only for 1 h, it gave the bis(hydrazonothioate) ester 6e.
Method B: To a solution of 0.01 mol of 10 in 40cm3 of EtOH and 10cm3 of DMF was added 3 g of
AcONa ꢃ 3H2O and the mixture was cooled in an ice-bath to 0–5ꢂC while being stirred. To the resulting

Novel Pentaheterocycles
217
cold solution a cold solution of p-chlorobenzenediazonium chloride, prepared as usual by diazotizing
2.55g of p-chloroaniline (0.02 mol) in 12 cm3 of 6 M HCl with 1.4g of NaNO2 (0.02 mol) in 10cm3 of
H2O, was added portionwise. After all the diazonium solution was added, the reaction mixture was
stirred for further 30min while being cooled in the ice bath. The precipitated solid was then filtered off,
washed with H2O, dried, and finally crystallized from the appropriate solvent to give the respective
hydrazonothioate ester 6k. The latter product proved to be identical in all respects (mp, mixed mp, and
IR) with that obtained by Method A.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-phenyl(phenylaminocarbonyl)methanehydrazonothioate) (6a, C43H31N11O4S2)
1
Yield 1.61 g (78%); mp 234ꢂC (EtOH dioxane); IR: ꢀꢀ¼ 3394, 3178, 1682, 1663cmꢁ1; H NMR
(DMSO-d6): ꢁ ¼ 7.07–7.84 (m, 25H), 10.12 (s, 2H), 11.68 (s, 2H), 11.97 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl bis(N-(4-
methylphenyl)(phenylaminocarbonyl)methanehydrazonothioate) (6b, C45H35N11O4S2)
Yield 1.71 g (80%); mp 222–4ꢂC (EtOH); IR: ꢀꢀ¼ 3387, 3158, 1689, 1659 cmꢁ1; 1H NMR (DMSO-d6)
ꢁ ¼ 2.40 (s, 6H), 7.14–8.80 (m, 23H), 10.18 (s, 2H), 11.74 (s, 2H), 12.03 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl bis(N-(4-
chlorophenyl)(phenylaminocarbonyl)methanehydrazonothioate) (6c, C43H29N11O4S2Cl2)
1
Yield 1.90g (85%); mp 236–8ꢂC (EtOH dioxane); IR: ꢀꢀ¼ 3395, 3194, 1688, 1658 cmꢁ1; H NMR
(DMSO-d6): ꢁ ¼ 7.12–8.24 (m, 23H), 10.25 (s, 2H), 11.66 (s, 2H), 12.1 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl bis(N-(4-
nitrophenyl)(phenylaminocarbonyl)methanehydrazonothioate) (6d, C43H29N13O8S2)
1
Yield 1.88 g (82%); mp 248ꢂC (EtOH dioxane); IR: ꢀꢀ¼ 3333, 3186, 1680, 1653cmꢁ1; H NMR
(DMSO-d6): ꢁ ¼ 7.05–8.58 (m, 23H), 10.35 (s, 2H), 10.72 (s, 2H), 11.5 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-phenyl-2-oxopropanehydrazonothioate) (6e, C33H25N9O4S2)
1
Yield 1.14 g (68%); mp 250ꢂC (EtOH); IR: ꢀꢀ¼ 3333, 3186, 1720, 1666 cmꢁ1; H NMR (DMSO-d6):
ꢁ ¼ 2.46 (s, 6H), 7.01–8.13 (m, 15H), 11.90 (s, 2H), 12.08 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-methylphenyl)-2-oxopropanehydrazonothioate) (6f, C35H29N9O4S2)
Yield 1.3 g (74%); mp 210ꢂC (dioxane); IR: ꢀꢀ¼ 3325, 3186, 1720, 1666cmꢁ1; 1H NMR (DMSO-d6):
ꢁ ¼ 2.39 (s, 6H), 2.5 (s, 6H), 6.8–7.94 (m, 13H), 11.85 (s, 2H), 12.19 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-chlorophenyl)-2-oxopropanehydrazonothioate) (6g, C33H23Cl2N9O4S2)
1
Yield 1.48 g (80%); mp 222ꢂC (EtOH dioxane); IR: ꢀꢀ¼ 3410, 3194, 1712, 1660cmꢁ1; H NMR
(DMSO-d6): ꢁ ¼ 2.50 (s, 6H), 6.8–8.18 (m, 13H), 11.86 (s, 2H), 12.08 (s, 2H) ppm.

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M. A. N. Mosselhi et al.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-nitrophenyl)-2-oxopropanehydrazonothioate) (6h, C33H23N11O8S2)
1
Yield 1.56 g (82%); mp 230ꢂC (EtOH); IR: ꢀꢀ¼ 3395, 3195, 1710, 1660 cmꢁ1; H NMR (DMSO-d6):
ꢁ ¼ 2.50 (s, 6H), 6.72–7.25 (m, 13H), 11.86 (s, 2H), 12.08 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-phenyl(ethoxycarbonyl)methanehydrazonothioate) (6i, C35H29N9O6S2)
Yield 1.52 g (83%); mp 188–90ꢂC (EtOH); IR: ꢀꢀ¼ 3410, 3186, 1744, 1670 cmꢁ1; 1H NMR (DMSO-d6):
ꢁ ¼ 1.31 (t, 6H, J ¼ 7 Hz), 4.40 (q, 4H, J ¼ 7 Hz), 6.96–8.15 (m, 15H), 11.85 (s, 2H), 12.18 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-methylphenyl)(ethoxycarbonyl)methanehydrazonothioate) (6j, C37H33N9O6S2)
1
Yield 1.62 g (85%); mp 192ꢂC (EtOH); IR: ꢀꢀ¼ 3317, 3180, 1755, 1678 cmꢁ1; H NMR (DMSO-d6):
ꢁ ¼ 1.31 (t, 6H, J ¼ 7 Hz), 2.38 (s, 6H), 4.37 (q, 4H, J ¼ 7 Hz), 6.84–7.95 (m, 13H), 11.82 (s, 2H),
12.10 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-chlorophenyl)(ethoxycarbonyl)methanehydrazonothioate) (6k, C35H27Cl2N9O6S2)
1
Yield 1.54 g (77%); mp 220ꢂC (EtOH); IR: ꢀꢀ¼ 3317, 3140, 1759, 1682 cmꢁ1; H NMR (DMSO-d6):
ꢁ ¼ 1.29 (t, 6H, J ¼ 7 Hz), 4.32 (q, 4H, J ¼ 7 Hz), 7.07–8.15 (m, 13H), 11.90 (s, 2H), 12.15 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-(4-nitrophenyl)(ethoxycarbonyl)methanehydrazonothioate) (6l, C35H27N11O10S2)
1
Yield 1.77 g (86%); mp 205ꢂC (EtOH); IR: ꢀꢀ¼ 3325, 3154, 1744, 1650 cmꢁ1; H NMR (DMSO-d6):
ꢁ ¼ 1.26 (t, 6H, J ¼ 7 Hz), 4.41 (q, 4H, J ¼ 7 Hz), 6.78–8.49 (m, 13H), 11.8 (s, 2H), 12.1 (s, 2H) ppm.
5-Phenylpyrido[2,3-d:6,5-d0]dipyrimidin-4,6(3H,7H)-dione-2,8-diyl
bis(N-phenylbenzenecarbohydrazonothioate) (6m, C41H29N9O2S2)
Yield 1.48g (80%); mp 240ꢂC (EtOH dioxane); IR: ꢀꢀ¼ 3313, 3109, 1670cmꢁ1; 1H NMR (DMSO-d6):
ꢁ ¼ 6.92–8.20 (m, 25H), 11.85 (s, 2H), 12.58 (s, 2H) ppm.
General Procedures for the Synthesis of 1,3,6,9,11-Pentasubstituted Pyrido[3,2-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-ones) 8
Method A: To a solution of EtONa, prepared from 0.12g of Na (5mmol) and 30 cm3 of absolute EtOH,
0.9 g of 4 (2.5mmol) and 5 mmol of the appropriate hydrazonoyl chloride 5 were added. The reaction
mixture was refluxed until H2S ceased to evolve (10–20 h), and then cooled. The precipitated product
was filtered off, washed with water, and crystallized from the appropriate solvent to give the respective
product 8.
Method B: To a solution of EtONa, prepared from 0.23g of Na (10mmol) and 30cm3 of absolute
EtOH, was added 5 mmol of the appropriate bis(hydrazonothioate) ester 6 and the mixture was refluxed
until H2S ceased to evolve (10–20 h), and then cooled. The precipitated product was filtered off,
washed with H2O and crystallized from the appropriate solvent to give the respective 8. The physical
constants of the products 8b, 8f, 8i–8l, and 8m, prepared by this method, proved to be identical in all
respects with those obtained by Method A.

Novel Pentaheterocycles
219
Method C: A mixture of 3.03g of 11 (10 mmol) and 0.63g of benzaldehyde (5mmol) in 30cm3 of
glacial AcOH was refluxed for 4 h, then the reaction mixture was diluted with H2O and allowed to cool
to room temperature. The crude product was collected and crystallized from EtOH to give the
corresponding product 8m, which proved to be identical in all respects with that one obtained by
either Method A or B.
3,9-Di(phenylaminocarbonyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) (8a, C43H27N11O4)
Yield 5.33 g (70%); mp 298–300ꢂC (EtOH dioxane); yellow-white crystals; UV (dioxane): ꢂmax
1
(log ") ¼ 363 (4.36) nm; IR: ꢀꢀ¼ 3417, 1689, 1670 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 7.12 (m, 25H),
11.72(s,2H)ppm;MS:m=z(%) ¼ 761(Mþ,26),524(28),475(30),236(53),122(34),116(64),88(100).
3,9-Di(4-methylphenylaminocarbonyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) (8b, C45H31N11O4)
Yield 6.47 g (82%); mp 252ꢂC (dioxane); yellow white crystals; UV (dioxane): ꢂmax (log") ¼ 336
(4.51) nm; IR: ꢀꢀ¼ 3314, 1690, 1670cmꢁ1
;
1H NMR (DMSO-d6): ꢁ ¼ 2.51 (s, 6H), 6.84–8.30
(m, 23H), 11.72 (s, 2H) ppm; MS: m=z (%) ¼ 788 (Mþ–1, 43), 718 (67), 634 (67), 599 (62), 433
(57), 366 (62), 332 (67), 287 (71), 202 (67), 79 (100).
3,9-Di(4-chlorophenylaminocarbonyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) (8c, C43H25Cl2N11O4)
Yield 6.56g (79%); mp 226ꢂC (EtOH dioxane); yellow crystals; UV (dioxane): ꢂmax (log") ¼ 372
1
(4.54) nm; IR: ꢀꢀ¼ 3386, 1700, 1658 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 7.22–8.12 (m, 23H), 11.20
(s, 2H) ppm; 13C NMR (DMSO-d6): ꢁ ¼ 163.4, 157.0, 153.8, 148.2, 139.3, 138.4, 136.9, 136.7, 131.8,
130.3, 129.8, 129.5, 128.5, 128.0, 125.5, 121.7, 120.4, 98.0 ppm; MS: m=z (%) ¼ 830 (Mþ, 7), 522 (7),
453 (10), 239 (6), 122 (6), 118 (6), 88 (30), 57 (100).
3,9-Di(4-nitrophenylaminocarbonyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) (8d, C43H25N13O8)
Yield 6.38 g (75%); mp 280ꢂC (dioxane); yellow crystals; UV (dioxane): ꢂmax (log ") ¼ 350 (4.57) nm;
1
IR: ꢀꢀ¼ 3344, 1701, 1670 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 7.22–8.12 (m, 23H), 11.20 (s, 2H) ppm;
MS: m=z (%) ¼ 853 (Mþ þ 2, 24), 849 (20), 524 (15), 451 (18), 153 (31), 121 (35), 87 (31), 56 (100).
3,9-Di(acetyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]di([1,2,4]triazolo[4,3-a]
pyrimidin-5(1H)-one) (8e, C33H21N9O4)
Yield 4.92g (81%); mp 190ꢂC (EtOH dioxane); brick red crystals; UV (dioxane): ꢂmax (log ") ¼ 380
(4.84) nm; IR: ꢀꢀ¼ 1717, 1677 cmꢁ1; 1H NMR (DMSO-d6): ꢁ ¼ 2.34 (s, 6H), 6.92–8.14 (m, 15H) ppm;
13C NMR (DMSO-d6): ꢁ ¼ 192.5, 163.7, 161.3, 154.1, 142.0, 138.7, 130.2, 129.9, 129.4, 129.3, 128.5,
128.3, 127.5, 126.0, 121.7, 25.1 ppm; MS: m=z (%) ¼ 607 (Mþ, 50), 408 (50), 375 (50), 199 (50), 172
(50), 141 (55), 136 (50), 69 (100).
3,9-Di(acetyl)-1,11-di(4-methylphenyl)-6-phenylpyrido[2,3-f:6,5-f0]
di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) (8f, C35H25N9O4)
Yield 5.40g (85%); mp 210–12ꢂC (EtOH dioxane); brown crystals; UV (dioxane): ꢂmax (log ") ¼ 382
1
(3.65) nm; IR: ꢀꢀ¼ 1715, 1670 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 2.30 (s, 6H), 2.39 (s, 6H), 7.14–7.98

220
M. A. N. Mosselhi et al.
(m, 13H) ppm; MS: m=z (%) ¼ 635 (Mþ, 41), 528 (50), 221 (41), 157 (50), 147 (82), 104 (100), 83
(86), 56 (18).
3,9-Di(acetyl)-1,11-di(4-chlorophenyl)-6-phenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8g, C33H19Cl2N9O4)
Yield 5.14 g (76%); mp 248–50ꢂC (EtOH dioxane); yellow solid; IR: ꢀꢀ¼ 1712, 1670 cmꢁ1; 1H NMR
(DMSO-d6): ꢁ ¼ 2.50 (s, 6H), 7.23–8.13 (m, 13H) ppm; MS: m=z (%) ¼ 679 (Mþ þ 3, 26), 676 (Mþ, 31),
560 (31), 522 (33), 415 (36), 370 (31), 260 (64), 207 (44), 199 (62), 170 (44), 138 (44), 93 (82), 70 (100).
3,9-Di(acetyl)-1,11-di(4-nitrophenyl)-6-phenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8h, C33H19N11O8)
Yield 5.51 g (79%); mp >320ꢂC (EtOH=dioxane); UV (EtOH=dioxane) ꢂmax (log ") ¼ 322 (4.40) nm;
IR: ꢀꢀ¼ 1715, 1670 cmꢁ1; 1H NMR (DMSO-d6): ꢁ ¼ 2.50 (s, 6H), 7.23–8.49 (m, 13H) ppm; MS: m=z
(%) ¼ 697 (Mþ, 16), 534 (17), 507 (12), 468 (23), 377 (18), 315 (16), 267 (20), 207 (22), 199 (13), 170
(19), 115 (100), 75 (53).
3,9-Di(ethoxycarbonyl)-1,6,11-triphenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8i, C35H25N9O6)
Yield 5.34g (80%); mp 224ꢂC (EtOH=dioxane); pale brown solid; IR: ꢀꢀ¼ 1751, 1670 cmꢁ1; 1H NMR
(DMSO-d6): ꢁ ¼ 1.29 (t, 6H, J ¼ 7 Hz), 4.39 (q, 4H, J ¼ 7 Hz), 6.96–8.45 (m, 15H) ppm; MS: m=z
(%) ¼ 667 (Mþ, 12), 529 (18), 335 (40), 289 (20), 240 (26), 221 (18), 210 (18), 185 (18), 156 (22), 113
(16), 99 (32), 90 (32), 86 (21), 72 (20), 51 (100).
3,9-Di(ethoxycarbonyl)-1,11-di(4-methylphenyl)-6-phenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8j, C37H29N9O6)
Yield 4.73 g (86%); mp 240ꢂC (EtOH=dioxane); pale yellow crystals; UV (dioxane): ꢂmax (log ") ¼ 304
1
(4.35) nm; IR: ꢀꢀ¼ 1743, 1674 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 1.23 (t, 6H, J ¼ 7 Hz), 2.39 (s, 6H),
4.44 (q, 4H, J ¼ 7 Hz), 7.20–7.96 (m, 13H) ppm; 13C NMR (DMSO-d6): ꢁ ¼ 164.7, 157.8, 156,3,
146.7, 139.4, 137.9, 135.8, 134.5, 130.3, 129.7, 128.3, 127.6, 125.9, 122.0, 89.9, 63.9, 21.3, 14.5 ppm;
MS: m=z (%) ¼ 697 (Mþþ 2, 23), 695 (Mþ, 26), 575 (31), 246 (26), 185 (23), 131 (23), 13 (23), 105
(51), 91 (100), 90 (44), 83 (44), 77 (69), 69 (74).
3,9-Di(ethoxycarbonyl)-1,11-di(4-chlorophenyl)-6-phenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8k, C35H23Cl2N9O6)
Yield 6.18 g (84%); mp 240ꢂC (EtOH=dioxane); yellow white crystals; UV (dioxane): ꢂmax (log") ¼
305 (4.52) nm; IR: ꢀꢀ¼ 1759, 1674 cmꢁ1; 1H NMR (DMSO-d6): ꢁ ¼ 1.31 (t, 6H, J ¼ 7 Hz), 4.42 (q, 4H,
J ¼ 7 Hz), 7.18–8.14 (m, 13H) ppm; MS: m=z (%) ¼ 741 (Mþþ 5, 22), 512 (24), 393 (24), 292 (24), 246
(26), 180 (24), 113 (28), 85 (30), 69 (52).
3,9-Di(ethoxycarbonyl)-1,11-di(4-nitrophenyl)-6-phenylpyrido[2,3-f:6,5-f0]di([1,2,4]
triazolo[4,3-a]pyrimidin-5(1H)-one) (8l, C35H23N11O10)
Yield 6.43 g (85%); mp 268ꢂC (EtOH=dioxane); yellow crystals; UV (dioxane): ꢂmax (log ") ¼ 339
1
(4.44) nm; IR: ꢀꢀ¼ 1751, 1682 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 1.34 (t, 6H, J ¼ 7 Hz), 4.41 (q, 4H,
J ¼ 7 Hz), 7.16–8.51 (m, 13H) ppm; MS: m=z (%) ¼ 759 (Mþþ 2, 15), 527 (30), 497 (84), 434 (62),
379 (34), 291 (22), 248 (21), 212 (60), 180 (62), 88 (100), 58 (61).

Novel Pentaheterocycles
221
1,3,6,9,11-Pentaphenylpyrido[2,3-f:6,5-f0]di([1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one)
(8m, C41H25N9O2)
Yield 5.40g (80%); mp 210ꢂC (EtOH); pale yellow crystals; UV (dioxane): ꢂmax (log ") ¼ 384 (3.32)
1
nm; IR: ꢀꢀ¼ 1670cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 7.01–8.12 (m, ArH) ppm; 13C NMR (DMSO-d6):
ꢁ ¼ 163.0, 159.0, 147.7, 144.9, 140.1, 137.5, 131.0, 130.8, 129.8, 128.2, 128.0, 127.6, 127.5, 127.4,
125.7, 121.3, 96.0, 67.0 ppm; MS: m=z (%) ¼ 675 (Mþ, 13), 650 (13), 626 (13), 393 (13), 303 (63),
236 (23), 194 (19), 160 (12), 133 (86), 103 (45), 91 (100), 76 (30), 51 (40).
2,8-Di(1-ethoxycarbonyl-2-oxopropylthio)-5-phenylpyrido[2,3-d:6,5-d0]
dipyrimidine-4,6(3H,7H)-dione (10, C27H25N5O8S2)
To a stirred solution of 0.9 g of the dithione 4 (2.5mmol) in 40cm3 of EtOH and 10cm3 of DMF
aqueous KOH solution (0.28 g, 5 mmol) in 10cm3 of H2O was added. To the resulting solution was
then added 0.82g of ethyl 2-chloro-3-oxobutanoate (5mmol). The mixture was stirred for 24h, then
diluted with H2O. The precipitated solid was filtered off, washed with H2O, dried, and finally crystal-
lized from dioxane ethanol to give 1.10 g of 10 (72%); mp 210–212ꢂC; IR: ꢀꢀ¼ 3340, 1745,
1
1680 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 1.22 (t, 6H, J ¼ 7 Hz), 2.5 (s, 6H), 4.2 (q, 4H, J ¼ 7 Hz), 5.37
(s, 2H), 6.73–7.24 (m, 5H), 12.03 (s, 2H) ppm.
7-Amino-1,3-diphenyl-1,2,4-triazolo[4,3-a]pyrimidin-5(1H)-one (11, C17H13N5O)
To a mixture of 1.43g of 6-amino-2-thiouracil (0.01 mol) and 2.30g of 5m (0.01 mol) in 30cm3 of
dioxane 1.4ml of Et3N (0.01 mol) were added and the whole mixture was refluxed until H2S ceased
to evolve (10 h). Then it was cooled, and the precipitated solid was filtered off and crystallized from
ethanol dioxane (1=1) to give 2.12g of 11 (70%); mp 250ꢂC (Ref. [23] 250ꢂC); IR: ꢀꢀ¼ 3454, 3300,
1
1680 cmꢁ1; H NMR (DMSO-d6): ꢁ ¼ 4.9 (s, 1H), 6.88 (s, 2H), 7.4–8.2 (m, 10H) ppm; 13C NMR
(DMSO-d6): ꢁ ¼ 164, 157, 149, 144, 137, 131, 130, 128, 127, 126, 122, 121, 76 ppm.
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