Phenylacetone as building blocks in heterocyclic synthesis: Synthesis of polyfunctionally-substituted pyridines, and fused pyridines

Article abstract of DOI:10.1080/10426500701542858

Many pyridinethiones are biologically active. In view of our interest in developing efficient syntheses of polyfunctionally substituted heteroaromatics utilizing the readily obtainable enaminone 3 as starting materials. So, treatment of enaminone 3 with cyanothioacetamide or cyanoacetamide afforded the pyridinethione 5a and pyridone 5b. compound 5a reacted with α -halo- ketones in refluxing sodium ethoxide to give the thienopyridine derivatives 9a-e. Compound 5a reacted with methyl iodide to give 2-methylthiopyridine 10. Condensation of pyridinethione 5a with dimethylformamide-dimethylacetal gave the adduct 11 and with hydrazine hydrate afforded 12. Compound 5a reacted with arylidenemalonitrile to give styryl derivatives 14a-d. Compound 14a-d also prepared from the condensation of 5a with the aromatic aldehydes under the same condition. Reflux of thienopyridine derivatives 9a-d with triethylorthoformat, acetic anhydride, carbon disulfide and sodium nitrite to give compounds 19-23, respectively. The aminopyrazole 12 reacted with dimethylaminopropiophenone hydrochloride 24 or enaminone 30 in refluxing DMF to yield compound 26a-d. Treatment of 12 with 32 afforded 34. Compound 34 can be also prepared from the reaction of 37 with aroylacetonitrile 31. Compound 12 reacted with DMF-DMA to give 37, which reacted with compound 1 to give 38 prepared directly from reaction of 12 with enaminone 2. Diazotization of 12 with nitrous acid followed by coupling with different active methylene reagents afforded the pyridothienotriazines 42a,b. Reaction of benzylideneacetophenone with 12 yielded the pyridopyrazolopyrimidine 44. Also, compound 12 reacted directly with active methylene to give the pyridopyrazolopyrimidine derivatives 46a,b. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500701542858

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Phenylacetone as Building
Blocks in Heterocyclic
Synthesis: Synthesis of
Polyfunctionally-Substituted
Pyridines, and fused Pyridines
A. M. Hussein a , E. A. Ishak a , A. A. Atalla a , S.
Abdel Hafiz b & M. H. Elnagdi c
a Department of Chemistry, Faculty of Science, Al
Azhar University, Assiut, Egypt
b Department of Chemistry, Faculty of Education,
Suez Canal University, Al-Arish, Egypt
c Department of Chemistry, Faculty of Science, Cairo
University, Egypt
Version of record first published: 03 Dec 2007.
To cite this article: A. M. Hussein, E. A. Ishak, A. A. Atalla, S. Abdel Hafiz & M. H.
Elnagdi (2007): Phenylacetone as Building Blocks in Heterocyclic Synthesis: Synthesis
of Polyfunctionally-Substituted Pyridines, and fused Pyridines, Phosphorus, Sulfur, and
Silicon and the Related Elements, 182:12, 2897-2917
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Phosphorus, Sulfur, and Silicon, 182:2897–2917, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701542858
Phenylacetone as Building Blocks in Heterocyclic
Synthesis: Synthesis of Polyfunctionally-Substituted
Pyridines, and fused Pyridines
A. M. Hussein
E. A. Ishak
A. A. Atalla
Department of Chemistry, Faculty of Science, Al Azhar University,
Assiut, Egypt
S. Abdel Hafiz
Department of Chemistry, Faculty of Education, Suez Canal University,
Al-Arish, Egypt
M. H. Elnagdi
Department of Chemistry, Faculty of Science, Cairo University, Egypt
Many pyridinethiones are biologically active. In view of our interest in develop-
ing efficient syntheses of polyfunctionally substituted heteroaromatics utilizing the
readily obtainable enaminone 3 as starting materials. So, treatment of enaminone
3 with cyanothioacetamide or cyanoacetamide afforded the pyridinethione 5a and
pyridone 5b. compound 5a reacted with α-halo- ketones in refluxing sodium ethox-
ide to give the thienopyridine derivatives 9a–e. Compound 5a reacted with methyl
iodide to give 2-methylthiopyridine 10. Condensation of pyridinethione 5a with
dimethylformamide-dimethylacetal gave the adduct 11 and with hydrazine hy-
drate afforded 12. Compound 5a reacted with arylidenemalonitrile to give styryl
derivatives 14a–d. Compound 14a–d also prepared from the condensation of 5a
with the aromatic aldehydes under the same condition. Reflux of thienopyridine
derivatives 9a–d with triethylorthoformat, acetic anhydride, carbon disulfide and
sodium nitrite to give compounds 19–23, respectively. The aminopyrazole 12 reacted
with dimethylaminopropiophenone hydrochloride 24 or enaminone 30 in refluxing
DMF to yield compound 26a–d. Treatment of 12 with 32 afforded 34. Compound 34
can be also prepared from the reaction of 37 with aroylacetonitrile 31. Compound
12 reacted with DMF-DMA to give 37, which reacted with compound 1 to give 38
prepared directly from reaction of 12 with enaminone 2. Diazotization of 12 with ni-
trous acid followed by coupling with different active methylene reagents afforded the
Received May 5, 2007; accepted June 5, 2007.
Address correspondence to M. Hussein, Department of Chemistry, Faculty of Science,
Al Azhar University, Assiut Egypt. E-mail: abdelhaleemmh@yahoo.com
2897

2898
A. M. Hussein et al.
pyridothienotriazines 42a,b. Reaction of benzylideneacetophenone with 12 yielded
the pyridopyrazolopyrimidine 44. Also, compound 12 reacted directly with active
methylene to give the pyridopyrazolopyrimidine derivatives 46a,b.
Keywords Pyrazolopyridines; pyridines; thienopyridines; Tria(Tetra)azafluorine
INTRODUCTION
Certain functionally substituted pyridines are potent inhibitors of
the human immunodeficiency virus,1 most widely used calcium chan-
nel blockers.2 They are also used for the treatment of congestive
heart failure.3,4 Also, many pyridinethiones are biologically active as
bactericides5,6 evaluated pharmacologically and it has been found that
they show activity against diabetes mellitus, as analgesics and anti-
inflammants.7 In this concern, our interest is to develop efficient synthe-
ses of polyfunctionally substituted heteroaromatics, utilizing the read-
ily obtainable enaminone 1 as a starting material.8–10 It is worthwhile
to explore the potential utility of the syntheses of polyfunctionally sub-
stituted pyridines. We report herein synthesis and chemistry of some
new derivatives of these compounds.
RESULTS AND DISCUSSION
It has been found that phenylacetone 1 was condensed with N,N-
dimethylformamide-dimethylacetal (DMF-DMA) in refluxing xylene to
yield structure 3. Compound 3 readily reacted with cyanothioacetamide
4 in refluxing ethanolic piperidine to yield 6-methyl-5-phenyl-2-thioxo-
1,2-dihydropyridine-3-carbonitrile 5a and with cyanoacetamide to give
pyridone 5b (Scheme 1).
SCHEME 1
With the aim of the preparing polyfunctionally substituted polycon-
densed pyridines, pyridinethione 5a reacted with a variety of α-
haloketones 6a–e in refluxing sodium ethoxide to give thienopyridine
derivatives 9a–e most likely via intermediacy of 7 and 8. The structure

Polyfunctionally Substituted Pyridines
2899
of this compound was confirmed with 1H NMR, which revealed the dis-
appearance of methylene group and the appearance of NH2 group. Alky-
lation of pyridinethione 5a with methyl iodide gave 10 as a well-known
reaction. Also, the reactivity of methyl function in 5a toward DMF-
DMA was also investigated. Thus, compound 5a condensed with DMF-
DMA to give the adduct 6-(2-dimethylamino-vinyl)-5-phenyl-2-thioxo-
1,2-dihydro-pyridine-3-carbonitrile 11. Condensation of pyridinethione
5a with hydrazine hydrate afforded pyrazolopyridine 12. Structure of
compound 12 was confirmed by spectroscopic data. Thus, IR spectrum
shows the appearance of NH2group at v cm−1 3433–3222. Also, the
mass spectrum of 12 revealed a molecular ion peak at m/z = 224 (M+)
(Scheme 2).
SCHEME 2

2900
A. M. Hussein et al.
Attempted addition of arylidinemalononitriles 13a–d to
pyridinethione 5a with the aim of preparing 4H-quinolizines 17
has resulted of formation of product condensation via malononitrile
elimination to give styryl derivatives 14a–d. This product also has
been obtained by direct condensation of 5a with aromatic aldehydes
18a–d. Structure 14 has been assigned for this product based on
1H NMR that revealed existence tarns olefinic protons at δ 7.00 and
7.80 ppm.
SCHEME 3
Reactions of 9a–d with triethylorthoformate in acetic acid gave the
pyridothienopyrimidines 19a–d. Also, compounds 9a–d were acety-
lated with acetic anhydride to afford the pyridothienopyrimidines
21a–d. The 1H NMR of compound 21a shows the presence of two signals
at δ 2.4 and 2.6 ppm corresponding to the methyl group of pyridine and
pyrimidine moieties, respectively. Similarly, the reaction of 9a–d with
carbon disulfide in pyridine afforded 22a–d. These compounds were
1
confirmed by H NMR and elemental analysis. Also, the orthoamides
have proved to be valuable for the synthesizing various heterocycles.

Polyfunctionally Substituted Pyridines
2901
So, diazotization and self coupling of the aminoamides 9a–d gave the
pyidothienotriazine derivatives 23a–d (Scheme 4).
SCHEME 4
In this part, we report synthesis of several new pyridopyrazolopyrim-
idines via reaction of aminopyrazolopyridine 12 with non-symmetrical
double bond system and with different active methylene reagents. Thus,
it has been found that the aminopyrazolopyridine 12 reacted with 3-
dimethylaminopropiophenone hydrochloride 24 in refluxing DMF to
yield product of condensation via elimination of water, dimethylamine
hydrochloride and hydrogen. This product can thus be formulated as
26 or isomeric 27. The structure 27 was ruled out on the bases of the
preparation of 27 via condensation of 12 with cinnamaldehyde 29 and
subsequent cyclization of resulting cinnamylidene derivative 28. This
product was proved to be different from product of reaction of 12 and
24. Thus, structure 26 could be established for the later derivative. The
formation of 26 was assumed to proceed by the addition of phenyl vinyl
ketone 25, resulting from elimination of dimethylamine hydrochloride
from 24, to ring nitrogen would afford intermediate which on cyclization
via water elimination and aromatization would yield 26. Compound 26
was also obtained on heating of aminopyrazole 12 with the enaminone

2902
A. M. Hussein et al.
30. Moreover, this find parallelism to reported behavior of aminopyra-
zoles toward enaminone (Scheme 5).11
SCHEME 5
Treatment
of
3-aryl-2-(N, N-dimethylamino)methylene-3-oxo-
propanenitriles 32a,b prepared from the reaction of 31 with DMF-
DMA according the literature12 with the aminopyrazolopyridine 12 in
ethanolic piperidine afforded products resulting the addition of both
dimethylamine and water elimination. Several structures seemed
possible for these products. Thus, initial formation of adduct 35 would
lead to 36, while the formation of adduct 33 can lead to 34. Structure
36 was ruled out on the basis of 1H NMR spectra of the isolated
product which revealed singlet signal in the range of δ 9.22 ppm which
was assigned for the pyrimidine CH-4 in structure 34 and not CH-6
in structure 36.13 The latter structure was firmly established for the
reaction product by the synthesis of the same product via condensing
compound 12 with DMF-DMA and subsequent condensation of the
so formed
N, N-dimethyl-Nꢀ-(6-methyl-5-phenyl-2H-pyrazolo[3,4-
b]pyridine-3-yl)-formamidine 37 with aroylacetonitrile 31 to afford
products identical in all respects (m.p. and mixed m.p.) with those
corresponding to compounds 34a–b. Similarly, the aminopyrazole 12
reacted with enaminone 2 to yield the product of addition and both
dimethylamine and water elimination 38. This structure was firmly
established for the reaction product by the synthesis of the same

Polyfunctionally Substituted Pyridines
2903
product via condensing compound 12 with DMF-DMA and subsequent
condensation of the so formamidine 37 with phenylacetone 1 to afford
product identical with corresponding to compound 38. Also, structure
of 38 was established with 1H NMR which revealed singlet signal at δ
2.32, 2.37 ppm for 2CH3, singlet at δ 7.73 ppm assigned for pyridine H-4
and singlet at δ 7.90 ppm assigned for pyrimidine H-4 (Scheme 6).14
SCHEME 6
Diazotization and coupling of amino functional group in 12 by the
action of sodium nitrite with different active methylene reagents 41a,b
namely malonoitrile and acetylacetone, gave the pyridopyrazolotri-
azine 42a,b. Also, compound 12 reacted with benzylideneacetophe-
none to yield product condensation via elimination of water and hy-
drogen molecule. This was formulated as 44. Formation of 44 is as-
sumed to proceed via a Michael type addition on the most basic ring
nitrogen in 12, interamolecular cyclodehydration and spontaneous au-
toxidation under the reaction conditions. Similar autoxidations was
reported previously.15,16 It should be pointed out that the reaction of
12 with benzylideneacetophenone might involve the exocyclic amino
group. However, the involvement of the endocyclic pyrazole-N was con-
sidered on the bases of literature reports which revealed that the ring

2904
A. M. Hussein et al.
N in aminopyrazoles is the most reactive center in the molecule17,18
(Scheme 7).
SCHEME 7
Also, aminopyrazole 12 reacted with active methylene reagents 45,
namely acetylacetone and ethyl acetoacetate to yield the pyridopyra-
zolopyrimidine derivatives 46a,b (Scheme 8).19
SCHEME 8
BIOLOGICAL ACTIVITIES
Most of the synthesized compounds have been tested against four dif-
ferent kinds of bacteria. The result of antimicrobial studies presented
in Table I. It has been found that the prepared compound shows

Polyfunctionally Substituted Pyridines
2905
TABLE I Antimicrobial activity of some synthesized compounds and
inhibition zones
No of compounds
A
B
C
D
12
++
+
+ + ++
+ + +
++
—
+ + ++
—
—
++
—
19a
21b
22a
23d
26a
26d
34a
46b
+ + ++
+
+ + ++
+ + ++
+
++
+ + +
++
++
+
+ + ++
+ + +
++
+ + +
+ + ++
++
+ + +
++
+
+ + +
++
++
+
++
+
Where: A = Staphylococcus; B = Streptococcus; C = Esherichia coli; D = Nisseria
sica; — = Negative; + = Poor; ++ = Fair; + + + = Good; and + + ++ = Very good.
antimicrobial activity against Staphylococcus aurous, Streptococcus
mitor, Esherichia coli, and Nisseria sica.20
CONCLUSION
The importance of the synthesized compounds as an intermediate for
the synthesis of biologically active as antistaphylococcus, antisstrepto-
coccus, antiesherichia coli, and antinNisseria sica.
EXPERIMENTAL
All melting points are uncorrected and were determined on a Gel-
lankap apparatus; IR (KBr) spectra were recorded on Schimadzu 470
1
spectrophotometer in potassium bromide discs; H NMR spectra were
recorded on a Varian EM-390 (90 MHz) spectrophotometer using TMS
as an internal standard; Mass spectrometer MS 30 (AEL) at 70 ev; Ana-
lytical data were obtained from the microanalytical data center at Cairo
university.
4-Dimethylamino-3-phenyl-but-3-en-2-one (2)
A mixture of phenylacetone 1 (1.34 g, 10.0 mmol) and dimethyl-
formamide-dimethylacetal (DMF-DMA) (1.19 g, 10.0 mmol) in dry xy-
lene (30 ml), was refluxed for 6 h. After cooling, the solid product
formed was collected by filtration and recrystallized from petroleum
ether (40–60) as colorless crystals, yield 65%; m.p. 82◦C. IR (KBr) ν =
3049 (CH-aliphatic), 1673 (C = O) cm−1; −1H NMR (DMSO-d6) δ = 2.05
(s, 6H, NMe2), 2.49 (s, 3H, CH3), 6.94–7.56 (m, 5H, Ar-H), 8.06 (s, 1H,

2906
A. M. Hussein et al.
CH); −MS (EI, 70 eV): m/z (%) = 189 [M+]. Calcd for C12H15NO (189.26):
C 76.16; H 7.99; N 7.40. Found C 76.21; H 8.01; N 7.45.
Preparation of Compounds 5a,b—General Procedure
A mixture of enaminone 2 (1.89 g, 10.0 mmol) and cyanothioacetamide
or cyanoacetamide (10.0 mmol) in absolute ethanol (30 ml), was treated
with few drops of piperidine and refluxed for 3 h. After cooling the solid
product formed was collected by filtration and recrystallized from the
proper solvent.
6-Methyl-5-phenyl-2-thioxo-1,2-dihydro-pyridine-3-
carbonitrile (5a)
Compound 5a was obtained as yellow crystals from DMF/EtOH (1:3),
yield 69%; m.p 265◦C; IR (KBr) ν = 3225–3100 (NH), 2190 (CN), 1220
(C = S) cm−1; 1H NMR (DMSO-d6) δ = 2.38 (s, 3H, CH3), 7.42–7.45 (m,
5H, Ar-H), 8.03 (s, 1H, pyridine-CH), 14.23 (s, 1H, NH); MS (EI,70 eV):
m/z (%) = 226 [M+]; C13H10N2S (226.30): Calcd for C13H10N2S (226.30):
C, 69.00; H, 4.45; N, 12.38; S, 14.17. Found 69.12; H, 4.53; N, 12.42; S,
14.24.
6-Methyl-2-oxo-5-phenyl-1,2-dihydro-pyridine-3-carbonitrile
(5b)
Compound 5b was obtained as white crystals from DMF/ethanol (1:3)
as yield 67%; m.p. 210◦C; IR (KBr) ν = 3332–3147 (NH), 2221 (CN),
1651 (C = O) cm−1; 1H NMR (300 MHz, DMSO) δ = 2.26 (s, 3H, CH3),
7.34–7.44 (m, 5H, Ar-H), 8.08 (s, 1H, pyridine-CH), 12.74 (s, 1H, NH);
MS (EI,70 eV): m/z (%) = 210 [M+]. Calcd for −C13H10N2O (210.24): C,
74.27; H, 4.79; N, 13.32. Found C, 74.28; H, 4.82; N, 13.42.
Preparation of Compounds (9a–e)— General Procedure
To a solution of compound 5a (2.14 g, 10.0 mmol) in absolute ethanol
(30 ml), the appropriate α-halo compound (0.01 mol) was added. The
reaction mixture was treated with a few drops of sodium ethoxide and
refluxed for 3 h. The solid product so formed was filtered off and recrys-
tallized from the appropriate solvent.
3-Amino-6-methyl-5-phenylthieno[2,3-b]pyridine-2-carboxylic
Acid Phenylamide (9a)
Compound 9a was obtained as yellow crystals from DMF/ethanol in
52% yield; m.p. > 350◦C; IR ν cm−1 3390–3225 (NH2); 3225–3100 (NH);
1645 (CO); Calcd. for C21H17N3OS: (359.45): C, 70.17; H, 4.77; N, 11.69:
S, 8.92; Found: C, 70.20; H, 4.83; N, 11.71; S, 9.05.

Polyfunctionally Substituted Pyridines
2907
3-Amino-6-methyl-5-phenylthieno[2,3-b]pyridine-2-carboxylic
Acid P-Tolylamide (9b)
This compound was obtained as yellow crystals from DMF/ethanol
in 50% yield; m.p. 360◦C; IR (KBr) ν cm−1 3390–3225 (NH2); 3225–3100
(NH); 1651(CO); Calcd. for C22H19N3OS (373.48): C, 70.75; H, 5.13; N,
11.25; S, 8.58; Found: C, 70.82;H, 5.23; N, 11.34; S, 8.65.
3-Amino-6-methyl-5-phenylthieno[2,3-b]pyridine-2-carboxylic
Acid (4-Methoxy-phenyl)amide (9c)
This compound was obtained as yellow crystals from DMF/ethanol
in 50% yield; m.p. >365◦C; IR (KBr) ν cm−1 3390–3225 (NH2);
3225–3100 (NH); 1649 (CO); 1H NMR (DMSO-d6) δ = 2.50 (s, 3H, CH3);
3.76 (s, 3H, OCH3); 6.89–6.93 (d, 2H, Ar-H); 7.35–7.51 (m, 5H, Ar-H);
7.56–7.60 (d, 2H, Ar-H); 8.37 (s, 1H, pyridine-CH); 9.36 (s, 1H, NH).
Calcd. for C22H19N3O2S (389.48):C, 67.85; H, 4.92; N, 10.79; S, 8.23.
Found: C, 67.91; H, 5.08; N, 10.87; S, 8.36.
3-Amino-6-methyl-5-phenylthieno[2,3-b]pyridine-2-carboxylic
Acid (3-Acetyl-phenyl)amide (9d)
This compound was obtained as yellow crystals from DMF/ethanol
in 50% yield; m.p. 348–350◦C; IR (KBr) ν cm−1 3390–3225 (NH2); 3225-
3100 (NH); 1649 (CO); Calcd. for C23H19N3O2S (401.49): C, 68.81; H,
4.77; N, 10.47; S, 7.99. Found: C, 68.96; H, 5.85; N, 10.44; S, 8.02.
3-Amino-6-methyl-5-phenylthieno[2,3-b]pyridin-2-yl)-phenyl-
methanone(9e)
This compound was obtained as yellow crystals from DMF/EtOH;
yield 58%; m.p.178◦C; IR (KBr) ν cm−1 3385–3016(NH2); 1674 (CO);
1H NMR (DMSO-d6) δ = 2.38 (s, 3H, CH3); 7.44–7.83 (m, 12H, Ar-H
and NH2); 8.57 (s, 1H, pyridine-CH); Calcd. for C21H16N2OS (344.44):
C, 73.23; H, 4.68; N, 8.13; S, 9.31. Found: C, 73.33; H, 4.75; N, 8.27; S,
9.49.
2-Methylthio-6-methyl-5-phenylpyridine-3-carbonitrile (10)
To stirring suspension of compound 5a (2.14 g, 10.0 mmol) in ethanol
(50 ml) an aqueous sodium hydroxide (5 ml, 10 %) was added. The so-
lution was stirred at room temperature for 10 min, then an excess of
methyl iodide was added dropwise to a stirred solution. The stirring was
continued for 15 min. The reaction mixture was poured into cold water
and the solid product formed was collected by filtration, washed several
times with water, dried and recrystallized from ethanol as yellow crys-
1
tals; m.p. 289◦C; IR (KBr) ν cm−1 2200 ( CN): H NMR (DMSO-d6)

2908
A. M. Hussein et al.
δ = 2.48 (s, 3H, CH3); 2.49 (s, 3H, SCH3); 7.41–7.41 (m, 5H , Ar-H); 8.02
(s, 1H, pyridine-CH). Calcd. for C14H12N2S (240.33): C, 69.97; H, 5.03;
N, 11.66; S, 13.34. Found: C, 70.03; H, 5.15; N, 11.72; S, 13.34.
6-(2-Dimethylamino-vinyl)-5-phenyl-thioxo-1,2-dihydro-
pyridine-3-carbonitrile (11)
A mixture of compound 5a (2.14 g, 10.0 mmol) and (DMF-DMA)
(2.26 g, 10.0 mmol) in xylene (50 ml), was refluxed for 12 h and left
to stand. The solid product formed after dilution with ethanol was col-
lected by filtration and recrystallized from ethanol in 43% yield; m.p.
355◦C; IR (KBr) ν cm−1 2200 (CN). Calcd for C16H15N3S (281.38): C,
68.30; H, 5.37; N, 14.93; S, 11.40. Found: C, 68.43; H, 5.45; N, 14.99; S,
11.51.
6-Methyl-5-phenyl-2H-pyrazolo[3,4-b]pyridin-3-ylamine (12)
A solution of compound 5a (2.14 g, 10.0 mmol) in ethanol (10 ml)
was treated with an excess of hydrazine hydrate (30 ml). The reaction
mixture was heated under reflux for 12 h and left to stand. It was poured
into ice cold water and acidified with HCl. The solid product so formed
was obtained by filtration and recrystallized from DMF/EtOH (1:3) as
green crystals; yield 52%; m.p. 245◦C; IR (KBr) ν cm−1 3433–3122 (NH2-
NH); 1H NMR (DMSO-d6) δ = 2.35 (s, 3H, CH3); 7.30–7.83 (m, 7H,
Ar-H and NH2); 8.25 (1H, pyridine-CH); 11.65 ( s.1 H, NH); Ms: m/z
= 224(M+); Calcd. for C13H12N4 (224.27): C, 69.62; H, 5.39; N, 24.98.
Found: C, 69.73; H, 5.45; N, 25.07.
Preparation of Compounds (14a–d)—General Procedure
Method (A)
To a solution of compound 5a (2.14 g, 10.0 mmol) in dry dioxan, the
appropriate of arylidenemalononitrile 13a–e (10.0 mmol) was added.
The reaction mixture was treated with few drops of piperidine and re-
fluxed for 4 h, poured on ice cold water and acidified with dilute HCl.
The solid product so formed was filtered off, washed with water several
times, dried, and recrystallized from the proper solvent.
Method (B)
To a solution of compound 5a (2.14 g, 10.0 mmol) in dry dioxan
(20 ml.) the appropriate of aromatic aldehyde 18a–d (10.0 mmol)
was added. The reaction mixture was treated with little amount of
trimethylamine and refluxed for 4 h. The solid product so formed was
collected by filtration, washed with water several times, dried, and re-
crystallized from the proper solvent.

Polyfunctionally Substituted Pyridines
2909
5-Phenyl-6-styryl-2-thioxo-1,2-dihydro-pyridine-3-carbonitrile
(14a)
Compound 14a was obtained as yellow crystals from ethanol in
50% yield; m.p. 189◦C; IR (KBr) ν cm−1 3225–3100 (NH); 2200
(CN); Ms: m/z = 314 (M+); Calcd. for C20H14N2S (314.41): C, 76.40;
H, 4.49; N, 8.91; S, 10.20. Found: C, 76.51; H, 4.53; N, 9.05; S,
10.17.
5-Phenyl-2-thioxo-6-(2-p-tolyl-vinyl)-1,2-dihydro-pyridine-3-
carbonitrile (14b)
Compound 14b was obtained as yellow crystals from ethanol
in 50% yield; m.p. 99–101◦C; IR (KBr) ν cm−1 3431 (NH); 2206
(CN); 1H NMR (DM50-d6) δ = 2.41 (s, 3H, CH3); 7.00–7.10 (d, 1H,
CH); 7.33–7.47 (m, 4H, Ar-H); 7.86–7.90 (d, 1H, CH); 8.49 (s, 1H,
pyridine-H); 14.20 (s, 1 H, NH); Calcd. for C21H16N2 S (328.44): C,
76.80; H, 4.91; N, 8.53; S, 9.76. Found: 76.93; H, 4.94; N, 9.76; S,
9.82.
6-[2- (4-Methoxy-phenyl)-vinyl]5-phenyl-2-thioxo-1,2-dihydro–
pyridine-3-carbonitrile (14c)
This compound was obtained as yellow crystals from ethanol in 50%
yield; m.p. 105–107◦C; IR (KBr) ν cm−1 3433 (NH); 2205 (CN); Calcd.
for C21H16N2OS (344.44): C, 73.23; H, 4.68; N, 8.13; S, 9.31. Found: C,
73.35; H, 4.72; N, 8.25; S, 9.43.
6-[2-(Napthalen-1-yl)-vinyl]-5-phenyl-2-thioxo-1,2-dihydro-
pyridine-carbonitrile (14d)
Compound 14d was obtained as yellow crystals from ethanol in 50%
1
yield; m.p. 115◦C; IR (KBr) ν cm−1 3348 (NH); 2212 (CN); H NMR
(DM50-d6) δ = 7.01–7.10 (d, 1H, CH); 7.46–7.55 (m, 12H, Ar-H);
7.87–7.96 (d, 1H, CH); 8.08 ( s, 1H, pyridine-H); 14.00 ( s, 1 H, NH);
Calcd. for C24H16N2S (364.47): C, 79.09; H, 4.42; N, 7.69; S, 8.80. Found:
C, 79.10; H, 4.52; N, 7.70; S, 8.89.
Preparation of Compound (19a-d)—General Procedure
To a solution of compound 9a–d (10.0 mmol) in acetic acid (30 ml),
triethylorthoformate (3 ml) was added. The reaction mixture was re-
fluxed for 3 h, then poured onto water and left to stand. The solid
product formed was filtered off and recrystallized from the appropriate
solvent.

2910
A. M. Hussein et al.
2-Methyl-3,7-diphenyl-7H-a-thia-1,5,7-triaza-fluoren-8-one
(19a)
Compound 19a was obtained as white crystals from dioxan; yield
66%; m.p. > 350◦C; IR (KBr) ν cm−1 1660 ( CO); Calcd. for C22H15N3OS
(369.45): C, 71.52; H, 4.09; N, 11.37; S, 8.68. Found: C, 71.62; H, 4.14;
N, 11.46; S, 8.78.
2-Methyl-3-phenyl-7-p-tolyl-7H-a-thia-1,5,7-triaaza-fluoren-8-
one (19b)
Compound 19b was obtained as grey crystals from dioxan; yield
65%; m.p. > 350◦C; IR (KBr) ν cm−1 1673 (CO); 1H NMR (DM50-
d6) δ = 2.41 (s, 3H, CH3); 2.61(s, 3H, CH3); 7.37–7.52 (m, 9H, Ar-
H); 8.27 (s.1H, pyridine-CH); 8.56 (s, 1H, pyrimidine-CH); Calcd. for
C23H17N3OS (383.48): C, 72.04; H, 4.47; N, 10.96; S; 8.36. Found: C,
72.52; H, 4.53; N, 11.01; S, 8.45.
7-(4-Methoxy-phenyl)-2-methyl-3-phenyl-7H-a-thia-1,5,7-
triaaza-fluoren-8-one (19c)
Compound 19c was obtained as yellow crystals from dioxan; yield
60%; m.p. >350◦C; IR (KBr) ν cm−1 1640 (CO); Calcd. for C23H17N3OS
(399.47): C, 69.15; H, 4.29; N, 10.52; S, 8.03. Found: 69.22; H, 4.34; N,
10.66; S, 8.18.
7-(3-Acetyl-phenyl)-2-methyl-3-phenyl-7H-a-thia-1,5,7-triaaza-
fluoren-8-one (19d)
Compound 19d was obtained as yellow crystals from dioxan; yield
60%; m.p. 358◦C; IR (KBr) ν cm−1 1640 (CO); Calcd. for C24H17N3O2S
(411.49): C, 70.06; H, 4.16; N; 10.21; S, 7.79. Found: 70.11; H, 4.25; N,
10.35; S, 7.81.
Preparation of Compounds (21a-d)—General Procedure
Compounds 21a–d (2 g) were dissolved in acetic anhydride (20 ml) and
refluxed for 3 h. The reaction mixture was poured onto ice water and
left to stand for 12 h. The solid product formed was filtered off and
recrystallized from the appropriate solvent.
2,6-Dimethyl-3,7-diphenyl-7H-a-thia-1,5,7-triaza-fluoren-8-one
(21a)
Compound 21a was obtained as yellow crystals from DMF/dioxan;
yield 50%; m.p. 355◦C; IR (KBr) ν cm−1 3390–3225 (NH2); 3225–3100
(NH); 2200 (CN); 1651 (CO); 1H NMR (DMSO-d6) δ = 2.48 (s, 3H, CH3);

Polyfunctionally Substituted Pyridines
2911
2.62 (s, 3H, CH3); 7.44–7.85 (m, 10H, Ar-H); 8.14 (s, 1H, pyridine-H);
MS: m/z = 383 (M+); Calcd. for C23H17N3OS (383.43): C, 72.04; H, 4.47;
N, 10.96; S, 8.36. Found: C, 72.13; H, 4.51; N, 11.08; S, 8.47.
2,6-Dimethyl-3-phenyl-7-p-tolyl-7H-a-thia-1,5,7-triaza-fluoren-
8-one (21b)
Compound 21b was obtained as yellow crystals from DMF/dioxan;
yield 60; m.p. > 350◦C; IR (KBr) ν cm−1 1673 (CO); Calcd. for
C24H19N3OS (397.50): C, 72.52; H, 4.82; N, 10.57; S, 8.07. Found: C,
72.68; H, 4.96; N, 10.64; S, 8.12.
7-(4-Methoxy-phenyl)-2,6-dimethyl-3-phenyl-7H-a-thia-1,5,7-
triaza-fluoren-8-one (21c)
Compound 21c was obtained as yellow crystals from DMF/dioxan
(1:3) in yield 55%; m.p. 298◦C; IR (KBr) ν cm−1 3430–3210 (NH2); 2200
(CN); 1640 (CO); 1H NMR (DMSO-d6) δ = 2.11 (s, 3H, CH3); 2.49 (s, 3H,
CH3); 3.74 (s, 3H, OCH3); 7.17–7.79 (m, 9H, Ar-H); 8.00 (s, 1H, pyridine-
H); Calcd. for C24H19N3O2S (413.50): C, 69.71; H, 4.63; N, 10.16; S, 7.75.
Found: C, 69.82; H, 4.73; N, 10.21; S, 7.89.
7-(3-Acetyl-phenyl)-2,6-dimethyl-3-phenyl-7H-a-thia-1,5,7-
triaza-fluoren-8-one (21d)
Compound 21d was obtained as yellow crystals from DMF/dioxan
(1:3); yield 55%; m.p. 334◦C; IR (KBr) ν cm−1 1665 (CO); 1640 (CO);
Calcd. for C25H19N3O2S (425.51): C, 70.57; H, 4.50; N, 9.88; S, 7.54.
Found: C, 70.68; H, 4.66; N, 9.94; S, 7.62.
Preparation of Compounds (22a–c)—General Procedure
A suspension of 9a–d (10.0 mmol) in pyridine (50 ml) was treated with
carbon disulfide (2 ml) and refluxed for 8 h. The reaction mixture was
poured onto cold water and acidified with diluted HCl. The solid prod-
uct so formed was collected by filtration and recrystallized from the
appropriate solvent.
2-Methyl-3,7-diphenyl-6-thioxo-6,7-dihydro-5H-a-thia-1,5,7-
triaza-fluoren-8-one (22a)
Compound 22a was obtained as yellow crystals from dioxan; yield
60%; m.p. 273◦C; IR (KBr) ν cm−1 3425–3163 (NH); 1651 (CO); 1H NMR
(DMSO-d6) δ = 2.49 (s, 3H, CH3), 7.04–7.98 (m,10H, Ar-H); 8.36 (s, 1H,
pyridine-CH); 14.15 (s, 1H, NH); Calcd. for C22H15N3OS2 (401.51): C,
65.81; H, 3.77; N, 10.47; S, 15.97. Found: C, 66.31; H, 3.82; N, 10.54; S,
16.06.

2912
A. M. Hussein et al.
2-Methyl-3,phenyl-6-thioxo-7-p-tolyl-6,7-dihydro-5H-a-thia-
1,5,7-triaza-fluoren-8-one (22b)
Compound 22b was obtained as yellow crystals from dioxan;
yield 65%; m.p. 277◦C ; IR (KBr) ν cm−1 1650 (CO); Calcd. for
C23H17N3OS2(415.54): C, 66.48; H, 4.12; N, 10.11; S, 15.43. Found: C,
66.52; H, 4.23; N, 10.22; S, 15.55.
7-(4-Methoxy-phenyl)-2-methyl-3-phenyl-6-thioxo-6,7-
dihydro-5H-a-thia-1,5,7-triaza-fluoren-8-one (22c)
Compound 22c was obtained as yellow crystals from dioxan; yield
65%; m.p. 275◦C; IR (KBr) ν cm−1 1650 (CO); Calcd. for C23H17N3O2S2
(431.54): C, 64.02; H, 3.97, N, 9.74; S, 14.86. Found: C, 64.15; H, 4.07;
N, 9.83; S, 14.93.
7-(3-Acetyl-phenyl)-2-methyl-3-phenyl-6-thioxo-6,7-dihydro-
5H-a-thia-1,5,7-triaza-fluoren-8-one (22d)
Compound 22d was obtained as yellow crystals from dioxan; yield
65%; m.p. 282◦C; IR (KBr) ν cm−1 1650 (CO); 1H NMR (DMSO-d6)
δ = 2.38 (s, 3H, CH3); 3.54 (s, 3H, COCH3); 7.01–7.92 ( m, 9H, Ar-H);
8.03 (s, 1H, pyridine-CH) ); 14.02 (s, 1H, NH); Calcd. for C24H17N3O2S2
(443.55): C, 64.99; H, 3.86, N, 9.47; S, 14.46. Found: C, 65.07; H, 3.98;
N, 9.50; S, 14.53.
Preparation of Compounds (23a–d)—General Procedure
To a cold solution of compound 9a–d (10.0 mmol) in acetic acid (30 ml),
a cold solution of sodium nitrite (1 g in 2 ml H2O) was added dropwise
with stirring. The stirring was continued for 1 h and left to stand at
room temperature for 1 h. The solid precipitate formed was collected by
filtration and recrystallized from the appropriate solvent.
2-Methyl-3,7-diphenyl-7H-a-thia-1,5,6,7-tetraaza-fluoren-8-
one (23a)
Compound 23a was obtained as red crystals from dioxan; yield 60%;
m.p. 260◦C; IR (KBr) ν cm−1 3395–3250 ( NH2), 3250–3170 (NH); 2200
(CN); 1656 (CO); Calcd. for C21H14N4OS (370.44): C, 68.09; H, 3.81; N,
15.12; S, 8.66. Found: C, 68.13; H, 3.97; N, 15.21; S, 8.79.
2-Methyl-3-phenyl-p-tolyl-7H-a-thia-1,5,6,7-tetraaza-fluoren-8-
one (23b)
Compound 23b was obtained as grey crystals from dioxan; yield 54%;
m.p. >350◦C; IR (KBr) ν cm−1 1667 (CO); 1H NMR (DMSO-d6) δ = 2.49
(s, 3H, CH3); 2.65 (s, 3H, CH3); 7.38–7.98 (m, 9H, Ar-H), 8.38 (s, 1H,

Polyfunctionally Substituted Pyridines
2913
pyridine-CH); Calcd. for C22H16N4OS (384.46): C, 68.73; H, 4.19; N,
14.57; S, 8.34. Found: C, 68.86; H, 4.24; N, 14.65; S, 8.42.
7-(4-Methoxy-phenyl)-2-methyl-3-phenyl-7H-a-thia-1,5,6,7-
tetraaza-fluoren-8-one (23c)
Compound 23c was obtained as white crystals from dioxan; yield
66%; m.p. > 350◦C; IR (KBr) ν cm−1 1660 (CO); Calcd. for C22H16N4O2S
(400.46): C, 65.99; H, 4.03; N, 13.99; S, 8.01. Found: C, 68.15; H, 4.12;
N, 14.13; S, 8.12.
7-(3-Acetyl-phenyl)-2-methyl-3-phenyl-7H-a-thia-1,5,6,7-
tetraaza-fluoren-8-one (23d)
Compound 23d was obtained as white crystals from dioxan; yield
1
66%; m.p. > 350◦C; IR (KBr) ν cm−1 1660 (CO); H NMR (DMSO-d6)
δ = 2.46 (s, 3H, CH3), 2.59 (s, 3H, COCH3), 7.23–7.60 (m, 9H, Ar-H);
8.30 (s, 1H, pyridine-CH); Calcd. for C23H16N4O2S (412.74): C, 66.98;
H, 3.91; N, 13.58; S, 7.77. Found: C, 67.03; H, 3.99; N, 13.66; S, 7.87.
Preparation of Compounds (26a–d)—General Procedure
To a solution of compound 12 (2.12 g, 10.0 mmol) in DMF (50 ml) dimthy-
laminopropiophenone hydrochloride 24a–c (10.0 mmol) was added. The
reaction mixture was refluxed for 3 h, and the solvent was concentrated
until third volume under vacuo, then pour into ice-cold water. The solid
product was obtained by filtration and recrystallized from the proper
solvent.
2-Methyl-3,6-diphenyl-1,5,8a,9-tetraaza-fluorene (26a)
This compound was obtained as yellow crystals from dioxane; yield
56%; m.p. 158◦C; IR (KBr) ν cm−1 2995 (CH-aliphatic); 1H NMR (DMSO-
d6) δ = 2.46 (s, 3H, CH3); 7.45–7.90 (m,10H, Ar-H); 8.70 (s, 1H, pyridine-
CH); Calcd. for C22H16N4(336.40): C, 78.55; H, 4.79; N, 16.65. Found: C,
78.65; H, 4.83; N, 16.71.
6-(Furan-2-yl)-2-Methyl-3-phenyl-1,5,8a,9-tetraaza-
flourene (26b)
It was obtained as deep blue crystals from dioxan; yield 60%; m.p.
115◦C; IR (KBr) ν cm−1 2905 (CH-aliphatic); Calcd. for C20H14N4O
(326.36): C, 73.61; H, 4.32; N, 17.17. Found: C, 73.74; H; 4.43; N, 17.21.
2-Methyl-3-phenyl-6-(1H-pyrrol-2-yl)-1,5,8a,9-tetraaza-
fluorene (26c)
It was obtained as brown crystals from dioxane; yield 56%;
m.p. 162◦C; IR (KBr) ν cm−1 2995 (CH-aliphatic); Calcd. for

2914
A. M. Hussein et al.
C20H15N5(325.38): C, 73.83; H, 4.65; N, 21.52. Found C, 73.94; H, 4.75;
N, 21.66.
2-Methyl-3-phenyl-6-(thiophene-2-yl)-1,5,8a,9-tetraaza-
fluorene (26d)
It was obtained as green crystals; yield 57%; m.p. 166◦C; IR (KBr)
ν cm−1 2995 (CH-aliphatic); 1H NMR (DMSO-d6) δ = 2.48 (s, 3H, CH3);
7.37–7.98 (m, 10H, Ar-H and thiophene-H); 8.31 (s.1H, pyridine-CH);
Calcd. for C20H14N4S (342.43): C, 70.15; H, 4.12; N, 16.36; S, 9.63.
Found: C, 70.26; H, 4.23. N, 16.45; S, 9.47.
N,N-Dimethyl-N‘-(6-methyl-5-phenyl-2H-pyrazolo[3,4-
b]pyridin-3-yl)-formamidine (37)
Dimethylformamide-dimethylacetyl (DMF-DMA) (119 g, 10.0 mmol)
was added to a solution of compound 12 (2.12 g, 10.0 mmol) in dioxan
(50 ml), and the reaction mixture was refluxed for 6 h. The removal of
solvent under reduced pressure yielded the crude product which was
crystallized from ethanol as orange crystals; yield 43%; m.p. 185◦C;
IR (KBr) ν cm−1 3363–3193 (NH);1 H NMR (DMSO-d6) δ = 1.90 (s, 3H,
CH3); 2.08 (s, 6H, NMe2); 7.41–7.70 (m, 5H, Ar-H ); 8.15 (s, 1H, pyridine-
CH); 10.95 (s, 1H, N = CH); 12.95 (s, 1H, NH); Calcd. for C16H17N5
(279.35): C, 68.80; H, 6.13; N, 25.07. Found C, 68.92; H, 6.26; N,
25.18.
General Preparation of Compounds (34a,b)
Method (A)
To a solution of 37 (2.79 g, 10.0 mmol) in DMF (30 ml), phenacyl
cyanide or p-methylphenacyl cyanide (10.0 mmole) were added. The
reaction mixture was refluxed for 3 h, and the solvent was removed
under vacuo the solid product so formed was recrystallized from the
proper solvent.
Method (B)
To a solution of 32 (2.0 g, 10.0 mmol) in absolute ethanol (20 ml) in
presence a few drops of piperidine, the aminopyrazolopyridine 12 (2.12
g, 10.0 mmol) was added. The reaction mixture was refluxed for 3 hand
then left to cool. After cooling the solid product so formed was collected
by filtration and recrystallized from the proper solvent.
2-Methyl-3,8-diphenyl-1,5,8a,9-tetraaz-flourene-7-carbonitrile
(34a)
It was obtained from DMF/ethanol (1:3) as yellow crystals; yield 55%;
1
m.p. 305◦C; IR (KBr) ν cm−1 2229 (CN); H NMR (DMSO-d6) δ = 2.60

Polyfunctionally Substituted Pyridines
2915
(s, 3H, CH3); 7.44–7.90 (m, 5H, Ar-H); 8.47 (s, 1H, pyridine-CH); 9.22
(s, 1H, pyrimdine- CH); Calcd. for C23H15N5 (361.41): C, 76.44; H, 4.18;
N, 19.38. Found C, 76.56; H, 4.21; N, 19.45.
2-Methyl-3-phenyl-8-p-tolyl-1,5,8a,9
tetraaza-fluorene-7-carbonitrile (34b)
It was obtained as brown crystals from DMF/ethanol; yield 73%; m.p.
213◦C; IR (KBr) ν cm−1 2129 (CN); Calcd. for C24H17N5 (375.44): C,
76.78; H, 4.56; N, 18.65. Found: C, 76.83; H, 4.67; N, 18.76.
2,8-Dimethyl-3,7-diphenyl-1,5,8a,9-tetraaza-fluorene (38)
Method (A)
A mixture of enaminone 3 (1.91 g, 10.0 mmol) and aminopyrazole 12
(2.12 g, 10.0 mmol) in absolute ethanol (30 ml), was treated with a few
drops of piperidine and refluxed for 3 h. After cooling, the solid product
formed was collected by filtration and recrystallized from DMF/ethanol
(1:3) as green crystals; yield 43%; m.p. 185–187◦C; IR (KBr) ν cm−1
2995 (CH-aliphatic). 1H NMR (DMSO-d6) δ = 2.32 (s, 3H, CH3); 2.37 (s,
3H, CH3); 7.05–7.68 (m, 5H, Ar-H ); 7.73 (s, 1H, Pyridine-CH); 7.90 (s,
1H, pyrimidine-CH); Calcd. for C23H18N4 (350.43): C, 78.83; H, 5.18; N,
15.99. Found: C, 78.92; H, 5.24; N, 16.06.
Method (B)
A mixture of phenylacetone 1 (1.34 g, 10.0 mmol) and compound 12
(2.12 g, 10.0 mmol) in absolute ethanol (30 ml), was treated with a few
drops of piperidine and refluxed for 3 h. After cooling, the solid product
formed was collected by filtration and recrystallized from DMF/ethanol
(1:3).
General Procedure of Triazine (42a–b)
To a stirred cold solution of diazonium chloride 40 (10.0 mmol, prepared
by treating of aminopyrazole 12 (2.12 g, 10.0 mmol) with sodium nitrite
(10.0 mmol) in HCl in ethanol (30 ml) and catalytic of sodium acetate,
the active methylene reagents was added dropwise after the complete
addition. The stirring was continuous for two hrs.. The sold product
so formed was filtered of, washed with water several times, dried and
recrystallized from the proper solvent.
8-Amino-2-methyl-3-phenyl-1,5,6,8a,9-pentaaza-fluorene-7-
carbonitrile (42a)
It was obtained as brown crystals from DMF/dioxan; yield 73%;
1
m.p.177◦C; IR (KBr) ν cm−1 2133 (CN); H NMR (DMSO-d6) δ = 2.48

2916
A. M. Hussein et al.
(s, 3H, CH3); 3.86 (s, 2H, NH2); 7.17–7.61 (m, 5H, Ar-H); 8.34 (s,
1H,pyridine-CH); Calcd. for C16H11N7 (301.31): C, 63.78; H, 3.68; N,
32.54. Found: C, 63.83; H, 3.75; N, 32.67.
1-(2,8-Dimethyl-3-phenyl-1,5,6,8a,9,-pentaaza-fluoren-7-yl)-
ethanone (42b)
It was obtained as red crystals from DMF/dioxan; yield 73 %; m.p.
166◦C; IR (KBr) ν cm−1 1674 (CO); Calcd. for C18H15N5O (317.35): C,
68.13; H, 4.76; N, 22.07. Found: C, 68.21; H, 4.87; N, 22.10.
2-Methyl-3,6,8-triphenyl-1,5,8a,9-tetraaza-fluorene (44)
To a solution of compound 12 (2.12 g, 10.0 mmol) in acetic acid (20 ml)
containing 2 g of ammonium acetate, 2-benezyle; deneacetophenone
(2.08 g, 10.0 mmol) was added. The reaction mixture was refluxed
for 3 h, then poured into ice-cold water. The solid product formed
was filtered off and recrystallized from acetic acid as yellow crystals;
1
yield 65%; m.p. 211◦C; IR (KBr) ν cm−1 2995 (CH-aliphatic); H NMR
(DMSO-d6) δ = 2.48 (s, 3H, CH3); 7.04–7.71 (m, 15H, Ar-H); 8.36 (s.1H,
pyridine-CH); 9.36 (s,1H, pyrimidine-CH); 14.15 (br, 1H, OH); Calcd.
for C28H20N4 (412.50): C, 81.53; H, 4.89; N, 13.58. Found C, 81.61; H,
4.93; N, 13.64.
General Preparation of Compounds (46a,b)
A mixture of compound 12 (2.12 g, 10.0mmol) and acteylaceton or ethyl
acetoacetate (10.0 mmol) in DMF (30 ml), a few drops of piperidine was
added. The reaction mixture was refluxed the 3 h. After cooling, the
solid product formed was collected by filtration and recrystallized from
DMF/EtOH (1:3).
2,6,8-Trimethyl-3-phenyl-1,5,8a,9-tetraaza-fluorene (46a)
It was obtained as red crystals; yield 73%; m.p. 176◦C; IR
(KBr) ν cm−1 2905 (CH-aliphatic); 1H NMR (DMSO-d6) δ = 2.23 (s, 3H,
CH3); 2.25 (s, 3H, CH3); 2.38 (s, 3H, CH3); 7.45–7.50 (m, 5H, Ar-H); 8.14
(s, 1H, pyridine-CH); 8.16 (s, 1H, pyrimidine-CH); Calcd. for C18H16N4
(288.36): C, 74.98; H, 5.59; N, 19.43. Found: C, 75.03; H, 5.62; N, 19.51.
2,6,-Dimethyl-3-phenyl-1,5,8a,9-tetraaza-fluoren-8-ol (46b)
It was obtained as brown crystals; yield 71%; m.p. 135◦C; IR (KBr)
ν cm−1 2905 (CH-aliphatic); 1H NMR (DMSO-d6) δ = 2.33 (s, 3H, CH3);
2.45 (s, 3H, CH3); 7.37–7.51 (m, 5H, Ar-H); 7.74 (s, 1H, pyridine-CH);

Polyfunctionally Substituted Pyridines
2917
8.68 (s, 1H, pyrimdine-CH); Calcd. for C17H14N4 O (290.33): C, 70.33;
H, 4.86; N, 19.30. Found: C, 70.46; H, 4.94; N, 19.45.
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