Studies with 3-functionally substituted 2-arylhydrazononitriles: A new route to 3-substituted-2-arylhydrazononitriles, 4-amino-pyrazole-5- carbonitriles, azadienes and cinnolines

Article abstract of DOI:10.1002/jhet.5570430418

3-Amino-3-phenyl-2-phenylazoacrylonitrile 6 is obtained in good yield via reaction of 5 with phenyl magnesium bromide. The compound 6 is readily converted into 4a. The so formed alkanenitrile reacted with phenylmagnesium bromide to yield 8. Compound 8 cou

Full text of DOI:10.1002/jhet.5570430418

Jul-Aug 2006
Studies With 3-Functionally Substituted 2-Arylhydrazononitriles:
A New Route to 3-Substituted-2-Arylhydrazononitriles,
4-Amino-pyrazole-5-carbonitriles, Azadienes and Cinnolines
931
Ramadan M. Abdel-Motaleb1, Abdel-Moneim A. Makhloof1,
Hamada M. Ibrahim1 and Mohamed H. Elnagdi*2
1) Department of Chemistry; Faculty of Science (fayium branch); Cairo University;
Fayium; A. R. Egypt
2) Department of Chemistry; Faculty of Science; Cairo University, Giza; A. R. Egypt
E-mail: shelmy@access.com.eg
Received September 17, 2005
OH
Ph
Ph
OH
NH2
Ph
Ph
r.t.
ClCH2CN
CN
N
CN
N
N
NHPh
PhMgBr
Ether
X
CN
Ph
O
Ph
N
Ph
OH NH
Ph
O
N
Ph
Ph
NHPh
Ph
AcOH
+
Ph
Ph
Ph
NHPh
N
N
N
N
Ph
H
hꢀ (sun light)
3-Amino-3-phenyl-2-phenylazoacrylonitrile 6 is obtained in good yield via reaction of 5 with phenyl
magnesium bromide. The compound 6 is readily converted into 4a. The so formed alkanenitrile reacted
with phenylmagnesium bromide to yield 8. Compound 8 could be also obtained from reaction of 9 with
phenylmagnesium bromide. The arylhydrazononitriles 8 and 4a reacted with chloroacetonitrile to yield the
4-aminopyrazoles 12a,b. Compound 12a reacted with acetic anhydride to yield the 15a and with benzoyl
chloride to yield the pyrazole 16 which was converted into 15b. Refluxing 10 in acetic acid gave a mixture
of the azadiene 21 and the cinnoline 22 is obtained. The azadiene 21 is converted into 22 either thermally
or photochemically.
J. Heterocyclic Chem., 43, 931 (2006).
O
O
O
O
The chemistry of 3-substituted-3-oxo-2-arylhydrazono-
nitriles 4 has received considerable attention [1-4] Elnagdi et.
al., have obtained these derivatives either via coupling 3-
substituted-3-oxoalkane nitriles 1 with aromatic diazonium
salts [1] or via reacting 3-oxo-2-arylhydrazonals 2 with
hydroxylamine in acetic acid and in presence of sodium
acetate [2]. On the other hand Shawalli et al., [3] has obtained
these compounds via reacting the hydrazidic halides 3 with
cyanide ion. The coupling reaction approach is not attractive
as substituted 1 are not readily obtainable. On the other hand,
the utility of the arylhydrazonal and hydrazonyl halides is
neither economic nor eco-friendly. In the present work we
report a new general route to 4 and its utility as precursor to 4-
aminopyrazole-5-carbonitriles, azadienes and cinnolines.
Thus, reacting the readily obtainable 2-phenylhydrazo-
nomalononitrile 5 with phenylmagnesium bromide in
ether solution at room temperature, afforded product of
addition of Grignard reagents at CN group. This can be
formulated as 6 or tautomeric 7. 1H NMR indicated amino
signals at ꢀ 5.6 ppm, thus structure 6 was established. The
eneazo compound 6 could be readily hydrolyzed into 4a
on reflux in aqueous acetic acid, in presence of
hydrochloric acid. Compound 4a reacted with phenylmag-
nessium bromide to yield the hydroxynitrile 8. This same
product was obtained from reaction of ethyl 2-phenyl-
-
CN
ArN2Cl
CN
CN
Cl
R
R
R
R
N
N
NH
Ar
NH
Ar
1
4
3
CN
NH2OH·HCl
N
AcOH/NaOAc
NH
Ar
2
Figure 1
hydrazono-2-cyanoethanoate 9 with phenyl-magnesium
bromide in ether at room temperature, while refluxing of
9 with excess of ethereal PhMgBr afforded 10.13C NMR
indicated that 10 exist as an equilibrium mixture of more
than one geometrical isomeric forms.
Compounds 4a or 8 reacted with chloroacetonitrile to
yield the 4-aminopyrazole-5-carbonitrile 12, most likely
via intermediacy of 11. This is a further extension to our
recently reported pyrazole synthesis from reaction of 2
with functionally substituted alkyl halide [2,5]. It is of
value here to report that when alkylation was first
conducted in acetone in presence of potassium carbonate,

932
R. M. Abdel-Motaleb, A. A. Makhloof, H M.Ibrahim and M. H. Elnagdi
Vol 43
as described in earlier work, the alkyl halides only
hydrolyzed and 4a or 8 were recovered unreacted. Only
when a recent alkylation procedure in excess triethyl-
amine [6] or in toluene in presence of two equivalents of
triethylamine was used, the reaction proceeded and 12
was obtained in 87 % and 58 % yields respectively.
Compounds 12 were successfully used as precursors to
condensed pyrazoles. Thus, acetylation of 12a afforded
the pyrazolo[4,3-d]pyrimidine 15a, which formed most
likely via intermediacy of 13 and 14 (cf. Figure 3). On
the other hand reacting 12a with benzoyl chloride
afforded 16 that could be cyclized on reflux in AcOH,
AcONH4 into 15b, which formed most likely via a
Dimroth rearrangement of a pyrazolopyrane. However,
possible hydrolysis of nitrile into amide and subsequent
cyclization cannot be overlooked.
acid. Compound 21 was converted into 22 on long reflux
in acetic acid or on exposure to sunlight for a long period
in toluene solution. We believe that in acetic acid the
protonated species 23 undergos cyclization into 22. On
the other hand, the photo-chemical conversion is a 6ꢀ
electrocyclization (cf. Figure 4).
R
CH3
N
NHCOCH3
CN
R
Ac2O
N
O
N
12a
N
N
NH
Ph
Ph
pyridine
PhCOCl
14
13
O
R
NHCOPh
CN
R1
NH
N
AcOH/AcONH4
Ph
N
N
N
N
Refluxing 8 in acetic acid afforded the eneazo derivative
17. Attempted utility of 17 as precursor to arylazopyrazoles
18 failed. Refluxing 17 with hydrazine hydrate resulted only
in reduction of the arylazo moiety to yield 19 or isomeric
20. 1H NMR indicated the presence of a proton linked to an
sp3 carbon atom and only one NH signal at ꢀ 8.60 and 8.75.
1H NMR indicated that the compound is a mixture of both E
and Z forms 20 and 20a in a ratio of 3:1.
Ph
Ph
16
O
15a, R, COPh, R1 = CH3
b, R,COPh, R1 = Ph
Figure 3
EXPERIMENTAL
All melting points are uncorrected. IR spectra were
recorded in KBr pellets with Satellite 2000 spectrophoto-
Thus structure 20 was established. On the other hand, a
mixture of the red eneazo derivative 21 and colorless
cinnoline 22 was obtained upon refluxing 10 in acetic
meter. H NMR and 13C NMR spectra were recorded on a
1
Bruker AC-300 300 MHz spectrometer in DMSO-d6 and
CDCl3 as solvents and TMS as internal standard; chemical
shifts are reported in ꢀ units (ppm). Mass spectra were
HN
Ph
CN
H2N
Ph
CN
N
NC
CN
PhMgBr
H2O/
i)
N
N
NHPh
N
H+
ii)
NH
Ph
Ph
H
N
6
7
N
Ph
Ph
NH2NH2
Ph
Ph
CN
N
5
AcOH
NH2
AcOH.HCl
8
N
NNHPh
OH
Ph
O
17
Ph
18
PhMgBr
H2O/
H+
CN
CN
CN
CH CH
Ph
Ph
Ph
Ph
Ph
Ph
CN
N
N
NHPh
NHPh
N
N
8
N NHPh
4a
19
Ph
20
PhMgBr
O
O
O
Ph
Ph
Ph
Ph
CN
Ph
Ph
Ph
AcOH
CN
Ph
+
ClCH2CN
EtO
10
N
N
N
N
Ph
N
HN
Ph
20a
N
H
NHPh
hv
/Toluene
9
21
22
R
NH2
CN
excess
PhMgBr
R
CN
N
N
O
N
OH NH
CN
N
Ph
Ph
Ph
Ph
NH
Ph
AcOH
Ph
C+
Ph
12a, R = COPh
Ph
Ph
Ph
21
N
N
11
b, R =
HO
NHPh
10
excess
PhMgBr
23
4a
Figure 2
Figure 4

Jul-Aug 2006
Studies With 3-Functionally Substituted 2-Arylhydrazononitriles
933
To a solution of 4a or 9 (10 mmol) in dry ether was added
gradually a solution of phenylmagnesium bromide (prepared
from 23 mmol of bromobenzene and the appropriate amounts of
magnesium and dry ether). The reaction mixture was refluxed
for 2 h then triturated with ammonium chloride solution and
separated with ether. The solvent was eliminated under reduced
pressure and the residue so formed was washed with petroleum
ether and crystallized from toluene.
measured at 70 eV using Shimadzu GCMS-QP 1000 EX
spectrometer. Microanalytical Data were obtained from the
Microanalytical data Unit at Cairo University. Compounds
5, 9 were prepared following published procedure [1].
2-Phenylhydrazono-3-phenyl-3-oxopropanenitrile (4a).
Method A: Benzoylacetonitrile (1.45 g, 10 mmol) was
coupled with benzene diazonium chloride utilizing procedure
described earlier [7,8].
Method B: A solution of 6 (2.5 g, 10 mmol) in acetic acid (20
mL) containing few drops of hydrochloric acid was refluxed for
3 h and allowed to cool to r.t. The solid product so formed was
collected by filtration washed with water and crystallized from
ethanol as yellow crystals.
This compound was obtained in 1.8 g (72%) yield; mp 136°C,
literature [2] mp. 141 °C. IR (KBr): 3223, (NH), 2213 (CN),
1653 cm-1(H-bonded C=O). MS (EI): m/z (%) = 249 (M+,
14.3%), and 250 (M++1, 3.0%).
Anal. Calcd. for C15H11 N3O (249.27): C, 72.28; H, 4.45; N,
16.86. Found: C, 72.08; H, 4.15; N, 16.47.
This compound was obtained in (71%) yield; mp 162-64°C. IR
(KBr): 3559, (OH), 3268, 3190 cm-1 (2 NH). MS (EI): m/z (%) =
1
405 (M+, 1.0 %) and 406 (M++1, 0.5 %). H NMR (CDCl3): ꢀ =
6.2 (s, 1 H, OH), and 6.9-7.6 (m, 20 H, arom-H), 7.9 (s, 1 H, NH)
and 9.4 (br, 1H, imine NH). 13C NMR: (CDCl3): ꢀ = 144.26
(imine C), 143.50, 142.08, 141.85, 129.99, 129.54, 129.44,
128.87, 128.81, 128.73, 128.36, 128.16, 127.93, 127.67, 122.19,
114.53, 113.63 (4 phenyl carbons), 123.67 (C-2), 82.27 (C-3).
Anal. Calcd. for C27H23 N3O (405.49): C, 79.97; H, 5.72; N,
10.36. Found: C, 79.67; H, 5.32; N, 10.21.
General Procedure for Preparation of 4-Amino-1-phenyl-1H-
pyrazole-5-carbonitriles (12a,b).
Equimolar amounts of chloroacetonitrile and 4 or 8 (10 mmol)
were refluxed in triethylamine (10 mL) for 30 min. The reaction
mixture was allowed to cool and poured into acidified ice-water.
The solid product so formed was collected by filtration and
crystallized from ethanol.
3-Amino-2-phenylazocinnamonitrile (6).
To a solution of 5 (1.7 g, 10 mmol) in dry ether was added
gradually a solution of phenylmagnesium bromide (prepared from
10 mmol of bromobenzene and the appropriate amounts of
magnesium and dry ether). The reaction mixture was left at r.t. and
stirred for 24 h, then poured onto saturated ammonium chloride
solution and extracted with ether. The ether layer was separated
and evaporated under reduced pressure. The residue, so formed,
was washed with petroleum ether and crystallized from toluene.
This compound was obtained in (95%) yield: mp 133 °C. IR
(KBr): 3450, 3308 (NH2), 2201 (CN), 1618 cm-1(C=C). MS (EI):
4-Amino-3-benzoyl-1-phenyl-1H-pyrazole-5-carbonitrile (12a).
This compound was obtained in (87%) yield; mp 170 °C. IR
(KBr): 3460, 3352 (NH2), 2216 (CN), 1637 cm-1 (CO). MS (EI):
m/z (%) = 288 (M+, 32.4) and 289 (M++1, 6.4 %).
Anal. Calcd. for C17H12N4O (288.30): C, 70.82; H, 4.20; N,
19.43. Found: C, 70.42; H, 4.00; N, 19.33.
m/z (%) = 248 (M+, 28.2) and 249 (M+ + 1 26.1%). H NMR
1
4-Amino-3-[hydroxy(diphenyl)methyl]-1-phenyl-1H-pyrazole-
5-carbonitrile (12b).
(CDCl3): ꢀ = 5.6 (br, 2 H, NH2), and 7.3-7.85 (m, 10 H, arom-
H). 13C NMR (CDCl3): ꢀ = 162.22 (C-3), 152.91 (C-2), 133.38,
132.42, 129.84, 129.50, 129.42, 128.75, 122.38, 106.35 (2
phenyl carbons), 116.67 (CN).
Anal. Calcd. for C15H12 N4 (248.28): C, 72.55; H, 4.87; N,
22.57. Found: C, 72.35; H, 4.66; N, 22.40.
This compound was obtained in (58%) yield; mp 149°C. IR
(KBr): 3440 (OH), 3244, 3135 (NH2), 2219 cm-1 (CN). MS (EI):
m/z (%): 366 (M+, 1.1 %).
Anal. Calcd. for C23H18 N4O (366.42): C, 75.39; H, 4.95; N,
15.29. Found: C, 75.16; H, 4.88; N, 15.16.
3-Hydroxy-3,3-diphenyl-2-phenylhydrazonopropane-nitrile (8).
3-Benzoyl-5-methyl-1-phenyl-1,6-dihydro-7H-pyrazol[4,3-d]-
pyrimidin-7-one (15a).
To a solution of 4a or 9 (10 mmol) in dry ether was added
gradually a solution of phenylmagnesium bromide (prepared
from 10 mmol of bromobenzene and the appropriate amounts of
magnesium and dry ether). The reaction mixture was left at r.t.
and stirred for 24 h, then poured onto a saturated ammonium
chloride solution and extracted with ether. The solvent was
eliminated under reduced pressure and the residue so formed
was washed with petroleum ether and crystallized from toluene.
This compound was obtained in (60%) yield; mp 126-28 °C.
IR (KBr): 3331 (OH), 3279 (NH), 2218 (CN), 1602 cm-1(C=N).
MS (EI): m/z (%) = 327 (M+, 10.2%) and 328 (M++1, 1.1%). 1H
NMR (CDCl3): ꢀ = 3.15 (s, 1 H, OH) and 7.0 -7.5 (m, 10 H,
arom-H),10.25 (br., 1 H, NH). 13C NMR (CDCl3): ꢀ = 142.54,
141.49, 135.56, 133.33, 129.70, 129.65, 129.40, 127.38 (3
phenyl carbons), 123.48 (C-2), 114.41 (CN), 83.35 (C-3).
Anal. Calcd. for C21H17 N3O (327.38): C, 77.04, H, 5.23, N,
12.84. Found: C, 77.22; H, 5.00; N, 12.59.
A solution of 12a (0.75 g, 2.5 mmol) in acetic anhydride (5 mL)
was refluxed for 4 h. The reaction was left to cool and acidified
with hydrochloric acid. The solid product obtained on standing was
collected by filtration and crystallized from ethanol.
This compound was obtained in (87%) yield; mp°154. IR (KBr):
3278 (NH), 1733 (CO), 1650 cm-1(amide CO). MS (EI): m/z (%) =
330 (M+, 32.3) and 331 (M++1, 6.5). 1H NMR (CDCl3): ꢀ = 1.56 (s,
3 H, CH3), 7.49-8.27 (m, 10 H, arom-H), 9.96 (br. 1 H, NH).
Anal. Calcd. for C19H14N4O2 (330.34): C, 69.08; H, 4.27; N,
16.96. Found: C, 69.20; H, 4.22; N, 16.75.
3-Benzoyl-1,5-diphenyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-
7-one (15b).
A mixture of 16 (0.4 g, 1.0 mmol), ammonium acetate (1 g)
and acetic acid (5 mL) was refluxed for 4 h. The reaction
mixture was left to cool to r.t. and the solid so formed was
collected by filtration and crystallized from acetic acid.
3-Imino-2-phenylhydrazono-1,1,3-triphenyl-1-propanol (10).

934
R. M. Abdel-Motaleb, A. A. Makhloof, H M.Ibrahim and M. H. Elnagdi
Vol 43
This compound was obtained in (62%) yield; mp 211°C. IR
formed was collected by filtration and identified as 22. Then the
mother liquor was concentrated and left to cool. The solid
product formed was collected by filtration and identified as 21.
(KBr): 3445 (NH), 1686, 1630 (two conjugate CO). MS (EI):
m/z (%) = 392 (M+, 17.4), 393 (M++1, 5.2). 1H NMR (CDCl3): ꢀ
= 7.58-8.96 (m, 15 H, arom-H), 10.89 (br, 1 H, NH).
Anal. Calcd. for C24H16N4O2 (392.41): C, 73.46; H, 4.11; N,
14.28. Found: C, 73.43; H, 4.00; N, 14.21
1-Benzoyl-2,2-diphenyl-1-phenylhydrazonoethylene (21).
This compound was obtained in (31%) yield; mp 146 °C. MS
(EI): m/z (%) = 388 (M+, 59.9 %) and 389 (M++1, 20.5%). IR
N-(3-Benzoyl-5-cyano-1-phenyl-1H-pyrazol-4-yl)benzamide (16).
1
(KBr):1670 (CO), 1592 cm-1 (C=C). H NMR (DMSO-d6): ꢀ =
6.4-7.9 (m, 20 H, arom-H). 13C NMR (DMSO-d6): ꢀ = 189.44
(CO), 149.6, 137.77, 137.69, 134.22, 134.01, 133.68, 130.39,
130.34, 129.88, 129.27, 129.11, 127.71, 126.14, 124.20, 122.75,
121.51, 120.79, 120.33 (4 phenyl carbons, C-1, C-2).
A mixture of 12a (0.75 g, 2.5 mmol) and benzoyl chloride
(0.35 g, 2.5 mmol) in pyridine was refluxed for 3 h. The solvent
was evaporated to one third of its volume under vacuum and the
solid product obtained upon neutralization with hydrochloric
acid was collected by filtration and crystallized from acetic acid.
This compound was obtained in (75%) yield; mp 230-32 °C.
IR (KBr): 3287 (NH), 2229 (CN), 1688, 1629 (two conjugate
Anal. Calcd. for C27H20N2O (388.46): C, 83.48; H, 5.19; N,
7.21. Found: C, 83.19; H, 5.34; N, 7.15.
1
CO). MS (EI): m/z (%) = 392 (M+, 22.7), 393 (M+ + 1, 7.8). H
3-Benzoyl-4,4-diphenyl-1,4-dihydrocinnoline (22).
NMR (DMSO-d6): ꢀ = 7.57-7.69 (m, 9 H, arom-H), 7.84 (d, 2 H,
arom-H) 7.98 (d, 2 H, arom-H), 8.15 (d, 2 H, arom-H) and 10.85
(brs, 1H, NH). 13C NMR: (DMSO-d6): ꢀ = 187.30, 164.61,
(2CO), 137.86, 136.15, 135.26, 133.72, 132.69, 132.55, 130.24,
130.10, 129.83, 128.88, 128.61, 127.73, 124.25, 122.01, 121.07,
(3ph, carbons and pyrazole ring carbons), 110.1 (CN).
This compound was obtained in (52%) yield; mp 176-78 °C.
IR (KBr): 3334 (NH), 1626 cm-1 (C=O). MS (EI): m/z (%) = 388
(M+, 49.7 %) and 389 (M++1, 13 %). 1H NMR: (DMSO-d6): ꢀ =
7.2-7.8 (m, 19 H, arom-H), 9.4 (brs, 1H, NH). 13C NMR
(DMSO-d6): ꢀ = 197.91 (C=O), 153.09 (C-3), 150.48, 150.18,
139.37, 139.14, 137.18, 134.41, 132.99, 132.44, 130.63, 130.33,
130.23, 130.11, 129.85, 129.53, 129.21, 128.53, 123.19 (3
phenyl carbons and benzeno carbons), 31.19 (C-4).
Anal Calcd. for C24H16N4O2 (392.41): C, 73.46; H, 4.11; N,
14.28. Found: C, 73.39; H, 4.01; N, 14.11
Anal. Calcd. for C27H20N2O (388.46): C, 83.48; H, 5.19; N,
7.21. Found: C, 83.30; H, 5.34; N; 7.11.
3,3-Diphenyl-2-phenylazoacrylonitrile (17).
Compound 8 (1.0 g, 0.03 mmol) in acetic acid (15 mL) was
refluxed for 3 h then allowed to cool to room temperature. The
solid product, so formed, was collected by filtration and
crystallized from ethanol.
Conversion of 21 into 22.
Method 1: A solution of 21 (10 mmol) in acetic acid (10 mL)
(10 mmol) was refluxed for 24 hrs then left to cool. The solid
product was collected by filtratoin and identified as 22 in 60 %
yield.
Method 2: A solution of 21 (10 mmol) in toluene (10 mL) was
left for several days in sunlight. The product precipitated was
collected by filtratoin and identified as 22.
This compound was obtained in (75%) yield; mp 154 °C. IR
(KBr): 2216 (CN), 1592, 1580 cm-1 (N=N, C=C). MS (EI): m/z
1
(%) = 309 (M+, 14.1), 310 (M++1, 10.8); H NMR: (DMSO-d6):
ꢀ = 7.3-7.8 (m, 15 H, arom-H). 13C NMR (DMSO-d6): ꢀ =
162.28 (C-3), 152.71 (C-2), 138.42, 137.83, 133.16, 132.26,
131.49, 131.11, 131.02, 129.61, 129.04, 128.68, 128.11, 124.04
(3 phenyl carbons), 114.68 (CN).
Anal. Calcd. for C21H15 N3 (309.36): C, 81.53, H, 4.89, N,
13.58. Found: C, 81.36; H, 4.42; N, 13.44.
REFERENCES
3,3-Diphenyl-2-phenylhydrazonopropanenitrile (20).
[1] M. H. Elnagdi, D. H Fleita, M. R. H. Elmoghayar,
Tetrahedron, 31, 63 (1975).
[2] B. Al-Saleh, M. A. El-Apasery, M. H. Elnagdi, J. Chem.
Res., 578 (2004).
[3] A. S. Shawali, M. H. Abdelkader, F. M. A. Eltalbawy,
Tetrahedron, 58(14) 2875 (2002).
[4] A. M. Farag, K. M. Dawood, H. A Abdel-Aziz, J. Chem. Res.
12, 808 (2004).
[5] M. A. Al-Shiekh, A. M. Salah El-Din, E. A. Hafez, and M.
H. Elnagdi, J. Heterocyclic Chem., 41, 647 (2004).
[6] M. ST. Goncalves, A. M. F. Oliveira-Campos, L. M.
Rodrigues, M. FR, P. Proenca, J. Griffiths, H. S. Maia, M. Kaja, F. R.
Hrdina, J. Chem. Res., 115 (2004).
A mixture of 17 (0.6 g, 2.0 mmol) and hydrazine hydrate (0.1
ml, 2.0 mmol) in dimethylformamide (10 mL) was refluxed for
4 h. The solid product, formed upon dilution with water was
collected by filtration and crystallized from ethanol.
This compound was obtained in (55%) yield; mp 108 °C. MS
(EI): m/z (%) = 311 (M+, 46.9 %) and 312 (M++1, 8.8 %). IR
(KBr): 3258 (NH), 2214 (CN), 1602, cm-1 (C=N). H NMR:
1
(CDCl3): ꢀ = 5.18 (s, 0.25 H, CH), 5.30 (s, 0.75 H, CH), 6.9-7.4
(m, 15 H, arom-H), 8.6 (br, 0.75 H, NH), 8.75 (br., 0.25 H, NH).
Anal. Calcd. for C21H17N3 (311.38): C, 81.00; H, 5.50; N,
13.49. Found: C, 80.90; H, 5.34; N, 13.26.
[7] M. H. Elnagdi, M. R. H. Elmoghayar, D. H. Fleita J. Prakt.
Chem., 316, 975 (1974).
The Azoalkene (21) and the Cinnoline (22).
A solution of 10 (2 g, 0.05 mmol) in glacial acetic acid (20
mL) was refluxed for 3 h and left to cool. The solid product, so
[8] R. E. Kitson and N. G. Griffith, Analytic Chem., 24, 3340
(1952).