F. M. Abdelrazek, M. S. Farghaly, and H. E. Abdelrahman
Vol 000
cmꢀ1. MS: m/z = 372 [M+]; dH = 2.16 (s, 12H, 4CH3), 3.91
(s, 4H, 2CH2), 7.08–7.10 (m, 6H, Ar-H), 9.63 (s, 2H D2O exch.,
2NH). dC = 21.4, 24.64, 114.59, 119.35, 124.28, 127.24, 146.03,
163.19. Anal. Calcd for C22H24N6 (372.47): C 70.94; H 6.49;
Compounds 16a,b were also reacted with DMFDMA in
refluxing xylene aiming to obtain the enaminones 19a,b;
however, only 19b was obtained from 16b as yellow
crystalline solid mp 286–287ꢁC, whereas 19a could not be
obtained even after reflux for 10 h. This may be attributed
to steric factors due to the presence of the two methyl
groups in the 2 and 6 positions. The IR showed two carbonyl
absorptions at υmax = 1718 and 1681 cmꢀ1 beside the NH
absorption. The mass spectrum showed m/z = 322 [M+].
N 22.56. Found: C 70.95; H 6.45; N 22.60.
3,4-Diaza-2,5-bis[(3,5-dimethylphenyl)-amino]hexa-2,4-diene-
1,6-dicarbonitrile 5b. White crystalline solid, yield 2.0 g (55%),
mp 185–186ꢁC. IR: υmax = 3255 (NH), 2254 (CN) cmꢀ1
.
MS: m/z=371 [M+ ꢀ 1]; dH= 2.32 (s, 12H, 4CH3), 3.53 (s, 4H, 2CH2),
6.84 (s, 2H, Ar-H), 7.13 (s, 4H, Ar-H), 7.63 (s, 2H D2O exch.,
2NH). Anal. Calcd for C22H24N6 (372.47): C 70.94; H 6.49;
1
The H NMR revealed signals at d = 2.29 (s, 6H, 2CH3),
2.32 (s, 6H, N(CH3)2), 6.96–7.88 (m, 9H, Ar-H+ CH),
N 22.56. Found: C 71.00; H 6.55; N 22.50.
4,5-Diaza-4-phenyl-3,6-bis[(2,6-dimethylphenyl)imino]octane-
1,8-dicarbonitrile 7a.
Brown crystalline solid, yield 2.9 g
8.18 (s, 1H, NH).
(64.7%), mp 208–209ꢁC. IR: υmax = 3137 (NH), 2258 (CN)
cmꢀ1. MS: m/z = 448 [M+]; dH = 2.29 (s, 12H, 4CH3), 3.54
(s, 4H, 2CH2), 6.84–7.13 (m, 11H, Ar-H), 7.74 (s, 1H D2O
exch., NH). Anal. Calcd for C28H28N6 (448.56): C 74.97;
EXPERIMENTAL
Melting points were measured on a digital Electrothermal 9100
apparatus (Kleinfeld, Gehrden, Germany) and are uncorrected. FTIR
spectra (KBr) were obtained on a Nicolet 205 spectrophotometer
(Nicolet, Madison, WI, USA). The 1H and 13C NMR spectra were
recorded on a Varian Mercury VX-300 NMR spectrometer
(Varian inc., Palo Alto, CA, USA) and 13C NMR spectra were
run at 75.46 MHz in DMSO-d6 or CDCl3 using TMS as refer-
ence. Chemical shifts are expressed in d values. The mass
spectra were recorded on a Shimadzu GCMS-QP-1000EX mass
spectrometer (Shimadzu, Kyoto, Japan) at 70 ev. Elemental
analysis were carried out at the Micro-analytical Center of
H 6.29; N 18.74. Found: C 75.07; H 6.38; N 18.95.
4,5-Diaza-4-phenyl-3,6-bis[(3,5-dimethylphenyl)imino]octane-
1,8-dicarbonitrile 7b.
Yellow crystalline solid, yield 3.0 g
(66.9%), mp 180–181ꢁC. IR: υmax = 3171 (NH), 2255 (CN)
cmꢀ1. MS: m/z = 448 [M+]; dH = 2.26 (s, 12H, 4CH3), 3.58 (s, 4H,
2CH2), 7.09–7.19 (m, 11H, Ar-H), 7.43 (s, 1H D2O exch., NH).
Anal. Calcd for C28H28N6 (448.56): C 74.97; H 6.29; N 18.74.
Found: C 75.12; H 6.40; N 18.85.
Reaction of 3a,b with dimethylformamide dimethylacetal.
A mixture of 3a or 3b (10 mmol) and DMFDMA (10 mmol) in
20 mL dry xylene was refluxed for 7 h and then left to cool to
room temperature over night. The precipitated solid was
filtered off and recrystallized from ethanol to afford
Cairo University.
Synthesis of the acetamide derivatives 3a,b. A mixture of
compounds 8a or 8b.
2,6-dimethylaniline 1a/3,5-dimethylaniline 1b (10 mmol) and
ethyl cyanoacetate 2 (10 mmol) in DMF (20 mL) was refluxed
for 5 h and then left to cool to room temperature. The reaction
mixture was then poured onto ice-cold water and the
precipitated solid was filtered off and recrystallized from
ethanol to afford compounds 3a and 3b, respectively.
2-Cyano-3-dimethylamino-N-(2,6-dimethyl-phenyl)-acrylamide
8a. White crystalline solid, yield 1.6 g (65.8%), mp 151–152ꢁC.
IR: υmax = 3246 (NH), 2180 (CN), 1666 (CO) cmꢀ1. MS: m/z = 243
[M+]; dH = 2.12 (s, 6H, 2CH3), 3.18 (s, 3H, CH3), 3.28 (s, 3H, CH3),
7.05 (m, 3H, Ar-H), 7.79 (s, 1H, CH), 8.53 (s, 1H D2O exch., NH).
Anal. Calcd for C14H17N3O (243.30): C 69.11; H 7.04; N 17.27.
2-Cyano-N-(2,6-dimethyl-phenyl)-acetamide 3a.
White
crystalline solid, yield 1.08 g (57.5%), mp 207–208ꢁC.
Found: C 69.15; H 7.14; N 17.20.
IR: υmax = 3146 (NH), 2258 (CN), and 1658 (CO) cmꢀ1
.
2-Cyano-3-dimethylamino-N-(3,5-dimethyl-phenyl)-acrylamide
8b. Yellow crystalline solid, yield 1.75 g (72%), mp 198–199ꢁC.
IR: υmax = 3247 (NH), 2186 (CN), 1665 (CO) cmꢀ1. MS: m/z = 243
[M+]; dH =2.22 (s, 6H, 2CH3), 3.19 (S, 3H, CH3), 3.26 (s, 3H, CH3),
6.65 (s, 1H, Ar-H), 7.22 (s, 2H, Ar-H), 7.80 (s, 1H, CH), 8.83 (s,
1H D2O exch., NH). dC = 21.02, 46.84, 70.97, 117.89, 119.21,
124.38, 137.20, 139.03, 156.19, 163.48. Anal. Calcd for
C14H17N3O (243.30): C 69.11; H 7.04; N 17.27. Found:
C 69.20; H 7.18; N 17.05.
MS: m/z=187 [M+ ꢀ 1]; dH = 2.13 (s, 6H, 2CH3), 3.91 (s, 2H, CH2),
7.06–7.09 (m, 3H, Ar. H), 9.65 (s, 1H D2O exch., NH). Anal.
Calcd for C11H12N2O (188.23): C 70.19; H 6.43; N 14.88.
Found: C 70.15; H 6.40; N 14.98.
2-Cyano-N-(3,5-dimethyl-phenyl)-acetamide 3b.
White
crystalline solid, yield 1.1 g (58.5%), mp 190–192ꢁC.
IR: υmax = 3154 (NH), 2254 (CN), and 1683 (CO) cmꢀ1
.
MS: m/z = 188 [M+]; dH = 2.23 (s, 6H, 2CH3), 3.86 (s, 2H, CH2),
6.73 (s, 1H, Ar-H), 7.15 (s, 2H, Ar-H), 10.15 (s, 1H D2O exch.,
NH). Anal. Calcd for C11H12N2O (188.23): C 70.19; H 6.43; N
Reaction of 8a,b with hydrazine hydrate and phenyl
hydrazine: synthesis of 11a,b and 14a,b.
A mixture of
compound 8a or 8b (10 mmol) and hydrazine hydrate or phenyl
hydrazine (10 mmol) in pyridine (15mL) was refluxed for 4 h
with stirring and then left to cool to room temperature. The
reaction mixture was then poured onto ice cold water (few drops
of HCl were added if no precipitate appeared), and the
precipitated solid was then filtered off and recrystallized from
ethanol to afford compounds 11a/11b and 14a/14b, respectively.
2-Cyano-3-{N0-[2-cyano-2-(2,6-dimethyl-phenylcarbamoyl)-
vinyl]-hydrazino}-N-(2,6-dimethyl-phenyl)-acrylamide 11a. White
crystalline solid, yield 2.70 g (63%), mp 193–194ꢁC. IR: υmax = 3254
(NH), 2258 (CN), 1662 (CO) cmꢀ1. MS: m/z= 428 [M+]; dH =2.26
(s, 12H, 4CH3), 3.58 (s, 2H D2O exch., 2NH), 7.09–7.27 (m, 8H,
Ar-H + 2 = CH), 7.40 (s, 2H D2O exch., 2NH). Anal. Calcd for
14.88. Found: C 70.22; H 6.50; N 14.85.
Reaction of 3a,b with hydrazine hydrate and phenyl
hydrazine. To a solution of compounds 3a or 3b (10 mmol)
in 15 mL pyridine was added hydrazine hydrate or phenyl
hydrazine (10 mmol) and the reaction mixture was refluxed for
2 h with stirring and then left to cool to room temperature. The
reaction mixture was then poured onto ice cold water followed
by few drops of conc. HCl. The precipitated solid that appeared
was filtered off and recrystallized from ethanol to afford
compounds 5a or 5b and 7a or 7b, respectively.
3,4-Diaza-2,5-bis[(2,6-dimethylphenyl)amino]hexa-2,4-diene-
1,6-dicarbonitrile 5a. Faint rose crystalline solid, yield 2.00 g
(53.8%), mp 211–212ꢁC. IR: υmax =1 3253 (br. NH), 2258 (CN)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet