KURBANOVA et al.
382
Scheme 2.
Me
O
MeC(O)CH2C(O)OEt
NCCH2CN
OH
OH
CN
O
CN
CN
2PhCHO
+
2
NC
CN
EtO
–2H2O
Ph
Ph
NC
Ph
Ph
NC
CN
nitrile with various aldehydes and carbonyl compounds
containing an active methylene group [5]. In con-
tinuation of these studies, herein we report the three-
component condensation of benzaldehyde with ethyl
acetoacetate and malononitrile in the presence of tri-
chloroacetic acid. It was found that, depending on the
conditions, the condensation product was the expected
product, ethyl 6-amino-5-cyano-2-methyl-4-phenyl-
4H-pyran-3-carboxylate (1), or previously unknown
ethyl 3,3,5,5-tetracyano-2-hydroxy-2-methyl-4,6-
diphenylcyclohexane-1-carboxylate (2) (Scheme 1).
Compound 1 was formed as the major product when
the reactants were heated in boiling ethanol for 1–2 h.
New compound 2 was obtained when the reaction
mixture was stirred for 7–9 h at room temperature. The
progress of the reaction was monitored by TLC, and
the product structure was confirmed by elemental
ethanol. The mixture was stirred under reflux or at
room temperature and cooled (if necessary), and the
precipitate was filtered off, washed with ethanol, dried,
and recrystallized from aqueous ethanol.
Ethyl 6-amino-5-cyano-2-methyl-4-phenyl-4H-
pyran-3-carboxylate (1). Yield 72%, mp 112–114°C
1
[6]. H NMR spectrum, δ, ppm: 7.30 t (1H, Harom),
7.25 m (1H, Harom), 7.17 d (1H, Harom), 6.89 s (2H,
NH2), 4.33 s (1H), 3.93 m (2H, CH2), 2.27 s (3H,
CH3), 1.06 t (3H, CH3). Found, %: C 67.63; H 5.59;
N 9.89. C16H16N2O3. Calculated, %: C 67.60; H 5.63;
N 9.85.
Ethyl 3,3,5,5-tetracyano-2-hydroxy-2-methyl-
4,6-diphenylcyclohexane-1-carboxylate (2). Yield
63%, mp 120–124°C. Found %: C 71.29; H 5.09;
N 12.72. C26H22N4O3. Calculated, %: C 71.23; H 5.02;
N 12.78.
1
analyses and H NMR and X-ray diffraction data
(Fig. 1). A probable mechanism for the formation of 2
is shown in Scheme 2.
1
The H NMR spectrum of 1 was recorded in
DMSO-d6 on a Bruker 300 spectrometer (300 MHz) at
25°C. The purity of the isolated compounds was
checked by TLC on Sorbfil plates using ethyl acetate–
benzene (1:3) as eluent; spots were visualized by
treatment with iodine vapor.
Compounds 1 and 2 (general procedure). A round-
bottom flask equipped with a reflux condenser and
a mechanical stirrer was charged with 0.102 mL
(1 mmol) of benzaldehyde, 0.07 g (1 mmol) of
malononitrile, 0.127 mL (1 mmol) of ethyl aceto-
acetate, 25 mg of trichloroacetic acid, and 10 mL of
A single crystal of 2 suitable for X-ray analysis was
obtained by double recrystallization from ethanol. The
X-ray diffraction data were obtained on a Bruker
APEX II CCD diffractometer at 100 K (Mo Kα radia-
tion, graphite monochromator, φ- and ω-scanning,
2θmax = 56°). The structure was solved by the direct
method and was refined by the least-squares method
in anisotropic approximation for non-hydrogen atoms.
The OH hydrogen atom was localized objectively by
difference Fourier syntheses, and its position was
refined in isotropic approximation with fixed posi-
tional and thermal parameters. The other hydrogens
were placed in geometrically calculated positions
which were refined in a similar way. All calculations
were performed using SHELXTL PLUS and SADABS
[7, 8]. The complete set of X-ray diffraction data for
compound 2 was deposited to the Cambridge Crys-
tallographic Data Centre (CCDC entry no. 1839026)
N4
C25
C26
H3
N3
C24
C5
C20
C6
C19
C21
O1
O2
C4
O3
C7
C18
C22
C23
C1
C8
N2
C17
C16
N1
C2
C3
C9
C15
C14
C10
C11
C13
C12
Fig. 1. Structure of the molecule of ethyl 3,3,5,5-tetracyano-
2-hydroxy-2-methyl-4,6-diphenylcyclohexane-1-carboxylate
(2) according to the X-ray diffraction data.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019
Kurbanova
