OSYANIN et al.
(C–O), 163.4 (C=N). Found, %: C 77.83; H 10.39;
126
N 7.49. C24H38N2O. Calculated, %: C 77.79; H 10.34;
N 7.56.
The mother liquor was evaporated, and the residue
was subjected to silica gel column chromatography
using chloroform as eluent to isolate 0.085 g (6%) of
bis-phenol 3 whose melting point and spectral charac-
teristics were consistent with published data [18].
O
N
N
X-Ray analysis of compound 2. Single crystals of
2 suitable for X-ray analysis were grown by slow
evaporation of a solution of 2 in methylene chloride–
ethanol (1:1) at room temperature. The X-ray diffrac-
tion data were acquired from a 0.20×0.20×0.20-mm
colorless prismatic single crystal at 295(2) K on a Stoe
STADI-VARI Pilatus-100K diffractometer. Monoclinic
crystal system; unit cell parameters: a = 11.9557(12),
b = 14.5366(15), c = 39.016(4) Å; β = 97.187(8)°;
V = 6727.6(12) Å3; M 370.56; dcalc = 1.098 g/cm3;
Z = 12; space group P21/c; μ(MoKα) = 0.066 mm–1;
F(000) = 2448. Total of 9790 independent reflections
were collected in the range 2.22° ≤ θ ≤ 25.70° (spher-
ical segment –1 ≤ h ≤ 14, –17 ≤ k ≤ 15, –47 ≤ l ≤ 46);
1057 reflections were characterized by I > 2σ(I).
The structure was solved by the direct method and was
refined by the full-matrix least-squares procedure in
anisotropic approximation (for non-hydrogen atoms) to
R1 = 0.1178 (wR2 = 0.2506); all hydrogen atoms were
localized on the basis of geometry considerations, and
their positions were refined according to the riding
model. All calculations were performed using SHELX-
97. The crystallographic data for compound 2 were
deposited to the Cambridge Crystallographic Data
Centre (entry no. CCDC 903281).
Structure of the molecule of 2,4-di-tert-butyl-6-(1,8-diaza-
bicyclo[5.4.0]undec-7-en-6-ylmethyl)phenol (2) according to
the X-ray diffraction data.
imino nitrogen atom (N···HO), whose length is 2.072,
2.150, and 2.154 Å for the three independent mole-
cules. Taking into account high basicity of DBU
(pKa 12), it may be presumed that compound 2 has
zwitterionic structure with the hydrogen atom attached
to the imino nitrogen atom. However, the C–O bond in
phenoxide ion should be shorter by about 0.1 Å than
that in the hydroxy structure due to stronger conjuga-
tion with the benzene ring, i.e., it should be ~1.27 Å
[14–17]. In fact, the C–O bond length in molecule 2 is
1.367 Å, which rules out dipolar structure.
2,4-Di-tert-butyl-6-(1,8-diazabicyclo[5.4.0]undec-
7-en-6-ylmethyl)phenol (2). A mixture of 1.75 g
(6.7 mmol) of phenol 1 and 2.1 mL (2.06 g, 13.6 mmol)
of DBU in 15 mL of DMF was heated for 16 h under
reflux. The mixture was cooled and poured into 30 mL
of cold water, and the precipitate was filtered off,
washed with water, and recrystallized first from
aqueous methanol and then from ethanol. Yield 1.41 g
(57%), colorless crystals, mp 156–157°C. IR spectrum,
ν, cm–1: 2932, 2859 (C–H), 1616, 1589, 1481, 1462,
1439, 1381, 1358, 1315, 1238, 1180, 1123, 1084, 999,
957, 876, 725. 1H NMR spectrum (DMSO-d6), δ, ppm:
1.13–1.44 m (21H), 1.61–1.67 m (4H), 1.74 d.d (1H,
J = 9.6 Hz, 4.6 Hz), 1.83 d (1H, J = 13.8 Hz), 2.27 d
(1H, J = 11.9 Hz), 2.76 t (1H, J = 10.5 Hz), 2.84 d
(1H, J = 14.2 Hz), 2.92–3.12 m (3H), 3.17–3.23 m
(2H), 3.55 d.d (1H, J = 15.1, 11.4 Hz), 6.90 d (1H,
The IR spectra were recorded from samples
pelleted with KBr on a Shimadzu IRAffinity-1 spec-
1
trometer. The H and 13C NMR spectra (including
DEPT spectra) were measured on a JEOL JNM-
ECX400 spectrometer at 400 and 100 MHz, respec-
tively, using tetramethylsilane as internal reference.
The elemental composition was determined on a Euro
Vector EA-3000 CHNS analyzer. The melting point
was measured in a capillary on a PTP-M melting point
apparatus. Analytical TLC was performed on Silufol
UV-254 plates; spots were visualized under UV light
or by treatment with iodine vapor.
4
4
Harom, J = 2.3 Hz), 6.92 d (1H, Harom, J = 2.3 Hz).
13C NMR spectrum (DMSO-d6), δC, ppm: 21.6 (CH2),
26.9 (CH2), 28.1 (CH2), 30.2 (3C, CH3), 32.2 (3C,
CH3), 34.2 (C), 34.5 (CH2), 35.2 (C), 35.5 (CH2), 42.0
(CH2), 46.7 (CH), 48.3 (CH2), 51.6 (CH2), 121.1 (CH),
125.6 (CH), 128.9 (C), 136.9 (C), 139.3 (C), 153.6
This study was performed under financial sup-
port by the Ministry of Education and Science of
the Russian Federation (base part of state contract
no. 2014/199).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 1 2015