Acid-catalyzed disproportionation of N,N-bis(4-tert-butylphenyl) hydroxylamine. Synthesis and structure of 10-[5-tert-butyl-2-(4-tert- butylphenylamino)phenyl]-3,7-di-tert-butylphenoxazine

Article abstract of DOI:10.1134/S1070428014050108

New method of synthesis was developed for N,N-bis(4-tert-butylphenyl) hydroxylamine by reduction of the corresponding aminoxyl with hydrazine hydrate. At the treatment with strong acids this hydroxylamine derivative is converted in bis(4-tert-butylphenyl)amine and 10-[5-tert-butyl-2-(4-tert-butylphenylamino) phenyl]-3,7-di-tert-butylphenoxazine. The structure of the latter was established by X-ray diffraction analysis. The mechanism was suggested of the acid-catalyzed disproportionation of N,N-bis(4-tert-butylphenyl) hydroxylamine.

Full text of DOI:10.1134/S1070428014050108

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 5, pp. 678–684. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © V.A. Golubev, V.V. Tkachev, V.D. Sen’, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 5, pp. 691–696.
Acid-Catalyzed Disproportionation
of N,N-Bis(4-tert-butylphenyl)hydroxylamine.
Synthesis and Structure of 10-[5-tert-Butyl-
2-(4-tert-butylphenylamino)phenyl]-3,7-di-tert-butylphenoxazine
V. A. Golubev, V. V. Tkachev, and V. D. Sen’
Institute of Problems of Chemical Physics, Russian Academy of Sciences,
pr. Akademika Semenova 1, Chernogolovka, Moscow oblast, 142432 Russia
e-mail: vgolubev@icp.ac.ru
Received November 15, 2013
Abstract—New method of synthesis was developed for N,N-bis(4-tert-butylphenyl)hydroxylamine by
reduction of the corresponding aminoxyl with hydrazine hydrate. At the treatment with strong acids this
hydroxylamine derivative is converted in bis(4-tert-butylphenyl)amine and 10-[5-tert-butyl-2-(4-tert-
butylphenylamino)phenyl]-3,7-di-tert-butylphenoxazine. The structure of the latter was established by X-ray
diffraction analysis. The mechanism was suggested of the acid-catalyzed disproportionation of N,N-bis(4-tert-
butylphenyl)hydroxylamine.
DOI: 10.1134/S1070428014050108
N,N-Diarylhydroxylamines and the corresponding
nitroxyl and aminyl radicals play a key role in the
stabilization with diarylamines of polymers, lubricants,
and the other organic materials [1, 2]. The most
comprehensive source of the data on the chemical
properties of N,N-diarylhydroxylamines still remain
the papers [3, 4]. The uncommon property of N,N-
diarylhydroxylamines consists, e.g., in their reaction
with acids giving instead of expected diaryl-
hydroxyammonium salts an intricate mixture of
reaction products. The corresponding diarylamines
were isolated from this mixture [3, 4]. In the case of
N,N-ditolylhydroxylamine (I) along with ditolylamine
presumably, 5,10-diaryl-5,10-dihydrophenazine (III)
[4].
Aiming at elucidation of the reaction mechanism
we studied the reaction with hydrochloric acid of N,N-
bis(4-tert-butylphenyl)hydroxylamine (IV) prepared
by reduction of bis(4-tert-butylphenyl)aminoxyl (V)
with hydrazine (Scheme 2). This method is a lot
simpler than the known procedure of diarylhydroxy-
lamine IV preparation from 4-tert-butylnitrosobenzene
[5].
At the addition of conc. HCl to a solution of
diarylhydroxylamine IV in MeCN or MeOH the
solution turned violet and according to the data of
(II)
a
second reaction product was isolated,
Scheme 1.
HCl
N
N
+ Products
+
N
N
H
OH
II
I
III
678

ACID-CATALYZED DISPROPORTIONATION
679
Scheme 2.
N2H4
+
N2
N
O
V
N
.
OH
IV
Scheme 3.
O
N
4
1
6
9
HX
IV
+ Products
+
H
N
N
H
1'
4'
1''
4''
VI
VII
HPLC a mixture formed containing 13 products. We
isolated from the mixture bis(4-tert-butylphenyl)amine
(VI) in 26% yield and phenoxazine derivative VII in
11% yield. Considering the structure of compound VII
48% of diarylhydroxylamine IV was consumed in the
formation of reaction products VI and VII.
Table 1. Bond lengths (d) in molecule А of compound VII
Bond
d, Å
Bond
d, Å
O1–C12
O1–C5
N1–C7
N1–C6
N1–C21
N2–C26
N2–C27
C1–C6
C1–C2
C2–C3
C3–C4
C3–C13
C4–C5
C5–C6
C7–C8
C7–C12
C8–C9
C9–C10
C10–C11
C10–C17
C11–C12
C13–C14
C13–C16
C13–C15
1.386(1)
1.390(1)
1.408(2)
1.413(2)
1.442(2)
1.405(2)
1.411(2)
1.391(2)
1.396(2)
1.388(2)
1.402(2)
1.532(2)
1.377(2)
1.398(2)
1.391(2)
1.399(2)
1.390(2)
1.395(2)
1.398(2)
1.529(2)
1.378(2)
1.528(3)
1.529(2)
1.537(3)
C17–C18
C17–C19
C17–C20
C21–C26
C21–C22
C22–C23
C23–C24
C23–C33
C24–C25
C25–C26
C27–C32
C27–C28
C28–C29
C29–C30
C30–C31
C30–C37
C31–C32
C33–C36
C33–C34
C33–C35
C37–C38
C37–C40
C37–C39
1.513(2)
1.515(2)
1.525(3)
1.392(2)
1.396(2)
1.387(2)
1.403(2)
1.531(2)
1.380(2)
1.404(2)
1.394(2)
1.395(2)
1.385(2)
1.391(2)
1.390(2)
1.534(2)
1.388(2)
1.513(3)
1.522(3)
1.537(3)
1.525(2)
1.526(2)
1.533(3)
The structure of diarylamine VI was proved by
comparing its melting point and spectral data with
those of an authentic sample [6]. The structure of
compound VII whose molecule is composed of a
phenoxazine and a diphenylamine fragments was
established by X-ray diffraction (XRD) analysis and
was confirmed by elemental analysis and spectral data.
XRD study of single crystals of compound VII
showed that it crystallized in a triclinic crystal system
in a centrosymmetric space group P-1. In the
independent part of the unit cell two molecules, A and
B, are present with different orientation of cyclic
fragments. The structure of molecule A is shown in the
picture, the bond lengths and bond angles are compiled
in Tables 1, 2. The corresponding data on the second
molecule are available from the authors. Owing to
three different substituents and the lone electron pair of
N2 atom both A and B molecules exist in the crystal as
mirror pairs.
The phenoxazine ring in the molecule А is bent at
the line of atoms N1–O1 [angle 19.4° (24.1°), here and
hereinafter the values in parentheses correspond to B
molecule]. The atoms of the left (see the figure) and
the right benzene rings of the phenoxazine scaffold lie
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 5 2014

GOLUBEV et al.
680
Table 2. Bond angles (ω) in molecule А of compound VII
each in its proper mean-square plane within the
accuracy of 0.012 (0.005) and 0.022 (0.011) Å. The
C13 and С17 atoms of the tert-butyl groups deviate from
the planes of the benzene rings by –0.13 (+0.05) and
–0.14 (–0.04) Å.
The dihedral angle C6N1C21C26 between the planes
of the bound benzene rings of the phenoxazine scaffold
and diphenylamine fragment is 107.0° (97.5°). This
reciprocal position of the fragments is stabilized by an
intramolecular hydrogen bond between the hydrogen
atom of the N2H and the nitrogen atom N1 of
phenoxazine fragment [2.38 (2.39) Å]. In the phenyl[4-
(phenoxazin-10-yl)phenyl]methanone where the
intramolecular hydrogen bond is lacking this angle
equals 58.4° [7].
Angle
ω, deg
Angle
ω, deg
C12O1C5
C7N1C6
C7N1C21
C6N1C21
C26N2C27
C6C1C2
C3C2C1
C2C3C4
C2C3C13
C4C3C13
C5C4C3
C4C5O1
C4C5C6
O1C5C6
C1C6C5
116.11(9)
C18C17C10
C19C17C10
C20C17C10
C26C21C22
C26C21N1
C22C21N1
C23C22C21
C22C23C24
C22C23C33
C24C23C33
C25C24C23
C24C25C26
C21C26C25
C21C26N2
C25C26N2
112.44(14)
111.59(12)
108.09(13)
121.34(11)
119.15(11)
119.46(11)
121.68(12)
16.43(12)
116.77(10)
118.77(10)
117.44(10)
123.80(11)
120.64(13)
122.16(12)
116/93(12)
123.49(12)
119.43(13)
120.97(12)
116.72(11)
122.20(11)
121.08(11)
117.09(12)
122.63(13)
120.90(12)
122.49(12)
120.63(12)
117.23(12)
120.17(11)
122.53(12)
The dihedral angle between the planes of the
benzene rings of the diphenylamine fragment of
compound VII is 42.7° (47.0°). In the unsubstituted
diphenylamine whose unit cell contains eight
molecules the angles between the planes of the
benzene rings lie in the range 37–49° [8]. In compound
VII the sums of the bond angles at atoms N1 and N2
are 353.0° (356.4°) and 355° (355°) respectively.
Consequently, the substituents of the nitrogen atoms
are located at the vertices of strongly flattened
pyramids.
C1C6N1
C5C6N1
C8C7C12
C8C7N1
C12C7N12
C9C8C7
123.55(11)
119.36(10)
116.94(11)
123.59(11)
119.46(10)
121.17(12)
121.80(12)
116.84(12)
123.53(12)
119.49(12)
121.30(12)
116.97(10)
121.91(11)
121.11(10)
109.50(16)
110.92(13)
112.11(14)
108.73(17)
107.92(15)
107.54(13)
108.47(18)
107.06(19)
C32C27C28
C32C27N2
C28C27N2
C29C28C27
C28C29C30
C31C30C29
C31C30C37
C29C30C37
C32C31C30
C31C32C27
C36C33C34
C36C33C23
C34C33C23
C36C33C35
C34C33C35
C23C33C35
C38C37C40
C38C37C39
C40C37C39
C38C37C30
C40C37C30
C39C37C30
117.53(12)
118.68(12)
123.77(12)
120.46(13)
122.69(14)
116.24(13)
123.85(13)
119.90(13)
122.03(13)
121.03(13)
108.11(18)
109.36(15)
112.82(13)
110.6(2)
In the single crystal of the molecule of compound
VII due to the formation of intermolecular hydrogen
bonds between the phenoxazine oxygen atom and the
C8C9C10
C9C10C11
C9C10C17
C11C10C17
C12C11C10
C11C12O1
C11C12C7
O1C12C7
C14C13C16
C14C13C3
C16C13C3
C14C13C15
C16C13C15
C3C13C15
C18C17C19
C18C17C20
С20
С19
С18
С14
С13
С15
С17
С11
С12
С4
С10
С9
С5
С6
С3
С2
С16
С7
С8
107.10(17)
108.80(14)
108.77(12)
109.05(16)
108.76(13)
109.74(13)
111.63(12)
108.85(13)
N1
С1
H8
HN2
С21
С22
С23
С34
С26
С32
С27
С28
С31
N2
С33
С35
С30
С39
С37
С38
С40
С25
С24
С29
С36
C19C17C20
109.0(2)
Molecular structure of phenoxazine VII. Molecule А.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 5 2014

ACID-CATALYZED DISPROPORTIONATION
681
Scheme 4.
+HC
H+
IV
+
N
– H2O
N
N
+
OH2
A
B
HO
O
H2O
– H+
B
B
VII
–VI
N
H
N
H
D
C
1
hydrogen of the NH group dimeric associates are
present with the following parameters: N2–НN2 0.88,
О1–N2 3.16, О1-НN2 2.31 ÅA, angle N2НN2О1 162.5°
(А); N2–НN2 0.83, О1–N2 3.01, О1–НN2 2.22 Å, angle
N2НN2О1 158.3° (B).
assignment based on the H-13C HSQC experiment is
presented in Experimental.
IR reflection spectrum of crystalline compound VII
contains a doublet absorption band of the amino group
(3338 and 3353 cm–1) caused by two types of
hydrogen bonds as is clear from XRD analysis. The
spectrum also contains the bands of the stretching
vibrations of the bonds Carom–H (3038 cm–1), CH3
(2867, 2903, and 2962 cm–1), and of benzene rings
(1497, 1513, 1589, and 1607 cm–1).
The NMR spectra are in complete agreement with
the structure of substituted phenoxazine VII. Three
1
signals at δ 1.24, 1.285, and 1.29 ppm in the Н NMR
spectrum belong to four tert-butyl groups. The signal at δ
1.24 ppm corresponds to two groups in the positions 3
and 7 of the phenoxazine structure, since according to the
NMR 1Н-1Н NOE spectrum the protons of these groups
are spatially coupled with the protons H2, H4 and H6, H8.
According to XRD data the average distance between
them is 2.3 Å. The signals at δ 1.285 and 1.29 ppm
correspond to the tert-butyl groups in the positions 5'
and 4" of the diphenylamine fragment for according to
the NOE data they are spatially coupled with the
protons H4', H6' and H3", H5" respectively. According to
XRD data the average distance between them is 2.3 Å.
The equal values of the chemical shifts of hydrogen
atoms located symmetrically with respect to O and N
atoms show the high symmetry of the phenoxazine
fragment as also follows from the XRD study. It follows
The bands λmax 320 sh, 288, 243, 238 sh, 203 nm in
the UV spectrum of compound VII originate from the
superposition of the absorption of phenoxazine and
diphenylamine moieties. The spectrum of diarylamine
VI contained only two bands, λmax 289 and 242 nm.
Compound VII readily dissolves in H2SO4 giving a
dark blue solution whose color is due to the absorption
band of a dye of unknown structure, λmax 604 nm (ε
18000 L mol–1 cm–1).
In the mass spectrum of electron impact of com-
pound VII the most abundant peak belongs to a
fragment ion, m/z 573, originating from hydrogen
abstraction from the molecular ion. The peak of the
latter, m/z 574, coincides with the isotope peak of on
[M – H]+ and is not unambiguously determined. Beside
this ion the spectrum contains fragment ions, m/z 558
and 543, formed by elimination methyl groups from
ion [M – H]+, and the ion of diphenylamine fragment,
m/z 280.
1
from the NMR Н-1Н NOE experiment that the proton
H3' is coupled with the proton H2'', and protons H1 and H9,
with protons H6' and H6''. The distances between protons
as measured by XRD analysis are as follows: between
H3' and H2'' 2.23, between H1 and H6' 3.07, between H9
and H6'' 3.89 Å. The latter two distances are too long for
the spatial coupling between the protons. However in
solution due to the rotation around the C1'–N10 bond
these protons can significantly approach each other.
Scheme 4 presents the possible route of diaryl-
hydroxylamine IV transformation into diarylamine VI
and phenoxazine derivative VII.
13C NMR spectrum is also completely consistent
with the structure of compound VII. The signals
Diarylhydroxylamine IV is protonated at the
oxygen atom giving rise to oxonium ion А that libe-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 5 2014

GOLUBEV et al.
grade, с 9.7 mol L−1, was used in experiments.
682
rates
a
water molecule transforming into
a
diarylaminium cation B, where the positive charge is
delocalized over all the molecule. Cation B adds water
into the ortho-position of the benzene rings and
transforms into aminophenol C that is oxidized with
cation B to give phenoxazine D. Therewith cation B is
reduced into diarylamine VI. In the last stage
phenoxazine D condensed with cation B affording
compound VII. Thus as a result of complex
disproportionation catalyzed by acid three molecules
of diarylhydroxylamine IV are converted into
diarylamine VI and substituted phenoxazine VII.
Chromatographic analysis was carried out on a
chromatograph Milikhrom equipped with UV detector
(column 2 × 64 mm, Separon C18, 5 µm). Preparative
TLC was performed on plates 200 × 200 mm covered
with a layer of silica gel G 1.5 mm thick.
XRD study of compound VII was carried out on an
automatic diffractometer XCalibur (Agilent Co)
equipped with coordinate CCD detector EOS (Agilent
Technologies UK Ltd, Yarnton, Oxfordshire,
England). The XRD data were obtained on a single
crystal of the sample of the size 0.40 × 0.40 × 0.40 mm
at the temperature 200.01(10) K, radiation MoKα (λ
0.71073 Å). C40H50N2O. M 590.8372. Colorless
transparent crystals, triclinic, a 11.9464(3), b 15.3612(4),
с 20.3645(6) Å; α 69.099(3), β 86.391(2), γ 82.933(2)°;
V 3463.88(16) Å3, Z 4, dcalc 1.102 g/cm3, space group
P-1. The parameters of the cell unit were determined
and refined using a special program package CrysAlis
PRO [Agilent (2011). CrysAlis PRO version
171.35.19, Agilent Technologies UK, μ(MоKα)
0.065 mm–1]. The structure was solved by the direct
method. The full-matrix refinement of the positions
and thermal parameters of nonhydrogen atoms were
carried out first in isotropic, then anisotropic
approximation of the least-squares method. Hydrogen
atoms were localized from the difference syntheses
and were further refined in the rider model wherever
possible. The hydrogen atom coordinates in the NH
groups were refined isotropically. All calculations
were performed using SHELXTL software [11]. The
completeness of the experimental array 99.9% (2θ
62.66°). 22691 reflections were collected among them
16378 with I > 2σ(I). The number of refined
parameters 792, R 0.061, GOF 1.022.
A large number of products of diarylhydroxylamine
IV transformation under the action of acids is
evidently due to the features of the structure of the
intermediate diarylaminium cation B. Owing to the
charge delocalization this cation is a multicenter
electrophile and can add nucleophiles both at the
nitrogen atom and the carbon atoms of the benzene
rings. Diarylhydroxylamine IV, water, MeOH, and
anion Cl– may act as primary nucleophiles. Besides,
cation B is a strong oxidant, its redox reaction with
diarylhydroxylamine IV would provide the correspond-
ing aminyl and nitroxyl radicals. In acid medium these
radicals convert into a complex mixture of products of
disproportionation and recombination. The majority of
diarylhydroxylamines are subjected to such transfor-
mations. A certain exclusion from this behavior is
diarylhydroxylamines containing alkoxy groups in the
ortho- and para-positions of the benzene rings. Their
reaction with HClO4 afforded stable diarylaminium
salts [9]. The stability of these salts is presumably
governed by an efficient delocalization of the positive
charge with the involvement of the alkoxy groups and
with a considerable decrease in the redox potential.
N,N-Bis(4-tert-butylphenyl)hydroxylamine (IV).
A solution of 1 g (3.55 mmol) of bis(4-tert-butyl-
phenyl)aminoxyl (V) in 15 mL of MeOH was heated
on a water bath to boiling. To the solution 0.2 mL
(4.1 mmol) of hydrazine hydrate was added, and the
mixture was heated for ~12 min till the solution got
colorless. The solvent was evaporated at a reduced
pressure, the residue was crystallized from hexane.
Yield 0.93 g (85%), Colorless crystals, t.decomp. 113–
EXPERIMENTAL
IR reflection spectra were recoded on
a
spectrophotometer 100, absorption spectra from solu-
tions of compounds, on a spectrophotometer Specord
75IR. NMR spectra were registered on a spectrometer
Bruker AIII (500 MHz). UV spectra were obtained on
a spectrophotometer Specord UV-VIS. Mass spectra of
electron impact (70 eV) were taken on an instrument
Finnigan INCOS 50. Melting points were measured on
a heating block РNMQ.
115°С (113–114°С [5]). UV spectrum (EtOH), λmax
,
nm (ε, L mol–1 cm–1): 286 (8000), 243 (9500). IR
reflection spectrum, cm–1: 3299 (ОНbound), 3058 and
3040 (СНaryl), 2963, 2903 and 2867 (СН3), 1607 and
1507 (aryl), 1476, 1461, 1405, 1361, 1269, 1202,
1190, 1165, 1114, 1024, 941, 835; in CCl4: 3562
Bis(4-tert-butylphenyl)aminoxyl (V) was obtained
by procedure [10] and was crystallized from methanol,
mp 137°С. Hydrochloric acid of “chemically pure”
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 5 2014

ACID-CATALYZED DISPROPORTIONATION
683
(ОНfree), 3257 (ОНbound); 3088, 3050, 3035 (СНaryl);
2957, 2903, 2870 (CH3); 1608, 1506 (aryl). Н NMR
δ, ppm: 1.30 s [18H, C(CH3)3], 5.56 s (1H, NH), 7.00
d.m (4H, Ho, J 8.8 Hz), 7.27 d.m (4Н, Nm, J 8.8 Hz).
1
spectrum (CD3CN + N2H4·H2O), δ, ppm: 1.30 s [18H,
C(CH3)3], 7.08 d.m (4H, Ho, J 8.7 Hz), 7.35 d.m (4Н,
Nm, J 8.7 Hz).
Compound VII. Colorless crystals (MeCN), mp
231°С. UV spectrum, λmax, nm (ε, L mol–1 cm–1), in
heptane: 320 sh (12900), 288 (28700), 243 (68800),
238 sh (57800), 203 (103000); in MeCN: 319 sh
(12800), 290 (24300), 243 (57800), 239 sh (49700),
203 (71200); in H2SO4: 604 (18000), 409 (3260), 327
(5000), 267 (27700), 263 sh (25800), 237 sh (22900),
210 sh (50600). IR reflection spectrum, cm–1: 3353,
3338 (NH); 3038 (СНaryl); 2962, 2903, 2867 (СН3);
1607 1587, 1514, 1497 (aryl); 1460, 1414, 1396, 1363,
1334, 1323, 1308, 1200, 1150, 1122, 1100, 1026, 963,
Bis(4-tert-butylphenyl)amine (VI) and 3,7-di-
tert-butyl-10-[5-tert-butyl-2-(4-tert-butyl-phenyl-
amino)phenyl]phenoxazine (VII). To a solution of
503 mg (1.69 mmol) of compound IV in 3 mL of
MeOH was added at 10°С 0.175 mL (1.70 mmol) of
conc. HCl. The reaction mixture turned violet and
quickly became brown. A colorless precipitate (131
mg) simultaneously separated and in ~15 min was
filtered off, washed with MeOH, and dried in a
vacuum. The precipitate was subjected to HPLC (λ
210 nm, MeCN), Vsp, µL (Irel, %): 250 (20) (VI); 660
(23), 910 (100) (VII). In order to isolate the substituted
phenoxazine VII the precipitate was dissolved in
benzene, the solution was applied to two chromato-
graphic plates covered with silica gel G. Elution with a
mixture benzene–heptane, 1 : 2. Com-pound VII
moved in the first zone. Its position was determined by
blue coloration with H2SO4 that was placed from a
capillary at the sides of the plate. The substance was
extracted from the adsorbent with a mixture CHCl3–
MeOH, 25 : 1. On evaporation of the solvents we
obtained 103 mg (11 mol %) of compound VII.
1
925, 872, 819, 810. Н NMR spectrum (CDCl3), δ,
ppm: 1.24 s [18H, 3- and 7-C(CH3)3], 1.285 s [9H,
5'-C(CH3)3], 1.29 s [9H, 4''-C(CH3)3], 5.98 s (1H, NH),
5.98 d (2H, H1 and H9, J 8.4 Hz), 6.63 d.d (2H, H2 and
H8, J 2.2 and 8.4 Hz), 6.77 d (2H, H4 and H6, J 2.2 Hz),
7.04 d.m (2H, H2'' and H6'', J 8.7 Hz), 7.25 d (1H, H6', J
2.3 Hz), 7.27 d.m (2H, H3'' and H5'', J 8.7 Hz), 7.30 d.d
(1H, H4', J 2.3 and 8.6 Hz), 7.37 d (1H, H3', J 8.6 Hz).
13C NMR spectrum (CDCl3), δ, ppm: 31.22 [3- and
7-C(CH3)3], 31.43 and 31.47 [5'-and 4''-C(CH3)3],
34.03 [3- and 7-C(CH3)3], 34.21 and 34.24 [5' -and
4''-C(CH3)3], 112.66 (C1 and C9), 112.91 (C4 and C6),
114.97 (C3'), 119.88 (C2 and C8), 120.04 (C2'' and C6''),
124.84 (C1'), 125.96 (C4''), 126.00 (C3'' and C5''), 127.75
(C6'), 130.75 (C11 and C14), 139.42 (C1''), 140.50 (C2'),
143.73 (C12 and C13), 144.77 (C3 and C7), 144.97 (C5').
1Н-1Н NOESY NMR spectrum (CDCl3): from
increased intensity of NMR signals the following
protons coupling was observed: 3-C(CH3)3 (δ 1.24)
with H2 (δ 6.63) and H4 (δ 6.77); 7-C(CH3)3 (δ 1.24)
with H6 (δ 6.77) and H8 (δ 6.63); 5'-C(CH3)3 (δ 1.285)
with H4' (δ 7.30) and H6' (δ 7.25); 4''-C(CH3)3 (δ 1.29)
with H3'' and H5'' (δ 7.27); H1 and H9 (δ 5.98) with
H6' (δ 7.25) and H6'' (δ 7.04); H3' (δ 7.37) with H2'' (δ
7.04). Mass spectrum, m/z (Irel, %): 576 (1.10), 575
(9.81), 574 (44.74), 573 (100) [M – H]+; 560 (1.50),
559 (7.71) [M – H – CH3]+; 543 (2.20) [M – H –
2 CH3]+, 280 (40.14) [C20H26N]+. Found, %: C 83.54;
H 8.55; N 4.73. C40H50N2O. Calculated, %: C 83.58; H
8.77; N 4.87.
HPLC of the brown solution obtained after removal
of the precipitate (λ 210 nm, MeCN), Vsp, µL (Irel, %):
188 (28), 204 (22), 250 (100) (VI); 288 (83), 322 (65),
377 (10), 433 (2.0), 497 (4.0), 520 (4.0), 553 (1.7), 634
(11), 910 (9.5) (VII); 995 (9.5). To this solution 1 mL
of water was added. A dark precipitate was filtered off,
washed with 50% MeOH, and dried in a vacuum. Yield
185 mg. According to the data of quantitative HPLC the
precipitate contained 124 mg (26 mol %) of diarylamine
VI. The precipitate was dissolved in 9 mL of heptane,
and to the solution 0.8 g of silica gel was added. At
mixing the solution decolorized. On evaporating heptane
we obtained 99 mg of diarylamine VI. Colorless crystals
(MeOH), mp 108°С (108°С [6]). UV spectrum (EtOH),
λmax, nm (ε, L mol–1 cm–1): 289 (31000), 242 (6600). IR
reflection spectrum, cm–1: 3374 (NH); 3055, 3031
(СНaryl); 2963, 2903, 2863 (СН3); 1611, 1522 (aryl);
1477, 1463, 1422, 1391, 1360, 1319, 127, 1246, 1190,
1114, 1012, 933, 887, 824. 1Н NMR spectrum (CDCl3),
ACKNOWLEDGMENTS
The authors are grateful to Candidate of Chemical
Sciences A.V. Chernyak for registering the NMR spectra.
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GOLUBEV et al.
6. Kostrab, G., Lovic, M., Janotka, I., Bajus, M., and
684
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