Hydrochlorination and hydrobromination of N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinonimines

Article abstract of DOI:10.1023/A:1012377401470

The direction of hydrohalogenation of N-substituted p-quinonimines was predicted on the basis of orbital coefficients of the C² and C³ atoms in the lowest unoccupied molecular orbital, calculated by the PM3 method. It was assumed that the reaction is orbital-controlled and that the initial act of hydrohalogenation is nucleophilic attack by halide ion. The proposed approach was verified by experimental hydrochlorination and hydrobromination of N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinonimines which take up HHlg molecule following the 1,4-addition scheme, i.e., the halogen atom adds to C² of the quinoid ring.

Full text of DOI:10.1023/A:1012377401470

Russian Journal of Organic Chemistry, Vol. 37, No. 1, 2001, pp. 72 82. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 1, 2001,
pp. 82 92.
Original Russian Text Copyright
2001 by Avdeenko, Marchenko, Konovalova.
Hydrochlorination and Hydrobromination
of N-(N-Arylsulfonylbenzimidoyl)-1,4-benzoquinonimines
A. P. Avdeenko, I. L. Marchenko, and S. A. Konovalova
Donbass State Machine-Building Academy, ul. Shkadinova 72, Kramatorsk, 84313 Ukraine
Received December 30, 1999
Abstract The direction of hydrohalogenation of N-substituted p-quinonimines was predicted on the basis
of orbital coefficients of the C2 and C3 atoms in the lowest unoccupied molecular orbital, calculated by the
PM3 method. It was assumed that the reaction is orbital-controlled and that the initial act of hydrohalogena-
tion is nucleophilic attack by halide ion. The proposed approach was verified by experimental hydrochlorina-
tion and hydrobromination of N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinonimines which take up HHlg
molecule following the 1,4-addition scheme, i.e., the halogen atom adds to C2 of the quinoid ring.
Hydrochlorination of various N-substituted
p-quinonimines has been studied in sufficient detail.
In most cases chlorine adds at position 2 or 6 of the
quinoid ring, i.e., the reaction follows the 1,4-addition
pattern. The C2 and C6 atoms in N-substituted
p-quinonimines are considered to be active in nucleo-
philic additions, specifically in hydrochlorination.
Adams and Looker [1] were the first to report on
the reaction of N-arylsulfonyl-p-quinonimines with
hydrogen chloride. The authors formulated a rule for
chlorine orientation, according to which the initial
step is protonation of the most basic center in the
molecule [2]; the subsequent attack by chloride ion on
position 2 of the quinoid ring is followed by proto-
tropic rearrangement:
and Burmistrov [4] found that hydrochlorination of
N-p-tolyl-1,4-benzoquinonimine involves chlorine
addition at C3, i.e., according to the 6,3-addition
scheme. This result suggests that protonation should
not necessarily be the primary act of hydrochlorina-
tion. In order to rationalize the direction of chlorine
addition to the N-p-tolyl-1,4-benzoquinonimine
molecule it was proposed to estimate the energies of
quinoid intermediates A and B by comparing redox
potentials of 1,4-benzoquinone (E0 = 0.583 V [5]) and
N-p-tolyl-1,4-benzoquinonimine (E0 = 0.566 V [6])
[4, 7]. Obviously, replacement of oxygen by p-tolyl-
imino group reduces E0 by 0.017 V (| E0| = 17 mV,
which corresponds to an energy of 3.3 kJ/mol); there-
fore, structure B in which the p-tolylimino group is
involved in the ortho-quinoid system is more favor-
able than structure A [7].
Chlorine addition to C3 was also observed in the
hydrochlorination of N-p-methoxyphenyl- and
N-phenyl-1,4-benzoquinonimines. The reaction with
N-p-nitrophenyl-1,4-benzoquinonimine followed the
1,4-addition pattern with formation of 2-chloro deriva-
tive, whereas N-p-iodophenyl-1,4-benzoquinonimine
gives rise to both 6,3- and 1,4-addition [8].
The protonation of N-substituted p-quinonimines
in the first step of hydrochlorination is really possible.
For example, protonation of N-aryl-1,4-benzoquinon-
imines yields stable solid salts [3]. However, Toropin
1070-4280/01/3701-0072$25.00 2001 MAIK Nauka/Interperiodica

HYDROCHLORINATION AND HYDROBROMINATION OF N-(N-ARYLSULFONYL-. . .
73
Although ortho-quinoid intermediates were charac-
terized by E0 values for para-quinoid structures, the
above approach turned out to be general for various
N-substituted p-quinonimines [7].
Table 1. Some electronic structure parameters of N-aryl-
1,4-benzoquinonimines I and 1,4-benzoquinone
The mechanism of hydrochlorination of N-substi-
tuted p-quinonimines was studied in detail by
Yurchenko [9]. The results of kinetic experiments in
a protic solvent (acetic acid) showed that the active
species is doubly protonated quinonimine rather than
its neutral form. ESR study of the reaction mixtures
showed the presence of radical species, and a radical
ion mechanism was proposed. In the first stage,
p-quinonimine dication reacts with Cl ion to form
the corresponding radical cation. Hydrochlorination
products are formed as a result of a series of conse-
cutive reactions involving radical and radical cation
species [9].
Charge, a.u.
E0,
mV
ELUMO
eV
,
EHOMO,
eV
X
O
N
4-MeOC6H4N 553
1.497
1.503
1.525
1.706
1.615
2.026
8.981
9.196
9.381
10.921
9.054
10.106
0.299 0.014
0.298 0.011
0.297 0.008
0.277
0.295 0.004
0.284 0.013
4-MeC6H4N
C6H5N
O
566
578
583
596
4-IC6H4N
4-NO2C6H4N 655
The reaction of N-substituted p-quinonimines with
hydrogen bromide has been studied to a considerably
lesser extent. The substrates were only N-arylsulfonyl-
1,4-benzo(naphtho)quinone mono- and diimines
[10, 11] and N-aryl-1,4-benzoquinonimines [11]. The
result of hydrobromination of N-p-tolyl-1,4-benzo-
quinonimine was the same as in the hydrochlorination:
bromine added at C3 of the quinoid ring [11].
Taking into account that hydrohalogenation of
N-substituted p-quinonimines is performed as a rule
in an aprotic solvent (CHCl3), where the probability
of protonation is low (the ionizing power of chloro-
form is weaker than that of acetic acid), alternative
hydrohalogenation mechanisms may be operative.
Below we discuss one of such mechanisms, according
to which chloride ion attacks neutral quinonimine as
reactive species. In terms of this mechanism we can
predict the site of halogen addition to the quinoid
ring with no regard to redox potentials of quinon-
imines, which are often difficult or even impossible
to determine experimentally.
We analyzed the process of hydrohalogenation of
N-substituted p-quinonimines on the basis of PM3
semiempirical calculations. Comparison of the cal-
culated energies of the lowest unoccupied molecular
orbitals (LUMO) of N-aryl-p-quinonimines I with
their redox potentials measured in [8] showed that
E0 regularly decreases as the LUMO energy rises
(Table 1). This result gave us grounds to use PM3
data for further theoretical interpretations.
According to the PM3 data (Table 1), the charge on
the oxygen atom in N-aryl-p-quinonimines I is about
0.3 a.u., whereas the charge on the nitrogen is close
to zero (Tabl. 1). This means that, had the reaction
been charge-controlled, the protonation would occur
at the oxygen atom. However, the hydrohalogenation
of N-(4-nitrophenyl)-1,4-benzoquinonimine follows
the 1,4-addition scheme which implies initial protona-
tion of the nitrogen atom. Taking into account that
the nitrogen atom is less negative than oxygen, it is
unlikely for the reaction to be charge-controlled.
The orbital control of the quinonimine protonation
is also improbable, for proton has a small ionic radius
and the energy gap between the highest occupied
molecular orbital (HOMO) of quinonimine and the
vacant orbital of proton (E = 0 eV) is large (Table 1).
Therefore, we can rule out protonation of quinon-
imine as the initial step of hydrohalogenation.
The calculated total energies (E) of intermediates A
and B for N-aryl-1,4-quinonimines are almost similar,
and comparison of their heats of formation ( H)
indicates that intermediate A is always more favorable
(Table 2). Therefore, formation of one or another
intermediate is not crucial for the direction of hydro-
halogenation. Moreover, assuming that the redox
potential of quinonimine determines the mode of
hydrogen halide addition, we cannot rationalize the
formation of a mixture of 1,4- and 6,3-addition prod-
ucts from N-(4-iodophenyl)-1,4-benzoquinonimine
(| E0| = 13 mV) and of only one isomer from
N-phenyl-1,4-benzoquinonimine (| E0| = 5 mV [8]).
While analyzing the results of PM3 calculations,
we have revealed an interesting relation between the
squared AO coefficients of C2 and C3 in the LUMO
of N-aryl-1,4-benzoquinonimines Ia Ig (Fig. 1). It
suggests that Cl and Br ions should attack C2 in
N-(4-nitrophenyl)-1,4-benzoquinonimine (Ig) and C3
in quinonimines Ia Ic, whereas compounds Id If
should give rise to mixtures of 2- and 3-isomers. This
is fully consistent with the experimental data [8].
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

74
AVDEENKO et al.
IIa IId and IIf with HCl or HBr should follow the
1,4-addition scheme, which is in full agreement with
the experimental data [1, 10, 12]. N-Acetyl-1,4-benzo-
quinonimine III should also take up halogen at posi-
tion 2 of the quinoid ring; however, the formation of
a mixture of two isomers cannot be ruled out, for the
orbital coefficients of C2 and C3 approach each other.
We failed to obtain N-acetyl-1,4-benzoquinonimine
(III) containing no substituent in the quinoid ring
(presumably, this compound is unstable); therefore,
it was impossible to verify the above supposition
experimentally. The results of hydrohalogenation of
N-acetyl-1,4-benzoquinonimines having a substituent
in the quinoid ring cannot be used for this purpose.
For example, N-acetyl-3,5-dimethyl-1,4-benzoquinon-
imine takes up hydrogen chloride according to the
1,4-addition pattern, whereas N-acetyl-2,6-dimethyl-
1,4-benzoquinonimine does not react with HCl [13].
Fig. 1. PM3 orbital coefficents of (1) C2 and (2) C3 in
the lowest unoccupied molecular orbital (LUMO) of N-aryl-
1,4-benzoquinonimines Ia Ig.
Fig. 2. PM3 orbital coefficents of (1) C2 and (2) C3 in
the lowest unoccupied molecular orbital (LUMO) of N-aryl-
sulfonyl-1,4-benzoquinonimines IIa IId and IIf, N-acetyl-
1,4-benzoquinonimine (III), and N-(N-arylsulfonylbenz-
imidoyl)-1,4-benzoquinonimines IVa IVg.
II, IV, Y = CH3O (a), CH3 (b, g), H (c), Cl (d), Br (e),
NO2 (f); Z = H (a f), Cl (g).
Hydrohalogenation of N-(N-arylsulfonylbenz-
imidoyl)-1,4-benzoquinonimines IV was not studied
previously. We calculated the orbital coefficients of
C2 and C3 in the LUMO of N-(N-arylsulfonylbenz-
imidoyl)-1,4-benzoquinonimines IVa IVg (Fig. 2).
According to the calculations, the reactions with
hydrogen chloride and hydrogen bromide should
follow the 1,4-addition pattern. Our experiments con-
firmed the results of calculations: successive addition
of two hydrogen chloride molecules (each addition
process was followed by oxidation of the adduct)
occurred at positions 2 and 6 of the quinoid ring of
N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinonimines
IVb, IVc, IVe, and IVg. The reaction was highly
regioselective. The hydrochlorination of both quinon-
imines IVb, IVc, IVe, and IVg and their monochloro
derivatives VIb, VIc, VIe, and VIg occurred under
very mild conditions, by passing gaseous hydrogen
The orbital control of hydrohalogenation with
initial nucleophilic attack by halide ion is supported
by the small difference between the HOMO energies
of Cl ( 3.479 eV) and Br ions ( 3.598 eV), on the
one hand, and the LUMO energies of quinonimines
(Table 1), on the other. We also calculated the orbital
coefficients of C2 and C3 in the LUMO of various
N-substituted p-quinonimines II IV whose hydro-
halogenation was studied experimentally (Fig. 2).
Y = CH3O (a), CH3 (b), H (c), Cl (d), Br (e), I (f), NO2 (g).
According to the calculation results, the hydrohalo-
genation of N-arylsulfonyl-1,4-benzoquinonimines
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

HYDROCHLORINATION AND HYDROBROMINATION OF N-(N-ARYLSULFONYL-. . .
75
Table 2. Total energies (E) and heats of formation ( H) of N-aryl-1,4-benzoquinonimines Ia Ic, If, and Ig and inter-
mediate structures A and B, calculated by the PM3 method
Ia Ic, If, Ig
A
B
Y
E, eV
H, kcal/mol
E, eV
H, kcal/mol
E, eV
H, kcal/mol
CH3O
CH3
H
2457.04
2163.90
2014.18
2287.34
2745.57
9.45
35.17
44.61
66.17
36.36
2790.04
2496.85
2347.10
2620.27
3078.56
21.00
8.25
18.52
39.65
8.46
2789.71
2496.64
2346.91
2620.09
3078.29
13.35
13.00
22.75
43.83
14.87
I
NO2
chloride through a solution of quinonimine at room
temperature (Scheme 1). The third and fourth chlorine
effected in dimethylformamide at room temperature,
and the fourth HCl molecule added to compounds Xb,
atoms can be introduced under more severe condi- Xc, Xe, and Xg in dimethylformamide on heating.
tions. The addition of hydrogen chloride to dichloro
derivatives VIIIb, VIIIc, VIIIe, and VIIIg was
We previously succeeded in introducing only three
chlorine atoms into N-arylsulfonyl-1,4-benzoquinon-
Scheme 1.
Ar = 4-CH3C6H4 (b, g), C6H5 (c), 4-BrC6H4 (e); Ar = C6H5 (b, c, e), 4-ClC6H4 (g).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

76
AVDEENKO et al.
Scheme 2.
Ar = C6H5 (a), 4-BrC6H4 (b).
Scheme 3.
Ar = C6H5 (a), 4-BrC6H4 (b).
imine molecules [12]. Products XIb, XIc, XIe, and
XIg of addition of four HCl molecules, as well as
adducts V, VII, and IX, were oxidized to the corre-
sponding quinonimines with lead tetraacetate in acetic
acid (Scheme 1).
As might be expected, N-(N-arylsulfonylbenzimid-
oyl)-3,5-dimethyl-1,4-benzoquinonimines XIIIa and
XIIIb took up in succession two hydrogen chloride
molecules in chloroform, yielding 2,6-dichloro deriva-
tives XVIIa and XVIIb (Scheme 2). As in the case
of N-(N-arylsulfonylbenzimidoyl)-2,6-dichloro-1,4-
benzoquinonimines VIII, the addition of one hydro-
gen chloride molecule to N-(N-arylsulfonylbenz-
imidoyl)-2,6-dimethyl-1,4-benzoquinonimines XVIIIa
and XVIIIb was presumed to occur under more
severe conditions (in dimethylformamide), and the
second HCl molecule was expected to add to com-
pounds XVIII in dimethylformamide on heating.
However, the first addition readily occurred in chloro-
form, and the second, in dimethylformamide at room
temperature (Scheme 3).
The structure of compounds V XII, XIV XVII,
and XIX XXII was proved by elemental analyses
1
(Table 3) and H and 13C NMR spectra. The NMR
spectra were recorded only for quinoid compounds
VI, VIII, X, XII, XV, XVII, XX, and XXII as the
1
most informative. The H NMR spectra of VIb, VIe,
VIIIb, VIIIc, Xb, Xg, XIIg, XVb, XVIIb, XXb,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

HYDROCHLORINATION AND HYDROBROMINATION OF N-(N-ARYLSULFONYL-. . .
77
Scheme 4.
Ar = 4-CH3C6H5 (b, g), C6H5 (c); Ar = C6H5 (b, c), 4-ClC6H4 (g).
Scheme 5.
Ar = C6H5 (a), 4-BrC6H4 (b).
and XXIIb were fully consistent with the proposed
structures (Table 4). The 13C NMR spectra of VIe,
VIIIe, XIIb, XIIe, XVIIb, XXIIa, and XXIIb con-
tain characteristic signals from carbon atoms of the
carbonyl group and benzimidoyl and quinonimine
successive hydrobromination of N-(N-arylsulfonyl-
benzimidoyl)-1,4-benzoquinonimines IVb, IVc, and
IVg (Scheme 4). The first two HBr molecules add
in acetic acid at room temperature according to the
1,4-scheme. N-(N-Arylsulfonylbenzimidoyl)-2,6-di-
bromo-1,4-benzoquinonimines XXVIb, XXVIc, and
XXVIg are reduced to compounds XXVb, XXVc, and
XXVg by the action of hydrogen bromide in acetic
acid on heating; the third HBr molecule adds in di-
methylformamide on heating. Oxidation of tribromo
C N groups at
169 182, 163 168, and 144
C
156 ppm, respectively. The other carbon signals were
in agreement with the proposed structures (Table 5).
Unlike hydrochlorination, only three bromine
atoms can be introduced into the quinoid ring by
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

78
AVDEENKO et al.
Table 3. Yields, melting points, and elemental analyses of compounds V XII, XIV XVII, XIX XXII, XXIII XXVI,
XXVII, XXVIII, and XXIX XXXII
Comp. no.
Yield, %
mp,a
C
Found Hlg, %
Formula
Calculated Hlg, %
Vb
Vc
Ve
Vg
VIb
VIc
VIe
VIg
VIIb
VIIc
VIIe
VIIg
VIIIb
VIIIc
VIIIe
VIIIg
IXb
IXc
IXe
IXg
Xb
90
88
64
71
51
69
77
50
80
91
90
56
83
75
91
56
63
95
83
75
89
90
63
60
85
66
84
67
51
55
40
53
57
86
77
74
69
80
63
40
68
57
50
86
92
51
52
50
215
8.93, 9.04
8.99, 9.11
24.42, 24.88
15.73, 15.94
8.61, 8.65
C20H17ClN2O3S
C19H15ClN2O3S
C19H14BrClN2O3S
C20H16Cl2N2O3S
C20H15ClN2O3S
C19H13ClN2O3S
C19H12BrClN2O3S
C20H14Cl2N2O3S
C20H16Cl2N2O3S
C19H14Cl2N2O3S
C19H13BrCl2N2O3S
C20H15Cl3N2O3S
C20H14Cl2N2O3S
C19H12Cl2N2O3S
C19H11BrCl2N2O3S
C20H13Cl3N2O3S
C20H15Cl3N2O3S
C19H13Cl3N2O3S
C19H12BrCl3N2O3S
C20H14Cl4N2O3S
C20H13Cl3N2O3S
C19H11Cl3N2O3S
C19H10BrCl3N2O3S
C20H12Cl4N2O3S
C20H14Cl4N2O3S
C19H12Cl4N2O3S
C19H11BrCl4N2O3S
C20H13Cl5N2O3S
C20H12Cl4N2O3S
C19H10Cl4N2O3S
C19H9BrCl4N2O3S
C20H11Cl5N2O3S
C21H19ClN2O3S
C21H18BrClN2O3S
C21H17ClN2O3S
C21H16BrClN2O3S
C21H16Cl2N2O3S
C21H17BrCl2N2O3S
C21H14Cl2N2O3S
C21H15BrCl2N2O3S
C21H19ClN2O3S
C21H18BrClN2O3S
C21H17ClN2O3S
C21H16BrClN2O3S
C21H16Cl2N2O3S
C21H17BrCl2N2O3S
C21H14Cl2N2O3S
C21H15BrCl2N2O3S
8.84
9.16
24.77
16.29
8.89
220
195
228
135
183
127
147
205
182
210
268
160
181
187
185
210
235
220
235
212
210
187
220
275
284
290
295
203
235
215
210
291
280
164
170
303
315
191
227
302
210
173
195
276
300
212
190
9.06, 9.13
9.21
24.17, 24.31
15.79, 15.98
15.84, 16.03
16.07, 16.52
30.07, 30.29
22.15, 22.44
16.05, 16.31
16.74, 16.77
29.63, 29.85
22.13, 22.37
22.31, 22.44
22.94, 23.16
34.01, 34.44
27.86, 27.97
22.18, 22.38
22.90, 23.19
34.22, 34.76
27.77, 27.96
27.55, 27.93
28.08, 28.45
38.19, 38.72
32.64, 32.87
27.88, 27.93
28.74, 28.83
24.91, 24.97
32.44. 32.63
8.34, 8.47
24.87
16.36
16.29
16.83
30.15
22.64
16.36
16.91
30.27
22.74
22.64
23.34
34.84
28.13
22.74
23.44
34.97
28.24
28.13
28.93
38.96
32.91
28.24
29.05
25.01
33.03
8.54
Xc
Xe
Xg
XIb
XIc
XIe
XIg
XIIb
XIIc
XIIe
XIIg
XIVa
XIVb
XVa
XVb
XVIa
XVIb
XVIIa
XVIIb
XIXa
XIXb
XXa
XXb
XXIa
XXIb
XXIIa
XXIIb
22.98, 23.25
8.36, 8.51
23.36
8.59
23.00, 23.17
15.61, 15.72
28.13, 28.21
15.66, 15.73
28.37, 28.46
8.35, 8.42
23.46
15.85
28.55
15.92
28.66
8.54
22.95, 23.16
8.36, 8.47
23.36
8.59
23.01, 23.32
15.45, 15.62
28.04, 28.37
15.46, 15.58
28.19, 28.31
23.46
15.85
28.55
15.92
28.66
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

HYDROCHLORINATION AND HYDROBROMINATION OF N-(N-ARYLSULFONYL-. . .
Table 3. (Contd.)
79
Comp. no.
Yield, %
mp,a
C
Found Hlg, %
Formula
Calculated Hlg, %
XXIIIb
XXIIIc
XXIIIg
XXIVb
XXIVc
XXIVg
XXVb
65
91
78
63
94
57
64
71
80
58
55
60
43
67
48
75
96
97
77
91
83
86
82
59
198
17.68, 17.89
18.43, 18.59
31.42, 31.74
18.01, 18.22
17.73, 17.95
31.22, 31.27
30.11, 30.28
30.95, 31.24
34.42, 34.58
30.17, 30.31
31.07, 31.28
34.67, 34.83
39.03, 39.17
40.52, 40.81
39.64, 39.82
40.59, 40.69
17.05, 17.22
29.36, 29.43
17.23, 17.32
29.70, 29.82
29.31, 29.45
38.82, 38.97
29.18, 29.44
38.91, 40.16
C20H17BrN2O3S
C19H15BrN2O3S
C20H16BrClN2O3S
C20H15BrN2O3S
C20H13BrN2O3S
C20H14BrClN2O3S
C20H16Br2N2O3S
C19H14Br2N2O3S
C20H15Br2ClN2O3S
C20H14Br2N2O3S
C19H12Br2N2O3S
C20H13Br2ClN2O3S
C20H15Br3N2O3S
C19H13Br3N2O3S
C20H13Br3N2O3S
C19H11Br3N2O3S
C21H19BrN2O3S
C21H18Br2N2O3S
C21H17BrN2O3S
C21H16Br2N2O3S
C21H18Br2N2O3S
C21H17Br3N2O3S
C21H16Br2N2O3S
C21H15Br3N2O3S
17.94
18.53
31.43
18.02
18.11
31.57
30.48
31.32
34.95
30.60
31.45
35.08
39.74
40.69
39.88
40.83
17.39
29.69
17.47
29.80
29.69
38.84
29.80
38.97
225
225
140
180
162
205
175
240
185
190
192
183
215
210
215
270
280
173
208
268
312
205
230
XXVc
XXVg
XXVIb
XXVIc
XXVIg
XXVIIb
XXVIIc
XXVIIIb
XXVIIIc
XXIXa
XXIXb
XXXa
XXXb
XXXIa
XXXIb
XXXIIa
XXXIIb
a
All products were recrystallized from acetic acid.
derivatives XXVIIb and XXVIIc yields the corre-
sponding quinonimines XXVIIIb and XXVIIIc. Our
attempt to effect addition of the fourth HBr molecule
resulted in reduction of XXVIII to tribromoamino-
phenols XXVII (Scheme 4).
involves initial formation of relatively stable bright
yellow intermediates D. In most cases the lifetime of
these intermediates ranges from 5 to 20 min. Taking
into account possible protonation at the nitrogen atom
of the arylsulfonylimino fragment, the most probable
salt-like structure of intermediate D is shown below:
N-(N-Arylsulfonylbenzimidoyl)-3,5-dimethyl-1,4-
benzoquinonimines XIIIa and XIIIb take up in suc-
cession two HBr molecules. The addition occurs only
on heating in dimethylformamide (Scheme 5). We
failed to effect addition of hydrogen bromide to
N-(N-arylsulfonylbenzimidoyl)-2,6-dimethyl-1,4-ben-
zoquinonimines XVIIIa and XVIIIb even under
severe conditions; as a result, only initial products and
those formed by hydrolysis were isolated. The adducts
obtained by reactions of quinonimines with hydrogen
bromide were then oxidized with lead tetraacetate
in acetic acid. The structure of compounds XXIII
XXXII was proved by elemental analyses (Table 3)
1
and H NMR spectra which were obtained for quinoid
The quinoid fragment in D is structurally related to
intermediate A (see above). Presumably, its stability
is explained by the presence of a positive charge on
the arylsylfonylimino nitrogen atom. The salt-like
structures XXVIb and XXVIIIb (Table 4).
The hydrohalogenation of N-(N-arylsulfonylbenz-
imidoyl)-1,4-benzoquinonimines IV, XIII, and XVIII
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

80
AVDEENKO et al.
Table 4. 1H NMR spectra of compounds VIb, VIe, VIIIb, VIIIc, VIIIe, Xb, Xg, XIIg, XVb, XVIIb, XXb, XXIIb,
XXVIb, and XXVIIIb
Chemical shifts , ppm (CDCl3)
Comp.
no.
quinoid ring
Ar C N
4-XC6H4SO2
VIb
VIe
6.78 d (1H, 6-H), 7.16 d (1H, 3-H), 7.04 d.d 7.42 7.80 m (5H) 7.31 7.86 d.d (4H), 2.44 s (3H, CH3)
(1H, 5-H)
7.21 d (1H, 3-H), 7.05 d.d (1H, 5-H), 6.82 d 7.44 7.79 m (5H) 7.67 7.86 d.d (4H)
(1H, 6-H)
VIIIb
VIIIc
VIIIe
Xb
Xg
XIIg
XVb
7.19 s (2H, 3-H, 5-H)
7.22 s (2H, 3-H, 5-H)
7.23 s (2H, 3-H, 5-H)
6.99 s (1H, 5-H)
7.43 7.79 m (5H) 7.31 7.87 d.d (4H), 2.44 s (3H, CH3)
7.44 7.80 m (5H) 7.53 8.00 m (5H)
7.45 7.79 m (5H) 7.68 7.87 d.d (4H)
7.44 7.80 m (5H) 7.32 7.87 d.d (4H), 2.44 s (3H, CH3)
7.42 7.74 d.d (4H) 7.32 7.85 d.d (4H), 2.44 s (3H, CH3)
7.42 7.71 d.d (4H) 7.33 7.92 d.d (4H), 2.45 s (3H, CH3)
6.97 s (1H, 5-H)
6.63 d (1H, 6-H), 2.12 d (3H, 5-CH3), 2.29 s 7.46 7.77 m (5H) 7.66 7.87 d.d (4H)
(3H, 3-CH3)
XVIIb
XXb
2.29 s (6H, CH3)
7.46 7.76 m (5H) 7.67 7.86 d.d (4H)
6.55 d (1H, 5-H), 2.02 s (3H, 6-CH3), 2.30 s 7.43 7.82 m (5H) 7.64 7.87 d.d (4H)
(3H, 2-CH3)
XXIIb
2.29 s (6H, CH3)
7.41 7.79 m (5H) 7.62 7.86 d.d (4H)
XXVIb
7.46 s (2H, 3-H, 5-H)
7.43 7.80 m (5H) 7.32 7.87 d.d (4H), 2.44 s (3H, CH3)
7.45 7.78 m (5H) 7.31 7.87 d.d (4H), 2.43 s (3H, CH3)
XXVIIIb 7.27 s (1H, 5-H)
structure decomposes by the action of water to form
benzoid structure, 2-halo-4-aminophenol V or XXIII,
via proton transfer. This process is accompanied by
liberation of 1 equiv of hydrogen halide which was
quantitated by the weight of silver halide formed in
reaction with silver nitrate.
In two cases, namely in the hydrochlorination of
N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinonimines
IVb and IVe, we succeeded in isolating stable inter-
mediate compounds XXXIIIb and XXXIIIe (D):
EXPERIMENTAL
The IR spectra were recorded on a UR-20 spec-
1
trometer in KBr. The H and 13C NMR spectra were
obtained on a Varian VXR-300 instrument operating
1
at 300 MHz for H and 75.4 MHz for 13C; chloro-
form-d was used as solvent, and tetramethylsilane, as
internal reference. Thin-layer chromatography was
performed on Silufol UV-254 plates. Samples were
applied from solutions in chloroform, and benzene
ethyl acetate (10:1) was used as eluent. The spots
were visualized with UV light. Initial compounds
IVb, IVc, IVe, IVg, XIIIa, XIIIb, XVIIIa, and
XVIIIb were synthesized as described in [14].
N-(N-Arylsulfonylbenzimidoyl)-4-amino-2-
chlorophenols Vb, Vc, Ve, and Vg; N-(N-arylsul-
fonylbenzimidoyl)-2,6-dichloro-4-aminophenols
VIIb, VIIc, VIIe, and VIIg; N-(N-arylsulfonylbenz-
imidoyl)-4-amino-2-chloro-3,5-dimethylphenols
XIVa and XIVb; N-(N-arylsulfonylbenzimidoyl)-
4-amino-2,6-dichloro-3,5-dimethylphenols XVIa
and XVIb; and N-(N-arylsulfonylbenzimidoyl)-
4-amino-3-chloro-2,6-dimethylphenols XIXa and
XIXb. A stream of gaseous hydrogen chloride was
passed over a period of 20 30 min through a solution
of 0.01 mol of appropriate quinonimine IVb, IVc,
1
We failed to record their H NMR spectra, but
the IR spectra of XXXIIIb and XXXIIIe contained
a characteristic absorption band at 1630 1640 cm
due to carbonyl group and two bands in the regions
3170 3180 and 3290 300 cm , which are typical
1
1
of N H bonds.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

HYDROCHLORINATION AND HYDROBROMINATION OF N-(N-ARYLSULFONYL-. . .
81
Table 5. 13C NMR spectra ( C, ppm) of compounds VIe, VIIIe, XIIb, XIIe, XVIIb, XXIIa, and XXIIb in CDCl3
Quinonimine fragment
Comp.
no.
C1 (C O)
C2
2-CH3
C6
6-CH3
C3
3-CH3
16.72
C5
5-CH3 C4 (C N)
VIe
178.25
172.15
169.31
169.22
171.59
181.73
181.64
142.04
141.28
139.16
139.17
138.83
141.40
141.60
134.64
141.28
139.16
139.17
138.83
141.40
141.60
135.17
132.26
138.92
139.05
141.66
138.26
138.14
131.98
132.26
138.92
139.05
141.66
138.26
138.14
156.00
154.42
143.92
144.55
152.54
146.08
146.19
VIIIe
XIIba
XIIe
XVIIb
XXIIa
XXIIb
16.72
14.66
14.67
14.66
14.67
Ar C N
C2, C6
ArSO2
C2, C6
Comp.
no.
C N
C1
C3, C5
C4
C1
C3, C5
C4
VIe
168.07
167.69
163.62
164.20
163.56
164.90
165.13
131.33
131.16
131.40
131.17
130.65
132.14
132.02
129.21
129.29
129.58
129.21
129.37
128.86
129.17
129.13
129.16
129.10
128.90
128.56
128.77
128.94
134.71
134.79
134.66
134.29
134.23
133.56
133.72
140.06
139.94
139.34
139.86
140.42
141.12
140.27
128.94
128.91
128.55
128.62
128.37
127.34
128.61
132.22
132.10
134.03
132.28
132.20
128.57
132.09
128.13
128.24
127.45
128.18
127.79
132.66
127.73
VIIIe
XIIba
XIIe
XVIIb
XXIIa
XXIIb
a
21.59 ppm (CH3 in CH3C6H4SO2).
C
IVe, IVg, VIb, VIc, VIe, VIg, XIIIa, XIIIb, XVa,
XVb, XVIIIa, or XVIIIb in 5 ml of dry chloroform.
The solution lightened, and a bright yellow solid
precipitated. The product was filtered off on exposure
to air, and it became colorless. It was washed with
a small amount of acetic acid, dried, and recrystallized
from acetic acid. The yields, melting points, and
elemental analyses (for halogen) of the products are
given in Table 3.
N-(N-Arylsulfonylbenzimidoyl)-4-amino-2,3,6-
trichlorophenols IXb, IXc, IXe, and IXg and N-(N-
arylsulfonylbenzimidoyl)-4-amino-3,5-dichloro-2,6-
dimethylphenols XXIa and XXIb. Gaseous hydro-
gen chloride was passed over a period of 40 45 min
through a solution of 5 mmol of quinonimine VIIIb,
VIIIc, VIIIe, VIIIg, XXa, or XXb in 5 ml of di-
methylformamide until the solution turned colorless.
The reaction was exothermic, and the mixture warmed
up during the process. The mixture was cooled and
diluted with 5 ml of aqueous acetic acid (1:1), and
the colorless precipitate was filtered off, washed with
water, dried, and recrystallized from acetic acid
(Table 3).
of 30 40 min through a solution of 5 mmol of
quinonimine Xb, Xc, Xe, or Xg in 5 ml of dimethyl-
formamide, preliminarily heated to 60 70 C. The
solution lightened, and a yellow solid precipitated and
quickly turned colorless. The product was filtered off,
washed with acetic acid, dried, and recrystallized from
acetic acid (Table 3).
Chlorinated N-(N-arylsulfonylbenzimidoyl)-1,4-
benzoquinonimines VIb, VIc, VIe, VIg, VIIIb,
VIIIc, VIIIe, VIIIg, Xb, Xc, Xe, Xg, XIIb, XIIc,
XIIe, XIIg, XVa, XVb, XVIIa, XVIIb, XXa, XXb,
XXIIa, and XXIIb. Lead tetraacetate, 6.5 mmol, was
added with stirring at room temperature to 5 mmol of
aminophenol Vb, Vc, Ve, Vg, VIIb, VIIc, VIIe,
VIIg, IXb, IXc, IXe, IXg, XIb, XIc, XIe, XIg,
XIVa, XIVb, XVIa, XVIb, XIXa, XIXb, XXIa, or
XXIb in 10 ml of acetic acid. the reaction was exo-
thermic, and it was necessary to cool the reaction
mixture. Ethylene glycol, 2 ml, was added, the mix-
ture was stirred for 2 min, and the precipitate was
filtered off, washed with methanol, dried, and recrys-
tallized from acetic acid (Table 3).
N-(N-Arylsulfonylbenzimidoyl)-4-amino-2-
bromophenols XXIIIb, XXIIIc, and XXIIIg and
N-(N-arylsulfonylbenzimidoyl)-4-amino-2,6-di-
bromophenols XXVb, XXVc, and XXVg. To a solu-
N-(N-Arylsulfonylbenzimidoyl)-4-amino-2,3,5,6-
tetrachlorophenols XIb, XIc, XIe, and XIg. Dry
gaseous hydrogen chloride was passed over a period
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001

82
AVDEENKO et al.
tion of 0.01 mol of quinonimine IVb, IVc, IVg,
XXIVb, XXIVc, or XXIVg in 10 ml of acetic acid
we added with stirring in portions 2 ml of 46% hydro-
bromic acid. The solution turned first bright yellow
and then (on further stirring and cooling) lightened,
and a yellow solid precipitated. The product was fil-
tered off (it became colorless during filtration in air),
dried, and recrystallized from acetic acid (Table 3).
N-(N-Arylsulfonylbenzimidoyl)-4-amino-2,3,6-
tribromophenols XXVIIb and XXVIIc; N-(N-aryl-
sulfonylbenzimidoyl)-4-amino-2-bromo-3,5-di-
methylphenols XXIXa and XXIXb; and N-(N-aryl-
sulfonylbenzimidoyl)-4-amino-2,6-dibromo-3,5-di-
methylphenols XXXIa and XXXIb. To a solution of
0.01 mol of quinonimine XIIIa, XIIIb, XXVIb,
XXVIc, XXXa, or XXXb in 30 ml of DMF, heated
to 110 C (XXVIb and XXVIc) or 70 C (XIIIa,
XIIIb, XXXa, and XXXb), we added with stirring
10 ml of 46% hydrobromic acid. The mixture was
stirred for 5 min, and it turned orange. The mixture
was cooled and diluted with 20 ml of water (in the
reactions with compounds XIIIb, XXXa, and XXXb,
the product separated from the solution without dilu-
tion), and the colorless precipitate was filtered off
and recrystallized from acetic acid (Table 3).
REFERENCES
1. Adams, R. and Looker, J.H., J. Am. Chem. Soc.,
1951, vol. 73, no. 3, pp. 1145 1152.
2. Adams, R. and Colgrove, R.S., J. Am. Chem. Soc.,
1954, vol. 76, no. 13, pp. 3584 3587.
3. Markava, E.Ya., Kanepe, D.V., Liepin’sh. E.E., and
Freimanis, Ya.F., Zh. Org. Khim., 1980, vol. 16,
no. 11, pp. 2362 2368.
4. Toropin, N.V. and Burmistrov, K.S., Zh. Org. Khim.,
1983, vol. 19, no. 7, p. 1546.
5. Dubina, V.L. and Burmistrov, K.S., Zh. Org. Khim.,
1977, vol. 13, no. 2, pp. 378 380.
6. Burmistrov, K.S. and Burmistrov, S.I., Ukr. Khim.
Zh., 1978, vol. 44, no. 8, pp. 832 835.
7. Burmistrov, K.S., Doctoral (Chem.) Dissertation,
Kiev, 1990.
8. Burmistrov, K.S. and Yurchenko, A.G., Zh. Org.
Khim., 1985, vol. 21, no. 3, pp. 575 578.
9. Yurchenko, A.G., Cand. Sci. (Chem.) Dissertation,
Dnepropetrovsk, 1993.
10. Avdeenko, A.P. and Velichko, N.V., Zh. Org. Khim.,
1992, vol. 28, no. 6, pp. 1257 1263.
11. Toropin, N.V., Burmistrov, K.S., Burmistrov, S.I.,
and Zaichenko, N.L., Zh. Org. Khim., 1986, vol. 22,
no. 5, pp. 999 1005.
Brominated N-(N-arylsulfonylbenzimidoyl)-1,4-
benzoquinonimines XXIVb, XXIVc, XXIVg,
XXVIb, XXVIc, XXVIg, XXVIIIb, XXVIIIc,
XXXa, XXXb, XXXIIa, and XXXIIb were obtained
from the corresponding aminophenols (XXIIIb,
XXIIIc, XXIIIg, XXVb, XXVc, XXVg, XXVIIb,
XXVIIc, XXIXa, XXIXab, XXXIa, and XXXIb)
by the procedure described above for the chlorinated
analogs, by oxidation with lead tetraacetate in acetic
acid (Table 3).
12. Avdeenko, A.P. and Velichko, N.V., Zh. Org. Khim.,
1993, vol. 29, no. 6, pp. 1167 1169.
13. Fernando, C.R., Calder, I.C., and Ham, K.N., J. Med.
Chem., 1980, vol. 23, no. 11, pp. 1153 1158.
14. Avdeenko, A.P., Burmistrov, K.S., Dubina, V.L.,
and Skripets, V.I., Ukr. Khim. Zh., 1980, vol. 46,
no. 10, pp. 1081 1083.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 1 2001