Activated sterically strained C=N bond in N-substituted p-quinonemono- and -diimines: X. Reactions of N-[N-arylsulfonylbenz(acet)imidoyl]-3,5-dimethyl-1,4-benzoquinonimines with alcohols

Article abstract of DOI:10.1023/A:1013860204257

N-[N-Arylsulfonylbenz(acet)imidoyl]-3,5-dimethyl-1,4-benzoquinonimines react with alcohols to give the corresponding adducts at the activated C=N bond. The adducts lose alcohol molecule on heating to afford initial quinonimines. Hydrolysis of the title co

Full text of DOI:10.1023/A:1013860204257

Russian Journal of Organic Chemistry, Vol. 37, No. 11, 2001, pp. 1587 1591. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 11, 2001,
pp. 1661 1665.
Original Russian Text Copyright
2001 by Avdeenko, Marchenko.
Activated Sterically Strained C=N Bond
in N-Substituted p-Quinonemono- and -diimines: X.* Reactions
of N-[N-Arylsulfonylbenz(acet)imidoyl]-3,5-dimethyl-
1,4-benzoquinonimines with Alcohols
A. P. Avdeenko and I. L. Marchenko
Donbass State Machine-Building Academy, ul. Shkadinova 72, Kramatorsk, 84313 Ukraine
e-mail: chimist@dgma.donetsk.ua
Received August 4, 2000
Abstract N-[N-Arylsulfonylbenz(acet)imidoyl]-3,5-dimethyl-1,4-benzoquinonimines react with alcohols
to give the corresponding adducts at the activated C N bond. The adducts lose alcohol molecule on heating
to afford initial quinonimines. Hydrolysis of the title compounds leads to formation of the corresponding
quinones and N-arylsulfonylamidines.
Our previous studies of N-arylsulfonyl-1,4-benzo-
quinonimines having substituents in both ortho-posi-
tions with respect to the C N bond revealed enhanced
reactivity of that bond [2 5]. It was found that its
reactivity originates from the steric effect leading to
increase of the C N C bond angle [1, 6] rather than
from electronic effects of the substituents. Obviously,
the nature of substituents both at the nitrogen atom
and in the ring should not affect the reactivity of the
C N bond.
trans with respect to the ArSO2 group relative to the
N2 C7 bond. According to our recent data [7], benzo-
quinonimines Ia and Ib in solution give rise to
dynamic Z,E isomerization about the C N bond of
the N-sulfonylimidoyl moiety, so that the ArSO2N
group in one isomer does not shield the quinonimine
C N bond. Therefore, nucleophilic attack on the
C N bond in Ia and Ib should not be sterically
In the present work we studied N-[N-arylsulfonyl-
benzimidoyl]- and N-[N-arylsulfonylacetimidoyl]-
3,5-dimethyl-1,4-benzoquinonimines Ia Id. These
compounds can be regarded as analogs of N-aroyl-
(acetyl)-1,4-benzoquinonimines in which the oxygen
atom of the ArCO (Ac) group is replaced by arylsul-
fonylimino group (ArSO2N). The reactivity of the
C N bond in benzoquinonimines Ia Id was estimated
on the basis of the X-ray diffraction data for Ib.
The C N C bond angle in molecule Ib turned
out to be 140.8 ; this means that the C N bond in
Ia Id is activated [6]. Figure shows the structure of
molecule Ib determined by X-ray analysis. The
quinoid fragment and the benzene ring in the ArSO2
group are almost coplanar: the angle between the
corresponding planes is 170.7 . The ArSO2N group
is arranged in such a way that it shields the activated
C N bond from one side. The CH3 group is located
____________
Structure of the molecule of N-(4-chlorophenylsulfonyl)-N -
(2,6-dimethyl-4-oxo-2,5-cyclohexadienylidene)acetamidine
(Ib) according to the X-ray diffraction data.
*
For communication IX, see [1].
1070-4280/01/3711-1587$25.00 2001 MAIK Nauka/Interperiodica

1588
AVDEENKO, MARCHENKO
Table 1. Yields, melting points, and elemental analyses of N-(arylsulfonyl)-N -(1-alkoxy-2,6-dimethyl-4-oxo-2,5-cyclo-
hexadienyl)benz(acet)amidines IIa IIm
Compound no.
Yield, %
mp,
C
Found S, %
Formula
Calculated S, %
IIa
IIb
IIc
IId
IIe
IIf
IIg
IIh
IIi
90
83
70
47
93
81
63
45
32
31
29
25
23
162
8.63, 8.72
8.49, 8.54
8.03, 8.11
8.08, 8.22
8.30, 8.41
8.02, 8.13
7.75, 7.79
7.74, 7.86
7.15, 7.27
7.02, 7.06
6.59, 6.65
6.51, 6.64
6.28, 6.38
C18H22N2O4S
C19H24N2O4S
C20H26N2O4S
C20H26N2O4S
C17H19ClN2O4S
C18H21ClN2O4S
C19H23ClN2O4S
C19H23ClN2O4S
C22H21ClN2O4S
C23H23ClN2O4S
C24H25ClN2O4S
C22H21BrN2O4S
C23H23BrN2O4S
8.85
8.52
8.21
8.21
8.37
8.08
7.80
7.80
7.21
6.99
6.78
6.55
6.37
170
145
140
154
148
146
155
165
130
160
156
146
IIj
IIk
IIl
IIm
hindered. Then compounds Ia and Ib should react
with alcohols as readily as do N-arylsulfonyl-1,4-
benzoquinonimines with activated C N bond [8].
In fact, the reactions of Ia and Ib with methanol,
ethanol, 1-propanol, and 2-propanol occurred under
mild conditions, following the 1,2-addition pattern,
to afford the corresponding N-(arylsulfonyl)-N -(1-
alkoxy-2,6-dimethyl-4-oxo-2,5-cyclohexadienyl)acet-
amidines IIa IIh (Scheme 1).
alcohol because of the large size of its molecule.
N-(N-Arylsulfonylbenzimidoyl)-3,5-dimethyl-1,4-ben-
zoquinonimines Ic and Id react only with unbranched
alcohols, CH3OH, C2H5OH, and n-C3H7OH, to give
products IIi IIm (Scheme 1). No reaction occurred
with isopropyl and tert-butyl alcohols. It should be
noted that the reactions of compounds Ia and Ib with
alcohols were complete in 5 10 min under reflux,
whereas the reactions with quinonimines Ic and Id
required heating for 40 50 h, and traces of initial
quinonimine were detected in the mixture by TLC.
The reduced reactivity of Ic and Id as compared to
Ia and Ib is explained by steric factor and hindered
Z,E isomerization about the C N bond in the imidoyl
fragment.
Scheme 1.
According to the X-ray diffraction data obtained
for N-(phenylsulfonyl)-N -(3,5-dimethyl-4-oxo-2,5-
cyclohexadienylidene)benzamidine [7] which is struc-
turally related to quinonimines Ic and Id, the phenyl-
sulfonylimino group is located below the quinoid ring
plane, and the benzene ring of the benzamidine moiety
appears above that plane (cf. the data for Ib). Insofar
as the phenyl group is considerably bulkier than
methyl, the quinonimine C N bond is shielded at
both sides. The reaction of Ic and Id with alcohols
is also hindered since these compounds in solution
and in the crystalline state exist as the corresponding
E isomers [7].
I, R = CH3, Ar = 4-CH3C6H4 (a); R = CH3, Ar = 4-ClC6H4
(b); R = C6H5, Ar = 4-ClC6H4 (c); R = C6H5, Ar = 4-BrC6H4
(d); II, Ar = 4-CH3C6H4 (a d), 4-ClC6H4 (e k), 4-BrC6H4
(l, m); R = CH3 (a h), C6H5 (i m); R = CH3 (a, e, i, l),
C2H5 (b, f, j, m), C3H7 (c, g, j), CH(CH3)2 (d, h).
An additional support to the proposed explanation
of the different reactivities of quinonimines Ia and Ib,
on the one hand, and Ic and Id, on the other, was
obtained by studying their hydrolysis. The hydrolysis
follows the 1,2-addition elimination pattern with
Like N-arylsulfonyl-1,4-benzoquinonimines, com-
pounds Ia and Ib failed to react with tert-butyl
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

ACTIVATED STERICALLY STRAINED C N BOND
1589
Table 2. 1H NMR spectra of N-(arylsulfonyl)-N -(1-alkoxy-2,6-dimethyl-4-oxo-2,5-cyclohexadienyl)benz(acet)amidines
IIc IIg and IIi, , ppm
Cyclohexene fragment
Comp.
Solvent
CDCl3
RC N
2.53 s
ArSO2
R O
NH
no.
2-H, 6-H 3-CH3, 5-CH3
6.05 s (2H) 1.81 s (6H)
IIc
7.16 7.55 d.d (4H), 0.87 t (3H, CH3), 5.88 br.s
(3H, CH3) 2.40 s (3H, CH3)
1.50 q (2H, CH2),
2.99 t (2H, CH2O)
IId
IIe
CDCl3
6.05 s (2H) 1.85 s (6H)
2.53 s
7.16 7.55 d.d (4H), 1.03 d (6H, CH3), 5.78 br.s
(3H, CH3) 2.39 s (3H, CH3)
2.35 s
(3H, CH3)
3.56 m (1H, CH)
DMSO-d6 6.10 s (2H) 1.73 s (6H)
7.48 7.55 d.d (4H)
7.37 7.59 d.d (4H)
7.35 7.60 d.d (4H)
7.35 7.60 d.d (4H)
2.91 s (3H, CH3) 9.53 br.s
CDCl3
CDCl3
CDCl3
6.09 s (2H) 1.81 s (6H)
6.06 s (2H) 1.82 s (6H)
6.06 s (2H) 1.81 s (6H)
2.53
s
2.97 s (3H, CH3) 6.11 br.s
(3H, CH3)
2.54 s
(3H, CH3)
2.53 s
IIf
1.13 t (3H, CH3), 5.89 br.s
3.12 q (2H, CH2)
0.86 t (3H, CH3), 6.34 br.s
1.48 q (2H, CH2),
IIg
(3H, CH3)
2.98 t (2H, CH2O)
IIi
DMSO-d6 5.97 s (2H) 1.81 s (6H) 7.37 7.57 m 7.45 7.53 d.d (4H)
2.89 s (3H, CH3) 9.76 br.s
(5H, C6H5)
intermediate formation of 4-hydroxy-4-amino-2,5-
cyclohexadienone structure and yields 2,6-dimethyl-
1,4-benzoquinone (III) and the corresponding N-aryl-
sulfonylbenz(or acet)amidine IVa IVd (Scheme 2).
hydrolysis of acetamidine (Ia, Ib) and benzamidine
derivatives (Ic, Id) should be comparable. We have
found that the hydrolysis of compounds Ia and Ib
is complete in 10 min and that the reaction with
quinonimines Ic and Id requires 40 50 min.
On heating to the melting point compounds IIa
IIm undergo dealkoxylation with formation of initial
quinonimines Ia Id. N-(Arylsulfonyl)-N -(3,5-di-
methyl-4-oxo-2,5-cyclohexadienylidene)benz(acet)-
amidines Va Vd did not react with alcohols (CH3OH,
C2H5OH, C3H7OH) under similar conditions (100 h).
Such a behavior is typical of N-substituted 1,4-benzo-
quinonimines in which the C N bond is not activated.
Scheme 2.
IV, Ar = 4-CH3C6H4, R = CH3 (a); Ar = 4-ClC6H4, R =
CH3 (b); Ar = 4-ClC6H4, R = C6H5 (c); Ar = 4-BrC6H4,
R = C6H5 (d).
V, Ar = 4-CH3C6H4, R = CH3 (a); Ar = 4-ClC6H4, R = CH3
(b); Ar = 4-ClC6H4, R = C6H5 (c); Ar = 4-BrC6H4, R =
C6H5 (d).
Taking into account that water molecule is much
smaller than any alcohol molecule, steric factor in
compounds Ic and Id should affect the rate of
hydrolysis to a lower extent; i.e., the rates of
The structure of compounds IIa IIm was proved
by the data of elemental analysis (Table 1) and IR,
1H NMR (Table 2), and 13C NMR spectroscopy. The
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

1590
AVDEENKO, MARCHENKO
Table 3. Coordinates of atoms and their equivalent isotropic temperature factors Uiso
phenylsulfonyl)-N -(2,6-dimethyl-4-oxo-2,5-cyclohexadienylidene)acetamidine (Ib)
(
2) in the structure of N-(4-chloro-
Atom
x
y
z
Uiso
Atom
x
y
z
Uiso
Cl1
S1
0.61755(8) 0.03259(4) 0.12114(5) 0.0581 C13
0.31953(7) 0.28528(3) 0.30941(4) 0.0382 C14
0.4378(3)
0.3703(3)
0.1857(3)
0.0576(3)
0.2465
0.0528
0.0445
0.1797
0.1027
0.5241
0.6398
0.4165
0.3013
0.0840
0.2479
0.2662
0.0741
0.1741
0.0168
0.05526(12) 0.27298(18) 0.0425
0.12567(12) 0.31416(17) 0.0387
0.25656(14) 0.40859(19) 0.0480
O1
O2
O3
N1
N2
C1
C2
C3
C4
C5
C6
C7
C8
C9
0.2101(3)
0.2344(2)
0.4594(2)
0.0240(2)
0.1804(2)
0.1595(3)
0.1878(3)
0.1439(3)
0.0473(2)
0.0240(3)
0.0737(3)
0.0462(3)
0.0829(3)
0.4021(2)
0.02265(12) 0.48398(17) 0.0762 C15
0.26870(11) 0.41460(13) 0.0545 C16
0.34037(9) 0.30391(18) 0.0616 H21
0.05245(15) 0.1319(2)
0.0529
0.0543
0.0642
0.0836
0.0907
0.0907
0.0425
0.0559
0.0524
0.0436
0.0653
0.0793
0.0751
0.0888
0.0645
0.0740
0.1208
0.0481
0.3721
0.3257
0.2930
0.2442
0.1231
0.0080
0.1222
0.2901
0.2626
0.2780
0.0007
0.08036
0.0743
0.5215
0.2991
0.1189
0.1796
0.0733
0.1190
0.0532
0.3098
0.3763
0.4109
0.4793
0.3612
0.1240
0.1193
0.0817
0.2035(1)
0.3214(1)
0.03006(15) 0.4211(2)
0.21140(14) 0.0368 H61
0.22837(14) 0.0377 H81
0.0516 H82
0.11295(15) 0.44956(18) 0.0487 H83
0.17245(13) 0.38205(16) 0.0381 H101
0.15240(12) 0.27621(15) 0.0329 H111
0.06919(13) 0.24349(17) 0.0400 H131
0.01200(13) 0.3141(2)
0.0480 H141
0.28173(12) 0.20138(16) 0.0351 H151
0.32357(15) 0.1360(2)
0.0501 H152
0.19486(11) 0.25589(16) 0.0333 H153
0.19490(13) 0.15820(17) 0.0394 H161
0.12445(13) 0.11743(17) 0.0416 H162
0.05560(12) 0.17499(17) 0.0393 H163
C10 0.5044(3)
C11 0.5712(3)
C12 0.5365(3)
IR spectra of IIa IIm contain absorption bands at
l
14). Total of 3016 reflections were measured,
3300 3200, 1680 1670, 1635 1630, 1610 1580,
1390 1305, and 1170 1105 cm , which are typical
2683 of which were symmetry-independent (Rint
0.041). Monoclinic crystals with the following unit
=
1
of the NH, C O, C N, C C, and SO2 groups. In
the 1N NMR spectra we observed signals from
magneticaly equivalent protons of the quinoid ring,
singlets from equivalent methyl groups, broadened
singlets from NH protons, and also appropriate signals
from the RC N, ArSO2, and R O fragments. Com-
pounds IIe and IIf showed in the 13C NMR spectra
cell parameters: a = 7.760(2), b = 16.937(3), c =
12.245(4)
;
= 93.97(2) ; V = 1605.5 3; M =
1
350.82; Z = 4; dcalc = 1.45 g/cm3; = 34.69 cm ;
space group R21/n (N = 14). The structure was solved
by the direct method and was refined by the least-
squares procedure in the full-matrix anisotropic
approximation using CRYSTALS software package
[9]. In the refinement 2424 reflections with I > 3(I)
were used (208 parameters were refined; the number
of reflections per parameter was equal to 11.7). All
hydrogen atoms were visualized from the difference
synthesis of electron density and were involved in
the calculation with fixed positional and thermal
factors. The absorption by the crystal was taken into
account by the azimuth scanning technique [10]. The
Chebyshev weight scheme [11] including four param-
eters: 2.89, 2.79, 1.23, and 2.10 was used in the
refinement. The final divergence factors were R =
0.046 and Rw = 0.049; GOF = 1.169. The residual
electron density from the Fourier difference series
was 0.35 and 0.47 e/ 3. Table 3 lists the coordinates
of atoms in molecule Ib.
signals from the carbonyl carbon atom at
184.25
C
184.32 ppm) and sp3-hybridized carbon atom in the
region
84.10 84.54 ppm. The other carbon signals
correspoCnd to the proposed structures.
EXPERIMENTAL
The IR spectra were taken on a UR-20 spectrometer
1
in KBr. The H and 13C NMR spectra were measured
1
on a Varian VXR-300 instrument (300 MHz for H)
relative to tetramethylsilane.
The X-ray diffraction data for a single crystal of
compound Ib (crystal habit 0.22 0.56 0.59 mm)
were obtained at room temperature on an Enraf
Nonius CAD-4 automatic four-circle diffractometer
(CuK irradiation, scan rate ratio /2 = 1.2,
65 , spherical segment 0 8, 0 19, 14
=
Compounds Ia Id were synthesized by the proce-
dure reported in [7].
max
h
k
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

ACTIVATED STERICALLY STRAINED C N BOND
1591
Reaction of N-(arylsulfonyl)-N -(2,6-dimethyl-4-
oxo-2,5-cyclohexadienylidene)acet(benz)amidines
Ia d with alcohols (general procedure). A solution
of 2 mmol of quinonimine Ia or Ib in 8 ml of the
corresponding anhydrous alcohol was refluxed for
5 10 min or for 40 50 h in the case of compound Ic
or Id. The yellow color due to initial quinonimine
Ia Id gradually disappeared. The progress of the
reactions was monitored by TLC, following the disap-
pearance of initial compound Ia Id. The mixture
was cooled, the solvent was removed, and the product
was recrystallized from benzene.
10 ml of a 1:1 DMSO H2O mixture was refluxed for
10 min (compounds Ia and Ib) or 40 50 min (Ic and
Id). The progress of the reaction was monitored by
TLC, following the disappearance of initial quinon-
imine Ia Id.
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184.32 (C1), 140.95 (C3, C5), 131.03 (C2, C6), 84.54
(C4), 16.90 (3-CH3, 5-CH3), 14.97 (CH3 in R O)
(cyclohexadiene fragment); 152.50 (C4), 135.15 (C1),
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(C4), 58.18 (CH2 in R O), 16.97 (3-CH3, 5-CH3),
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Ia d. A solution of 0.5 g of quinonimine Ia Id in
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001