Reaction of N,N-dichlorosulfonamides with tribromoethylene

Article abstract of DOI:10.1134/S1070428007050016

Reaction of aryl-and trifluoromethanesulfonic acids N,N-dichloroamides with tribromoethylene led to the formation of a mixture of N-(2,2-dibromo-2- chloroethylidene)-and N-(2,2,2-tribromoethylidene)amides of the corresponding sulfonic acids. The azomethin

Full text of DOI:10.1134/S1070428007050016

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 5, pp. 641−645. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © E.V. Kondrashov, I.B. Rozentsweig, I.V. Ushakova, G.G. Levkovskaya, A.N. Mirskova, 2007, published in Zhurnal
Organicheskoi Khimii, 2007, Vol. 43, No. 5, pp. 647−651.
Reaction of N,N-Dichlorosulfonamides with Tribromoethylene
E. V. Kondrashov, I. B. Rozentsweig, I. V. Ushakova, G. G. Levkovskaya, and A. N. Mirskova
Faworsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, 664033 Russia
e-mail: i_roz@irioch.irk.ru
Received May 31, 2006
Abstract—Reaction of aryl- and trifluoromethanesulfonic acids N,N-dichloroamides with tribromoethylene led
to the formation of a mixture of N-(2,2-dibromo-2-chloroethylidene)- and N-(2,2,2-tribromoethylidene)amides
of the corresponding sulfonic acids. The azomethines ratio is governed by the reaction temperature.
DOI: 10.1134/S1070428007050016
temperature under sunlight and proceeded with a con-
siderable heat evolution. The the bright sunlight the
temperature of the reaction mixture attained 100°C and
more. If the reaction temperature was maintained below
40°C the process led to the exclusive formation of
trifluoromethanesulfonic acid N-(2,2-dibromo-2-chloro-
ethylidene)amide (IIc) (Scheme 1). In other cases the
reaction yielded a mixture of imines IIc and IIIc in
a molar ratio 1:1.
It was shown formerly [1] that N,N-dichlorobenzene-
sulfonamide (Ia) reacted with tribromoethylene giving
N-(2,2-dibromo-2-chloroethylidene)amide of benzene-
sulfonic acid (IIa). Imine IIa was suggested [1] to exist
as a mixture of E- and Z-isomers for the proton and carbon
atom of the CH=N group appeared as two signals in the
1H and 13C NMR spectra respectively.
In extension of the investigation of reactions between
N,N-dichlorosulfonamides and polyhaloethenes we studi-
ed the reaction of N,N-dichloroamides of benzene-sulfon-
ic acid (Ia), 4-chlorobenzenesulfonic acid (Ib), and tri-
fluoromethanesulfonic acid (Ic) with tribromoethylen under
various conditions. The reactions were carried out using
four-fold molar excess of tribromoethylene in CCl4 solution.
The liberated halogens added to the tribromoethylene
giving a mixture of polybromochloroethanes [1].
Therefore as mentioned above the chemoselectivity
of reaction between dichloroamides Ia–Ic and tribromo-
ethylene depended on the temperature of the process:
On decreasing the temperature the amount of tribromo-
acetic aldehyde sulfonylimines III diminished, and from
compound Ic formed exclusively dibromochloroacetic
aldehyde sulfonylimine IIc.
It was established that the reaction of dichloroarene-
sulfonamides Ia and Ib with tribromoethylene completed
in 5–8 h at boiling the reaction mixture or within 7–10
days at 15–20OC and provided a mixture of arene-
sulfonylimines of dibromochloroacetic (IIa and IIb) and
tribromoacetic (IIIa and IIIb) aldehydes. Therewith the
molar ratio of azomethines II:III varied from 4:3 at
boiling to 3:1 at lower temperature (Scheme 1).
Under low temperature dichloroamides Ia–Ic added
to tribromoethylene forming saturated adduct C. The
possibility of adducts of type C formation in the reactions
of N,N-dichlorosulfonamides with polychloroethenes
under mild conditions we showed in [2]. Saturated adduct
C is further dehalogenated (slowly at the room tempera-
The reaction of N,N-dichlorotrifluoromethanesulfon-
amide (Ic) with tribromoethylene started at room
Scheme 1.
RSO N CH
CBr2Cl +
RSO2N CH
CBr3
2
BrCH CBr2
_Br2,_ Cl2
_
_
IIIа IIIc
IIа IIc
R = CF3, <40oC
RSO2NCl2
_
Iа Ic
CF3SO2N CH CBr2Cl
IIc
R = C6H5 (a), 4-ClC6H4 (b), CF3 (c).
641

KONDRASHOV et al.
642
intensity as the azomethine protons. In the 13C NMR
spectra signals were observed of CBr3 group at 31 ppm
and CBr2Cl group at 53 ppm, and all the other carbon
atoms of the molecules (azomethine and aromatic)
appeared as two groups of signals.
ture and fast at heating) to give dibromochloroacetic
aldehyde sulfonylimines IIa–IIc. Thus the stages of
dichloroamide addition to tribromoethylene and dehalo-
genation occur in succession.
In reaction at heating saturated adduct C is unstable
and rapidly eliminates halogen, namely, the addition
and dehalogenation stages proceed simultaneously
(Scheme 2). Therefore in the reaction mixture certain
amounts exist of molecular chlorine, bromine, and
bromine chloride which may concurrently react with
radical-adduct B giving saturated adducts D and further
azometines IIIa–IIIc.
The presence of the mixture containing dibromo-
chloro- and tribromoacetic aldehyde imines was also
confirmed by the study of their transformation products
which in contrast to imines II and III were chemically
stable, easily isolable from the reaction mixture, and fit
for further investigation. For instance, the C-amido-
alkylating activity of the prepared polybromoaldehydes
sulfonylimines was tested on reactions with benzene and
toluene.
It should be also admitted that N,N-dichloroamides
Ia–Ic may react with the liberated bromine to form
N,N-dibromoamides that then add to tribromoethylene
giving imines IIIa–IIIc.
The C-amidoalkylation of arenes (Scheme 3) proceed-
ed similarly to the previously studied reactions of chloral
arenesulfonyl- and trifluoromethanesulfonylimines [3, 4]
in the presence of oleum within 3–5 h and led to the
formation of corresponding N-(1-aryl-2-polyhaloethyl)-
sulfonamides IV–VII.
In the 1H NMR spectra of the alkylation products of
benzene (IVa–IVc and VIa–VIc) and toluene (Va–Vc
and VIIa–VIIc) the fragment NH–CH gave rise to two
doublets from NH group and two doublets from CH group
with the same ratio of the integral intensities of signals
as was observed for the signals of the azomethine protons
in the spectra of the initial mixtures of azomethines II
and III. In the 13C NMR spectra signals were observed
of CBr2Cl groups (65–68 ppm) and CBr3 groups (46–
50 ppm), and all the other carbon atoms of the molecules
appeared as two groups of signals corresponding to two
amides containing either dibromochloromethyl or
The imine mixtures formation was proved by 1H and
1
13C NMR spectroscopy. For instance, in the H NMR
spectra of compounds IIa–IIc and IIIa–IIIc two signals
of azomethine protons appeared in the region 8.3–
8.6 ppm of integral intensity ratio from 4:3 to 3:1. The
signals of aromatic protons of compound IIb gave rise
to two groups of signals with the same ratio of integral
Scheme 2.
RSO2NCl2
RSO2NCl + Cl
_
Iа Iс
А
A +
BrCH CBr2
RSO2N CH CBr2
Cl Br
B
RSO2NCl2
_RSO2NCl
_
IIа IIс tribromomethyl groups.
RSO2N CH
CBr2Cl
_Br2,_ Cl2
Cl Br
The study of the mixture produced by reaction of
B
C
imines IIc and IIIc with toluene by GC-MS procedure
confirmed the presence of two amidoalkylated arenes.
The mass spectrum of one among them according to the
molecular ion peak and those of fragment ions (see
Br2
_Br
_
RSO2N CH
IIIа IIIc
CBr3
_BrCl
Cl Br
D
Scheme 3.
RSO2NH CH
RSO2NH CH
CBr2Cl
CBr3
RSO2N CH
CBr2Cl
CBr3
C6H5X
Oleum
_
IIа IIc
+
RSO2N CH
_
IIIа IIIc
X
X
_
_
_
VIа, b, VIIа VIIc
IVа IVc, Vа IVc
R = C6H5 (a), 4-ClC6H4 (b), CF3 (c); X = H (IVa–IVc, VIa, VIb), CH3 (Va–Vc, VIIa–VIIc).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 5 2007

REACTION OF N,N-DICHLOROSULFONAMIDES WITH TRIBROMOETHYLENE
643
EXPERIMENTAL) was consistent with the structure of
dibromochloroethylamide Vc. We failed to observe the
molecular ion peak of the second compound, but all the
other peaks were well consistent with the structure of
amide VIIc. In the mass spectra of both amides IIc and
IIIc the most abundant were the fragment peaks [M –
CBr2Cl] and [M –CBr3].
2.6 g (0.01 mol) of dichloroamide Ib and 10.6 g
(0.04 mol) tribromoethylene was obtained 4.0 g of
a mixture of 4-chlorobenzenesulfonic acid N-(2,2-
dibromo-2-chloroethylidene)amide (IIb) and N-(2,2,2-
tribromoethylidene)amide (IIIb) in a ratio 4:3. 1H NMR
spectrum (CDCl3), δ, ppm, imine IIb:7.56 and 7.93
AA'BB' (C6H4), 8.46 s (1H, N=CH); imine IIIb:
7.58 and 7.93 AA'BB' (C6H4), 8.34 s (1H, N=CH). 13C
NMR spectrum, δ, ppm, imine IIb: 53.19 (CBr2Cl),
129.95, 134.67, 141.63 (C6H4), 165.55 (CH=N); imine
IIIb: 31.66 (CBr3), 129.91, 134.78, 141.58 (C6H4),
165.89 (CH=N).
Thus we established for the first time that the reaction
of arene- and trifluoromethanesulfonic acid dichloro-
amides with tribromoethylene led to the formation of
a mixture of arene- or trifluoromethanesulfonylimines
of bromal and dibromochloroacetic aldehyde. The
depend-ence of the molar ratio of the azomethines on
the process temperature was observed.
Reaction of N,N-dichlorotrifluoromethanesulfon-
amide with tribromoethylene. Through a solution of
2.18 g (0.01 mol) of dichloroamide Ic in 10.6 g
(0.04 mol) of tribromoethylene was bubbled argon for
5 min, then the reaction mixture was left standing at
roomtemperature in a bright sunlight. The reaction
mixture self-heated to 100°C. After the end of heat
liberation the solution was kept for 23 h at room
temperature.According to 1H NMR spectrum the reaction
products contained a mixture of trifluoromethanesulfonic
acid N-(2,2-dibromo-2-chloroethylidene)amide (IIc) and
N-(2,2,2-tribromoethylidene)amide (IIIc) in a ratio 1:1.
1H NMR spectrum (tribromoethylene), δ, ppm: 8.52 s
(1H, CH=N) (IIIc), 8.63 s (1H, CH=N) (IIc).
EXPERIMENTAL
1H, 13C, 15N, and 19F NMR spectra were registered
on a spectrometer Bruker DPX-400 at operating
frequencies 400.13, 101.61, 40.56, and 376 MHz
respectively from solutions in CDCl3 or DMSO-d6.
Chemical shifts of 1H and 13C were measured with respect
to TMS with accuracy of 0.01 ppm, as internal references
for 15N and 19F were used nitromethane and trichloro-
fluoromethane respectively. The coupling constants JHH
and JCF were measured with accuracy of 0.1 Hz. IR
spectra were recorded on a spectrophotometer Specord
75IR from KBr pellets. The mass spectrum was taken on
Shimadzu GC-17/GCMS-QP5050-1 instrument.
N-(2,2-Dibromo-2-chloroethylidene)trifluoro-
methanesulfonamide (IIc). A solution of 2.18 g
(0.01 mol) of dichloroamide Ic in 10.6 g (0.04 mol) of
tribromoethylene was maintained 24 h in a sunlight under
argon atmosphere at a temperature not higher than 40°C.
Oleum used in reactions contained 5% of SO3.
Reaction of N,N-dichlorobenzenesulfonamide with
tribromoethylene. A solution of 2.26 g (0.01 mol) of
dichloroamide Ia in 10.6 g (0.04 mol) of tribromo-
ethylene and 4 ml of CCl4 was boiled for 6 h with
continuous bubbling of argon. Then the reaction mixture
was maintained for 10 h at –10°C, the formed precipitate
was separated by filtration, washed on the filter with a
little cold CCl4, and dried. We obtained 3.5 g of a mixture
of benzenesulfonic acid N-(2,2-dibromo-2-chloro-
ethylidene)amide (IIa) and N-(2,2,2-tribromo-ethylid-
1
According to H NMR spectrum the reaction product
contained imine IIc without impurity of imine IIIc. The
obtained imine was used in further synthesis without
isolation. IR spectrum of the reaction mixture (micro-
film), ν, cm–1: 1120, 1200, 1390 (CF3SO2), 1620 (C=N).
1H NMR spectrum (tribromoethylene), δ, ppm: 8.63 s
(CH=N).
C-Amidoalkylation of benzene with a mixture of
imines IIa and IIIa. To 3.5 g of a mixture of imines IIa
and IIIa obtained as described above was added 10 ml
of benzene and 0.5 ml of oleum. The reaction mixture
was stirred for 5 h, diluted with 20 ml of water, and the
acid was neutralized with sodium carbonate. The
separated precipitate was filtered off, washed with water
on the filter, and dried to obtain 3.2 g of a mixture of
benzenesulfonic acid N-(1-phenyl-2,2-dibromo-2-chloro-
ethyl)amide (IVa) and N-(1-phenyl-2,2,2-tribromoethyl)-
1
ene)amide (IIIa) in a ratio 4:3. H NMR spectrum
(CDCl3), δ, ppm, imine IIa: 7.60–8.0 m (5H, C6H5),
8.47 s (1H, N=CH); imine IIIa: 7.60–8.0 m (5H, C6H5),
8.35 s (1H, N=CH). 13C NMR spectrum, δ, ppm, imine
IIa: 53.07 (CBr2Cl), 128.10, 129.16, 134.32, 135.83
(C6H5), 164.88 (CH=N); imine IIIa: 31.60 (CBr3),
128.06, 129.18, 134.28, 135.94 (C6H5), 165.22 (CH=N).
Reaction of N,N-dichloro(4-chlorobenzene)sulfon-
amide with tribromoethylene. In the same way from
1
amide (VIa) in a ratio 4:3 (1H NMR data). H NMR
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 5 2007

KONDRASHOV et al.
644
spectrum (DMSO-d6), δ, ppm, amide IVa: 5.19 d (1H,
CH, 3JCH–NH 10.5 Hz), 7.0–7.6 m (10H, 2C6H5), 9.14 d
(1H, NH, 3JCH–NH 10.5 Hz); amide VIa: 5.20 d (1H, CH,
3JCH–NH 10.5 Hz), 7.0–7.6 m (10H, 2C6H5), 9.09 d (1H,
NH, 3JCH–NH 10.5 Hz). 13C NMR spectrum (DMSO-d6),
δ, ppm, amide IVa: 68.24 (CBr2Cl), 72.60 (CH), 126.32,
127.22, 128.35, 128.42, 129.85, 132.01, 133.97, 140.39
(2C6H5); amide VIa: 49.94 (CBr3), 72.87 (CH), 126.36,
127.11, 128.26, 128.37, 129.92, 131.96, 134.20, 140.33
(2C6H5).
benzenesulfonic acid N-(1-tolyl-2,2-dibromo-2-chloro-
ethyl)amide (Vb) and N-(1-tolyl-2,2,2-tribromoethyl)-
1
amide (VIIb) in a ratio 4:3 (1H NMR data). H NMR
spectrum (DMSO-d6), δ, ppm, amide Vb: 2.20 s (3H, CH3),
5.11 d (1H, CH, 3JCH–NH 10.6 Hz), 6.91, 7.30, 7.52 m
3
(8H, 2C6H4), 9.10 d (1H, NH, JCH–NH 10.6 Hz);
amide VIIb: 2.20 s (3H, CH3), 5.11 d (1H, CH ,
3JCH–NH 10.6 Hz), 6.90, 7.30, 7.50 m (8H, 2C6H4),
9.05 d (1H, NH, 3JCH–NH 10.6 Hz). 13C NMR spectrum
(DMSO-d6), δ, ppm, amide Vb: 20.69 (CH3), 68.15
(CBr2Cl), 72.59 (CH), 127.95, 128.46, 128.61, 129.92,
131.01, 137.07, 137.98, 139.20 (2C6H4); amide VIIb:
20.69 (CH3), 49.80 (CBr3), 72.88 (CH), 127.86, 128.49,
128.56, 130.00, 131.25, 137.03, 137.90, 139.12 (2C6H4).
C-Amidoalkylation of toluene with a mixture of
imines IIa and IIIa was carried out similarly using
3.5 g of a mixture of imines IIa and IIIa and 10 ml of
toluene. We obtained 3.8 g of a mixture of benzene-
sulfonic acid N-(1-tolyl-2,2-dibromo-2-chloroethyl)-
amide (Va) and N-(1-tolyl-2,2,2-tribromoethyl)amide
(VIIa) in a ratio 4:3 (1H NMR data). 1H NMR spectrum
(DMSO-d6), δ, ppm, amide Va: 2.17 s (3H, CH3), 5.14 d
(1H, CH,3JCH–NH 10.5 Hz), 6.8–7.6 m (9H, C6H5+C6H4),
9.07 d (1H, NH, 3JCH–NH 10.5 Hz); amide VIIa: 2.16 s
(3H, CH3), 5.15 d (1H, CH, 3JCH–NH 10.5 Hz), 6.8–7.6 m
C-Amidoalkylation of benzene with imine IIc. To
a solution of imine IIc obtained as above described from
2.18 g of dichloroamide Ic and tribromoethylene was
added 12 ml of benzene and 0.5 ml of oleum. After
stirring for 3 h the solvent was removed in a vacuum,
the residue was washed with water, dried, and recrystal-
lized from hexane. Yield of trifluoromethanesulfonic acid
N-(1-phenyl-2,2-dibromo-2-chloroethyl)amide (IVc)
1.11 g (25%), mp 136–138°C. IR spectrum (KBr), ν, cm–1:
1130, 1200, 1230, 1375 (CF3SO2), 3275 (NH). 1H NMR
3
(9H, C6H5+C6H4), 9.02 d (1H, NH, JCH–NH 10.5 Hz).
13C NMR spectrum (DMSO-d6), δ, ppm, amide Va: 20.63
(CH3), 68.69 (CBr2Cl), 72.46 (CH), 126.33, 127.79,
128.42, 129.73, 131.15, 131.92, 137.71, 140.53
(C6H5+C6H4); amide VIIa: 21.03 (CH3), 50.49 (CBr3),
72.75 (CH), 126.36, 127.69, 128.37, 129.81, 131.37,
131.86, 137.61, 140.45 (C6H5+C6H4).
3
spectrum, δ, ppm: 5.29 d (1H, CH, JCH–NH 10.2 Hz),
3
6.39 d (1H, NH, JCH–NH 10.2 Hz), 7.35–7.55 m (5H,
C6H5). 13C NMR spectrum, δ, ppm: 65.45 (CBr2Cl),
1
73.20 (CH), 119.04 q (CF3, JC–F 321.7 Hz), 128.44,
129.29, 130.06, 133.51 (C6H5).
C-Amidoalkylation of benzene with a mixture of
imines IIb and IIIb was carried out similarly using
4.0 g of a mixture of imines IIb and IIIb and 12 ml of
benzene. We obtained 4.1 g of a mixture of 4-chloro-
benzenesulfonic acid N-(1-phenyl-2,2-dibromo-2-chloro-
ethyl)amide (IVb) and N-(1-phenyl-2,2,2-tribromoethyl)-
C-Amidoalkylation of toluene with a mixture of
imines IIc and IIIc was performed in the same way using
a mixture of imines IIc and IIIc prepared from 2.18 g of
dichloroamide Ic and tribromoethylene. Yield of
a mixture of trifluoromethanesulfonic acid N-(1-tolyl-
2,2-dibromo-2-chloroethyl)amide (Vc) and N-(1-tolyl-
2,2,2-tribromo-ethyl)amide (VIIc), 1:1, 0.8 g. IR
spectrum (KBr), ν, cm–1: 3250 (NH), 1420, 1370, 1220,
1
amide (VIb) in a ratio 4:3 (1H NMR data). H NMR
spectrum (DMSO-d6), δ, ppm, amide IVb: 5.18 d (1H,
3
CH, JCH–NH 10.8 Hz), 7.0–7.6 m (9H, C6H4+C6H5),
1
1180, 1120 (CF3SO2). H NMR spectrum (CDCl3), δ,
9.20 d (1H, NH, 3JCH–NH 10.8 Hz); amide VIb: 5.19 d
(1H, CH,3JCH–NH 10.8 Hz), 7.0–7.6 m (9H, C6H4+C6H5),
9.15 d (1H, NH, 3JCH–NH 10.8 Hz). 13C NMR spectrum
(DMSO-d6), δ, ppm, amide IVb: 68.36 (CBr2Cl), 73.16
(CH), 127.83, 128.87, 129.04, 130.43, 134.46, 137.53,
139.68 (C6H4+C6H5); amide VIb: 49.93 (CBr3), 73.43
(CH), 127.73, 128.89, 128.99, 130.51, 134.70, 137.50,
139.62 (C6H4+C6H5).
ppm, amide Vc: 2.36 s (3H, CH3), 5.24 d (1H, CH, 3JCH–
10.2 Hz), 6.17 d (1H, NH, 3JCH–NH 10.2 Hz), 7.20,
NH
7.42 AA'BB' (4H, C6H4); amide VIIc: 2.36 s (3H, CH3),
5.28 d (1H, CH, 3JCH–NH 10.2 Hz), 6.18 (1H, NH, 3JCH–
10.2 Hz), 7.20, 7.43 AA'BB' (4H, C6H4). 13C NMR
NH
spectrum (CDCl3), δ, ppm, amide Vc: 21.40 (CH3), 66.05
1
(CBr2Cl), 73.01 (CH), 119.01 q (CF3, JC–F 321.1 Hz),
129.06, 129.12, 130.77, 140.19 (C6H4); amide VIIc:
21.38 (CH3), 46.59 (CBr3), 73.21 (CH), 119.04 q (CF3,
1JC–F 321.0 Hz), 129.14, 129.24, 130.51, 140.22 (C6H4).
19F NMR spectrum, δ, ppm: –76.93 s, –76.89 c. 15N NMR
spectrum δ, ppm: –279.4 (Vc), –278.5 (VIIc). Mass
C-Amidoalkylation of toluene with a mixture of
imines IIb and IIIb was carried out similarly using
4.0 g of a mixture of imines IIb and IIIb and 12 ml of
toluene. We obtained 3.9 g of a mixture of 4-chloro-
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REACTION OF N,N-DICHLOROSULFONAMIDES WITH TRIBROMOETHYLENE
645
spectrum, m/z (Irel, %) amide Vc: 457/459/461 (0.74)
REFERENCES
[M]+, 343/345 (0.99) [M – Br – Cl]+, 309/311/313 (0.93)
[M –CF3SO2NH]+, 252 (100) [M – CBr2Cl]+, 205/207/
209 (3.29) [CBr2Cl]+, 118 (19.1) [M – CF3SO2H –
CBr2Cl]+, 103 (4.65) [M – CF3SO2NH – CBr2Cl–H]+,
91 (11.21) [C6H5CH2]+, 69 (14.99) [CF3]+; amide VIIc:
423/425/427 (0.41) [M – HBr]+, 343/345 (0.75) [M –
Br2]+, 275/277/279 (1.27) [M – CF3SO2NH – HBr]+,
252 (100) [M – CBr3]+, 195/197 (1.07) [M – CF3SO2NH
– Br2]+, 196/198 (3.4) [M – CF3SO2NH – Br2 + H]+, 171/
173/175 (5.17) [CHBr2]+, 118 (28.00) [M – CF3SO2H –
CBr3]+, 103 (9.44) [M –CF3SO2NH – CBr3 – H]+, 91
(16.37) [C6H5CH2]+, 69 (23.22) [CF3]+.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 5 2007