Synthesis and properties of N-(2,2,2-trichloroethylidene)-trifluoromethanesulfonamide and its derivatives

Article abstract of DOI:10.1023/A:1013899918370

The reaction of N,N-dichloromethanesulfonamide with trichloroethylene gave N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide which showed high reactivity toward oxygen-and nitrogen-centered nucleophiles, as well as in C-alkylation of aromatic compo

Full text of DOI:10.1023/A:1013899918370

Russian Journal of Organic Chemistry, Vol. 37, No. 11, 2001, pp. 1559 1563. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 11, 2001,
pp. 1635 1639.
Original Russian Text Copyright
2001 by Rozentsveig, Levkovskaya, Kondrashov, Evstaf’eva, Mirskova.
Synthesis and Properties of N-(2,2,2-Trichloroethylidene)-
trifluoromethanesulfonamide and Its Derivatives*
I. B. Rozentsveig, G. G. Levkovskaya, E. V. Kondrashov,
I. T. Evstaf’eva, and A. N. Mirskova
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
fax: (3952)396046
Received June 26, 2000
Abstract The reaction of N,N-dichloromethanesulfonamide with trichloroethylene gave N-(2,2,2-trichloro-
ethylidene)trifluoromethanesulfonamide which showed high reactivity toward oxygen- and nitrogen-centered
nucleophiles, as well as in C-alkylation of aromatic compounds.
The reactivity of nitrogen-centered radicals like
RNCl toward halogenated ethenes is determined by
the electrophilicity of the radical center. For example,
N-halo- and N,N-dihaloamines (R = Alk) do not add
to trichloroethylene [1]. By contrast, N-centered
radicals derived from N,N-dihaloacylamines (R =
R CO, R SO2, R2PO) react with polyhaloethenes,
resulting in formation of Schiff bases [2, 3]. Thus
increase in electron-acceptor properties of the R sub-
stituent enhances the reactivity of nitrogen-centered
radicals toward haloethenes. It might be expected that,
among N,N-dichloro derivatives, N,N-dichloro sulfon-
amides and especially N,N-dichloroperfluoroalkane-
sulfonamides should exhibit high reactivity with
respect to ethenes.
In continuation of our systematic studies on the
reactivity of compounds possessing an N Hlg bond
and polyhalogenated ethenes, we examined the reac-
tion of N,N-dichlorotrifluoromethanesulfonamide
[4] with trichloroethylene in order to reveal the effect
of the trifluoromethyl group on the properties of the
initial N,N-dichloro amide and the resulting Schiff
base. The reaction was carried out with excess tri-
chloroethylene at a reactant ratio of 1:(8 10). Unlike
previously studied reactions of N,N-dichloro sulfon-
amides [2, 3], the reaction of N,N-dichlorotrifluoro-
methanesulfonamide with trichloroethylene required
neither the presence of radical initiators nor thermal
or photochemical initiation. The reaction occurred on
mixing the reactants at room temperature and was
accompanied by heat evolution. The process was
complete in 20 25 h to afford N-(2,2,2-trichloro-
ethylidene)trifluoromethanesulfonamide (I), chlorine,
and pentachloroethane (Scheme 1).
1
In the H NMR spectrum (CDCl3) of the reaction
mixture we observed a signal at
6.44 ppm from
trichloroethylene, a singlet at 8.65 ppm from the
CH N proton, and a singlet at 6.09 ppm from the
dichloromethyl group of pentachloroethane. The
formation of Schiff base I is also confirmed by the
IR data (Table 1). Its IR spectrum contains absorption
bands typical of N CH and CF3SO2 fragments.
The mechanism of reactions of N,N-dichloro
sulfonamides with polyhaloethenes was studied in [5].
Judging by the structure of the products, in our case
an analogous mechanism is operative.
Scheme 1.
Schiff base I very readily reacts with oxygen- and
nitrogen-centered nucleophiles, yielding addition
products at the CH N bond. The addition is favored
by strong electron-acceptor character of the trifluoro-
methylsulfonyl and trichloromethyl groups. Com-
pound I undergoes fast hydrolysis on exposure to
atmospheric moisture and takes up alcohols with
a strong exothermic effect. It also reacts with arene-
____________
*
This study was financially supported by the Youth Committee
of the Russian Academy of Sciences (project no. 158/2000).
1070-4280/01/3711-1559$25.00 2001 MAIK Nauka/Interperiodica

1560
ROZENTSVEIG et al.
Scheme 2.
sulfonamides on keeping for 24 h and (on heating)
with 4-nitrophenol and trifluoromethanesulfonamide
(Scheme 2). It should be noted that known Schiff
bases derived from sulfonamides and polyhalogenated
aldehydes do not react even with chlorophenols [6];
also, we failed to react N-(2,2,2-trichloroethylidene)-
arenesulfonamides with trifluoromethanesulfonamide.
Our attempts to synthesize N-(2,2,2-trichloro-1-
hydroxyethyl)trifluoromethanesulfonamide (IIa) by
independent method, namely by reaction of trichloro-
acetaldehyde or its hydrate with trifluoromethanesul-
fonamide were unsuccessful, although such reactions
with arenesulfonamides occur fairly readily [7]. Pre-
sumably, this is the result of reduced nucleophilicity
of the amide nitrogen atom due to electron-acceptor
effect of the trifluoromethylsulfonyl group.
yields 1,1,1-trichloro-2,2-bis(trifluoromethylsulfonyl-
amino)ethane (IIe) (Scheme 3).
The structure of N-(trichloroethyl)trifluoromethane-
1
sulfonamides II IIe was proved by the H NMR and
IR spectra (Table 1). Compounds IIa, IIc, and IId
1
showed in the H NMR spectra characteristic doublets
from protons of the CH NH moiety; signals from the
CH and NH protons of bis-sulfonamide IIe appeared
as broadened singlets. The NH proton in IIb is readily
replaced by deuterium in CDCl3, and the CH signal
becomes a singlet. Likewise, fast H D exchange
occurs in the trifluoromethanesulfonamide moiety of
IIc; however, the less labile NH proton in the ben-
zenesulfonamide moiety is retained. The resulting
ND CH NH fragment gives rise to two doublets
1
in the H NMR spectrum. In the spectrum of IIb
Distillation of product I at a temperature exceeding
60 C resulted in partial formation of 1,1,1-trichloro-
2,2-bis(trifluoromethylsulfonylamino)ethane (IIe).
Probably, when contacted with air, compound I is
converted into hydroxy derivative IIa which decom-
poses to give trifluoromethanesulfonamide on heating
above 60 C. Addition of the latter to Schiff base I
a singlet from the methoxy group was also present,
the spectra of amides IIc and IId contained signals
from aromatic protons. The intensity of the doublet
NH signal of bis-amide IIe was twice as large as the
intensity of the CH multiplet.
In the IR spectra of compounds IIa IIe we ob-
served absorption bands belonging to Caliph H and
N H bonds; the CF3SO21 fragment gives rise to
Scheme 3.
a broad band at 1380 cm and three bands in the
1
region 1150 1230 cm ; hydroxy derivative IIa
showed absorption of the hydroxy group.
N-(2,2,2-Trichloroethylidene)trifluoromethanesul-
fonamide (I) is also capable of alkylating aromatic
and heteroaromatic compounds. Its reaction with furan
requires no catalyst and is accompanied by evolution
of heat, yielding N-[2,2,2-trichloro-1-(2-furyl)ethyl]-
trifluoromethanesulfonamide (IIIa). The reactions of
I with benzene and chlorobenzene occur only in the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

SYNTHESIS AND PROPERTIES OF N-(2,2,2-TRICHLOROETHYLIDENE)-. . .
1561
Scheme 4.
IIIb, X = H; IIIc, X = Cl.
presence of oleum. The products are N-(1-aryl-2,2,2-
trichloroethyl)trifluoromethanesulfonamides IIIb and
IIIc. Compound IIIb was also synthesized from
N-(2,2,2-trichloro-1-hydroxyethyl)trifluorosulfon-
amide (IIa) and benzene in the presence of sulfuric
acid [8, 9] (Scheme 4).
(0.16 0.20 mol) of freshly distilled anhydrous tri-
chloroethylene was purged with argon for 1 h, and the
mixture was left to stand for 20 25 h at room tem-
perature until the yellow color disappeared. The prod-
uct can be used in further syntheses without isolation.
Pure Schiff base I was isolated by vacuum distillation,
a fraction with bp 27 33 C (18 22) being collected.
Yield 1.93 g (35%), nD20 1.4538. According to the
1H NMR data, fractions with a lower boiling point
were contaminated with pentachloroethane, and those
boiling at higher temperature contained an admixture
of 1,1,1-trichloro-2,2-bis(trifluoromethylsulfonyl-
amino)ethane (IIe).
N-(2,2,2-Trichloro-1-hydroxyethyl)trifluoro-
methanesulfonamide (IIa). a. Compound I was
prepared as described above from 2.09 g (0.01 mol)
of N,N-dichlorotrifluoromethanesulfonamide and
6 7 ml (0.08 0.1 mol) of trichloroethylene, and the
solution was left to stand on exposure to air. After
20 h, the precipitate of IIa was filtered off and
washed with dry chloroform. Yield 1.54 g (52%).
b. Water, 0.9 ml (0.05 mol), was added to 1.39 g
(0.005 mol) of compound I. The mixture sponta-
neously warmed up to 60 70 C. The product was
dried under reduced pressure ( 100 mm) over P2O5.
Yield 1.8 g (95%).
N-(2,2,2-Trichloro-1-methoxyethyl)trifluoro-
methanesulfonamide (IIb). To a solution of Schiff
base I, prepared as described above in a, 0.5 ml of
anhydrous methanol was added, and the mixture
warmed up to 40 50 C. The product was isolated by
vacuum distillation, a fraction with bp 85 87 C
(10 mm) being collected. Yield 1.18 g (38%), nD20
The structure of amides IIIa IIIc was proved by
1
the IR and H NMR spectra (Table 1) and elemental
analyses (Table 2). The IR spectra of IIIa IIIc con-
tain absorption bands due to the CF3SO2 and NH
1
groups. In the H NMR spectra of these compounds,
apart from signals of aromatic protons, a signal from
the CHCCl3 fragment was present at 5.2 5.3 ppm,
in keeping with published data for N-(2,2,2-trichloro-
ethyl) sulfonamides [8 10].
N-(2,2,2-Trichloroethylidene)trifluoromethanesul-
fonamide (I) is a colorless liquid with a specific odor;
it is readily soluble in organic solvents. Nucleophile
addition products and C-aryl derivatives IIIa IIIc
are liquids or crystalline substances having an odor
typical of trichloroacetaldehyde. They readily sublime
or decompose on heating and are insoluble in water
and soluble in organic solvents.
EXPERIMENTAL
1
The H NMR spectra were recorded on Bruker
DPX-400 (400 MHz) and Jeol FX-90Q (90 MHz)
instruments from 5 10% solutions in deuterated
solvents; the chemical shifts were measured relative
to HMDS as internal reference. The IR spectra were
obtained on a Specord 75IR spectrometer from
samples prepared as KBr pellets or thin films.
N,N-Dichlorotrifluoromethanesulfonamide was syn- 1.4395.
thesized by the procedure reported in [4].
N-(2,2,2-Trichloro-1-phenylsulfonylaminoethyl)-
trifluoromethanesulfonamide (IIc). To a solution of
compound I (see above) 1.57 g (0.01 mol) of benzene-
sulfonamide was added. The mixture was stirred for
N-(2,2,2-Trichloroethylidene)trifluoromethane-
sulfonamide (I). A solution of 4.18 g (0.02 mol) of
N,N-dichlorotrifluoromethanesulfonamide in 12 15 ml
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

1562
ROZENTSVEIG et al.
1
Table 1. IR and H NMR spectra of N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide (I) and N-(2,2,2-trichloro-
ethyl)trifluoromethanesulfonamides II and III
1
IR spectrum, , cm
CF3SO2
1H NMR spectrum, , ppm
Comp.
no.
JNH,CH,
Hz
N H
other bands
solvent
CH
NH
Harom
I
1390, 1230, 1650 (C N) CDCl3
1210, 1130
8.65 s
5.12 d
4.95 s
5.61 d
5.97 d
5.54b
IIa
IIba
IIc
IId
IIe
IIIa
3220
3280
1380, 1230, 3400 (OH)
1200, 1130
C6D6
6.52 d
9.5
1380, 1230,
1200, 1130
2950
(CHaliph
CDCl3
)
3240 3280 1380, 1230,
1200, 1130
DMSO-d6
CDCl3
9.38 d
6.89 d
11.51b
6.37 d
7.11 7.87 m
9.5
8.4
3280
3250
3270
1350, 1230,
1200, 1130
1380, 1230,
1200, 1130
1380, 1230,
1200, 1140
3000
(CHaliph
2950
(CHaliph
2850
7.09, 8.18
)
)
)
(AA BB )
DMSO-d6
CDCl3
5.34 d
7.46 d (2-H),
6.44 d.d (3-H),
6.59 d (4-H)
7.42 7.93 m
9.0
(CHaliph
IIIb
IIIc
3280
3280
1380, 1220,
1200, 1130
1380, 1230,
1200, 1140
CDCl3
5.24 d
6.41 d
9.11 d
9.0
9.0
2980
(CHaliph
CD3COCD3 5.30 d
7.65, 7.37
)
(AA BB )
a
(CH3) 3.67 ppm, s.
Broadened signal.
b
8 h, and the precipitate was filtered off, washed with
chloroform, dried under reduced pressure, and
examined by H NMR spectroscopy. The product was
a mixture of benzenesulfonamide, hydroxy derivative
IIa, and addition product IIc. The latter was formed
in 51% yield (2.22 g).
prepared as described above from N,N-dichlorotri-
fluoromethanesulfonamide and trichloroethylene. The
mixture was kept for 60 h at 60 70 C and then for
20 h at room temperature. The large transparent crys-
tals of bisamide IIe were separated by decanting and
dried. Yield 1.08 g (37%).
1
N-(2,2,2-Trichloro-1-p-nitrophenoxyethyl)tri-
fluoromethanesulfonamide (IId). p-Nitrophenol,
1.39 g (0.01 mol), was added to a solution of com-
pound I, prepared from N,N-dichlorotrifluoromethane-
sulfonamide and trichloroethylene as described above.
The mixture was heated for 50 h at 50 60 C with
occasional shaking, and p-nitrophenol dissolved.
When the reaction was complete, the liquid part was
separated from undissolved p-nitrophenol by decant-
N-[2,2,2-Trichloro-1-(2-furyl)ethyl]trifluoro-
methanesulfonamide (IIIa). To a solution of Schiff
base I, prepared as described above, 0.68 g (0.01 mol)
of furan was added. A slight exothermic effect was
observed. The mixture was kept for 24 h at room tem-
perature and then for 24 h in the cold. The precipitate
was filtered off and dried under reduced pressure.
Yield of amide IIIa 1.84 g (53%).
N-(2,2,2-Trichloro-1-phenylethyl)trifluoro-
methanesulfonamide (IIIb). a. Dry benzene, 5 ml,
was added to a solution of Schiff base I (see above),
and 0.5 0.7 ml of oleum (15 20% of SO3) was then
added under vigorous stirring. The mixture was stirred
for 5 6 h at room temperature, 5 ml of chloroform
was added, the mixture was shaken, and the organic
phase was separated by decanting and evaporated.
1
ing and was analyzed by H NMR spectroscopy. The
yield of addition product IId was 1.59 g (38%). In
addition, the mixture contained initial p-nitrophenol
and hydroxyethyl amide IIa.
1,1,1-Trichloro-2,2-bis(trifluoromethylsulfonyl-
amino)ethane (IIe). Trifluoromethanesulfonamide,
1.49 g (0.01 mol), was added to a solution of amide I,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

SYNTHESIS AND PROPERTIES OF N-(2,2,2-TRICHLOROETHYLIDENE)-. . .
1563
Table 2. Yields, melting points, and elemental analyses of N-(2,2,2-trichloroethyl)trifluoromethanesulfonamides II
and III
Found, %
Cl
Calculated, %
Cl
Comp.
no.
Yield,
%
mp,
C
Formula
C
N
S
C
N
S
IIa
95
38
37
107 110
11.97 35.15 4.81 10.94
15.41 34.08 4.43 10.48
11.18 30.47 6.73 15.07
C3H3Cl3F3NO3S
C4H5Cl3F3NO3S
C4H3Cl3F6N2O4S2
C7H5Cl3F3NO3S
C9H7Cl3F3NO2S
12.15 35.87 4.72 10.81
15.47 34.25 4.51 10.33
11.24 24.88 6.55 15.00
IIba
IIe
151 152
88 90
118 120
IIIa
IIIb
53
24.17 30.59 4.11
30.25 29.70 4.01
9.37
9.12
24.26 30.69 4.04
30.32 29.83 3.93
9.25
8.99
70b
78c
72
IIIc
174 175
27.56 36.19 3.62
8.34
C9H6Cl4F3NO2S
27.65 36.27 3.58
8.20
a
b
c
For boiling point, see Experimental.
From N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide (I).
From N-(2,2,2-trichloro-1-hydroxyethyl)trifluoromethanesulfonamide (IIa).
The solid residue was washed with water, dried over
P2O5, and recrystallized from benzene. Yield of amide
IIIb 2.5 g (70%).
3. Levkovskaya, G.G., Drozdova, T.I., Rozen-
tsveig, I.B., and Mirskova, A.N., Usp. Khim., 1999,
vol. 68, no. 7, pp. 638 652.
4. Nazaretyan, V.P., Radchenko, O.A., and Yagupol’-
skii, L.M., Zh. Org. Khim., 1974, vol. 10, no. 11,
p. 2460.
b. A mixture of 2.97 g (0.01 mol) of N-(2,2,2-tri-
chloro-1-hydroxyethyl)trifluoromethanesulfonamide
(IIa), 10 ml of dry benzene, and 3 4 ml of concen-
trated sulfuric acid was vigorously stirred for 5 h.
The organic phase was separated by decanting and
was then treated as described above. Yield of amide
IIIb 2.78 g (78%).
5. Taraban, M.B., Mar’yasova, B.I., Leshina, T.V.,
Mirskova, A.N., Levkovskaya, G.G., Drozdova, T.I.,
Gogoberidze, I.T., and Voronkov, M.G., Zh. Org.
Khim., 1986, vol. 22, no. 5, pp. 925 930.
6. USSR Inventor’s Certificate no. 803361, 1980;
N-(2,2,2-Trichloro-1-p-chlorophenylethyl)tri-
fluoromethanesulfonamide (IIIc) was synthesized as
described above for compound IIIb (method a) from
Schiff base I and 5 ml of dry chlorobenzene in the
presence of 0.5 0.7 ml of oleum. Yield 2.82 g (72%).
Byull. Izobret., 1990, no. 3.
7. Luknitskii, F.I., Chem. Rev., 1975, vol. 75, no. 3,
pp. 259 288.
8. Rozentsveig, I.B., Levkovskaya, G.G., and Mirsko-
va, A.N., Russ. J. Org. Chem., 1998, vol. 34, no. 6,
p. 897.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001