Reactions of N-sulfinyltrifluoromethanesulfonamide with carboxylic acids

Article abstract of DOI:10.1134/S1070428008080022

Phenylacetic, diphenylacetic, salicylic, and cinnamic acids reacted with N-sulfinyltrifluoromethanesulfonamide (CF₃SO₂NSO) to give the corresponding N-acyltrifluoromethanesulfonamides CF₃SO ₂NHCOR (R = PhCH

Full text of DOI:10.1134/S1070428008080022

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 8, pp. 1121–1125. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © B.A. Shainyan, L.L.Tolstikova, A.V. Bel’skikh, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 8,
pp. 1136–1140.
Reactions of N-Sulfinyltrifluoromethanesulfonamide
with Carboxylic Acids
B. A. Shainyan, L. L.Tolstikova, and A. V. Bel’skikh
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: bagrat@irioch.irk.ru
Received October 6, 2007
Abstract—Phenylacetic, diphenylacetic, salicylic, and cinnamic acids reacted with N-sulfinyltrifluoromethane-
sulfonamide (CF3SO2NSO) to give the corresponding N-acyltrifluoromethanesulfonamides CF3SO2NHCOR
(R = PhCH2, Ph2CH, o-HOC6H4, PhCH=CH). The reaction of N-sulfinyl-trifluoromethanesulfonamide with
3-hydrazinobenzoic acid occurred at the hydrazino group of the latter with conservation of the carboxy group
and without elimination of SO2, and the product was 3-(2-sulfinylhydrazino)benzoic acid OSNNHC6H4CO2H.
DOI: 10.1134/S1070428008080022
Reactions of N-sulfinylamines RN=S=O and
fluorine-containing heterocumulenes, such as
RFSO2N=S=O, C6F5N=S=O, and RFSO2N=C=O, with
aromatic aldehydes [1, 2], dimethylformamide [2], and
carboxylic acids [3] have been extensively studied, and
they are widely used in organic synthesis [1–8]. These
reactions are accompanied by elimination of SO2 or
CO2, and the products have the general formula RN=Y
where Y = CHAr, CHNMe2, or C(OH)R′, respectively.
Reactions of N-sulfinylperfluoroalkanesulfonamides
with carboxylic acids, followed by prototropic tau-
tomerization, yield mixed carboxylic sulfonic acid
imides RFSO2NHC(O)R′. N-Sulfinylamines and N-sul-
finylperfluoroalkanesulfonamides react with carboxyl-
ic acids in the presence of HCl or SOCl2 [3–5] as
catalyst on prolonged heating at 150–160°C [3].
finyltrifluoromethanesulfonamide (CF3SO2NSO, I)
with other functionally substituted, as well as with
strong polyhalogenated, carboxylic acids, namely
phenylacetic (II), diphenylacetic (III), salicylic (IV),
cinnamic (V), 3-hydrazinobenzoic (VI), trichloro-
acetic, pentafluoropropionic, and perfluorononanoic
(perfluoropelargonic) acids.
Acids II and III smoothly reacted with compound I
at room temperature with formation of the correspond-
ing N-acyltrifluoromethanesulfonamides VII and VIII
in nearly quantitative yield (Scheme 1).
Scheme 1.
CF3SO2N=S=O
+
PhCHXCOOH
I
II, III
CF3SO2NHC(O)CHXPh
The conditions of the reactions of heterocumulenes
with carboxylic acids strongly depend on the acidity
of the latter. For example, fluorosulfonyl isocyanate
FSO2NCO reacts with acetic and chloroacetic acids
with heat evolution, and the yield reaches 94%, where-
as the reactions with stronger di- and trichloroacetic
acids require prolonged heating, and the yield de-
creases to 50 and 21%, respectively [6]. N-Sulfinylper-
fluoroalkanesulfonamides also react with acetic acid
under milder conditions (60°C) than with stronger ben-
zoic acids (150–160°C) [3]. Reactions of only acetic,
benzoic, and p-iodobenzoic acids with N-sulfinylper-
fluoroalkanesulfonamides have been reported [3]. In
the present work we examined the behavior of N-sul-
–SO2
VII, VIII
II, VII, X = H; III, VIII, X = Ph.
The product structure was proved by elemental
analysis, IR spectroscopy (NHCO stretching vibration
band at 1720 cm–1), and 1H (δNH 8.2–8.3 ppm) and 13C
NMR (δC=O 170 ppm). Addition of a catalytic amount
of thionyl chloride strongly accelerates the process: for
example, the reaction time for phenylacetic acid (II)
shortens from 6 h to 10 min.
The reaction of compound VII with phenylhydra-
zine involved cleavage of the N–C bond and replace-
1121

SHAINYAN et al.
1122
ment of the trifluoromethanesulfonamide group by the
phenylhydrazine residue (Scheme 2). The reaction was
carried out in methylene chloride at –40°C, and the
yields of trifluoromethanesulfonamide and N′-phenyl-
(phenyl)acetohydrazide (IX) were quantitative; com-
pound IX thus obtained was identical to a sample
described in [9].
CF3SO2NHC(O)R′ were formed, the reaction of I with
hydrazino acid VI did not involve the carboxy group
1
(according to the H and 13C NMR and mass spectra).
The elemental analysis of the product showed the ab-
sence of fluorine, and it was assigned the structure of
3-(2-sulfinylhydrazino)benzoic acid (XII) (Scheme 5).
Scheme 5.
Scheme 2.
COOH
COOH
VII
+
PhNHNH2
PhCH2C(O)NHNHPh
I
+
IX
O
S
NHNH2
VI
HN
+
CF3SO2NH2
N
XII
We previously showed that, despite easy addition of
proton donors to heterocumulenes, the hydroxy group
in salicylaldehyde does not disappear in the reaction
with compound I, which occurs only at the aldehyde
group [2]. Likewise, i.e., with conservation of the
hydroxy group, salicylic acid (IV) reacted with com-
pound I (Scheme 3). The 1H NMR spectrum of product
X contained two broadened downfield singlets with
equal intensities, which were assigned to the OH and
NH protons.
+ CF3SO2NH2
The second product formed in this reaction was tri-
fluoromethanesulfonamide, which was separated from
compound XII by recrystallization from ethanol. The
mass spectrum of XII contained the molecular ion
peak with m/z 198, and its fragmentation pattern was
consistent with the assumed structure. Compound XII
1
displayed in the H NMR spectrum signals from four
aromatic protons and downfield signals from protons
of the COOH and NH groups at δ 13.0 and 12.8 ppm,
respectively. In the 13C NMR spectrum of XII we
observed signals from aromatic carbon atoms and
carboxy group, while no CF3 signal was present. The
1H signal at δ 13 ppm disappeared upon addition of
D2O (simultaneously, a signal from water appeared at
about δ 4.8 ppm). In going from acid VI to compound
XII, the signal from the carboxy carbon atom almost
did not change its position, whereas the C3 signal
displaced upfield by 10.5 ppm, indicating that the reac-
tion involved the hydrazine fragment rather than the
carboxy group.
Scheme 3.
O
COOH
OH
SO2CF3
N
I
+
H
–SO2
OH
IV
X
Cinnamic acid (V) reacted with N-sulfinyltrifluoro-
methanesulfonamide (I) to afford trifluoro-N-[(2E)-
3-phenylprop-2-enoyl]methanesulfonamide (XI)
(Scheme 4). Here, the double bond remained intact: in
the 1H NMR spectrum of the product we observed two
doublets from vinylic protons at δ 6.45 and 7.27 ppm
(J = 15.6 Hz).
Unusual behavior of 3-hydrazinobenzoic acid (VI)
toward N-sulfinyltrifluoromethanesulfonamide is
likely related to specificity of its structure. The IR
spectrum of a crystalline sample of VI contains ab-
sorption bands at 2000–3000 cm–1 due to stretching
vibrations of the NH3+ group and at 1360 cm–1 due to
stretching vibrations of the carboxylate group. The
1H NMR spectrum of acid VI in DMSO-d6 lacks signal
assignable to COOH group, but broadened signals
from NH (δ 6.9 ppm, 1H) and NH3+ groups (δ 3.5 ppm,
3H) were present. These data suggest that 3-hydrazino-
benzoic acid in crystal and in solution exists as zwit-
terion VIa. Presumably, the reaction occurs as addition
of the hydrazinium fragment in the zwitterionic form
of acid VIa at the N=S bond of heterocumulene I,
Scheme 4.
I
+
(E)-PhCH=CHCOOH
V
CF3SO2NHC(O)CH=CHPh-(E)
–SO2
XI
Unexpected results were obtained in the reaction
of compound I with 3-hydrazinobenzoic acid (VI).
Unlike published data [3] and the above described
reactions (Schemes 1, 3, and 4) where mixed trifluoro-
methanesulfonic and carboxylic acid imides
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REACTIONS OF N-SULFINYLTRIFLUOROMETHANESULFONAMIDE
1123
Scheme 6.
COOH
COO–
COO–
COOH
CF3SO2N=S=O
O
S
O
S
NHNH2
VI
NHNH3
VIa
HN
HN
N
NHSO2CF3
N
NHSO2CF3
H
H
H
XII
–CF3SO2NH2
followed by elimination of trifluoromethanesulfon-
amide molecule from the adduct (Scheme 6).
Decomposition of the molecular ion of XII under
electron impact involves elimination of HSO· radical
and subsequent elimination of nitrogen molecule from
the diazonium ion thus formed (Scheme 7).
genated carboxylic acids. Obviously, the reason is
reduction of the reactivity of acids with rise in their
acidity. No reaction occurred between compound I and
trichloroacetic acid at room temperature even in the
presence of thionyl chloride, whereas prolonged heat-
ing of the reaction mixture resulted in strong tarring.
The only fact indicating formation of expected
N-(2,2,2-trichloroacetyl)trifluoromethanesulfonamide
CF3SO2NHCOCCl3 was the presence in the 19F NMR
spectrum of the reaction mixture of a signal at
δF –76 ppm, i.e., in the region typical of analogous
compounds VII, VIII, X, and XI. According to the
NMR data, no mixed trifluoromethanesulfonic and
carboxylic acid imides were formed when compound I
was heated with pentafluoropropionic or perfluoro-
nonanoic acid with N-sulfinyl amide I at the boiling
point over a period of 1 h in the presence of thionyl
chloride.
Scheme 7.
+·
COOH
COOH
·
–HSO
NHN=S=O
m/z 198 (27%)
N2
m/z 149 (30%)
COOH
–N2
m/z 121 (100%)
EXPERIMENTAL
Compound XII is fairly stable, and it does not
undergo hydrolysis to initial acid VI even on recrystal-
lization from aqueous ethanol. N-Sulfinyl derivatives
XII and I show different reactivities toward nucleo-
philes since the N=S=O heterocumulene fragment in
the latter is linked to one of the strongest electron-
withdrawing groups, CF3SO2, which sharply facilitates
hydrolysis of compound I. By contrast, the N=S=O
fragment in XII is contiguous to the NH group, and
conjugation with unshared electron pair on the NH
nitrogen atom hampers nucleophilic attack on the
N=S=O group.
We have found no published data on N-sulfinyl-
substituted hydrazines or their analogs having an
N–N=X=Y moiety. Therefore, the reaction of 3-hydra-
zinobenzoic acid (VI) with compound I may be re-
garded as the first example of reactions of N-sulfinyl-
sulfonamides with hydrazines, and compound XII, as
the first representative of hydrazine heterocumulenes.
The IR spectra were recorded in mineral oil or KBr
on an IKS-29 spectrometer. The mass spectra (electron
impact, 70 eV) were obtained on a TRACE DSQ II
GC–MS system (Thermo); samples were injected as
dispersions in DMSO. The NMR spectra were meas-
ured on a Bruker DPX-400 instrument at 400 (1H), 100
(13C), and 376 MHz (19F); the chemical shifts were
determined relative to tetramethylsilane (1H, 13C) and
trichlorofluoromethane (19F).
Trifluoro-N-(phenylacetyl)methanesulfonamide
(VII). a. Phenylacetic acid (II), 0.27 g (2 mmol), was
added to 0.78 g (4 mmol) of compound I, the mixture
was stirred for 6 h at room temperature until it crystal-
lized completely, kept for 16 h more, and evaporated to
dryness. Yield 0.50 g (94%), mp 129°C. IR spectrum,
ν, cm–1: 3200, 1720, 1440, 1400, 1390, 1240, 1200,
1
1180, 1140, 880, 700, 600, 490. H NMR spectrum
(CDCl3), δ, ppm: 3.77 s (2H, CH2), 7.36–7.23 m (5H,
We failed to obtain products of reactions of N-sul-
finyltrifluoromethanesulfonamide (I) with polyhalo-
Harom), 8.21 br.s (1H, NH). 13C NMR spectrum (CDCl3),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 8 2008

SHAINYAN et al.
1124
δC, ppm: 43.56 (CH2), 120.68 q (CF3, 1JCF = 318.0 Hz),
128.50 (Cm), 129.35 (Cp), 129.49 (Co), 131.09
(C1), 168.07 (C=O). 19F NMR spectrum (CDCl3):
δF –76.31 ppm. Found, %: C 39.96; H 3.25; F 21.90;
N 5.37; S 12.39. C9H8F3NO3S. Calculated, %: C 40.45;
H 3.02; F 21.33; N 5.24; S 12.00.
Trifluoro-N-(2-hydroxybenzoyl)methanesulfon-
amide (X). A mixture of 0.49 g (2.5 mmol) of com-
pound I, 0.28 g (2 mmol) of salicylic acid (IV), and
0.05 ml of thionyl chloride was stirred for 1 h at
60–80°C and left overnight. It was then evaporated
to dryness, and trifluoromethanesulfonamide was re-
moved by sublimation. Yield of X 0.44 g (75%),
mp 132°C. IR spectrum, ν, cm–1: 3400, 3200, 1680,
1605, 1470–1440, 1380, 1240, 1210, 1190, 1130, 880,
740, 600, 490. 1H NMR spectrum (CDCl3–CD3CN), δ,
ppm: 6.96 m (2H, 3-H, 5-H), 7.47 t (1H, 4-H, J =
7.7 Hz), 7.80 d (1H, 6-H, J = 7.7 Hz), 9.85 br.s
(1H, NH), 10.55 br.s (1H, OH). 13C NMR spectrum
(CDCl3–CD3CN), δC, ppm: 113.97 (C1), 117.82 (C3),
119.20 q (CF3, J = 322.1 Hz), 120.51 (C5), 130.11 (C6),
136.65 (C4), 159.07 (C2), 165.11 (C=O). 19F NMR
spectrum (CDCl3–CD3CN): δF –75.41 ppm. Found, %:
C 36.39; H 2.39; N 5.05; S 11.63. C8H6F3NO4S. Cal-
culated, %: C 35.69; H 2.25; N 5.20; S 11.91.
b. The reaction was carried out as described above
but with addition of 0.1 ml of thionyl chloride. The
mixture was stirred for 10 min at room temperature.
Yield 0.50 g (94%).
N-(2,2-Diphenylacetyl)trifluoromethanesulfon-
amide (VIII) was obtained from 0.39 g (2 mmol) of
compound I and 0.21 g (1 mmol) of diphenylacetic
acid (III) according to method b. Yield 0.31 g (91%),
mp 120°C. IR spectrum, ν, cm–1: 3150, 1720, 1460,
1390, 1240, 1200, 1140, 1090, 890, 690, 590. 1H NMR
spectrum (CDCl3), δ, ppm: 5.01 s (1H, CH), 7.19–
7.32 m (10H, Harom), 8.32 br.s (1H, NH). 13C NMR
spectrum (CDCl3), δC, ppm: 59.01 (CH), 119.04 q
Trifluoro-N-[(2E)-3-phenylprop-2-enoyl]-
methanesulfonamide (XI). A mixture of 0.39 g
(2 mmol) of compound I and 0.15 g (1 mmol) of cin-
namic acid (V) was stirred for 1 h at room temperature
and left overnight. The mixture was treated with anhy-
drous diethyl ether, the precipitate of trifluoromethane-
sulfonamide was separated, and the filtrate was evap-
orated to dryness. Yield 0.24 g (86%), mp 165°C. IR
spectrum, ν, cm–1: 3190, 1700, 1620, 1440, 1380,
1240, 1200, 1140, 1095, 870, 760, 600. 1H NMR spec-
trum (CDCl3–CD3CN), δ, ppm: 6.45 d (1H, =CHCO,
J = 15.6 Hz), 7.34 m (3H, m-H, p-H), 7.47 m (2H,
o-H), 7.72 d (1H, PhCH=, J = 15.6 Hz), 9.77 s (1H,
1
(CF3, JCF = 322.4 Hz), 128.31 (Cm), 128.68 (Cp),
129.19 (Co), 135.89 (C1), 169.28 (C=O). 19F NMR
spectrum (CDCl3): δF –75.38 ppm. Found, %: C 52.38;
H 3.51; N 4.28; S 10.02. C15H12F3NO3S. Calculated,
%: C 52.48; H 3.52; N 4.08; S 9.34.
N′-Phenyl(phenyl)acetohydrazide (IX). A solu-
tion of 0.24 g (0.89 mmol) of compound VII in 2 ml of
methylene chloride was cooled to –40°C, a solution of
0.096 g (0.89 mmol) of phenylhydrazine in 2 ml of
methylene chloride was added dropwise under stirring,
and the mixture was stirred for 15 min at that tempera-
ture and was left overnight at –12°C. The white precip-
itate was filtered off and dried. Yield 0.07 g (35%),
mp 175–176°C; published data [9]: mp 175°C. The
filtrate was treated with cold methylene chloride, and
the precipitate of N-trifluoromethanesulfonamide,
0.13 g (100%), was filtered off. Evaporation of the
filtrate gave an additional 0.13 g (65%) of compound
IX. Overall yield 0.20 g (100%). IR spectrum, ν, cm–1:
3280, 3200, 3030, 1660–1640, 1600, 1490, 960, 740,
SO2NH). 13C NMR spectrum (CDCl3–CD3CN), δC,
1
ppm: 116.19 (=CHCO), 118.75 q (CF3, JCF
=
321.6 Hz), 128.09 (Co), 128.58 (Cm), 130.90 (Cp),
132.94 (C1), 147.05 (PhCH=), 161.99 (C=O).
19F NMR spectrum (CDCl3): δF –76.52 ppm. Found,
%: C 43.05; H 2.87; N 5.22; S 10.94. C10H8F3NO3S.
Calculated, %: C 43.01; H 2.89; N 5.02; S 11.48.
3-Hydrazinobenzoic acid (VI). 1H NMR spectrum
(DMSO-d6), δ, ppm: 3.51 br.s (3H, NH3+), 6.92 br.s
(1H, NH), 6.97 d (1H, 4-H, J = 7.4 Hz), 7.16 m (2H,
5-H, 6-H), 7.38 s (1H, 2-H). 13C NMR spectrum
(DMSO-d6), δC, ppm: 112.23 (C4), 115.76 (C2), 117.73
(C6), 128.64 (C5), 131.27 (C1), 152.54 (C3), 168.05
(C=O).
1
680. H NMR spectrum (DMSO-d6), δ, ppm: 3.49 s
(2H, CH2), 6.66 m, (3H, o-H and p-H in PhNH), 7.09 t,
(2H, m-H in PhNH, J = 7.8 Hz), 7.32 m (4H, o-H and
m-H in PhC), 7.24 m (1H, p-H in PhC), 7.73 s (1H,
NHPh), 9.86 s (1H, NHCO). 13C NMR spectrum
(DMSO-d6), δC, ppm: 40.46 (CH2), 112.03 (Co in
NPh), 118.43 (Cp in NPh), 126.48 (Cp in PhC), 128.24
(Cm in NPh), 128.62 (Co in PhC), 128.98 (Cm in
PhC), 135.90 (C1 in PhC), 149.27 (C1 in NPh), 169.92
(C=O).
3-(2-Sulfinylhydrazino)benzoic acid (XII). A so-
lution of 0.30 g (2 mmol) of 3-hydrazinobenzoic acid
(VI) in 2 ml of methylene chloride was cooled to
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REACTIONS OF N-SULFINYLTRIFLUOROMETHANESULFONAMIDE
1125
REFERENCES
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ness, and the residue was recrystallized from ethanol.
Yield 0.25 g (62%), sublimes at 230°C. IR spectrum,
ν, cm–1: 3420 (OH), 3194 (NH), 1684 (C=O), 1592,
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 8 2008