Triflamides and triflates of six-membered heterocyclic amines

Article abstract of DOI:10.1023/B:RUJO.0000010190.79187.b9

Reactions of secondary cyclic amines (piperidine, morpholine, thiomorpholine, 1λ⁶,4-thiazinane-1,1-dione) with trifluoromethanesulfonic anhydride or with N-phenyltriflimide both in the presence and in the absence of a base (Et₃N) result in formation of corresponding triflamides and triflates of the initial amines. The triflates and triflamides can be distinguished by their ¹⁹F and ¹⁵N NMR spectra and the presence in the IR spectra of salts of absorption bands in the region 3270-3000 cm^-1 lacking in the spectra of triflamides.

Full text of DOI:10.1023/B:RUJO.0000010190.79187.b9

Russian Journal of Organic Chemistry, Vol. 39, No. 8, 2003, pp. 1180 1182. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 8, 2003,
pp. 1251 1253.
Original Russian Text Copyright 2003 by Shainyan, Tolstikova, Zhinkin.
Triflamides and Triflates of Six-membered Heterocyclic Amines
B. A. Shainyan, L. L. Tolstikova, and A. R. Zhinkin
Faworsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
Irkutsk, 664033 Russia; e-mail: bagrat@irioch.irk.ru
Received December 11, 2002
6
Abstract Reactions of secondary cyclic amines (piperidine, morpholine, thiomorpholine, 1 ,4-thiazinane-
1,1-dione) with trifluoromethanesulfonic anhydride or with N-phenyltriflimide both in the presence and in
the absence of a base (Et3N) result in formation of corresponding triflamides and triflates of the
initial amines. The triflates and triflamides can be distinguished by their 19F and 15N NMR spectra
1
and the presence in the IR spectra of salts of absorption bands in the region 3270 3000 cm lacking
in the spectra of triflamides.
Triflamides
CF3SO2NHR
and
triflimide
corresponding triflamides and triflates and at establish-
ing spectral criteria for their distinguishing, and,
secondly, at elucidating whether the heterocyclic
secondary amines may be brought into reaction with
N-phenyltriflimide. The reaction of compounds I V
with (CF3SO2)2O was performed in the absence of
triethylamine or any other substance for binding the
liberated acid in order to obtain both types of reaction
products, triflamides and triflate salts. The reaction
follows the general equation
(CF3SO2)2NH are strong NH-acids which find
application as catalysts in various chemical processes,
and their lithium salts are used nowadays as electro-
lytes in the high-voltage current sources [1 3]. When
treated with nucleophiles these compounds are
capable to be cleaved both at the R N and S N bonds
[4], and sometimes even at the C S bond [5, 6]. Tri-
flamides and triflimides are readily obtained in reac-
tion of amines with one or two equiv of trifluoro-
methanesulfonic anhydride (CF3SO2)2O in the
presence of triethylamine used for binding the liberat-
ed acid and preventing the formation of the initial
amine triflate salt [4, 7]. In the absence of the binding
base the reaction affords a mixture of triflamide and
triflate salt as in the synthesis of 1-trifluoromethyl-
sulfonyl-1H-imidazole currently applied as triflating
agent [8]. As an alternative triflating agent for
aliphatic and primary aromatic amines was suggested
N-phenyltriflimide (CF3SO2)2NPh [7]. The reaction
with primary amines and piperidine occurred with a
high yield, but the secondary amines failed to react
[9]. Although the procedure was obviously simple,
sometimes mistakes still arose: For instance, a com-
pound obtained from piperidine and N-phenyltrifl-
imide and described as piperidine triflamide [9]
turned actually to be its triflate salt (see below), and
the conclusion on unexpected selectivity of the reac-
tion was also wrong. In the present study in exten-
sion of the investigation of N-triflated derivatives
from heterocyclic series [10] we carried out reactions
of piperidine, morpholine, piperazine, thiomorpho-
X = CH2 (I, VII, XII); O (II, VIII, XIII); NH (III);
S (IV, X, XV); CF3SO2N (IX); CF3SO3 N+H2 (XIV);
SO2 (V, XI, XVI).
The triflate salts precipitate if the reaction is
carried out in a mixture Et2O CH2Cl2 and thus are
easily separated from triflamides. Triflamides VII
XI and salts XII XVI have very similar 1H and
13C NMR spectra (save the very easily exchangeable
NH-protons of the salts), their elemental composition
also is much alike. As criteria for distinguishing may
serve the position of the signal in the 19F NMR
spectra that for triflamides VII XI is located down-
field ( 76 ppm) with respect to that of salts XII XVI
( 79 ppm), and the chemical shift of 15N quite dis-
similar for these types of compounds (see table). As
line,
6,4-thiazinane-1,1-dione) with trifluoro-
methanesulfonic anhydride and N-phenyltriflimide
aiming, firstly, at comparison of characteristics of the
1070-4280/03/3908-1180$25.00 2003 MAIK Nauka/Interperiodica

TRIFLAMIDES AND TRIFLATES
1181
Physicochemical constants and NMR spectra of compounds VII XVI
bp (mp), 1H NMR spectrum, , ppm
13C NMR spectrum, , ppm
19F NMR
spectrum,
, ppm
15N NMR
spectrum,
, ppm
Compd
no.
C
1
mm 1 Hg
X
XCH2
CH2N
X
XCH2 CH2N CF3 (J, Hz)
VII
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
63 64/1
59 60/1
1.68 1.68
3.75
3.50
23.76 26.33 48.19 121.16 (323.1)
67.00 47.39 121.11 (323.0)
47.26 47.26 120.87 (322.3)
27.64 49.33 120.61 (322.4)
52.24 46.74 120.63 (322.0)
22.58 23.17 45.94 121.72 (319.0)
64.30 45.03 121.63 (319.8)
41.61 41.61 121.03 (319.4)
24.75 47.17 121.77 (320.3)
49.10 45.18 121.55 (319.8)
76.82
77.05
76.82
76.99
77.34
79.05
79.23
78.87
78.88
78.90
292.3
295.8
3.50
3.78
3.50
4.08
3.33
3.46
3.67
3.06
4.02
133
3.78
2.89
3.35
a
162
145
101
370
103
207
1.72 1.88
3.99
341.93
345.0
3.67
3.66
3.65
a
The physicochemical constants of 1-trifluoromethylsulfonyl)thiomorpholine (X) were not determined because of its easy tarring.
The structure was proved by 1H, 13C, and 19F NMR spectra.
independent criterium serves the presence in the IR
spectra of salts XII XVI of the characteristic bands
of vibrations from the H2N+ group in the region
in the triflamide region besides the signal of com-
pound IX is observed a less strong peak located
around 76.41 ppm that is tentatively assigned to
monosubstituted compound XVIII.
1
3270 3000 cm lacking in the spectra of triflamides.
Triflamide VII was previously prepared from
piperidine and N-phenyltriflimide in the presence of
triethylamine and described (almost simultaneously)
both as a liquid (without mentioning the boiling point)
[11] and as crystalline substance of mp 134 135 C
[9].
EXPERIMENTAL
IR spectra were recorded on spectrophotometer
IKS-29 from thin film, KBr pellets, or mulls in
mineral oil. 1H, 13C, 15N, and 19F NMR spectra
were registered on spectrometer Bruker DPX 400
(400 MHz for protons) from solutions in CDCl3,
internal reference HMDS, the chemical shifts are
presented with respect to TMS (1H, 13C), CH3NO2
(15N), and CCl3F (19F). Chemical shifts of 15N
signals were obtained from the two-dimensional
spectra 2D(1H 15N)with the use of a gradient probe
According to our data triflamide VII is a liquid
boiling at 63 64 C at 1 mm Hg. But both in the
presence and in the absence triethylamine formed also
piperidinium triflate (XII). The N-triflamide reacted
similarly also with the other secondary amines II, III,
V in the absence of triethylamine affording both types
of products, triflamides VII XI and salts XII XVI,
the latter prevailing.
in a mode hmbcgp.
N-Phenyltriflimide was prepar-
1
ed by procedure [7], mp 95 96 C. H NMR spectrum
In the 19F NMR spectrum of the reaction mixture
obtained from piperazine III and N-phenyltriflimide
(acetone-d6), , ppm: 7.6 7.7 m (Ph). 13C NMR
1
spectrum (acetone-d6), , ppm: 120.16 q (CF3, JCF
324.3 Hz), 131.03 (Co), 131.95 (Cm), 132.64 (C1),
133.27 (Cn). 19F NMR spectrum (acetone-d6),
,
ppm: 72.49.
Reaction of amines with trifluoromethane-
sulfonic anhydride (general procedure). To a solu-
tion of 0.01 0.02 mol of amine in 10 20 ml of di-
chloromethane cooled to 78 c was added dropwise
at stirring 0.005 0.01 mol (with piperazine equimolar
amount) of solution of trifluoromethansulfonic
anhydride in dichloromethane. The cooling was re-
moved, the reaction mixture was stirred at room
X = CH2 (I, VII, XII); O (II,+VIII, XIII); NH (III,
XVIII); CF3SO2N (IX); CF3SO NH2 (XIV); SO2 (V, XI,
3
XVI).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 8 2003

1182
SHAINYAN et al.
temperature and left standing for 24 h. The precipitat-
ed amine triflate salt was filtered off, and evaporation
of the filtrate afforded the corresponding triflamide.
If the salt did not precipitate, the reaction mixture
was evaporated, treated with anhydrous ether, and
the precipitated amine triflate was separated.
Thiomorpholinium trifluoromethanesulfonate
(XV). IR spectrum, cm : 3230 3070, 1600, 1330
1230, 1170, 1030, 630. Found, %: C 23.12; H 3.92;
N 5.94; S 25.49. C5H10F3NO3S2. Calculated, %:
C 23.71; H 3.98; N 5.53; S 25.32.
1
1, 1-Dioxo-1 6,4-thiazinan-4-ium trifluoro-
1-(Trifluoromethanesulfonyl)piperidine (VII).
methanesulfonate (XVI). Yield 87%. IR spectrum,
cm : 3250 3000, 1390 1170, 1070, 1020, 950, 840,
630, 520, 430. Found, %: C 21.86; H 3.59; N 4.86.
C5H10F3NO5S2. Calculated, %: C 21.05; H 3.53;
N 4.91.
Yield43%. Colorless liquid, n2D2 1.4134. IR spectrum,
1
1
cm : 3000 2860, 1460, 1390, 1230 1130, 1050,
950, 770, 710, 600, 500. Found, %: C 32.79; H4.76;
F 25.32; N 6.56; S 15.87. C6H10F3NO2S. Calculated,
%: C 33.18; H 4.64; F 26.24; N 6.45; S 14.76.
Reaction of amines I III, V with N-phenyltri-
flimide (XVII) (general procedure). To a solution
of N-phenyltriflimide (0.5 mmol) in dichloromethane
(3 ml) was added at room temperature 0.5 mmol of
amine. The reaction mixture was stirred at room
temperature and left overnight. The solution was
evaporated. The crystalline residue was a mixture of
the initial N-phenyltriflimide (XVII), triflamide VII
IX, XI, triflate XII XIV, XVI, and N-phenyltri-
flamide.
1-(Trifluoromethanesulfonyl)morpholine (VIII).
Yield 53%. Colorless liquid, n2D0 1.4127.
1
IR spectrum, cm : 2980 2860, 1460, 1390, 1280
1110, 1070, 970, 770, 710, 620, 590, 500. Found,
%: C 27.49; H 3.37; F 24.93; N 6.23; S 14.83.
C5H8F3NO3S. Calculated, %: C 27.40; H 3.68;
F 26.00; N 6.39; S 14.63.
1, 4-Bis(trifluoromethanesulfonyl)piperazine
1
(IX). Yield 66%. IR spectrum, cm : 1390, 1350,
1230 1140, 1080, 950, 770, 710, 610, 590, 440.
Found, %: C 20.61; H 2.34; N 7.38; S 18.74.
C6H8F6N2O4S2. Calculated, %: C 20.58; H 2.30;
N 8.00; S 18.31.
The authors are grateful to L. I. Larina for measur-
ing the 15N NMR spectra.
REFERENCES
6
4-(Trifluoromethanesulfonyl)-1 ,4-thiazinane-
1. Mathieu, B. and Ghosez, L., Tetrahedron Lett., 1997,
vol. 38, p. 5497.
1
1,1-dione (XI). Yield 35%. IR spectrum, cm : 1390,
1305, 1280 1110, 1080, 1020, 920, 700, 710, 600,
580, 450. Found, %: C 22.32; H 3.11; N 5.29;
S 23.68. C5H8F3NO4S2. Calculated, %: C 22.47;
H 3.02; N 5.24; S 23.99.
2. US Patent 5072040, 1991; Chem. Abstr., 1991,
184787.
3. US Patent 5874616, 1999; Chem. Abstr., 1999,
184069.
4. Hendrickson, J.B., Bergeron, R., Giga, A., and
Sternbach, D.D., J. Am. Chem. Soc., 1973, vol. 95,
p. 3412.
Piperidinium trifluoromethanesulfonate (XII).
1
Yield 100%. IR spectrum, cm : 3270 3050, 1290
1230, 1165, 1120, 640. Found, %: 30.76; H 5.19;
F 23.86; N 6.00; S 14.34. C6H12F3NO3S. Calculat-
ed, %: C 30.64; H 5.14; F 24.23; N 5.95; S 13.63.
5. Lyle, T.A., Magill, C.A., and Pitzenberger, S.M.,
J. Am., Chem. Soc., 1987, vol. 109, p. 7890.
6. Bozec-Ogor, S., Salou-Guiziou, V., Yaouanc, J.J.,
and Handel, H., Tetrahedron Lett., 1995, vol. 36,
p. 6063.
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Giga, A., Skipper, P.L., Sternbach, D.D., and
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8. Effenberger, F.and Mack, K.M., Tetrahedron Lett.,
1970, vol. 45, p. 3947.
9. Hendrickson, J.B. and Bergeron, R., Tetrahedron
Lett., 1973, vol. 46, p. 4607.
Morpholinium trifluoromethanesulfonate (XIII).
1
Yield 96%. IR spectrum, cm : 3250 3000, 1600,
1460, 1310 1230, 1170, 1105, 1030, 900, 880, 640,
510. Found, %: C 25.88; H 4.46; N 5.99; S 14.13.
C5H10F3NO4S. Calculated, %: C 25.32; H 4.25;
N 5.91; S 13.52.
Piperazinium trifluoromethanesulfonate (XIV).
1
Yield 100%. IR spectrum, cm : 3240 3000, 1560,
1440, 1320 1240, 1170, 1080, 1030, 950, 870, 650,
590, 520. Found, %: C 19.79; H 3.14; F 27.43;
N 7.85; S 15.79. C6H12F6N2O6S2. Calculated, %:
C 18.66; H 3.13; F 29.51; N 7.25; S 16.60.
10. Shainyan, B.A. and Meshcheryakov, V.I., Zh. Org.
Khim., 2001, vol. 37, p. 1877.
11. Hendrickson, J.B. and Bergeron, R., Tetrahedron
Lett., 1973, vol. 39, p. 3839.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 8 2003