ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 5, pp. 747–748. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © B.A. Shainyan, Yu.S. Danilevich, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 5, pp. 757–758.
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N-Propargyltrifluoromethanesulfonamide
B. A. Shainyan and Yu. S. Danilevich
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
е-mail: bagrat@irioch.irk.ru
Received December 4, 2013
DOI: 10.1134/S1070428014050212
N-Propargylsulfonamides are synthesized by
reactions of propargylamines with sulfonyl chlorides
[1] or of tosylamides with propargyl carbonate [2]
(along with isomeric N-allenylsulfonamides), and also
by the InCl3-catalyzed substitution of the acetate group
of propargyl acetate by the tosylamide residue [3]. The
synthesis of fluorine-containing N-propargyl-
sulfonamides was not described up till now.
propargylamine with trifluoromethanesulfonic acid
anhydride (Scheme 1).
To avoid the subsequent reaction of amide I with
the trifluoromethanesulfonic acid anhydride the latter
was taken in a deficit with respect to propargylamine.
The structure and the composition of compound I were
1
19
unambiguously proved by IR and Н, 13С, F spectra
and by elemental analysis. The signals of the isomeric
N-allenyltriflamide were absent from the NMR
spectra. In the IR spectrum recorded from thin film the
vibration bands ν(≡С–Н) and ν(NH) are overlapped
and form a single band at 3307 cm–1; in CCl4 solution
the bands are separated and individual bands are
observed: ν(≡С–Н) at 3395 and ν(NH) at 3311 cm–1.
We have recently synthesized first N-allyl-
triflamide derivatives CF3SO2NHCH2CH=CH2 and
CF3SO2· NHCH2CBr=CH2, but the attempt to perform
the dehydrobromination of the latter in order to obtain
N-propargyltriflamide or its isomer N-allenyltriflamide
was unsuccessful [4], apparently due to the high
acidity of the substrate. The preliminary protection of
the nitrogen atom made it possible to carry succes-
sfully the dehydrobromination of the N-protected
substrate CF3SO2N(CH2Ph)CH2CBr=CH2 and to
obtain N-allenyl-N-benzyltriflamide CF3SO2N·
(CH2Ph)CH=C=CH2 [4]. The careful analysis of the IR
and NMR spectra revealed the presence in the reaction
product of a small (~3%) admixture of the isomeric N-
benzyl-N-propargyltriflamide CF3SO2N(CH2Ph)·
CH2C≡CH [4], as seen from the appearance of the
absorption band ν(≡С–Н) 3299 cm–1 in the IR
spectrum and of the minor signals in the NMR spectra:
a triplet at 2.4 ppm, 4JНН 2.4 Hz (≡СН) in the 1Н NMR
spectrum and signals at 74.6 (≡СН) and 35.9 ppm
(СН2С≡СН) in the 13С NMR spectrum.
N-Propargyltriflamide (I) does not suffer
rearrangement into N-allenyltriflamide CF3SONH·
CH=C=CH2 or N-(prop-1-ynyl)triflamide CF3SO2NH·
C≡CCH3 under the treatment with potassium butoxide
1
in DMSO-d6, as shows the lack in the Н NMR
spectrum of signals in the region 1.5–2.0 (C≡CCH3)
and 4.5–6.5 ppm (НС=С=СН2).
N-Propargyltrifluoromethanesulfonamide (I). To
a mixture of 6.0 g (7.5 mL, 0.11 mol) of propargyl-
amine, prepared by the Gabriel method from propargyl
bromide and phthalimide [5] with subsequent heating
with ethanolamine, and 16.6 g (23 mL, 0.16 mol) of
triethylamine was added dropwise 23.3 g (14 mL,
0.083 mol) of trifluoromethanesulfonic acid anhyd-
ride, the reaction mixture was stirred for 2 h at 50°С,
excess Et3N was evaporated on a rotary evaporator, the
residue was acidified with 10–15% HCl till pH 5,
In this work we synthesized for the first time NH-
unsubstituted propargyltriflamide (I) by the reaction of
Scheme 1.
Et3N
_Et3NH+ CF3SO3_
CH2NH2
(CF3SO2)2O
CH2NHSO2CF3
+
I
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Shainyan
