USHAKOVA, SHAINYAN
352
1
Unlike compound 3 which showed in the H NMR
spectrum a triplet of the ≡CH proton and a doublet and
a singlet of the CH2 protons, the spectrum of 4 con-
tained only one CH2 signal shifted upfield from that
of 3. The 13C NMR spectrum of 4 displayed one CH2
signal and two triple-bonded carbon signals, in contrast
to the two CH2 signals and four C≡C(H) signals in the
spectrum of 3. The 19F NMR signal of 4 was also ob-
served ~3 ppm upfield from the signal of 3. Compound
4 is hygroscopic and is hydrolyzed to diacetylene 1 on
exposure to atmospheric moisture.
EXPERIMENTAL
The IR spectra were recorded in KBr on a Bruker
Vertex 70 spectrometer. The NMR spectra were re-
corded on a Bruker DPX 400 spectrometer at 400 (1H),
100 (13C), and 386 MHz (19F); the chemical shifts were
measured relative to the residual proton and carbon
signals of the solvent (1H, 13C) or CCl3F (19F).
1,8-Bis(trifluoromethanesulfonyl)-1,8-diaza-
cyclotetradeca-3,5,10,12-tetrayne (4). N,N-Di(prop-
2-yn-1-yl)trifluoromethanesulfonamide (2) [3], 0.5 g
(2.2 mmol), was added dropwise to a solution of 0.11 g
(2.2 mmol) of ammonium chloride and 0.22 g
(2.2 mmol) of CuCl in methanol–water (1:2). The
mixture was stirred for 8 h, the precipitate was filtered
off and washed with a small amount of chloroform and
with acetone, and the combined washings were dried
over MgSO4 and evaporated. Yield 0.29 g (30%),
mp 120–122°C. IR spectrum (KBr), ν, cm–1: 3316,
2251, 2215, 1441, 1376, 1201, 1146, 1072, 869.
1H NMR spectrum (CD3CN): δ 4.18 ppm, s (CH2).
13C NMR spectrum (CD3CN), δC, ppm: 33.79 (CH2),
67.49 (CH2C≡), 73.98 (≡C–C≡), 118.07 q (CF3,
JCF = 320.4 Hz). 19F NMR spectrum (CD3CN):
δF –78.43 ppm. Found, %: C 16.00; H 1.60; F 26.03;
N 7.17; S 14.74. C14H8F6N2O4S2. Calculated, %:
C 14.37; H 1.81; F 25.54; N 6.28; S 14.37.
Thus, the solvent nature essentially affects the be-
havior of ethynyl derivatives of trifluoromethanesul-
fonamide. A striking example of such effect was the
behavior of diacetylene 1 in an attempt to separate it
from tarry products formed on storage by treatment
with hexane where compound 1 is insoluble. After
a week, the hexane solution became colored, and
diphenyldiacetylene 5 precipitated after separation of
undissolved compound 1 and evaporation (Scheme 2).
Scheme 2.
H
Tf
N
H
N
Tf
1
Hexane
Ph
Ph
5
Diphenyldiacetylene (5). A mixture of 0.5 g of
compound 1 and 5–7 mL of hexane was stirred for 3 h.
Compound 1 did not dissolve, but the hexane solution
became colored. The mixture was left to stand for
a week at room temperature and filtered, and the
darkened filtrate was evaporated. The residue was
compound 5 as colorless crystals with mp 77°C;
published data: mp 86–87°C [4], 87–88°C [5]. IR
spectrum (KBr), ν, cm–1: 3316, 2251, 2215, 1441,
The formation of 5 in the absence of any aromatic
compound or any other reagent in the reaction mixture
may be rationalized assuming that the benzene rings
could be built up only from the triple-bonded carbon
chain in molecule 1. Without special studies, any
mechanism of formation of 5 would be rather specu-
lative; we can only state that, apart from cyclization to
produce a benzene ring, it should include elimination
of trifluoromethanesulfonamide and trifluoromethane-
sulfonamidomethyl residues. Scheme 3 illustrates the
overall reaction with account taken of material bal-
ance. Diacetylene 5 was identified by IR and NMR
spectroscopy and by comparison with published data.
1
1376, 1201, 1146, 1072, 869, 757, 615. H NMR
spectrum (CDCl3): δ 7.34–7.58 ppm, m (Ph). 13C NMR
spectrum (CDCl3), δC, ppm: 73.95 (≡C–Ph), 81.59
(≡C–C≡); 121.85, 128.47, 129.24, 132.54 (Carom).
ACKNOWLEDGMENTS
Scheme 3.
This study was performed using the facilities of
the Baikal Joint Center, Siberian Branch, Russian
Academy of Sciences.
H
Tf
3
N
N
Tf
H
1
CONFLICT OF INTERESTS
Ph
Ph
5
The authors declare the absence of conflict of
interests.
+
[2Tf2NH + 2TfN=CHNH2]
Tars
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019
Ushakova
