Synthesis of diaryl sulfides by the reactions of activated aryl halides with potassium ethyl dithiocarbonate under conditions of phase-transfer catalysis [2]

Full text of DOI:10.1023/A:1022406011983

278
Russian Chemical Bulletin, International Edition, Vol. 52, No. 1, p. 278, January, 2003
Synthesis of diaryl sulfides by the reactions of
activated aryl halides with potassium ethyl dithiocarbonate
under conditions of phaseꢀtransfer catalysis
ꢀ
D. V. Davydov and I. P. Beletskaya
Department of Chemistry, M. V. Lomonosov Moscow State University,
Leninskie gory, 119899 Moscow, Russian Federation.
Fax: +7 (095) 939 1854. Eꢀmail: dvdav@elorg.chem.msu.ru
Activated aryl halides are used to synthesize diaryl
second molecule of aryl halide, yielding the target diaryl
sulfides by the reaction with sodium sulfide or other sulꢀ
furꢀcontaining compounds both in dipolar aprotic solꢀ
vents1 and under the conditions of phaseꢀtransfer catalyꢀ
sis.2—4 The main drawback of the known routes to symꢀ
metrical diaryl sulfides is the formation of side products,
e.g., diaryl disulfides.4,5 It is known that dialkyl sulfides
can be obtained from alkyl halides and potassium ethyl
dithiocarbonate under the conditions of phaseꢀtransfer
catalysis with subsequent alkaline decomposition of subꢀ
stitution products.6 We found that activated aryl halides
1a—g react with potassium ethyl dithiocarbonate under
the conditions of phaseꢀtransfer catalysis to give diaryl
sulfides 2a—g directly without the formation of diaryl
disulfides as byꢀproducts (Scheme 1).
sulfide. The physicochemical characteristics of the known
diaryl sulfides agree well with the literature data.
Synthesis of diaryl sulfides 2a—g (general procedure). A mixꢀ
ture of an aryl halide (1a—g) (1 mmol), potassium ethyl
dithiocarbonate (1.1 mmol), and C16H33Me3NBr (0.05 mmol)
in 100 mL of toluene was refluxed with vigorous stirring for
4—8 h until complete disappearance of the starting aryl halide
(monitoring by TLC on Silufol UVꢀ254 plates or GLC). In the
case of volatile perfluorinated aryl halides 1f,g, the reactions
were carried out in a sealed tube. Then the reaction mixture was
filtered through silica gel, and the product was eluted with toluꢀ
ene (TLC). The solution obtained was concentrated in vacuo,
and the residue was recrystallized twice from light petroleum.
The 19F (with C6F6 as the internal standard) and 13C NMR
spectra were recorded on a Varian VXRꢀ400 instrument. Mass
spectra were recorded on a Finnigan MATꢀ113 instrument.
Bis(2,3,5,6ꢀtetrafluoroꢀ4ꢀpyridyl) sulfide (2f). Yield 95%,
m.p. 54—56 °C. Found (%): C, 36.00; F, 45.67; N, 8.42; S, 9.55.
Scheme 1
C
10F8N2S. Calculated (%): C, 36.10; F, 45.76; N, 8.40; S, 9.65.
19F NMR (CDCl3), δ: –90.5 (m, 4 F, F(2), F(6)); –135.2 (m,
4 F, F(3), F(5)). 13C NMR (CDCl3), δ: 125.2 (m, C(4)); 143.2
(dm, C(3), C(5), JC,F = 259.8 Hz); 144.3 (dm, C(2), C(6),
JC,F = 243.3 Hz). MS (EI, 70 eV), m/z: 332 [M]+.
Bis(2,3,5,6ꢀtetrafluoroꢀ4ꢀtrifluoromethylphenyl) sulfide (2g).
Yield 90%, m.p. 62—64 °C. Found (%): C, 35.94; F, 56.92;
S, 6.75. C14F14S. Calculated (%): C, 36.07; F, 57.05; S, 6.88.
19F NMR (CDCl3), δ: –59.0 (s, 6 F, CF3); –133.3 (m, 4 F,
F(3), F(5)); –140.8 (m, 4 F, F(2), F(6)). 13C NMR (CDCl3), δ:
111.2 (m, C(4)); 115.2 (t, C(1), JC,F = 21.1 Hz); 120.4 (q, CF3);
144.2 (dm, C(3), C(5), JC,F = 261.0 Hz); 146.7 (dm, C(2), C(6),
JC,F = 250.4 Hz). MS (EI, 70 eV), m/z: 466 [M]+.
References
1. Organic Chemistry of Sulfur, Ed. S. Oae, Plenum Press, New
York, 1977, 231.
2. T. L. Evans, Synth. Commun., 1984, 14, 435.
3. H. Alsaidi, R. Gallo, and J. Metzger, C. R. Sci. Paris, Ser. C,
1979, 289, 203.
4. P. Stingh and G. Arora, Tetrahedron, 1988, 44, 2625.
5. T. L. Evans and R. D. Kinnard, J. Org. Chem., 1983, 48, 2496.
6. I. Degani, R. Fochi, and V. Regondi, Synthesis, 1979, 178.
Apparently, the reaction mechanism includes the forꢀ
mation of Sꢀaryl Oꢀethyl dithiocarbonate in the first step,
which reacts with the second molecule of potassium ethyl
dithiocarbonate to give diethyl trithiodicarbonate (deꢀ
tected by mass spectrometry) and the corresponding poꢀ
tassium arenethiolate. The latter in turn reacts with the
Received July 16, 2002;
in revised form November 5, 2002
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 263—264, January, 2003.
1066ꢀ5285/03/5201ꢀ278 $25.00 © 2003 Plenum Publishing Corporation