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Zaburdaeva and Dodonov
(m, 6 H). 13C NMR (75.5 MHz, δ): 132.5, 131.3, 128.7, 127.6,
127.2, 125.9, 125.7, 122.6, 97.8, 75.5.
Disulfide 3 and Sꢀphenyl benzenethiosulfonate (4) were
identified by TLC on Silufol UVꢀ254, eluent hexane—ether (9 : 1)
with UV detection.
The conversion of diphenyl disulfide (3) under the same
conditions at a molar ratio substrate : ButOOH : (ButO)3Al =
= 1 : 2 : 1 was 53%, and Sꢀphenyl benzenethiosulfonate (4)
was formed as the only product (Scheme 2).
Methyl phenylethynyl sulfone (2a). To a solution of (ButO)3Al
(3 mmol) and sulfide 1a (3 mmol) in benzene (10 mL), ButOOH
(6 mmol) was added. After 50 min, the formation of methyl
phenylethynyl sulfone (2a) in amount equivalent to that of the
sulfide 1a was determined by GLC and GCꢀMS. After 20 h, only
sulfone 2a was present in the reaction mixture. The solvent and
volatile components were condensed in a trap cooled with liquid
nitrogen. The colorless powderꢀlike residue was hydrolyzed with
aqueous NH4Cl, extracted with ether, the extract was dried with
Na2SO4, and ether was removed. Sulfone 2a was isolated in
a form of colorless crystals, m.p. 65—66 °C. IR, ν/cm–1: 2185 (C≡C);
1304, 1129 (SO2); 687 (C—S).13 HRMS, m/z: 180.0236.
С9H8O232S1. Calculated: M = 180.0245. 1H NMR (400 MHz,
δ): 7.01—7.06 (m, 1 H); 6.82—6.87 (m, 2 H); 6.68—6.73 (m, 2 H);
2.38 (s, 3 H). 13C NMR (75 MHz, δ): 127.7, 127.6, 127.4, 127.3,
117.6, 90.1, 85.6, 45.7.
Scheme 2
With doubled amounts of (ButO)3Al and ButOOH, the
conversion of disulfide 3 increased to 93%, no formation
of the disulfone was observed.
The proposed synthesis method can be used in preparꢀ
ative organic chemistry for the oxidation of other sulfides
to sulfones under mild conditions.
The oxidation of compounds 1b and 3 was performed analoꢀ
gously. The conversion of sulfides into respective sulfones was
monitored by GLC and MS. No formation of sulfoxides was
observed.
The characteristics of phenyl phenylethynyl sulfone (2b) are
presented in Refs 14, 15.
Experimental
SꢀPhenyl benzenethiosulfonate (4) was obtained at the ratio
3 : (ButO)3Al : ButOOH = 1 : 2 : 4. From the reaction mixture
after hydrolysis, a colorless crystalline substance was isolated
without special purification, m.p. 43 °C; according to different
data,16 Sꢀphenyl benzenethiosulfonate (4) has melting point in
a range of 36—53 °C. IR, ν/cm–1: 1325, 1141 (SO2).13 1H NMR
(400 MHz, δ): 7.27—7.24 (m). 13C NMR (75 MHz, δ): 125.8,
129.5, 130.0, 130.9, 131.2, 134.0, 135.9. The obtained sample
coincided by the Rf value with the authentic Sꢀphenyl benzeneꢀ
thiosulfonate sample in TLC analysis.
NMR spectra were recorded on a Varian INOVA 400 instruꢀ
ment in C6D6; IR spectra were recorded on an IR Prestigeꢀ21
spectrometer (Shimadzu) in a thin layer; high resolution GCꢀMS
analysis (HRMS) was performed on a Finnigan MAT 95 inꢀ
strument.
Gas chromatography analysis of the starting sulfides and the
respective sulfones was performed on an Agilentꢀ6890 instruꢀ
ment (capillary column HPꢀ5, 15000×0.25, carrier gas — nitroꢀ
gen); GCꢀMS analysis was performed on the instrument of the
same company equipped with a massꢀdetector Net Workꢀ5973
(column HPꢀ5ꢀMS, carrier gas — helium). Samples were injectꢀ
ed at 70 °С or 90 °С, then the temperature was increased in
15 min to 300 °C. The calculation was made using internal stanꢀ
dard method, the internal standard was nonane.
Benzene (c.p.) was purified by distillation from P2O5 and
stored over metallic sodium. Aluminum triꢀtertꢀbutoxide was
obtained by the reaction of tertꢀbutyl alcohol with aluminum
according to the earlier described procedure10 followed by
sublimation (160—170 °C, 1 Torr). Found (%): Al, 11.52.
С12Н27AlO3. Calculated (%): Аl, 10.96. All operations with
(ButO)3Al were carried out under argon. ButOOH was syntheꢀ
sized according to the earlier described procedure,11 the conꢀ
centration of the latter was at least 99.5—99.8%. Ph2S2 (99%)
(Acros) was used. Methyl and phenyl phenylethynyl sulfides
(1a,b) were synthesized according to the known procedure12 by
metalation of phenylacetylene with butyllithium with subseꢀ
quent treatment of the obtained phenylethynyl lithium with
MeSO2SMe and PhSO2SPh, respectively. Sulfide 1a was puriꢀ
fied by distillation, b.p. 49—51 °C (7.5•10–3 Torr). 1H NMR
(400 MHz, δ): 7.40—7.36 (m, 2 H); 6.95—6.93 (m, 3 H); 1.88
(s, 3 H). 13C NMR (75 MHz, δ): 131.2, 127.8, 127.5, 127.1,
123.5, 91.9, 81.3, 18.3. Sulfide 1b was isolated by column
chromatography, eluent — pentane with addition of 2% triethylꢀ
amine. 1H NMR (400 MHz, δ): 7.41—7.35 (m, 4 H); 7.00—6.85
The authors express their acknowledgment to V. Yu.
Malakhov and A. E. Gavryushin for the help in registraꢀ
tion and interpretation of the spectra and chromatograms.
This work was performed within the collaboration proꢀ
gram "Mikhail Lomonosov II" between the Ministry of
Education and Science of the Russian Federation (Project
No. 2.2.2.3.16148) and German Academic Exchange Serꢀ
vice (Project A/07/72363), and was financially supported
by the Russian Foundation for Basic Research (Project
No. 08ꢀ03ꢀ97050ꢀVolga region_a).
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