50
N. Iranpoor, B. Zeynizadeh
SHORT PAPER
ols are rare.18 We studied the possibility of coupling of
1,3-propanedithiol to 1,2-dithiacyclopentane with our
method under high dilution conditions.19 The reaction was
found to give some polymeric materials, but 1,2-dithi-
acyclopentane was also obtained in 55% yield.
Acknowledgement
We are grateful to Shiraz University Research Council for partial
support of this work and Professor H. Firouzabadi for discussion
and assistance.
In order to see the efficiency of other Lewis acids for this
catalytic transformation, coupling of thiophenol with dif-
ferent metal halides were studied. The results are tabulat-
ed in Table 3.
References
(1) Cornelis, A.; Laszalo, P. Synthesis 1985, 909.
(2) McKillop, A.; Koyuncu, D. Tetrahedron Lett. 1990, 31, 5010.
(3) (a) Firouzabadi, H.; Iranpoor, N.; Parham, H.; Sardarian, A.;
Toofan, J. Synth.Commun. 1984, 14, 717.
(b) Firouzabadi, H.; Iranpoor, N.; Hajipoor, G.; Toofan, J.
Synth. Commun. 1984, 14, 1033.
(c) Firouzabadi, H. and Mohammadpour, I.B., Bull. Chem.
Soc. Jpn. 1992, 65,1131.
(d) Firouzabadi, H., Iranpoor, N., Kiaeezadeh, F. and Toofan,
Table 3 The Effect of 0.1 Molar Equivalents of Different Lewis Acids
for Coupling of Thiophenol with Equimolar of NaI in Acetonitrile at
Room Temperature.
Entry
Lewis Acida
Time (h)
Conversion (%)b
J., Tetrahedron 1986, 42, 719.
(e) Firouzabadi, H. and Iranpoor, N., Synthetic Commun.
1984, 14, 875.
(4) Gasco, A.M., Medna, C. and Gasco, A., Synthetic Commun.
1
3
4
5
FeCl3
CrCl3
CoCl2 6 H2O
SnCl2 2 H2O
ZrCl4
TiCl4
0.1
6
5
1
10
10
100
50
30
90
10
40
•
1994, 24, 2707.
•
(5) Ramadas, K. and Srinivasan, N., Synthetic Commun. 1995, 25,
227.
(6) Cornelis, A. and Laszlo, P. Synlett 1994,155.
(7) Askew, S.C., Barnett, D.J, McAninly, J. and Williams,
D.L.H., J. Chem. Soc. Perkin Trans. 2 1995, 741.
(8) Barnet, D.J., Rios, A. and Williams, D.L.H., J. Chem. Soc.
Perkin Trans. 2 1995, 1279.
a
The conversion yield was found to be 0%, when chloride of Ni, Zn,
Al, Ce(III), Pb(II), Mn(II), Hg(I), Nb(V), Cd(II) and Mg(II) were
used as catalyst.
GC Yield.
b
(9) Dick, A.P., Swift, H.R., Williams, D.L.H., Butler, A.R.,
Al-Sa,doni, H.H. and Cox, B.G. J. Chem. Soc., Perkin Trans.
2 1996, 481.
(10) Meshram, H.M. and Kache, R., Synthetic Commun. 1997, 27,
2403.
(11) Hirano, M., Yakabe, S., Fukami, M. and Morimoto, T., Synt-
hetic Commun. 1997, 27, 2783.
(12) Iranpoor, N., Salehi, P. and Shiriny, F., J. Org. Prep. Proc.
In conclusion, this catalytic method is very simple and ef-
ficient for coupling of thiols. The easy procedure and sim-
ple workup, simplicity, availability of reagents, short
reaction times and excellent yield of the products make
this method a useful addition to the present methodolo-
gies.
Inter. 1995, 27, 216.
(13) Firouzabadi, H., Iranpoor, N. and Zolfigol, M.A., Synthetic
Commun. 1998, 28, 1179.
(14) Ogura, F., Yamguchi, H., Ostubo, T. and Tanaka, H. Bull.
Products were characterized by comparison of their physical data
with those of known samples. All yields refer to isolated products.
IR spectra were recorded on a Perkin Elmer 781 and Pye Unicam
8725 spectrometers. NMR spectra were recorded on a Bruker DPX
250 spectrometer. The purity determination of the substrates and re-
action monitoring were accomplished by TLC on silica gel poly-
gram SILG/UV 254 plates or by GC on a Shimadzu GC-14A
instrument.
Chem. Soc. Jpn.1982, 55, 641.
(15) (a) Huang, M. and Chan, C.C. Synthesis 1982,1091.
(b) Aldrich Hand Book of Fine Chemicals 1996Ð97.
(16) (a) Colichman, E.L. and Love, D.L., J. Am. Chem. Soc. 1953,
75, 5736.
(b) Tinyakova, E.I., Khrennidova, E.K., Dolgoplosk, B.A.,
Zhur. Obschei Khim., 1958, 28, 1632.
(c) Firouzabadi, H., Mohager, D. and Entezari-Moghadam,
M., Bull. Chem. Soc. Jpn., 1988, 61, 2185.
Oxidative Coupling of Thiophenol with FeCl3,
Phenyl Disulfide; Typical Procedure
(17) Drabowicz, J. and Mikolajczyk, M. Synthesis 1980, 32.
(18) Wallace, T.J. J. Org. Chem. 1966, 31, 1217.
(19) The reaction was performed between 1,3-propanedithiol
(0.216 g, 2 mmol), FeCl3 (0.048 g, 0.3 mmol) and NaI (0.3g,
2 mmol) in MeCN (100 mL) at r.t. After 20 min the product
was isolated according to the procedure and identified by its
1H, 13C NMR and mass spectral data.
To a solution of thiophenol (1.1 g, 10 mmol) in MeCN (30 mL)
were added NaI (0.299 g , 2 mmol) and FeCl3 (0.162 g, 1 mmol).
The resulting mixture was stirred at r. t. for 6 min. After completion
of the reaction, the solvent was evaporated and 1% aq solution of
Na2S2O3 (30 mL) was added. The mixture was then extracted with
CH2Cl2 (3 × 40 mL) and dried (Na2SO4). The solvent was evaporat-
ed and the residue was chromatographed on a short column of silica
gel using CCl4 as the eluent. The pure product was obtained as col-
orless crystals (1.06 g, 97%).
Synthesis 1999, No. 1, 49Ð50 ISSN 0039-7881 © Thieme Stuttgart · New York