1892
M. Tajbakhsh et al. / Tetrahedron Letters 45 (2004) 1889–1893
O
S
2
,6-DCPCC
Ph CH SH
+
Ph
S
Me
PhCH S SCH Ph
Ph
Me
2
2
2
+
rt / MeCN
1
2
3
4
>
93%
<4%
Cl
Cl
2
,6-DCPCC
+
rt / MeCN
N
SH+
N
S
>
S
N
SCH Ph
SCH Ph
2
2
O
5
6
7
8
95%
<3%
Scheme 3.
Table 3. Camparison of 2,6-DCPCC with some of the other reagents for oxidation of thiols and sulfides
Substrate
Conditions
Time (min)/Yield (%)
Reagent
Reference
PhSH
PhSH
PhSH
CH
CH
CH
3
3
2
CN/rt
CN/rt
8/93
2,6-DCPCC
––
3c
3l
120/99
114/97
10/79
270/93
10/95
60/99
90/98
60/100
15/89
Bu
PCC
(NH
3
SnOMe/FeCl
3
2
Cl /rt
PhSH
Solid state
4
)
2
S
2
O
8
3m
8
PHSH
PhSMe
PhSMe
PhSMe
PhSMe
PhSMe
CH
CH
CH
CH
CH
CH
3
3
3
2
2
2
CN/20 ꢁC
CN/rt
Caroꢀs acid/SiO
2
2,6-DCPCC
––
6h
6i
OH/20 ꢁC
MnO
2
–TMSCl
N) O8
Cl
Cl
Cl
2
2
2
/rt
/rt
(n-Bu
CAN
4
2 2
S
6j
NaClO
2
/Alumina
6k
General procedure for the oxidation of thiols with 2,6-
DCPCC. In a round-bottomed flask, a solution of thiol
References and notes
(
1 mmol) in MeCN (10 mL) was treated with 2,6-dicar-
1. Bodanszky, M. Principles of Peptide Synthesis; Springer:
Berlin, 1984; Chapter 4.
boxypyridinium chlorochromate (1 mmol) and the mix-
ture stirred at room temperature. The progress of the
reaction was monitored by GC or TLC. The reaction
2
3
. Johnson, J. R.; Bruce, W. F.; Dutcher, J. D. J. Am. Chem.
Soc. 1943, 65, 2005–2009.
. (a) Liu, K. T.; Tong, Y. C. Synthesis 1978, 669–670; (b)
Wallace, T. J. J. Org. Chem. 1966, 31, 3071–3079; (c) Sato,
T.; Otera, J.; Nozaki, H. Tetrahedron Lett. 1990, 31, 3591–
2 2
mixture was filtered and washed with CH Cl (20 mL).
The filtrate was washed with water (3 · 10 mL), dried,
and evaporated to give the corresponding disulfide in
almost pure form. If necessary, the product was purified
3
594; (d) Pryor, W. A.; Church, D. F.; Govindan, C. K.;
Crank, G. J. Org. Chem. 1982, 47, 156–159; (e) Schaeffer, J.
R.; Goodhue, C. D.; Risle, H. A.; Stevens, R. E. J. Org.
Chem. 1967, 32, 392–395; (f) Drabowicz, J.; Mikolajczyk,
M. Synthesis 1980, 32–34; (g) Ali, M. H.; McDermott, M.
Tetrahedron Lett. 2002, 43, 6271–6273; (h) Aida, T.;
Akasaka, T.; Furukawa, N.; Oae, S. Bull. Chem. Soc.
Jpn. 1976, 49, 1441–1448; (i) McKillop, A.; Koyuncu, D.
Tetrahedron Lett. 1990, 31, 5007–5010; (j) Choi, J.; Yoon,
N. M. J. Org. Chem. 1995, 60, 3266–3267; (k) Ramadas, K.;
Srinivasan, N. Synth. Commun. 1996, 26, 4179–4184; (l)
Salehi, P.; Farrokhi, A.; Gholizadeh, M. Synth. Commun.
2 2
by column chromatography (eluent: hexane/CH Cl ).
General procedure for the oxidation of sulfides with 2,6-
DCPCC. In a round-bottomed flask, a solution of sul-
fide (1 mmol) was treated with 2,6-dicarboxypyridinium
chlorochromate (2 mmol) and the mixture was stirred at
room temperature. The progress of the reaction was
monitored by GC or TLC. The reaction mixture was
filtered and the solid material was washed with CH Cl
2
2
(20 mL). If necessary, the product was purified by col-
umn chromatography (eluent: hexane/EtOAc).
2
001, 31, 2777–2781; (m) Varma, R. S.; Meshram, H. M.;
Dahiya, R. Synth. Commun. 2000, 30, 1249–1255; (n)
Noureldin, N. A.; Caldwell, M.; Hendry, J.; Lee, D. G.
Synthesis 1998, 1587–1589; (o) Evans, B. J.; Doi, J. T.;
Musker, W. K. J. Org. Chem. 1990, 55, 2337–2344; (p)
Shaabani, A.; Lee, D. G. Tetrahedron Lett. 2001, 42, 5833–
Acknowledgement
5
836; (q) Iranpoor, N.; Firouzabadi, H.; Pourali, A. R.
Tetrahedron 2002, 58, 5179–5184; (r) Shah, A. S. T.; Khan,
M. K.; Fecker, M.; Volter, W. Tetrahedron Lett. 2003, 44,
6789–6791.
Financial support of this work from the Research Council
of Mazandaran University is gratefully acknowledged.