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2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
Silica-Gel Supported Potassium Thioacetate
3823
used supported reagent and removing the solvent under vacuum, and are
generally spectroscopically pure.
EXPERIMENTAL
Preparation of supported reagent AcSK/SiO : Silica-gel supported
2
potassium thioacetate was prepared as follows. Silica-gel (Wakogel
C-200(Wako pure chemical ind. Ltd.), 8.86 g) was added to a solution
of potassium thioacetate (10 mmol, 1.14 g) in methanol, and the mixture
was stirred at room temperature for 0.5 h. The methanol was removed by
rotary evaporator under reduced pressure, and the resulting reagent was
dried in vacuo (10 mmHg) at room temperature for 1 h.
In a typical procedure, a mixture of benzyl bromide (5 mmol) and
AcSK/SiO (7.5 mmol, 7.5 g) was stirred in benzene at room temperature
2
for 1 h, and then filtered to remove the uesd supported reagents. The
filtrate was evaporated to afford the product, benzyl thioacetate, in
9
1% yield, and the purity was >99%.
ꢁ
b. liquid; IR(neat): 1691 cm . H NMR(CDCl ) ꢀ 2.31 (3H, s), 2.33
3
1 1
2
(
3H, s), 4.08 (2H, s), 7.10 (2H, d, J ¼ 8Hz), 7.17 (2H, d, J ¼ 8Hz).
þ
MS(EI). m/z ¼ 180(M ).
ꢀ
ꢁ1
1
2
d. M.p. 53–54 C. IR(KBr): 2233, 1685 cm
.
H NMR(CDCl3)
ꢀ
2.37 (3H, s), 4.13 (2H, s), 7.41 (2H, d, J ¼ 8Hz). 7.59 (2H, d, J ¼ 8Hz).
þ
MS(EI) m/z ¼ 191(M ).
ꢀ
ꢁ1
1
r. M.p. 43–44 C. IR(KBr): 1695, 1684 cm . H NMR(CDCl ) ꢀ
2
3
2
7
.41 (3H, s), 4.41 (2H, s), 7.48 (2H, t, J ¼ 8Hz), 7.60 (1H, d, J ¼ 8Hz),
þ
.99 (2H, d, J ¼ 8Hz). MS(EI) m/z ¼ 194(M ).
ꢀ
ꢁ1 1
c. M.p. 52–53 C. IR(KBr): 1662 cm . H NMR(CDCl ) ꢀ 4.30 (4H,
3
3
s), 7.27 (3H, m), 7.38 (1H, s), 7.43 (4H, t, J ¼ 8Hz), 7.56 (2H, d, J ¼ 8Hz),
þ
7
.96 (4H, d, J ¼ 8Hz). MS(EI) m/z ¼ 378(M ).
ꢀ
[11]
ꢀ
ꢁ1
3
f. M.p. 84–85 C (Lit.
79–80 C). IR(KBr): 1697, 1657 cm .
1
H NMR(CDCl ) ꢀ 4.59 (2H, s), 7.46 (2H, t, J ¼ 8Hz), 7.50 (2H, t,
3
J ¼ 8Hz), 7.59 (1H, t, J ¼ 8Hz), 7.61 (1H, t, J ¼ 8Hz), 8.00 (2H, d,
þ
J ¼ 8Hz), 8.07 (2H, d, J ¼ 8Hz). MS(EI) m/z ¼ 256(M ).
REFERENCES
1
. Mukaiyama, T.; Araki, M.; Takei, H. Reaction of S-(2-pyridyl)
thioates with grignard reagents. A convenient method for the pre-
paration of ketones. J. Am. Chem. Soc. 1973, 95, 4763–4765.