Synthesis of Trimethylsilyl Pseudohalides
1275
Potassium cyanide was finely grounded and dried at 1208C under vacuum for
h. PEG400 and zinc iodide are commercially available and used directly
without further disposal.
6
Procedure for the Preparation of TMSNCS
A 100 ml, three-necked, round-bottomed flask equipped with nitrogen inlet
tube was charged successively with 0.5 g of ZnI , 30 ml of CH Cl , 2 g
2
2
2
(
(
0.005 mol) of PEG400, 7.8 g (0.12 mol) of potassium thiocyanide, and 12 g
0.11 mol) of TMSCl. The mixture was partly immersed into the ultrasound
cleanser thermostated at 208C for the period of time designated in Table.1
The process of the reaction was monitored by GC. After the completion of
the reaction, the inorganic solids were filtered off and washed with small
amount of dried CH Cl . After dichloromethane was distilled through a
2
2
[5]
5
-cm Vigreux column, 8.5 g of TMSCN was collected at 142–1448C (lit.
bp 143–1448C). Yield, 86%; purity by GC, 99.5%; IR (KBr, g cm ): 435,
21
6
34, 764, 845, 956, 1257, 1952, 2072, 2964. EI-MS (m/z): 132, 131, 116,
8, 86, 73, 43.
8
TMSNCO was prepared in the same fashion as described for TMSNCS.
[5]
Bp 90–938C (lit. bp 90–928C); yield, 86%; purity by GC, 98.5%; IR (KBr,
g cm ): 525, 620, 645, 761, 850, 1258, 1432, 2281, 2965, 3698. EI-MS
2
1
(
m/z): 115, 100, 72, 70, 43.
TMSCN was prepared in the same fashion as described for TMSNCS. Bp
[5]
1
15–1178C. (lit. bp 114–1178C); yield, 78%; purity by GC, 99.5%; IR
21
(
KBr, g cm ): 640, 770, 855, 1260, 1420, 2190, 2905, 2970. EI-MS (m/z):
9, 84, 73, 54, 43.
9
REFERENCES
1
2
. Livinghouse, T. Trimethylsilyl cyanide. Org. Synth. 1990, Coll. Vol. VII, 517.
. Duboudin, F.; Cazeau, Ph.; Moulines, F.; Laporte, O. A new one-pot synthesis of
silylated cyanohydrins. Synthesis 1982, 212.
3
. Bailey, J. M. Sequential C-terminal degradation of peptides and proteins using
alkali metal salts of lower trialkylsilanes and trialkylamine N-oxide as coupling
reagents and derivatized activated polyethylene supports. U.S. Patent 5254475
(
Chem. Abstr.1994, 121, 77798r).
4
5
6
. Parker, K. A.; Gibbos, E. G. A direct synthesis of primary amides from Grignard
reagents. Tetrahedron Lett. 1975, 981–984.
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con halides, pseudohalides, and sulphides. J. Chem. Soc. 1950, 3077–3089.
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