Protection of Alcohols with Hexamethyldisilazane
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EXPERIMENTAL
Chemicals were obtained from Merck and Fluka. FT-IR spectra were
1
recorded with a Perkin Elmer RXI spectrophotometer. H NMR spectra
were recorded with a Bruker Avance DPX 250 MHz instrument. The
products were purified by column chromatography and the purity of the
products was determined by GC on a Shimadzu GC 10-A instrument
using n-octane as internal standard or by thin layer chromatography
using silica gel polygram on SIL G/UV 254 plates.
General Procedure for Protection of Alcohols
To a flask containing La(NO3)3 · 6 H2O (0.004 g, 0.01 mmol) in dry ace-
tonitrile (3–5 mL), HMDS (0.576 g, 1 mmol) was added under stirring
at room temperature. Subsequently, the alcohol (1 mmol) was added.
GC analysis showed that the reaction was completed immediately. The
solvent was evaporated under reduced pressure. Column chromatogra-
phy of the crude product on silica gel using n-hexane as eluent gave the
corresponding trimethylsilyl ether in quantitative yield.
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