N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide

Chemical properties

clear colorless to slightly yellow liquid

Physical properties

bp 168–170°C; d 1.12 g cm?3.

The Uses of N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide

N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide is a silylating agent used in the derivatization of various organic compounds (such as amino acids) for gas chromatogography-mass spectrometry (GC-MS) analysis.

The Uses of N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide

In the presence of 1% of t-butyldimethylchlorosilane as the catalyst, N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (BSMTFA) functions as an extremely reactive t-butyldimethylsilylating reagent for alcohols, amines, carboxylic acids, and thiols. Silylation is generally completed within 5 min at 25°C in acetonitrile. This amide is more reactive than N-(t-butyldimethylsilyl)-N-methylacetamide.
In the protection of a hydroxy group, the resultant tbutyldimethylsilyl (TBDMS) ethers are stable under the conditions for acetate saponification and hydrogenation.These silyl ethers also remain intact towards the Jones reagent and Wittig reagents. The TBDMS ethers are approx. 10 times more stable against hydrolysis than the corresponding trimethylsilyl (TMS) ethers.Selective removal of the TBDMS group can be accomplished by use of dilute acetic acid or tetra-n-butylammonium fluoride in THF at 25°C.
Silylation of ketones by use ofBSMTFAoccurs in triethylamine and DMF at 40–60°C to give the corresponding silyl enol ethers in good to excellent yields (eq 1).In addition, silyl ether formation takes place in N-hydroxysuccinimide (88% yield) and Nhydroxypyrrole (99% yield) by use of BSMTFA in THF.

The Uses of N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide

N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tert-butyldimethylchlorosilane is commonly used for the preparation of N-tert-butyldimethylsilyl ethanolamines resulting from the hydrolysis of nitrogen mustards. It is also used for selective O-silylation of N,O-diacylhydroxyl amines.

Definition

ChEBI: An N-silyl compound that is N-methyltrifluoroacetamide in which the amide nitrogen is replaced by a tert-butyldimethylsilyl group.

Preparation

obtained in 91% yield by reaction of N-methyl-2,2,2-trifluoroacetamide (1.0 equiv) in benzene and acetonitrile (1:1 v/v) with NaH (1.0 equiv) and then with t-BuMe2SiCl (1.2 equiv) at 4°C.

General Description

N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide is a silylating reagent which replaces the active hydrogen with tert-Butyldimethylsilyl group. The tert-Butyldimethylsilyl derivatives are found to be more resistant to hydrolysis and stable compared to trimethylsilyl (TMS) derivatives. This reagent is suitable for GC-MS analysis since it produces mass spectra, which can be easily interpreted. It is widely used for the silylation of different alcohols, thiols, phenols, carboxylic acids, amines, and amides.