Bis-Trimethylsilyl trifluoroacetamide

A/,0-Bis(trimethylsilyl)trifluoroacetamide. This reagent is suitable for the silylation of carboxylic acids, alcohols, phenols, amides, and ureas. It has the advantage over bis(trimethylsilyl)acetamide in that the byproducts are more volatile. 

The many derivatizing reagents commercially available include methanolic HC1 and diazomethane for methylation, and iV,(9-bis(trimethylsilyl)trifluoroacetamide (BSTFA), with or without 1% trimethylchlorosilane (TMCS), for silylation. Using BSTFA, hydroxyl moieties also can be silylated, giving the corresponding trimethylsilyl ethers. 

Silylation-promoted oxidationA new method for oxidation of 4-aza-3-ke-tosteroids (3) to the unsaturated lactams 4 involves DDQ (1 equiv.) as the oxidant and a silylating reagent (4 equiv.) such as bis(trimethylsilyl)trifluoroacetamide (2, BSTFA).2 An initial reaction at 20° results in an adduct of DDQ and 3, which on... 

Figure 7.3 Derivatization of organic acid and alcohol compounds by diazomethane (CH2N2 top two reactions) by BSTFA (N, O-bis(trimethylsilyl) trifluoroacetamide middle two reactions), and transmethylation of fatty acid esters by saponification using methanolic sodium hydroxide.

Anhydroalditols can be easily generated by Lewis acid catalysed reduction of the corresponding aldoses or glycosides with triethylsilane (Fig. 2). The reaction requires protection of the hydroxyl groups, which can be performed temporarily by preliminary treatment with bis(trimethylsilyl)-trifluoroacetamide (BSTFA).1... 

Further steps may include derivatisation, necessary when using GC methods for the final detection [29]. Derivatisation has been performed with pentafluorobenzyl bromide [22,30], acetic anhydride [24], or N,0-bis(trimethylsilyl)trifluoroacetamide [25] (see also Chapter 2.1). A liquid-liquid separation with i-hexane and an alkaline aqueous solution proved to be unsuccessful as a clean-up step for alkylphenols, as the compounds ended up in both phases [23]. 

The advantage of trimethylsilyl (TMS) derivatives lies in the simplicity of the derivatization procedure, which is carried out by the addition of N,0-bis(trimethylsilyl)trifluoroacetamide (BSTFA) in acetonitrile and heating for approximately 2 h at 150 °C under anhydrous conditions in a sealed tube. However, there may be problems owing to the formation of multiple derivatives of each amino acid. Another technique involves the formation of n-butyl esters of the amino acids and their subsequent trimethylsilylation by a similar procedure. The n-butyl esters are formed by heating the amino acids for 15 min in n-butanol and HC1 and these are then converted to the A-TMS-n-butyl ester derivatives. A-acyl amino acid alkyl esters are commonly used. Acetylation of the butyl, methyl or propyl esters of amino acids,... 

Krahn et al. [479] developed a similar multi-residue scheme for the determination of organochlorines and PAHs in sediments. In this scheme, the preparation is semi-automated with GPC to separate the biogenic material and the sulfur from both the PAHs and organochlorines in the samples. The sterols were separated and purified with an amino-cyano HPLC column prior to derivatiza-tion with bis(trimethylsilyl)trifluoroacetamide (BSTFA). 

The analysis of codeine, morphine, 6-monoacetylmorphine (6-MAM, a metabohte of heroin), and cocaine is important for many toxicology labs to determine illicit drug use. When analyzing opiates in urine samples, frequently the matrix chosen for drug screening, the conjugated metabolites must be hydrolyzed however, this process can break down 6-MAM (Christophersen et al., 1987). These compounds can be derivatized to increase sensitivity, and both BCD and NPD are used for these assays. Derivatizations used include reaction with N-methyl-N-trimethylsilyltrifluoroacetamide followed by GC-FID (Lin et al., 1994) or with N,0-bis(trimethylsilyl)trifluoroacetamide (Christophersen et al., 1987 Lee and Lee, 1991), PFPA (Christophersen et al., 1987), or heptafluorobutyric anhydride (HFBA) followed by GC-ECD. All these methods show good sensitivity and selectivity. 

Neurosteroids (in this book) Exogenous Chemicals Amphetamine, methamphetamlne. Pentafluorobenzyl bromide Bis(trimethylsilyl) trifluoroacetamide El Purdy et al. (2006) Yonamine et al. 

NBP, 4-(4-nitrobenzyl)pyridine TFTP, 2,3,5,6-tetrafluorothiophenol DDTC, Diethyldithiocarbamate BSTFA, bis (trimethylsilyl) trifluoroacetamide TFAA, trifluo-roacetic anhydride o-PA, o-phthalaldehyde HFBA, heptafluorobutyric anhydride. 

N,N-(Bis-trimethylsilyl)-trifluoroacetamide (BSTFA) with 1% trimethylchlorosi-lane (TMCS) (Pierce). 

TMS, trimethylsilane BSTFA, N,O-Bis(trimethylsilyl)trifluoroacetamide. Other abbreviations as in Tables 29.1 and 29.3. 

Gas chromatographic separation of -agonist residues is generally complicated by the necessity of derivatization of their polar hydroxyl and amino functional groups. Silyl derivatives are preferentially prepared by treating sample extracts with N,0-bis(trimethylsilyl)trifluoroacetamide (470,471,473,475,483, 487), N-metliyl-N-(trimethylsilyl)trifluoroacetamide (482) or N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (473, 487). Pentafluoropropionic anhydride (481), phosgene (484), trimethylboroxine (480), methyl- and butylboronic acid (489), or a combination of N,O bis(trimethylsilyl)trifluoroacetamide with... 

Abbreviations BSTFA, N,0-bis(trimethylsilyl)trifluoroacetamide MTBSTFA, N-methyl-N-(tetr.-butyldimethylsilyl)trifluoroacetamide ... 

NBD-CI, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole MSTFA, N-methyl-N-(trimethylsilyl)trifluoroacetamide BSA, N, O-bis(trimethylsily-l)acetamide MTBSTFA, N-methyl-N-(tetr.-butyldimethylsily)trifluoroacetamide BSTFA, N,0-bis(trimethylsilyl)trifluoroacetamide HFB, heptafluorobutyric acid SFE, supercritical-fluid extraction. 

Subsequent ring closure with ammonia, hydrogenation using PtO2/H2 or Pd-C/H2 [32], DCC/HOBt-mediated amidation with t-butyl amine, followed by dehydrogenation using benzeneseleninic anhydride or 2,3-dichloro-5,6-dicyano-l, 4-benzoquinone (DDQ)/bis(trimethylsilyl)-trifluoroacetamide (BSTFA) [33] combination afforded 4. 

The Ti-MCM-41 sample, TM-1, was synthesized according to the method of Koyano and Tatsumi [8]. The hydrophobic Ti-MCM-41 catalyst, TM-2, was prepared by silylation of TM-1 with N,0-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The silylation was carried out following the procedure described by D Amore and Schwarz [11], The procedure for the silylation of catalyst with N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) is as follows A solution of 1 g MSTFA (99%, Aldrich) in 10 g of toluene was added to the sample TM-1 (0.5 g). The mixture was stirred at room temperature for 2h, then the treated catalyst was filtered, washed with toluene and dried in air for 8 h to give the sample TM-3. 

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