Bis trifluoroacetamide

In a study by Stresser and co-workers, the effect on tumor modulation by 227 has been investigated. HPLC on liver extracts from Fisher 344 rats revealed two major compounds, 3,3 -bisindolylmefliane (133) and a linear trimer, together with a < l(KX)-fold lower content of 4 in comparison with the two major substances. The HPLC isolate was derivatized with /V-methyl-/V-bis(trifluoroacetamide) that, upon MS detection, gave a compound identical to /V,W -ditrifluoroacetylindolo-[3,2-()]carbazole. The content of 4 in this system was estimated to be 0.(XKX)13% of the total dose of 227 given. Thus, it was concluded that the beneficial effect of oral distribution of 227 is due to the total content of derivatives formed (95MI5). 

Gas chromatographic separation has not gained wide acceptance in spite of being quite sensitive and specific. This mode of separation is complicated by the need for derivatization of sulfonamide residues before gas chromatographic analysis. These drugs are subjected to derivatization via methylation with diazomethane (223, 224, 253, 254, 271), or double derivatization via methylation followed either by silylation with Ai-methyl-Ai-trimethylsilytrifluoroacetamide (261) or by acylation with A-methyl-bis(trifluoroacetamide) (256). This derivatization step is required not only to form the volatile derivatives of the sulfonamides but also to improve their chromatographic properties (thermal stability and decreased polarity). 

The acylation of —NH2, -OH and —SH groups with bis(acetylamines), e.g., N-methyl-bis(trifluoroacetamide), proceeds under mild conditions and does not require an acidic medium [71] (Scheme 4.14). 

Analysis of heroin does not require derivatization however, analysis of other opioids requires derivatization prior to GC/MS analysis. Commonly used derivatization reagents include BSTFA with 1% TMCS, PFPA, MSTFA, acetic anhydride (AA), trifluoroacetic anhydride (TFAA), and N-methyl-bis-trifluoroacetamide (MBTFA). For ease of analysis and stability of the derivatives, the authors prefer BSTFA with 1% TMCS or MBTFA. 

Saady et al. preferred acylation of morphine with N-methyl-bis-trifluoroacetamide for its determination in blood and serum. Extraction was performed at pH 9.9 with toluene hexane isoamylalcohol (78 20 2), and the extraction efficiency of the method was found to be between 55 and 60 %. The use of nalorphine as an internal standard, coupled with the sensitivity of the GC-MS, did not necessitate further extraction. Quantitative determinations were carried out from less than 0.2 mg/1 to at least 8 mg/1 for morphine and codeine with good results. 

King and Krespan (1974) used the bis-trifluoroacetamide derivative of a diamine rather than the bis-sulfonamide to prepare a diaza-crown. The tri-... 

Other amide derivatives have been used to prepare macrocycles. King and Krespan, for example, used the bis(trifluoroacetamide) derivatives rather than the bis(/7-toluenesulfonamides) for the preparation of diaza-crowns (method E-12) (King and Krespan, 1974). Removal of the trifluoroacetyl group was accomplished by a simple hydrolysis step rather than the more difficult re-... 

Acylation converts compounds with active hydrogen, for example, in the -SH into thioesters by reaction with carboxyl acids or their derivatives. The presence of a carbonyl group next to the halogenated carbon increases the ECD response. For thiols, using Af-methyl-bis(trifluoroacetamide) (MBTFA) is recommended. 

Heroin and metabolites have been isolated from the hair of heroin addicts with a single-step liquid-liquid extraction procedure. Under mild alkaline conditions, a mixture of toluene-heptane-isoamyl alcohol is added to the specimen and, after mixing, the organic phase is removed, evaporated, and deri-vatized with N-methyl-bis(trifluoroacetamide). The derivatized extract is subjected to GC-MS analysis. 

Poly(methacrylic acid-ethylene glycol dimetracrylate) monolith microextraction Methyl-bis(trifluoroacetamide)... 

A -methyl bis(trifluoroacetamide). The resulting 1,5-diol diesters 116 were applied crude to the GLC colunui (Section 8.6, Fig. 15). 

The syntheses of all four stereoisomers of the 1,3-diol diesters 117 comprised a total of 4 X 2 steps (Scheme 23). Moreover, the four initial reactions were described in the literature. These parameters were so reassuring that MLH did not ponder the alternative of another killing-two-birds-with-one-stone approach, akin to the one that had furnished the 1,5-diol diesters 116 (Scheme 22). The first transformation of the syntheses of Scheme 23 was the NaBHt reduction of the aldols 36a anti) and 36a (ent,anti) by an in-house procedure " and the LiBli reduction of the aldols 36b ent,syn) and 36b (syn) following another literamre protocol. The second transformation was the respective bis(trifluoroacetate) formation. It was realized by treatment with an excess of Af-methyl bis(trifluoroacetamide). The resulting 1,3-diol diesters 117 were applied cmde to the GLC column (Section 8.6, Fig. 16). 

Williams showed that the heptafiuorobutyryl derivatives of the three unphosphorylated forms of vitamin Bg may be separated by GLC. The highly electronegative nature of the derivatives made electron capture detection suitable for the sensitive assay of the Bg vitamers (152). Patzer and Hilker used N-methyl-bis-trifluoroacetamide (MBTFA) to form derivatives of B vitamers which could be separated by GLC and quantitated by flame ionization detection (153). However, the sensitivity of the flame ionization detector was insufficient to allow quantitation of the Bg vitamers in biological samples. Lim et al. showed that the MBTFA derivatives of B vitamers could be measured at increased sensitivity with a GLC equipped with a N electron capture detector (154). Lim and coworkers used this method to determine the vitamin Be content of bread, skimmed milk, and peas (154). 

PX was isolated from Fucus serratus (Brittany coast) as described before [ 3 ], then deacylated with 0.1 N NaOH in methanol for 20 min at room temperature and hydrolyzed with 6 N HCl for 5 hours at 100°C. The product was treated with W-methy 1 -W-trimethylsi ly 1 trifluoroacetamide (MSTFA) followed by W-methyl-bis-trifluoroacetamide (MBTFA). N-(2-hydroxyethyl)glycine (HEG) was synthesized by reacting 2-bromoacetic acid ethylester and ethanolamine in a molar ratio of 1 10, respectively, in tetrediydrofurane. The product was treated with MSTFA and MBTFA and the 0,0-bis-trimethylsilyl-W-trifluoroacetyl derivative characterized by GC-MS. 

Bis(trifluoroacetamide), B-00461 [Bis(trifluoroacetoxy)iodo]benzene, B-00462 3,3 -Bis(trifluoromethyl)dithizone, B-00463 A-(3,5-Bis(trifluoromethyl)phenyl)-3,5-... 

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