Trimethylsilyl acetamide

A newer method for the preparation of nitronic esters, namely utilizing the (9-trimethyl-silyl ester, has been reported and these are prepared by the reaction of alkylnitro compounds and (V,(V-bis(trimethylsilyl)acetamide. These nitronic esters also undergo cycloaddition with alkenes to produce isoxazolidines (equation 54) (74MIP41601, 74DOK109, 78ACS(B)ll8). 

Me3SiNHS020SiMe3, CH2CI2, 30°, 0.5 h, 92-98% yield. Higher yields of trimethylsilyl derivatives are realized by reaction of aliphatic, aromatic, and carboxylic hydroxyl groups with A, <9-bis(trimethylsilyl)sulfamate than by reaction with N,<9-bis(trimethylsilyl)acetamide. ... 

A,<9-Bis(trimethyIsilyl)trifluoroacetamide. The reagent is suitable for the silylation of carfjoxylic acids, alcohols, phenols, amides, and ureas. It has the advantage over bis(trimethylsilyl)acetamide in that the byproducts are more volatile. 

Trimethylsilyl acetamide [13435-12-6] M 131.3, m 38-43", 52-54 , b 84 /13mm, 185-186 /atm. Repeated distillation in an inert atmosphere, all operations to be performed under anhydrous atmosphere. In the presence of moisture trimethylsilanol (b 31-34 /26mm) is formed and is a likely impurity (check by NMR). [Chem Ber 96 1473 1963.]... 

TMSOCH2CH2OTMS, TfOH or FsOH (fluorosulfonic acid), BTMSA [bis(trimethylsilyl)acetamide] orBTMSU [bis(trimethylsilyl)urea], 76-97% yield-" ... 

DBU, A,0-bis(trimethylsilyl)acetamide." Thiophosphorylated derivatives are cleaved more rapidly than the phosphorylated counterpart. 

In another example treating anilines 40 with acetone under similar conditions gave the desired quinoline 41 as a single regioisomer. It has been reported that the addition of silylating reagents, in particular bis(trimethylsilyl)acetamide, may be beneficial for these types of substrates. ... 

Use of bis(trimethylsilyl)acetamide and bis(trimethylsilyl)urea for protection and as control reagents in reactions with participation of heterocycles 98S357. 

Treatment of the substrate (34) with catalytic (Ph3P)4Pd and dppe provided the desired bicyclo[3.3.0]octanes (35) and the acetate elimination product (36). The choice of ligand is crucial in this case since using only dppe or Ph3P increased the amount of (36). On the other hand addition of BSA (N,0-bis(trimethylsilyl) acetamide) minimized this side product (Scheme 2.12) [24]. 

Preparation of 7-(D-0t-phenyigiycyiamido)-3-chioro-3-cephem-4-carboxyiic acid To a suspension of 280 mg (1.2 mmol) of 7-amino-3-chloro-3-cephem-4-carboxylic acid in 14 ml of acetonitrile was added with stirring at room temperature 0.5 ml of N, 0-bis-(trimethylsilyl)acetamide to form the soluble disilylmethyl derivative thereof. The solution was cooled to 0°C and was slowly added to a solution of the mixed anhydride formed by reacting 408 mg (1.5 mmol) of methyl-3-a-carboxybenzylaminocrotonate sodium salt with 161 mg (1.7 mmol) of methyl chloroformate in the presence to 2 drops of N, N-dimethylbenzyl amine in 7 ml of acetonitrile. 

A suspension of 37.3 g (0.1 mol) of 7/3-amino-3-methoxy-3-cephem-4-carboxylic acid hydrochloride dioxanate in 500 ml methylene chloride is stirred for 15 minutes at room temperature under an argon atmosphere and treated with 57.2 ml (0.23 mol) of bis-(trimethylsilyl)-acetamide. After 45 minutes the faintly yellow slightly turbid solution is cooled to 0°C and treated within 10 minutes with 31.2 g (0.15 mol) of D-Ct-amino-Ct-d, 4-cyclohexadienyl (acetyl chloride hydrochloride. Thirty minutes thereafter 15 ml (about 0.21 mol) of propylene oxide is added and the mixture is further stirred for 1 hour at 0°C. A cooled mixture of 20 ml of absolute methanol in 200 ml of methylene chloride is added within 30 minutes, after another 30 minutes the precipitate is filtered off under exclusion of moisture, washed with methylene chloride and dried under reduced pressure at room temperature. The obtained hygroscopic crystals of the hydrochloride of 7j3-[D-a-(1,4-cyclohexadienyl)acetylamino] -... 

Methoxyimino-2-(2-amino-1,3-thiazol-4-yl)acetic acid Bis(Trimethylsilyl)acetamide 7-Aminocephalosporanic acid... 

Phosphorus oxychloride (2.0 g) was added at one time at 5°C to 10°C to a suspension of 2-methoxyimino-2-(2-amino-1,3-thiazol-4-yl)acetic acid (syn isomer) (2 g) in dry ethyl acetate (20 ml). After stirring for 20 minutes at 7°C to 10°C, bis(trimethylsilyl)acetamide (0.4 g) was added thereto at the same temperature. After stirring for 10 minutes at 7°C to 10°C, phosphorus oxychloride (2.0 g) was dropwise added thereto at the same temperature. The resulting mixture was stirred for 10 minutes at 7°C to 10°C, and dry dimethylformamide (0.8 g) was dropwise added thereto at the same temperature. The mixture was stirred for 30 minutes at 7°C to 10°C to give a clear solution. On the other hand, trimethylsilylacetamide (7.35 g) was added to a suspension of 7-aminocephalosporanic acid (2.45 g) in dry ethyl acetate (8 ml), after which the mixture was stirred at 40°C to give a clear solution. 

BIs-triethylammonium pyrophosphate Adenosine triphosphate Bis(trimethylsilyl) acetamide Cefaclor Cefroxadine Ceftizoxime... 

A -[(l,2 -trimetliylpropy))carboniinidoyl]-4-pyridinamine (C12H,7N3 672J6-4S-0) see Pinacidil 23,5-trimethylpyridine N-oxide (CgH, NO 74409-42-0 see Omeprazole 13,4-trimethylpyridiniuni iodide (CgH 2lN 6283-41-6) see Pentazocine iV-(trimethylsilyl)acetamide... 

To prepare the corresponding cytosine containing nucleoamino acid 9, N -Boc cytosine was first silylated using N,0-bis(trimethylsilyl)acetamide (BSA) under carefully controlled conditions to produce mono-silylated-N -Boc cytosine 7. The mono-silylated product 7 undergoes l2-mediated nucleosidation with the O-MTM... 

Pd-catalyzed asymmetric allylic alkylation is a typical catalytic carbon-carbon bond forming reaction [ 126 -128]. The Pd-complex of the ligand (R)-3b bearing methyl, 2-biphenyl and cyclohexyl groups as the three substituents attached to the P-chirogenic phosphorus atom was found to be in situ an efficient catalyst in the asymmetric allylic alkylation of l-acetoxy-l,3-diphenylprop-2-en (4) with malonate derivatives in the presence of AT,0-bis(trimethylsilyl)acetamide (BSA) and potassium acetate, affording enantioselectivity up to 96% and quantitative... 

Thioethers 210 are smoothly formed upon cyclization of silyl nitronates 209, generated in situ from the nitro compounds 208, on treatment with N,0-bis(trimethylsilyl)acetamide (BSA, Scheme 24) [57]. Fluorodesilylation of 210 gave the AT-oxide 212, presumably via highly reactive aldehyde 211, which was reduced to the target compound actinidine 213 in an overall 27% yield. 

Alternative silylating reagents such as N,0-bis(trimethylsilyl)acetamide 22a (BSA) [39-43], N,0-bis(trimethylsilyl)trifluoracetamide 22b (BSTFA) [44], or N,N-bis(trimethylsilyl)formamide 22c (BSF) [41, 46], in which the N- and O-trimethyl-silyl groups are in equilibrium [45] (Scheme 2.4), are much more powerful silylating reagents [40, 45] but are more expensive than FIMDS 2, because they are usually prepared by heating formamides or acetamides with TCS 14/triethylamine... 

It is obvious that N,0-bis(trimethylsilylated)acetamides or N,0-bis(trimethyl-silylated)formamides 22 or N,0-bis(trimethylsilyl)benzamide 296 should react likewise with the hydrochlorides or hydriodides of primary or secondary amines or with the free amines in the presence of equivalent amounts of e.g., NH4CI or NH4I to give the corresponding amidinium salts. 

Silylated pyrrohdone 388 reacts with formaldehyde to give 429 [41] whereas N-trimethylsilylsucdnimide 201 reacts with formaldehyde only in the presence of MesSiONa 96 at 100°C to give N-trimethylsilyloxymethylenesuccinimide ]42]. The silylating agent BSA 22a with formaldehyde at 75 °C gives the 0,N-acetal 430 [41]. Hydrated ninhydrin 431 is converted by N,0-bis-(trimethylsilyl)acetamide 22 a to the 0,N-acetal 432 ]43] (Scheme 5.12). 

A mixture of sarcosine (45 mg, 0.5 mmol) and bis(trimethylsilyl)acetamide 22a (272 iL, 1.1 mmol) in 0.5 mL acetonitrile is stirred at room temperature for 1 h and at 40 °C for 30 min to give 441, which is then combined with a solution of the glyoxamide 440 in 1 mL abs. toluene. The resulting mixture is heated under reflux for 18 h, cooled, diluted with CHjClj, washed with 1 M NaOH, and the aqueous layer is extracted with CH2CI2. The combined organic layers are washed with brine, dried, concentrated, and purified by chromatography to give 40 mg (40%) 444 as a yellowish oil [49] (Scheme 5.89). 

N,0-bis(trimethylsilyl)acetamide (BSA, 22 a 2.5 mmol) is added to 1-nitro-naphthalene 1026 (1 mmol) and sulfone 1027 (1 mmol) in acetonitrile (2 mL) and the resulting mixture is stirred until dissolution occurs. After addition of DBU (776 pL, 5 mmol, in one portion) the reaction mixture is stirred at room temperature for 24 h then poured into a cold aqueous solution of NH4CI in H2O and extracted with CH2CI2 (3x20 mL). The extracts are washed with 20 mL brine, dried with MgS04, and evaporated. On addition of 3 mL chloroform crystalline 1028, m.p. 227-228°C (82%) is obtained [97] (Scheme 7.64). 

BSTFA provided the highest yield of product in comparison to other silylating agents. BSA [bis(trimethylsilyl)acetamide] reacted with DDQ. TMSOTf with luti-dine or collidine in toluene offered the best alternative but the yield was lower than the yield achieved with BSTFA. 

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