N,N-Bis(trimethylsilyl)formamide Property

Melting point:

158 °C

Boiling point:

158 °C

Density 

0.885 g/mL at 20 °C(lit.)

refractive index 

n20/D 1.437

Flash point:

37 °C

solubility 

benzene, CCl4, CH2Cl2, CHCl3.

pka

0.16±0.70(Predicted)

CAS DataBase Reference

15500-60-4(CAS DataBase Reference)

EPA Substance Registry System

Formamide, N,N-bis(trimethylsilyl)- (15500-60-4)

Safety

Risk Statements 

10

RIDADR 

UN 1993 3/PG 3

WGK Germany 

3

F 

10-21

HazardClass 

3.2

PackingGroup 

III

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H226Flammable liquid and vapour

N,N-Bis(trimethylsilyl)formamide Chemical Properties,Usage,Production

Physical properties

81–82 °C/20 mmHg; 154 °C/760 mmHg; mp 16–17 °C; n20 D 1.4388.

Uses

N,N-Bis(trimethylsilyl)formamide can be used as source of nucleophilic formamide and N-silylaldimine synthon.
N,N-Bis(trimethylsilyl)formamide (BSF) exists in the amide form with both silyl groups attached to the nitrogen atom. This is in contrast to most other bis(TMS)amides (e.g., bis(TMS)- acetamide), which favor the N,O-bis(TMS)imidate isomer. BSF behaves as an N-formamido nucleophile, reacting with the carbonyl group of aldehydes and activated ketones to give N-formyl-O-trimethylsilyl-N,O-acetals. Similarly, reaction with imines (or their precursors) can in some cases give N-formylN,N-acetals. BSF undergoes reactions with a range of other electrophiles including acid chlorides, chloroformate esters, and isocyanates to give a range of interesting products. When treated with organolithium nucleophiles, attack occurs at the carbonyl function, to provide N-silylaldimines after elimination of a silyloxy unit. Such imines are reported to undergo further reactions to give heterocycles. There are also reports of BSF acting as a silylating agent, to give silyl enol ethers, although it is not commonly used for this application.

Preparation

chlorotrimethylsilane was added at room temperature to a solution of formamide and triethylamine in dry benzene and the mixture was heated at reflux for 1 h. The reaction mixture was filtered, and the filtrate was evaporated to give a crude oil. This was purified by high-vacuum distillation to afford N,N-bis(trimethylsilyl)formamide (BSF) as an oil in 75% yield.