DIISOPROPYLSILYL BIS(TRIFLUOROMETHANESULFONATE) Property

Boiling point:

85-86 °C2 mm Hg(lit.)

Density 

1.396 g/mL at 25 °C(lit.)

refractive index 

n20/D 1.382(lit.)

Flash point:

>230 °F

Specific Gravity

1.396

Hydrolytic Sensitivity

8: reacts rapidly with moisture, water, protic solvents

BRN 

3567500

Safety

Hazard Codes 

C

Risk Statements 

34-37

Safety Statements 

26-36/37/39-45

RIDADR 

UN 3265 8/PG 2

WGK Germany 

3

F 

10-21

HazardClass 

8

PackingGroup 

III

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H314Causes severe skin burns and eye damage

Precautionary statements

P280Wear protective gloves/protective clothing/eye protection/face protection.

P303+P361+P353IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P363Wash contaminated clothing before reuse.

P405Store locked up.

DIISOPROPYLSILYL BIS(TRIFLUOROMETHANESULFONATE) Chemical Properties,Usage,Production

Physical properties

bp 85–86°C/2mmHg;d 1.396 g cm?3; fp 110°C.

Uses

Diisopropylsilyl bis(trifluoromethanesulfonate) has more recently been used to prepare diisopropylsilyl-linked oligonucleotide analogs. Silylation of 5'-O-(dimethoxytrityl)-2'-deoxynucleosides using diisopropylsilyl bis(trifluoromethanesulfonate) and the hindered base 2,6-di-t-butyl-4-methylpyridine (Dtbp) provided quantitative yield of 3'-O-diisopropylsilanols (eq 2). Hence, silylation of 5'-O-(dimethoxytrityl)thymidine, N6-benzoyl-2'-deoxy-5'-O- (dimethoxytrityl)adenosine, N4-benzoyl-2'-deoxy-5'-O-(dimethoxytrityl) cytidine, and N2-isobutyryl-2'-deoxy-5'-O-(dimethoxytrityl) guanosine gave the desired products 5a–d in excellent yields.
Coupling of products 5a–d with unprotected thymidine resulted in formation of 3',5'-linked dinucleosides 6a–d selectively, and the dimer 7 from reaction with secondary hydroxyl group of thymidine was not observed (eq 3). Subsequent silylation and coupling with another molecule of thymidine gave 3,5- linked trinucleoside 8 in 76% yield (eq 4). A tetrathymidylate oligomer was prepared by 3'-O-silylation of 8 followed by coupling with thymidine. Although no self-condensation was observed, only 30% of the product 9 was obtained after purification by preparative HPLC.

Preparation

conveniently prepared by the slow addition of 2 equiv of trifluoromethanesulfonic acid to a stirring mixture of chlorodiisopropylsilane, followed by direct distillation of the product from the reaction flask to yield the product as a pale yellow oil.