1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane Property

Boiling point:

70 °C0.5 mm Hg(lit.)

Density 

0.986 g/mL at 25 °C(lit.)

refractive index 

n20/D 1.454(lit.)

Flash point:

>230 °F

storage temp. 

Inert atmosphere,2-8°C

solubility 

Miscible with dimethylformamide, hexane, ethyl acetate, chloroform and dichloromethane.

form 

Oil

color 

Colourless

Specific Gravity

0.986

Hydrolytic Sensitivity

8: reacts rapidly with moisture, water, protic solvents

Sensitive 

Moisture Sensitive

BRN 

1934216

InChI

InChI=1S/C12H28Cl2OSi2/c1-9(2)16(13,10(3)4)15-17(14,11(5)6)12(7)8/h9-12H,1-8H3

InChIKey

DDYAZDRFUVZBMM-UHFFFAOYSA-N

SMILES

[Si](Cl)(C(C)C)(C(C)C)O[Si](Cl)(C(C)C)C(C)C

CAS DataBase Reference

69304-37-6(CAS DataBase Reference)

Safety

Hazard Codes 

C

Risk Statements 

34

Safety Statements 

26-27-28-36/37/39-45

RIDADR 

UN 3265 8/PG 2

WGK Germany 

3

F 

10-21

Hazard Note 

Corrosive

TSCA 

No

HazardClass 

8

PackingGroup 

II

HS Code 

29319090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H290May be corrosive to metals

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.

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane Chemical Properties,Usage,Production

Description

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane is a moisture-sensitive, colourless, transparent, corrosive liquid that is miscible with a wide range of organic solvents but insoluble in water. It can be used to protect the two hydroxyl groups in nucleoside and carbohydrate substrates simultaneously. It can also be used as a solvent for chromatography and as a reagent for polymer synthesis. In addition, it is a stabiliser for polymers and a surfactant for emulsions.

Chemical Properties

Colorless liquid

Physical properties

bp 70°C/0.5 mmHg; d 0.986 g cm?3.

Uses

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane is a silylating reagent used for simultaneous protection of 3'- and 5'-hydroxy functions of ribonucleosides. It is used in the analysis of Watson-Crick and Hoogstein base pairing in nucleotides. It is also employed in the formation of ribavirin chemical delivery systems. Further, it serves as a protecting group reagent for open-chain polyhydroxy compounds. In addition to this, it is involved in the preparation of cyclic bridged peptides.

Uses

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane can be used as simultaneous protection of the 3'- and 5'-hydroxyl functions of furanose nucleosides;protecting group for carbohydrates;3,4 protecting group reagent for open-chain polyhydroxy compounds; preparation of cyclic bridged peptides.
The reagent design was based upon the fact that triisopropylsilyl chloride reacts 1000 times faster with primary alcohols than secondary alcohols. Thus in the case of 3',5'-dihydroxy nucleosides the reagent initially silylates at the 5'-position. This is then followed by intramolecular reaction with the secondary alcohol at the 3'-position to give the doubly protected derivative (eq 1).

Uses

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane is used in the analysis of Watson-Crick and Hoogstein base pairing in nucleotides. Also used in the formation of ribavirin chemical delivery systems.

Preparation

can be prepared starting from trichlorosilane by treatment with i-PrMgCl, H2O, and acetyl chloride. Alternatively, it can be prepared by the reaction of 1,1,3,3- tetraisopropyldisiloxane with CCl4 in the presence of catalytic PdCl2.This method is also suitable for its in situ preparation.

Hazard

1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane is a silane-based reagent that is irritating to the eyes on contact and corrosive to the skin, causing burns; inhalation can cause corrosive damage to the upper respiratory tract and lungs.

Synthesis

General procedure for the synthesis of 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane from 1,1,3,3-tetraisopropyldisiloxane: The chlorination reaction needs to be carried out in THF, making sure that all Si-H bonds are chlorinated, using an excess of TCCA (molar ratio 1:1, TCCA to siloxane). This was done as follows: 1,1,3,3-tetraisopropyldisiloxane and THF (ratio 20 mL THF/g raw material) were added to the reaction flask and the mixture was cooled to -20 °C. TCCA was added in batches with vigorous stirring, and after the addition of TCCA, stirring was continued for 15 min, after which the cooling bath was removed and the reaction mixture was allowed to warm slowly to room temperature. It should be noted that the chain length, substituent or Si-H bond position of the siloxanes may affect the subsequent separation and characterization methods. Upon completion of the reaction, THF and unreacted TCCA need to be removed immediately to prevent denaturation of the product after several days.

References

[1] Synthetic Communications, 1987, vol. 17, # 11, p. 1299 - 1308
[2] Journal of Organometallic Chemistry, 2018, vol. 875, p. 1 - 4
[3] Tetrahedron Letters, 1999, vol. 40, # 6, p. 1197 - 1200
[4] Synthetic Communications, 1999, vol. 29, # 20, p. 3499 - 3501
[5] Journal of the American Chemical Society, 1983, vol. 105, # 12, p. 4059 - 4065