2857-97-8

Basic information

• Product Name: Bromotrimethylsilane
• Synonyms: Bromotrimethylsilane Trimethylsilylbromide;TMBS, Trimethylbromosilane, Trimethylsilyl bromide;Bromotrimethylsilane,98%;Bromotrimethylsilane,TMBS, Trimethylbromosilane, Trimethylsilyl bromide;Bromotrimethylsilane, AcroSeal, 98%;BroMotriMethylsilane, Stab. With Copper Powder or Silver Wire;Trimethylsilyl bromide, TMBS;BroMotriMethylsilane, 98% 100GR
• CAS NO: 2857-97-8
• Molecular Formula: C₃H₉BrSi
• Molecular Weight: 153.09
• EINECS: 220-672-0
• Product Categories: Synthetic Organic Chemistry;Alkyl Silanes;Blocking Agents;Protective Agents;Silylating Agents;Pharmaceutical Intermediates;Si-X (F, Br, I) Compounds;Si (Classes of Silicon Compounds);Silicon Compounds (for Synthesis)
• Mol File: 2857-97-8.mol

Chemical Properties

• Melting Point: -43 °C
• Boiling Point: 79 °C(lit.)
• Flash Point: 90 °F
• Appearance: Clear colorless to yellow/Liquid
• Density: 1.16 g/mL at 25 °C(lit.)
• Vapor Pressure: 100mmHg at 25°C
• Refractive Index: n20/D 1.424(lit.)
• Storage Temp.: 2-8°C
• Solubility: DECOMPOSES
• Water Solubility: DECOMPOSES
• Sensitive: Moisture Sensitive
• Stability: Stable. Flammable. Incompatible with strong acids, strong oxidizing agents. May decompose on exposure to water or moist air.
• BRN: 1731135
• CAS DataBase Reference: Bromotrimethylsilane(CAS DataBase Reference)
• NIST Chemistry Reference: Bromotrimethylsilane(2857-97-8)
• EPA Substance Registry System: Bromotrimethylsilane(2857-97-8)

Safety Data

• Hazard Codes: C
• Statements: 10-34-29-14
• Safety Statements: 16-26-36/37/39-45-8
• RIDADR: UN 2920 8/PG 2
• WGK Germany: 3
• F: 10-21
• TSCA: Yes
• HazardClass: 3
• PackingGroup: II
• Hazardous Substances Data: 2857-97-8(Hazardous Substances Data)

Usage

Chemical Description

Bromotrimethylsilane is a reagent used for the protection of hydroxyl groups in organic synthesis.

Uses

1. Used in Organic Synthesis:
Bromotrimethylsilane is used as a silylating agent for the protection or deprotection of functional groups selectively in organic synthesis. It acts as a silane blocking agent, which is widely used in the syntheses of drugs.
2. Used in Cleavage of Lactones, Epoxides, and Other Functional Groups:
Bromotrimethylsilane is a mild and selective reagent for the cleavage of lactones, epoxides, acetals, phosphonate esters, and certain ethers. It is also an effective reagent for the formation of silyl enol ethers and can function as a brominating agent.
3. Used in the Formation of Enamines:
Amines react with TMS-Br to form isolable adducts, which react readily with ketones to form enamines under mild conditions.
4. Used in the Synthesis of Adefovir Intermediate:
Bromotrimethylsilane is utilized in the synthesis of adefovir intermediate, which is an important compound in the pharmaceutical industry.
5. Used as a Powerful Silylating Agent:
Due to its reactivity and selectivity, Bromotrimethylsilane is considered a powerful silylating agent in various chemical reactions and applications.
6. Used in Catalysis:
Bromotrimethylsilane is used with Cl3 to catalyze the direct allylation of a variety of alcohols with allyltrimethylsilane, which is an important reaction in the synthesis of complex organic molecules.

Preparation

although many methods are reported, only a few are provided here: chlorotrimethylsilane undergoes halogen exchange with either magnesium bromide in Et2O or sodium bromide in MeCN, which allows in situ reagent formation (eq 1); alternatively, hexamethyldisilane reacts with bromine in benzene solution or neat, to afford only TMS-Br with no byproducts (eq 2).4 TMS-Br may also be generated by reaction of hexamethyldisiloxane and aluminum bromide (eq 3).However, it should be noted that the reactivity of in situ generated reagent appears to depend upon the method of preparation.

Purification Methods

Purify it by repeated fractional distillation and store it in sealed ampoules in the dark. [McCusker & Reilly J Am Chem Soc 75 1583 1953.] Also fractionate it through a 15-plate column (0.8 x 32cm packed with 1/16in single turn helices of Pt-Ir wire). [Gilliam et al. J Am Chem Soc 68 1161 1946, Pray et al. J Am Chem Soc 70 433 1948, Beilstein 4 IV 4008.]

InChI:InChI=1/C3H9BrSi/c1-5(2,3)4/h1-3H3

Upstream product

• 993-07-7 trimethylsilan 
• 768-32-1 trimethylphenylsilane 
• 109-04-6 2-bromo-pyridine 
• 754-05-2 ethenyltrimethylsilane 
• 13735-81-4 1-styrenyloxytrimethylsilane 
• 75-62-7 Bromotrichloromethane 
• 506-96-7 Acetyl bromide 
• 118467-50-8 S,S-diethyl O-(trimethylsilyl) phosphorodithioite 
• 3385-94-2 hexamethyldisilathiane 
• 6213-94-1 trimethylsiloxyethene 
• 1833-53-0 2-(Trimethylsilyloxy)propene 
• 18205-02-2 dibromo-tris-(trimethylsilanyl-methyl)-arsorane 
• 618-32-6 Benzoyl bromide 
• 4333-56-6 cyclopropyl bromide 

Downstream Products

• 34176-76-6 6-Bromhexansaeure-trimethylsilylester 
• 18243-41-9 (bromomethyl)trimethylsilane 
• 59253-21-3 2-bromo-tetrahydro-furan 
• 78980-79-7 C₁₂H₂₂BrNO₂SSi₂ 
• 1825-62-3 ethyl trimethylsilyl ether 
• 18142-75-1 trimethyl-tribromomethyl-silane 
• 74-95-3 1,1-dibromomethane 
• 19980-35-9 1-trimethylsilyloxy-2-methyl-1-cyclohexene 
• 19980-33-7 6-methyl-1-trimethylsiloxycyclohex-1-ene 
• 19980-43-9 1-(trimethylsilyloxy)cyclopentene 
• 13735-81-4 1-styrenyloxytrimethylsilane 
• 2083-91-2 N,N-Dimethyltrimethylsilylamine 
• 20502-36-7 Brom-bis-dimethylamino-phosphan 

Relevant articles and documents

Redistribution equilibria of substituents between the methyl- and trimethylsilicon moieties

Scrambling equilibria resulting from the exchange of pairs of monofunctional substituents (halogen, methoxyl, methylthio, and dimethylamino) between the methyl- and trimethylsilicon moieties have been studied by proton nuclear magnetic resonance. Unexpect

N-H cleavage as a route to new pincer complexes of high-valent rhenium

A novel PNN-type pincer ligand has been accessed via imine reduction with LiAlH4 to provide the phosphine diamino proligand, PNHNH (1). The ligand, 1, as well as PNHP can be metallated directly, via N-H cleavage, with L2ReOX2(OEt) precursors to access six-coordinate (PNP)ReOCl2 (2) and (PNNH)ReOX2 (3-Cl, X = Cl; 3-Br, X = Br) in good yield. 3-Cl and 3-Br undergo dehydrohalogenation upon treatment with NEt3, furnishing the five-coordinate phosphine/diamido PNN-type compounds (PNN)ReOX (4-Cl, X = Cl; 4-Br, X = Br) in excellent yield, presenting as a mixture of rotameric diasteromers. The reversibility of this deprotonation, and the coordinative unsaturation of 4-Cl is shown in reactions with HCl(aq) and PMe3 providing 3-Cl and 4-PMe3, respectively. Treatment of 4-Cl with AgOAc, AgOTf, or NaHBEt3 lead to formation of (PNN)ReO(OAc) (4-OAc), (PNN)ReO(OTf) (4-OTf), and (PNN)ReO(H) (4-H), all isolated in excellent yields in varying diasteromeric ratios. The nature of the isomerism was analyzed based on solid-state structural studies and solution NMR data.

The First Gallium-Arsenic Compound containing a Single Ga3As Unit: Isolation and Crystal Structure of 3As (thf=tetrahydrofuran)

3As (thf=tetrahydrofuran), isolated from the products of the reaction of (Me3Si)3As with GaBr3, has been shown by X-ray crystallographic analysis to be the first example of a compound containing a single Ga3As unit.

STEPWISE CONVERSION OF OXIRANES TO ALLYLIC ALCOHOLS BY IODOTRIMETHYLSILANE AND DBU

Iodotrimethylsilane, prepared from hexamethyldisilane and iodine, reacts smoothly with oxiranes to give (2-iodoalkoxy)trimethylsilanes which can be converted to allylic alcohols with DBU in good yields.The whole conversion can be carried out in one-pot operation.

A simple one-pot synthesis of methyltribromosilane

A simple one-pot synthesis of methyltribromosilane has been developed. The straightforward reaction of a slight excess of silicon tetrabromide with one equivalent of powdered methyllithium in refluxing pentane produces methyltribromosilane in high yields.

C3-Heteroaroyl cannabinoids as photolabeling ligands for the CB2 cannabinoid receptor

A series of tricyclic cannabinoids incorporating a heteroaroyl group at C3 were prepared as probes to explore the binding site(s) of the CB1 and CB2 receptors. This relatively unexplored structural motif is shown to be CB2 selective with Ki values at low nanomolar concentrations when the heteroaromatic group is 3-benzothiophenyl (41) or 3-indolyl (50). When photoactivated, the lead compound 41 was shown to successfully label the CB2 receptor through covalent attachment at the active site while 50 failed to label. The benzothiophenone moiety may be a photoactivatable moiety suitable for selective labeling.

An efficient large-scale synthesis of gemcitabine employing a crystalline 2, 2-difluoro-α-ribofuranosyl bromide

An efficient large-scale synthesis of gemcitabine was achieved without chromatography or fractional crystallization. The key steps include stereospecific conversion of a novel β-ribofuranosyl phosphate into a highly crystalline a-ribofuranosyl bromide and coupling of the α-ribofuranosyl bromide and trime- thylsilyl cytosine to produce a β-nucleoside. p-Phenylbenzoyl group was introduced for the protection of one of hydroxy groups in order to enhance the crystallinity of intermediates. Continuous removal of trimethylsilyl bromide, generated during the coupling reaction, by distillation from the reaction medium substantially enhanced the β-selectivity of the crucial coupling reaction.

Homolytic reactions of N-bromohexamethyldisilazane with trialkyl(phenylalkoxy) derivatives of silicon and tin

The main product of the photoinduced reaction of N- bromohexamethyldisilazane with trialkyl-(benzyloxy)derivatives of silicon and tin R3MO(CH2)nPh (R = Me, Et; M = Si, Sn; n = 1) is N,N-dibenzylidene-C-phenylmethanediamine (hydrobenzamide). For M = Si, with increase of the length of the methylene chain between the oxygen atom and the phenyl group (n = 2, 3), the similar reaction affords the product of bromination of the benzylic carbon atom R3MO(CH2) n-1CHBrPh. For M = Sn, the reaction results in the formation of 2-phenyloxacycloalkanes PhCHO(CH2)n-1. Pleiades Publishing, Ltd., 2010.

Structural chemistry of borazines

The solid-state structure of (HN=BF)3 has been redetermined. It is characterised by a stacking of the molecules, similar to hexagonal boron nitride. In contrast, (F3CH2N=BF)3 shows no intermolecular interactions between the planar borazine rings. In (Cl 2BN=BCl)3, the Cl2B groups are almost perpendicularly oriented to the planar borazine ring and its B-Cl bonds are shorter than the Cl-B bonds to the ring boron atoms. Reactions of (Cl 2BN=BCl)3 with Me3SiNMe2 allows a successive Cl/Me2N exchange. Depending on the molar ratio, the compounds [Cl(Me2N)BN=BCl]3, [(Me2N) 2BN=BCl]3 and [(Me2N)2BN=BNMe 2]3 are obtained. The latter two react with CH 2Cl2 by B-N bond cleavage of one ring boron bonded Me 2N group with formation of an N-H bond. These molecules not only possess a strongly distorted BN hexagon with short B-NH bonds but also a nonplanar borazine ring. The nonplanarity of the borazine ring is even more pronounced in [Me3SiN=BCl]3. A planar borazine ring is observed for (MeN=BBr)3. Its molecules are ordered into stacks by translation with borazine planes 4.2 A apart from each other. Characteristic of the structure are close contacts between neighbouring bromine atoms. Due to the steric demand of pentafluorophenyl groups, the borazine ring of (F5C6N=BBr)3 forms no stacks because one of the three F5C6 rings stands almost perpendicular to the borazine plane while the other two are twisted by 70°. Aminolysis of (F 5C6N=BBr)3 yields (F5C 6N=BNH2)3 with NH2 groups that are coplanar with the borazine ring. The phenyl groups of (HN=BPh)3 are twisted by only 30-40° relative to the borazine ring. A threefold crystallographic axis stands perpendicular to the ring plane. The sixfold crystallographic axis of the unit cell generates a channel structure with an internal diameter of 4.5 A. The two isomeric borazines, (iPrN=BMe) 3 and (MeN=BiPr)3 are structurally rather similar although the first of these has longer B-N bonds due to the shorter N-C bonds. Moreover, the B-N-B and N-B-N bond angles are slightly different. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Spin chemistry of organometallic compounds 5. Interaction of N-bromohexamethyl disilazane with substituted silyl hydrides

Reaction of N-bromohexamethyl disilazane (Me3Si)2NBr with substituted triorganyl silanes R1R2R3SiH results in asymmetric disilazanes Me3SiNHSiR1R2R3 and bromination product, bromotrimethyl silane Me3SiBr. The reaction has demonstrated an unusual dependence on specific solvation. In benzene, bromination occurs immediately after mixing of the reagents, while in cyclohexane, the reaction products are formed only under UV-irradiation. Application of photoinduced CIDNP method has shown that the mechanism of bromination of triorganyl silanes is comprised of a series of consecutive radical stages involving N-centered disilazanyl (Me3Si)2N{radical dot} and Si-centered silyl R1R2R3Si{radical dot} radicals.