2612-42-2 Usage
Physical properties
bp 49.5–51.5°C/12 mmHg; d 1.519 g cm?3.
Uses
Reaction of (dibromomethyl)-
trimethylsilane with n-butyllithium at ?110°C results in the
formation of trimethylsilylbromomethyllithium. The silane and
the n-BuLi are added simultaneously in order to suppress side
reactions. Treatment of the intermediate lithium reagent with
chlorotrimethylsilane (eq 1) or mercury(II) bromide (eq 2)
affords bis(trimethylsilyl)bromomethane or bis(trimethylsilylbromomethyl)
mercury, respectively. If the lithium reagent is allowed to warm in the presence of cyclohexene, the only reaction
observed is an alkylation with the n-butyl bromide formed
in the exchange reaction. The alkylated product is formed in 89%
yield.
Preparation
to a dry, 1.0 L three-neck flask, equipped
with a mechanical stirrer, a pentane thermometer, a nitrogen inlet
tube, and a pressure-equalizing addition funnel, was added
62.0 g (0.245 mol) of bromoform and 300 mL of dry THF.
The reaction was cooled to ?90°C and 0.25 mol of isopropylmagnesium
chloride in 200 mL of THF was added during 30
min at such a rate that the temperature was kept at ?80°C
or below. The reaction was stirred at ?90°C for 15 min and
then 0.25 mol of chlorotrimethylsilane in 100 mL of THF was
added at such a rate that the temperature did not exceed?80°C.
After 1 h, the reaction was allowed to warm to rt. The reaction
mixture was hydrolyzed with saturated NH4Cl solution
until large lumps of salt cake formed. The organic layer was
poured off, dried over anhydrous Na2SO4, and distilled at atmospheric
pressure to remove most of the THF. A trap-to-trap
distillation of the residue at 0.1 mmHg was followed by distillation
through an 11 in. Vigreux column. The fraction boiling at
49.5–51.5°C/12 mmHg was collected, affording 47.9 g (79%)
of (dibromomethyl)trimethylsilane.
Check Digit Verification of cas no
The CAS Registry Mumber 2612-42-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,6,1 and 2 respectively; the second part has 2 digits, 4 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 2612-42:
(6*2)+(5*6)+(4*1)+(3*2)+(2*4)+(1*2)=62
62 % 10 = 2
So 2612-42-2 is a valid CAS Registry Number.
2612-42-2Relevant articles and documents
Simplified preparations of trialkylsilyl- and bis(trialkylsilyl)dihalomethanes via the deprotonation of dihalomethanes
Yoon, Kunsang,Son, David Y.
, p. 185 - 189 (2007/10/03)
Simple, high-yield routes to trialkylsilyl- and bis(trialkylsilyl)dihalomethanes are described. These compounds are prepared by the deprotonation of dibromomethane or dichloromethane by lithium diisopropylamide in the presence of a chlorosilane. The reactions are carried out at temperatures below - 70°C in THF/hexane solvent mixtures. After aqueous workup, the air- and water-stable products are isolated by either distillation or crystallization. Further reactions on these compounds are possible, as illustrated by one example.
Preparation des α-monohalogenoalkyllithiums non fonctionnels
Villieras, Jean,Tarhouni, Radhouane,Kirschleger, Bernard,Rambaud, Monique
, p. 825 - 830 (2007/10/02)
The preparation of very unstable α-monohaloalkyllithiums (carbenoids), potential electro- and nucleophiles, from easily accessible gem-halogenated alkanes, by halogen-lithium exchange at low temperatures is described.R-CHXLi type carbenoids (R aryl, H or CH3 ; X = Cl, Br) are obtained by bromine-lithium exchange in a THF-ether-pentane mixture at temperatures below -115 deg C.The α-silylated organolithiums Me3SiCXLiR (R = H, alkyl; X = Cl, Br) despite their greater stability, must be prepared at the same temperature; secondary reactions are limited by the use of an inverse addition of secondary butyllithium.CH2XLi an RCXLiMe carbenoids (R = H, CH3 ; X = Cl, Br) have to be prepared in the presence of one equivalent of lithium bromide in order to reduce the halogen-lithium carbenoid interaction which is responsible for their instability.
