With dichlorodimethylsilane

Ethyl l//-azepine-l-carboxylate and chlorotrimethylsilane, in hexamethylphosphoric triamide in the presence of magnesium, followed by quenching into water, yields the 1 2 trans-adduct 3.279 The reaction follows a similar path with dichlorodimethylsilane, whereas with dichloro-diphenylsilane a mixture of the 1 2 adduct 4 and the disiloxane 5 is obtained. 

FIGURE 6.31 Simultaneous protection of the amino and carboxyl groups of an amino acid by reaction (A) with copper(II) basic carbonate133 or acetate,134 giving the copper complex, (B) with triethyl borane giving the boroxazolidone,139 and (C) with dichlorodimethylsilane giving the dimethylsilyl derivative.138141... 

The effect of pore impregnation with nonpolar material was studied by treating samples with dichlorodimethylsilane (DCDMS). In each case a decrease in hysteresis area, compared to the untreated material, was observed after coating samples with DCDMS. The increases in the extrusion contact angle, with DCDMS compared to untreated sample, resulted in decreases in W q. In some cases impregnation with DCDMS led to greater mercury retention or an increase in IF, over the untreated material. However, this was always accompanied by a larger decrease in and thus a decrease in the pore potential. 

Termination of these polymerizations with dichlorodimethylsilane followed by hydrolysis of the protecting group generated polymeric diamines with functionalities of 1.7-1.9 and relatively broad MW distributions (1.49-2.22). The authors considered that the titrimetric method was less reliable for the higher molecular weight polymers and perhaps is a reason for the apparent ineficiency of this amination procedure. A major limitation of this method is the fact that the initiator is insoluble in hydrocarbon solvents and therefore most of the diene polymerizations were carried out in mixtures of hexane and ether which has a deleterious effect on the microstructure of the diene polymers. 

GC/MS interfaces constructed of all glass or glass-lined materials are required. Glass can be deactivated by silanizing with dichlorodimethylsilane. Inserting a fused silica column directly into the MS source is recommended care must be taken not to expose the end of the column to the electron beam. 

Reductive lithiation of trisilapentane 82 with lithium 4,4 -di-, r -butylbiphenylide (LDBB) and silylation with 1,2-dichloro-l,l,2,2-tetramethyldisilane at —78°C gave pentasilacycloheptane 83 in 69% yield (Scheme 16). A similar cyclization proceeded with dichlorodimethylsilane, while no cyclization occurred with l,3-dichloro-l,l,2,2,3,3-hex-amethyltrisilane due to steric hindrance <2000JOM12>. 

As shown in Equation (62), 1,2-/fe(mcthylthio)bcnzene 338 was dimetallated using butyllithium or superbasic mixture of butyllithium/potassium r/-butoxide (LICKOR), and then quenched with dichlorodimethylsilane to obtain 1,5,3-benzodithiasilepin 339 <1999T14069>. 

The DD-Na is synthesized in a high yield (>70%) by the treatment of trime-thoxyphenylsilane in the presence of sodium hydroxide in aqueous 2-propanol. We optimized the reaction conditions for the formation of DD-Na it can be prepared by preparative scale (33kg/batch). DD-Na give POSS derivatives (Scheme 3). For example it reacts with dichlorodimethylsilane to give a cage structure compound... 

Cabiddu et al. reported that the addition of -butyllithium to (vinylthio)benzene 176 followed by an electrophilic quenching with dichlorodimethylsilane afforded the 2-methylene-3,3-dimethyl-l,3-benzothiasilole 178 containing an exocyclic double bond (Scheme 23) <1998T14095>. 

For the reaction of vinyl chloride with dichlorodimethylsilane, a disilane is isolated, not the expected divinyldimethylsilane [Eq. (62) 124]. 

Summary Mono(silyl)hydrazines condense to bis(silyl)hydrazines at higher temperature. The degree of oligomerization of mono- and dilithiated silylhydrazines in the crystal depends on the bulkiness of the substituents. Reactions of lithiated silylhydrazines with fluorosilanes lead, for example, to the formation of tetrakis(silyl)-hydrazines, six-, four- and five-membered rings. Formaldehyde derivatives of mono-(silyl)hydrazones are obtained in a reaction of mono(silyl)hydrazines with aqueous formaldehyde solution. 0-Silylpyrazolones can be synthesized by treating mono(silyl)-hydrazines with acetoacetic ester. A dipyrazolonesilane is formed in the reaction of an O-silylpyrazolone with dichlorodimethylsilane. 

The reaction of two equivalents 0-silylpyrazolone with dichlorodimethylsilane leads to the formation of the first dipyrazolonesilane ... 

Tadpole polymers are polymers consisting of one cyclic chain and one or more linear chains. Quirk and Ma182 prepared a tadpole copolymer consisting of a cyclic PBd and two linear PS chains. First they reacted PDPPE with two monofunctional living PS chains. The resulting difunctional PS was used to initiate the polymerization of butadiene. The living PBd chains were then cyclized with dichlorodimethylsilane in benzene as shown in Scheme 91. The separation of the tadpole copolymer from the polycondensates was achieved by fractional precipitation. 

Soon after, Howard and Martin (1950) published an account of the first use of what was to become known as reversed-phase chromatography. Instead of using a polar stationary phase, such as silica or calcium carbonate, to sorb polar compounds from a nonpolar solvent, they made the stationary phase nonpolar to sorb the nonpolar compounds from a polar solvent. They treated silica with dichlorodimethylsilane, which modified the surface of the silica to a nonpolar phase. This phase effectively held a nonpolar solvent stationary while a polar solvent was acted as a mobile phase. They separated long-chain fatty acids in an aqueous-methanol (80 20) mobile phase by partitioning of the solutes into the nonpolar stationary phase, which was n-octane saturated with methanol. 

Poly[acenaphthyylene-co-dlmethyl-(2-naphthoxy)-vinyloxysilaneJ was prepared by treating poly(ACN-co-vinyl alcoholKO.4 g) in 50 mL of THF with dichlorodimethylsilane (0.8 mL) and triethylamlne (0.5 mL) at 60°C for 10 h. Then, 2-naphthol (1.0 g) in 20 mL of THF was added and heating was continued for another 10 h at 60 C. The mixture was cooled and poured into 600 mL of diethyl ether. The polymer was purified by two precipitations from THF into ether. 

In the past, non-after-treated SAS bore the Chemical Abstracts Service (CAS) registry number 7631-86-9, aluminum silicates bore the number 58425-86-8, and calcium silicates the number 1344-95-2. SAS that were after-treated with dichlorodimethylsilanes were given the number 60842-32-2 (formerly 68611-44-9), and SAS after-treated with polysi-loxanes the number 67762-90-7. Thanks to efforts by SASSI (Synthetic Amorphous Silica and Silicates Industrial Association), new numbers have been assigned since June 7, 1989, which are designed to allow a better differentiation between the amorphous and crystalline substances. The following numbers are now valid for the different types of SAS ... 

Lithiation of diphenyl ether followed by the addition of dichlorodimethylsilane affords a phenoxa-silin <87JGU632> and a phenothiasilin is formed in the reaction of diphenylsulfone with dichlorodimethylsilane and lithium 2,2,6,6-tetramethylpiperidide at 0°C in THF <83JA6155>. 

Reductive coupling of RCHO and allylic alcohols A synthesis of tunicaminyl-uracil (5) involves a novel coupling of an aldehyde with an allylic alcohol, effected with dichlorodimethylsilane. Thus treatment of the alcohol 1 and the aldehyde 2 with bcnzenesclcnol and (CH,)2SiCI2 (excess) in pyridine at 23° provides the product 3 in 92% yield as a mixture of cpimers (1 1). Radical cyclization of 3 in acetonitrile with BuiSnll and (C2Hi)B, followed by siloxanc hydrolysis provides the protected... 

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