Silanol, trimethyl

Silanediol, diphenyl-, 3 62 Silanol, trimethyl-, formation of, by hydrolysis of hexamethyl-disilazane, 5 58... 

The diolefin 1064 gives rise to the isoxazoline 1065, which cannot eliminate tri-methylsilanol 4 [122]. Cychzation of the co-nitroolefin 1066 with trimethylchloro-silane (TCS) 14/triethylamine at -35 °C then HCl-induced removal of trimethyl-silanol 4 leads, in 85% yield, to the dimer 1067, which is converted in two more steps into racemic pyrenophorin 1068 [112] (Scheme 7.39). Further cyclizations of co-nitroolefins [109] to monomeric or dimeric isoxazolines have been described. Conjugated dienes such as butadiene afford a mixture of the mono or bis adducts [115-117]. 

AlRg groups. The latter assumption is favored by the experience that incomplete reaction of the silanol groups occurs always with trimethyl-silyl chloride. This is caused by steric hindrance (219, 220). Diisobutyl aluminum groups are at least as bulky as trimethylsilyl groups. Therefore, since one aluminum atom is bound for every silanol group, a smaller ratio than two of alkyl groups to aluminum must prevail. No carbon determinations have been made, unfortunately. 

After peroral administration of 86b, 32—40% of radioactivity appeared in the urine within the First 24-hr period. Another 8—20% appeared during the second 24-hr period, and activity decreased to trace amounts after the second day. Three radioactive metabolites, (hydroxymethyl)dimethylphenylsilane (88), p-trimethyl-silylphenol (89), and an unknown conjugate of 90, could be isolated and characterized (cf. Scheme 9). Metabolism of 87b leads to silanol 91 (90% in the urine within 36 h). 

The trimethylsilylated ylides (1), easily generated from trimethyl chlorosilane and ylides, react with aldehydes 2 to form vi-nylsilanes 3 (2,3). The vinylphosphonium silanolates 4 are also formed. Compounds 3 are versatile reagents for further reactions (4). The ylide J (with R1 =H) reacts with aldehydes 2 to give the dienes j). The oxidation of with the adduct 6, from triphenyl-phosphite and ozone, gives access to a generaT synthesis of acyl-silanes (trimethylsilylketones) (2). The silylated ylides react to form phosphonium salts 7 with halogen compounds. The salts 7.can be desilylated by fluorine ions. The disubstituted ylides JO Tormed can be converted in statu nascendi with aldehydes V[ into the tris-substituted olefin J2 (2,3). In the case of R3-I, vinyl... 

Several enlightening comparisons can be made from the data of Table I. First an estimate of the vapor phase HMDS surface reaction efficiency vs that of the liquid phase can be obtained. The features of the vapor phase and liquid phase treatments are found in Tables II and III. From Table I, the values for Y58 substrates are 0.22 and 0.11, respectively, thus indicating an approximate 100% greater efficiency towards silanol conversion to trimethyl silyl labelled reaction product for the vapor treatment. An approximate 30% gain is obtained for the oxide substrate comparison. 

Amides are by no means the only substances to be studied by freezing point depression. Phenols have received attention (507, 1743), as well as such widely varying substances as organophosphorus compounds (1136), pyrrole (1066), arylstibonic acid (527), and trimethyl-silanol (169). 

Beim Erwarmen einer vollstandig wasserfreien Ldsung von Trimethyl-silanol in Xylol entwickelt Natrium die nach... 

Die einfachste Kondensationsreaktion ist die Bildung von Hexa-meth3d-disiloxan aus Trimethyl-silanol ... 

Durch Schwejelsdure Trimethyl-silicium-monochlorid oder Tri-methyl-silanol bilden mit konzentrierter Schwefelsaure krystallisierbares... 

The activities of the often used hydroxides and siloxanolates decreases in the order Cs > Rb > K > Li (33). At equal molar concentrations, the rates using the hydroxide or siloxanolate of the same metal have been found to be similar (30). Tetramethy1ammonium siloxanolates exhibit activities close to the cesium siloxanolates (33). Tetramethy1ammonium hydroxide, silanolate, and siloxanolate rapidly decompose above 130 C yielding methanol, methoxy trimethylsilane, or methoxysiloxane respectively and trimethyl amine ( 35). In the cases of the first two compounds listed above, the catalyst breakdown products are fugitive at the decomposition temperature. Thus, the usual need for catalyst neutralization and removal following polymerization is eliminated. They are often termed "transient" catalysts (34). 

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