TMBS-ethers

The t-butyldimethylsilyl ether (TMBS-ether), formed from the alcohol with t-butyldimethylsilyl chloride in the presence of imidazole in dimethylformamide solution,84 is more stable to hydrolysis than the TMS-ether (see also Section 4.2.66, p. 461). Deprotection is readily effected by treatment with 2-3 equivalents of tetrabutylammonium fluoride in tetrahydrofuran at 25 °C,84a or tetrabutyl-ammonium chloride and potassium fluoride dihydrate in acetonitrile.84b... 

TMBA-ICI4 (19.3 g, 46 mmol) is added portionwise to the aryl ether (46 mmol) in AcOH (100 ml) and the mixture is stirred for 24 h at 70°C. Over this time the yellow solution becomes reddish brown and TMB A-ICL precipitates. The salt is collected and the filtrate is washed with aqueous NaHSO, (5%, 200 ml) and extracted with PhH (3 x 40 ml). The extracts are washed with aqueous NaHCO, (5%, 150 ml), dried (MgS04), and evaporated to yield the chlorophenyl ether. 

Kreft, J.-U. and B. Schink. 1993. Demethyation and degradation of phenylmethyl-ethers by the sulfide-methylating homoacetogenic bacterium strain TMBS 4. Arch. Microbiol. 159 308-315. 

The application of CFD methods also makes it possible to carry out the analysis of such inorganic substances as anions and metals. As an example let us consider the analysis of trace amounts of nitrates in water. Tan [44] proposed a simple and sensitive method for determining nitrates in aqueous solutions using GC—mass spectrometry (MS) with an ionic detector-multiplier. The method is based on the nitration of 1,3,5-trimethoxy-benzene (TMB) in sulphuric acid. In this medium the nitration follows the hydrolysis of the ether groups of TMB, and nitrobenzene is formed as the final product [44]. The reaction mixture is analysed by GC and detected with a mass spectrometer. Hexamethyl-benzene (HMB) is used as an internal standard. To avoid interference from nitrates and chlorides, sulphamic acid and mercury(ll) sulphate are used. 

The decomposition process of bispyridinium aldoximes TMB-4, by acetylcholine esterase reactivators, were observed in D2O solutions of different pD values and various temperatures [35]. Whereas the aldoximes turned out to be rather stable, corresponding ether and cyano derivatives were found to convert to the pyridone in alkaline medium at high temperatures. 

The studies on the diglycidyl ethers of phenolphthalein (DGEPP) used a trimethoxyboroxine (TMB) cure at elevated temperature and were compared to the bisphenol-A based systems (DGEBA)1 1. ... 

The following additional cardopolymer systems were evaluated as di- or tetraglycidyl ethers using trimethoxyboroxine (TMB) and diaminodiphenylsulfone (DDA) as curing agents26 -... 

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