Thiourea tetramethyl

Tetramethyl succinonitrile Tetramethyl thiourea Tetramethyl thiuram disulphide (thiram) Tetranitromethane... 

Finally, Gugala etal. [132] have analyzed the effect of the concentration of the base electrolyte on adsorption of 1,1,3,3-tetramethyl-2-thiourea at mercury electrode. The Flory-Huggins and the Frumkin models were utilized for the quantitative analysis of the adsorption data. 

The preparation of N-(2-p-toluenesulfonylethyl)-3,5-dimethylpyrazole is described elsewhere in this volume.5 l,l,3,3-Tetramethyl-2-thiourea and other reagents are available from the usual commercial sources. 

The single report of an oxygen- and sulfur-containing five-membered ring formed from a thiourea is that of Hartmann,211 who prepared the 1,3-oxathiolium salt 91 from a-bromoacetophenone and tetramethyl-thiourea. 

Less useful preparations of 1,3,5-thiadiazines in which they are formed as components of mixtures include that of Chase and Walker.262 They isolated a thiadiazine as a product of the reaction of thiourea, bromine, and p-chlorophenylacetonitrile in acetone. The function of the nitrile, which was not incorporated into the product, is not apparent. The product of a similar reaction, without the nitrile, was assigned a dithiazine structure by Baumann.304 Oliver and Stokes202 also reported that a 1,3,5-thiadiazine is formed among the myriad of identified products of the 15-month air oxidation of l,l,5,5-tetramethyl-2,4-dithiobiuret. 

A recent report of Winterfeldt214 indicated that 2,3,5,6-tetracarbo-methoxy-4/f-thiin-4-one (172) is obtained, among other products, when l,l,3,3-tetramethyl-2-thiourea is treated with dimethyl acetylene-dicarboxylate. 

In 1993, Kuhn reported that cyclic thiourea derivatives like 1,3,4,5-tetramethyl-2(3H)-thione can be used as NHC precursors [62]. In most cases the thione affords an easy access to the free carbenes by treatment with sodium or potassium [62-71]. This method provides an efficient way to prepare unsymmetrically substituted saturated NHCs (Scheme 16) [35,72],... 

Equation (at) is the more general, as more substitution is tolerated on starting material LXXXIII than on LXXXII. Yields are good to excellent. Starting material LXXXIII is accessible in a facile procedure from allylic halide, 1,1,3,3-tetramethyl-thiourea, [S=C(NMe2)a], and a salt, e.g., [NHJCIO4, K[PFJ, etc. . 

Thiolanes have been prepared by cyclization of 2-(3-hydroxyalkyl)-2-thiopseudoureas with base, a reaction which has also been used to prepare thiiranes and thietanes (see previous sections.) Liittringhaus and Brechlin reported the formation of ci.s-2-thiahydrindane (94) by treatment of e( >s -l,2-bis(bromoniethyl)cyclohexane with 2 moles of thionrc a. The tr/ms dibromide, however, failed to give the analogous ])roduct. Winterfeldt discovered that one of the by-products of the reaction of dimethylpropiolate with l,l,3,3-tetramethyl-2-thiourea was the thiophene 95. 

Shaw and co-workers (1838) have finished a series of papers on the decomposition of thioureas. They suggest an ionized, H bonded intermediate (Fig. 5-6) and note that the tetramethyl compound does not... 

Branched Alkanes. 2,6,10,14-Tetramethyl-hexadecane (phytane) and 2,6,10,14-tetramethyl-pentadecane (pristane) were found in considerable amounts (3). The dominance of phytane over pristane was observed. Other aliphatic isoprenoid alkanes C15 (2,6,10-trimethyl-dodecane, farnesane), C-, (2,6,10-trimethyl-tridecane), and C-g (2,6,10-trimethyl-pentaaecane) were also identified (4). In tne thiourea adduct of the branched-cyclic fraction, a homologous... 

The tetramethyl thiourea gave a much higher yield of the difluorodiamine upon reaction with COFj [632]. 

Determination of the components of industrial effluents (Castillo et al. 1997) that included phthalate esters, 4-nonylphenol, pen-tachlorophenol, 2-methylbenzenesulfonamide, and tetramethyl-thiourea. 

Tetramethyl thiourea Thiourea o-Toluidcne T richloroethylene Vinylcyclohexene dioxide Zinc chromate... 

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