Tes-KOH

Thiele TE, Koh MT, Pedrazzini T Voluntary alcohol consumption is controlled via the neuropeptide YYl receptor. J Neurosci 22 RC208, 2002... 

Reaction ofvinylacetylene with Te-KOH-DMSO triad A mixtnre of Te (25.9.), KOH (20 g), H2O (10.9 mL) and DMSO (100 mL) was heated (110°C) with vinylacetylene (31.7 g) in 1 L steel-rotating autoclave for 3 h. The reaction mixtnre was ponred into water, and extracted with Et20. The extracts were washed with H2O. The solvent was stripped off and the residne was distilled in vacuum to collect the rnn with b.p. 80-86°C (2.2 g) consisting of bis(l,3-butadienyl) telluride (1.1 g). 

Reaction of phenylacetylene with Te/KOH/SnCf A mixtnre of 6.4 g of tellurium, 42 g of potassium hydroxide, 22.6 g of SnCl2 2H20, 10.2 g of phenylacetylene, 20 mL of toluene, 60 mL of water and 1.2 g of Adogen 464 was heated (80-97°C) with vigorous stirring for 7 h. The organic layer was separated, and the aqneons layer was extracted with benzene. The benzene was removed under vacnnm. The residne was dissolved in a small amount of ether, poured into 200 mL of isopropyl alcohol, and placed in the refrigerator for 3 days. The yellow crystals of distyryl telluride (2.5 g, yield 15%) and the red needle crystals of distyryl ditelluride (0.7 g, yield 6%) were separated. 

Preparation of alkylvinyl tellurides by reaction of Te/KOH/alkyl iodides, SnCf in HMPA/H2O with pressurized acetylene. Methylvinyl telluride. 12.8 g of Te, 1.42 g of methyl iodide, 48.7 g KOH, 24.7 g SnCl2, 80 mL HMPA and 70 mL HjO were heated (105-115°C) in a rotating autoclave 1 L under acetylenic pressure (initial pressure 14 atm, residual pressure 7 atm, absorbed acetylene 0.8 mol) tor 5 h. The reaction mixture is evacuated at 1 mmHg. The fraction (10.5 g) collected into a cooled trap (-70°C) contains, according to GLC data, methylvinyl telluride (0.34 g, yield 20%), divinyl telluride (10 g, yield 55%) and dimethyl telluride (0.12 g, yield 8%) b.p. 115-116°C. 

Thiele TE, Marsh DJ, Ste Marie L, Bernstein IL, Palmiter RD (1998) Ethanol consumption and resistance are inversely related to neuropeptide Y levels. Nature 396 366-369 Thiele TE, Koh MT, Pedrazzini T (2002) Voluntary alcohol consumption is controlled via the neuropeptide Y Y1 receptor. J Neurosci 22 RC208 Thorsell A, Rimondini R, Heilig M (2002) Blockade of central neuropeptide Y (NPY) Y2 receptors reduces ethanol self-administration in rats. Neurosci Lett 332 1-4 Timmusk T, Palm K, Metsis M (1993) Multiple promoter direct tissue-specific expression of rat BDNF gene. Neuron 10 475-489... 

Pinacolformatiotu The coupling of carbonyl compounds can be effected by Te-KOH at room temperature (7 examples, 85-95%). 

Table-1 Coupling of carbonyl compounds with Te - KOH in methanol...

Run Ar-COR Ar R min Reaction Time Molar Ratio ArCOR Te KOH % Yield (+ meso )... 

This method has many advantages over the other methods as it is very fast reaction. We are investigating further the application of this reagent (Te-KOH-MeOH) on variety of carbonyl compounds and the effect of chiral additives and the stereoselectivity, as well as the probable reaction pathway. 

The electrochemical behavior of single-crystal (100) lead telluride, PbTe, has been studied in acetate buffer pH 4.9 or HCIO4 (pH 1.1) and KOH (pH 12.9) solutions by potentiodynamic techniques with an RRDE setup and compared to the properties of pure Pb and Te [203]. Preferential oxidation, reduction, growth, and dissolution processes were investigated. The composition of surface products was examined by XPS analysis. It was concluded that the use of electrochemical processes on PbTe for forming well-passivating or insulating surface layers is rather limited. 

The yields were markedly increased by the addition of a reducing agent such as SnCl2." The reaction of elemental Te, phenylacetylene, KOH in hydrazine hydrate/ water/toluene was performed under three-phase catalytical system (in the presence of AlKjN+MeCr) giving (Z,Z)-distyryl telluride in 50% yield. ... 

Reaction of phenylacetylene with Te/K0H/N2HfXH20f (Z,Z)-distyryl telluride. A mixture of Te (12.8 g), phenylacetylene (20.4 g), KOH (84 g), NjH XHjO (120 mL), H2O (24 mL), toluene (40 mL), and AlKjN MeCl (1 g) was heated (100-110°C) with a stirring of 6 h. The mixtnre was dilnted with water and extracted with benzene. The organic layer was washed with water, dried over K2CO3 and evaporated. The residue was dissolved in ether, the ether solntion was ponred into ethanol and put into refrigerator. After several days yellow cristals of the tellnride (16.7 g, 50% yield) were separated and dried. 

Figure 8. Time dependence of short-circuit current for several Cd(Se,Te) electrodes in 2 M KOH, S and S. Further details as in Figure 2. See Table I for determination of stoichiometry (upper numbers, Se/Te) and crystal structure flower numbers) (1).

Neither element shows any simple aqueous chemistry in the M(IV) state, as the oxides M02 are insoluble in water at all pH values. Reaction of Sn02 in molten KOH gives the octahedral hydroxanion [Sn(OH)6]2-, in contrast to the normal tetrahedral silicates and germinates, but in parallel with isoelectronic compounds such as Te(OH)6 also found in period 5. Other stannates are mixed oxides without discrete oxoanions (e.g. CaSn03 with the perovskite structure). 

Figure 1. The current strength plotted against the potential difference between electrodes for the different operating solutions (a) - toluene-ethanol (TE) (b) - toluene-fullerene-ethanol (TFE) (c) - TFE with KOH addition.

If the alternative potassium hydroxide method is employed for the separation of Groups IIA and IIB, the KOH extract may contain As, Sb, Sn, Se, Te, and part of the Mo the residue may contain, in addition to HgS, PbS, Bi2S3, CuS, CdS, and PdS, the gold and platinum partly as sulphides and possibly partly in the form of the free metals. Mo is readily identified by the potassium xanthate or a-benzoin oxime test. The Au and Pt will accompany HgS after extraction with dilute nitric acid upon dissolution in aqua regia, Pt may be identified as the dimethylglyoxime complex in the presence of m hydrochloric acid after the Pb, Bi, Cu, and Cd have been removed. 

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