4,4 ,6,6 -tetra- -butyl

Increased molecular association iacreases viscosity. Tetra-/-butyl titanate and tetraisopropyl titanate are mobile Hquids at room temperature tetra- -butyl titanate and tetra- -propyl titanate, TYZOR NPT [3087-37-4], are thick and sympy. The boiling poiats of these materials also reflect association (Table 1). 

P-Ketoester Chelates. p-Ketoesters react in a fashion similar to the p-diketones. TYZOR DC [27858-32-8] is the hght-yeUow Hquid from TYZOR TPT and two moles of ethyl acetoacetate (eaa) after removal of the isopropyl alcohol. TYZOR BEAT, the bis-ethylacetoacetate [20753-28-0] derived from the tetra- -butyl titanate, and TYZOR IBAY [83877-91-2] the isobutoxy analogue, perform similarly to TYZOR DC. Both, however, have better cold-storage stabiHty. 

A number of alkyl-substituted cyclobutadienes have been prepared by related methods Increasing alkyl substitution enhances the stability of the compounds. The tetra-/-butyl derivative is stable up to at least 150°C but is very reactive toward oxygen. This reactivity reflects the high energy of the HOMO. The chemical behavior of the cyclobutadienes as a group is in excellent accord with that expected from the theoretical picture of the structure of these compounds. 

In addition to two-phase conditions, phase transfer catalysts have been used to improve the Skraup/Doebner-von Miller reaction.Condensation of 32 with 5 in a two-phase system of toluene/con HCI provides 33 in 47% yield. Addition of 5 mol% tetra- -butyl ammonium chloride increased the yield to 57%. 

An interesting case of the benzannulated B, N complex is species 58 (X = C1) (00AGE948), prepared from [(OC)Os(PPh3)2Cl(BCl2)] and 8-aminoquinoline. It reacts with tetra- -butyl ammonium iodide and forms 58 (X = I). 

Trimethylsiloxyphenyl isocyanide enters the cyclization reaction with [MCl2(NCPh)2] (M = Pt, Pd) to yield the homoleptic tetracarbenes 77 (M=Pt, Pd) (97JOM(541)51). Complex 77 (M = Pd) enters an interesting reaction with ammonia to yield the species 78 where two of this benzoxazol-2-ylidene ligands are deprotonated and become C-coordinated benzoxazole moieties, while the other two remain intact. Palladium(II) iodide in these conditions behaves differently yielding the di-Mo-cyanide complex, which in the presence of tetra- -butyl ammonium fluoride gives the dicarbene 79. 

An exception to the lone pair or donor electron requirement of organic inhibitors is provided by the quaternary ammonium compounds. Meakins reports the effectiveness of tetra-alkyl ammonium bromides with the alkyl group having C 10. Comparative laboratory tests of commercial inhibitors of this type have been described . The inhibiting action of tetra-butyl ammonium sulphate for iron in H S-saturated sulphuric acid has been described, better results being achieved than with mono-, di- or tri-butylamines . 

When multiple peripheral substituents, as in [Ni(2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenyl-porphyrin)], [Ni(5,10,15,20-tetra(/-butyl)porphyrin)], [Ni(2,3,7,812,13,17,18-tetracyclohexenyl-5,10,15,20-tetraphenylporphyrin)], and [Ni(OETPP)], cause the macrocycles to become nonplanar,283,284 the HOMOs of the porphyrins are destabilized and the molecules become easier to oxidize.283,285 In accord with the general discussion above, these compounds are oxidized to tt cation radicals and remain so even at low temperatures in CH2C12. However, upon addition of... 

An elegant approach toward formation of the central tetrahydropyrimidine ring has been reported by Tamura and co-workers who utilized an aza-Diels-Alder cyclization of ethyl ( )-3-aza-3-(l,3-benzoxazol-2-yl)propenoate 266 with a range of cinnamyl alcohols 267 catalyzed by l,l,3,3-tetra- -butyl-l,3-diisothiocyanatodistannoxane, and subsequent lactonization to generate the tricyclic core structure 268 (Scheme 18) <1998J(P1)3389>. 

Co-photolysis of 2,5-di(trifluoromethyl)-l,3,4-oxadiazole with cyclotrisilane, which under these conditions decomposes to afford tetra-(/-butyl)disilene and di-(/-butyl)silylene, provides dihydrodioxadiazadisilocine and trihydro-oxazatrisiline derivatives (Scheme 13) <1996JOM355>. 

Tetraalkyl-9,10-dihydrodistannaanthracenes 4 have been prepared via the lithiation73 or the magnesiation of 1,2-dibromobenzene,166 followed by reaction with R2SnCl2. The tetramethyl derivative is butterfly shaped with a dihedral angle of 142°, but the tetra-/-butyl derivative is planar.73 The stannepin 5 and stannolane 6 were obtained as byproducts of the former reaction. 

Scheme 1.9 Steps in the reaction of (tetra-butyl)tin with silica supported platinum particles.

Bimetallic M-Sn alloys (M = Rh, Ru, Ni) supported on siHca and prepared by reaction of M with tetra(butyl)tin display catalytic properties quite different from those of the monometallic catalysts. Indeed, they are very selective for the hydrogenolysis of ethyl acetate to ethanol [110, 112-115]. For example, while the... 

Monomers 1 and 2 were also used as comonomers with dimethyl dialkanoates and monomers containing furan rings, for the synthesis of copolyesters by bulk polycondensations, in the presence of titanium isopropoxide or tetra-butyl-1,3-dichloro-distannoxane. In general, the biodegradability of the copolyesters of 1 decreased with increasing difuran dicarboxylate content, and copolymers... 

A. cm-DICHLOROBIS(PROPANONEOXIME)PLATINUM(II) and TETRA( -BUTYL)AMMONIUM TRICHLORO (PROPANONEOXIME) PLATINATE(II), m-PtCl2 (CH3)2C=NOH 2 AND [( -C4H9)4N][PtCl3 (CH3)2C=NOH ]... 

Heating a solution of stannole 168 in benzene-thermal cleavage of the S-C bond and the formation of four-membered 2,2,4,4-tetra-/-butyl-l,3,2,4-dithiadistannetane. Interestingly, this reaction is reversible. Cooling down the resulting solution leads to a quantitative re-formation of stannole 168 (Equation 1) <2001TL7063>. 

M. anisopliae Prl isoforms subtilisin-like serine 28.5-30.2 9.0-10.2 tetra-butyl- oxycarbonyl-Gly-Leu- Phe-chloromethyl ketone St. Leger etal. (1994a)... 

Perfluoroalkyl-chroman-4-ones react with (perfluoroalkyl)trimethylsilane in the presence of a catalytic amount of tetra- -butyl ammonium fluoride (TBAF) to give 2-bis(perfluoroalkyl)-277-chromenes 75 as the major products along with trace amounts of the corresponding 477-chromenes 76 (Equation 41) <2003TL2097>. 

The standard manufacturing method for tetraalkyl titanates, such as TYZOR TPT, or tetra- -butyl titanate, TYZOR TBT [5593-70-1]> involves the addition of TiQ4 to an alcohol. In a series of reversible displacement reactions, the alkoxy substitution products and hydrochloric acid form as follows ... 

An attempt was also made to accelerate the same reaction performed in a microemulsion based on water, nonionic surfactant and hydrocarbon oil [9]. The reaction was performed in a Winsor III system and the same Q salt, tetra-butyl ammonium hydrogen sulfate, was added to the formulation. In this case the addition of the phase transfer catalyst gave only a marginal increase in reaction rate. Similar results have been reported for an alkylation reaction performed in different types of micellar media [52]. The addition of a Q salt gave no effect for a system based on cationic surfactant, a marginal increase in rate for a system based on nonionic surfactant and a substantial effect when an anionic... 

The fluoride ion complex of 5-octamethyl-[12]-mercuracarborand-4 26 is an effective source of naked fluoride <2004AGE1854>. Treatment of a tosylated sugar with fluoride 26, in the presence of tetra- -butyl ammonium iodide 27, leads to 49% tosylate replacement. The reaction does not occur without co-reagent 27, so presumably its role is to help release fluoride ion from complex 24. Scheme 3 illustrates the preparation of fluoride reagent 26 by decomplexa-tion of diiodide 25 with AgBp4 forming neutral tetramer 24, followed by treatment with tetramethylammonium fluoride. 

To obtain the azo-polymers (Scheme 1), the polysiloxanes containing chloroben-zyl groups in the side-chain were modified with 4-(phenylazo)phenol. hi a typical reaction, 1.4mmol of polysiloxanes was dissolved in 6mL DMSO and mixed with the corresponding amount (as a function of the imposed substimtion degree) of sodium salt of 4-(phenylazo)phenol and 0.5-0.7 g tetra-butyl-ammonium hydrogen-sulphate. The mixture was introduced in a flask and heated 5h at 90°C. The polymer was precipitated in methanol and washed 5-6 times with methanol to eliminate the imreacted products. The polymer was dried under vacuum (10mm Hg and 35°C). 

Ionic liquids [e.g. l-ethyl-3-methylimidazolium triflate (mp. —9 C) l-n-butyl-3-methyl-pyridinium chloride (mp. 98 °C) tetra- -butyl-ammonium bromide (mp. 130 °C)]... 

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