Butyl compounds

ButyUithium is available as a 15—20 wt % solution in //-pentane or heptane. Noticeable decomposition occurs after alb reflux in heptane (bp 98.4°C) but not after a 15 min reflux in ben2ene (bp 80.1°C) or hexane (bp 68°C). /-ButyUithium in pentane or heptane is more stable than //-butyUithium in hexane (125). Solutions of /-butyUithium in pentane and heptane are flammable Hquids and are considered pyrophoric. The /-butyl compound is more reactive than either the n- and sec-huty. Di-//-butylether is cleaved by /-butyUithium in 4—5 h at 25°C, compared to the 2 d for j iZ-butyUithium and 32 d for //-butyUithium (126). /-ButyUithium can be assayed by aU of the techniques used for //-butyUithium. /-ButyUithium is a useful reagent in syntheses where the high reactivity of the carbon—lithium bond and smaU si2e of the lithium atom promote the synthesis of stericaUy hindered compounds, eg,... 

Also due to the high barrier of inversion, optically active oxaziridines are stable and were prepared repeatedly. To avoid additional centres of asymmetry in the molecule, symmetrical ketones were used as starting materials and converted to oxaziridines by optically active peroxyacids via their ketimines (69CC1086, 69JCS(C)2648). In optically active oxaziridines, made from benzophenone, cyclohexanone and adamantanone, the order of magnitude of the inversion barriers was determined by racemization experiments and was found to be identical with former results of NMR study. Inversion barriers of 128-132 kJ moF were found in the A-isopropyl compounds of the ketones mentioned inversion barriers of the A-t-butyl compounds lie markedly lower (104-110 kJ moF ). Thus, the A-t-butyloxaziridine derived from adamantanone loses half of its chirality within 2.3 days at 20 C (73JCS(P2)1575). 

Cyclopropanations by carbenes from chlorodiazirines were observed in several cases, e.g. with the r-butyl compound. Cyclopropanation and stabilization by ring enlargement and by elimination compete in chlorocyclobutyldiazirine photolysis. 

Arrhenius parameters for nitration of 4-aikylphenyltrimethyiammonium ions in nitric acid-sulphuric acid mixtures (Table 12). It was argued that the observed Baker-Nathan order of alkyl substituent effect was, in fact, the result of a steric effect superimposed upon an inductive order. However, a number of assumptions were involved in this deduction, and these render the conclusion less reliable than one would like it would be useful to have the thermodynamic parameters for nitration of the methyl substituted compound in particular, in order to compare with the data for the /-butyl compound, though experimental difficulties may preclude this. It would not be surprising if a true Baker-Nathan order were observed because it is observed for all other electrophilic substitutions in this medium1. 

Trimethylaluminum, which exhaustively methylates ketones (16-27), also exhaustively methylates carboxylic acids to give tert-butyl compounds (see also 10-99) ... 

With some substrates, a P hydrogen is present on only one carbon and (barring rearrangements) there is no doubt as to the identity of the product. For example, PhCH2CH2Br can give only PhCH=CH2. However, in many other cases two or three alkenyl products are possible. In the simplest such case, a sec-butyl compound can give either 1-butene or 2-butene. There are a number of rules that enable us to predict, in many instances, which product will predominantly form. ... 

Kurogoshi and Hori [ 104] determined the crystal structures of the mesogenic ethyl and butyl 4-[4-(4-n-octyloxybenzoyloxy)benzylidene]aminobenzoates. The compounds have different phase sequences crystal-smectic A-nematic-isotropic and crystal-smectic C-smectic A-nematic-isotropic for the ethyl and butyl compounds, respectively. Both compounds have layer structures in the solid phase. The butyl compound contains two crystallographically independent molecules. Within the layers, adjacent molecules are arranged alternately so as to cancel their longitudinal dipole moments with each other. In the ethyl compound the core moieties are almost perpendicular to the layer plane, while in the butyl compound these moieties are tilted in the layer. 

The inner liner forms the vital internal membrane which holds the inflation medium at an elevated pressure within the structure of the tire. In early days the liner was a separate tube of natural or butyl, or more particularly, XIIR compound as an integral part of the tire structure. Adhesion levels of butyl compounds can be critically low requiring an insulating or barrier layer of an NR compound to act as an interface between the liner and the casing. 

Refluxing [C x i2 tc)] in CHCI3 yields a compound which analyses as Cu3(Et2C tc)2Cl 124). The analogous butyl compounds could be prepared by the reaction of 1 mole [Cu(Bu2C tc)]4, 2 moles Cu and 1 mole X2 (X = C1, Br) in CS2. Molecular weight determinations in benzene show an association factor 3 and infrared data point to terminal halogen atoms 99). No crystal structure data of these compounds are available. 

The readily available organotin compounds include tin hydrides (stannanes) and the corresponding chlorides, with the tri-n-butyl compounds being the most common. Trialkylstannanes can be added to carbon-carbon double and triple bonds. The reaction is usually carried out by a radical chain process,137 and the addition is facilitated by the presence of radical-stabilizing substituents. 

The reactivity of diazo carbonyl compounds appears to be related to the conformational equilibria between s-cis and s-trans conformations. A concerted rearrangement is favored by the s-cis conformation.237 The /-butyl compound 19, which exists in the s-trans conformation, gives very little di-/-butylketene on photolysis.238 A similarly... 

The molecules I, II and III of Scheme 3 can be obtained, depending on the molarities of the reactants 176) or the nature of the substituent R 177). When R is tert-butyl, thermolysis of the adduct from tert-butylamine and stannylene leads to a mixture of I and II these compounds can be isolated in the molarities indicated in Scheme 3. In the case R = tert-butyl, compound III is not formed directly. It can however be synthesized by thermolysis of I or II at elevated temperatures. On the other hand, if R is dimethylamino, the reaction leads directly to compound III without formation of I or II177). 

Resin cures utilise phenol-formaldehyde resins with reactive methylene groups and a small added amount of either a chlorinated rubber, e.g., polychloroprene, or stannous chloride. If halogenated phenolic resins are used the additional source of a halogen may not be required. Resin cures give butyl compounds excellent heat stability and are used to good effect where this is required, e.g., in tyre curing bags which have to resist service at 150 °C in a steam atmosphere. 

A range of mechanisms is possible for the acidolysis of phosphorus amides, depending on the nucleophilicity of the departing amine. A recent study of phosphinic amides (160) in acidic media demonstrated that, when R2 is aryl, the presence of an o-Me group reduced the hydrolysis rate significantly, and also that the mechanism appears to be of an associative type.128 The phosphinic halides (161 X = Cl or F R = Me) are more reactive, probably for steric reasons, than the corresponding halides (161 R = Bu1) in 5 n2(P) solvolyses with aqueous acetone and with alkali. In the case of the t-butyl compounds, the fluoride is more reactive to OH- than is the chloride.129... 

The primary products obtained from 2-butanol are of mechanistic. significance and may be compared with other eliminations in the sec-butyl system 87). The direction of elimination does not follow the Hofmann rule 88) nor is it governed by statistical factors. The latter would predict 60% 1-butene and 40% 2-butene. The greater amount of 2-alkene and especially the unusual predominance of the cis-olefin over the trans isomer rules out a concerted cis elimination, in which steric factors invariably hinder the formation of cis-olefin. For example, the following ratios oicisjtrans 2-butene are obtained on pyrolysis of 2-butyl compounds acetate, 0.53 89, 90) xanthate, 0.45 (S7) and amine oxide, 0.57 86) whereas dehydration of 2-butanol over the alkali-free alumina (P) gave a cisjtrans ratio of 4.3 (Fig. 3). 

Some benzylic mono- and di-cations have been studied by the NMR/DFT/IGLO technique. Of the stable dications, the trimethyl species (76 R = Me) was found to be the major resonance contributor to the structure of (75), and the same was found to be true for the trimethoxy derivative. In the related monocations, for (77) the major resonance contributor was (78), and this was also the case for the pentamethyl and 2,5-dimethyl-4-r-butyl compounds. The dication (79) and the trication (80),... 

Polynuclear aromatics fcis-phenols, triphenyl -r-butyl compounds Stabilizers... 

In addition, the butylated compounds ClEt2SiP(SiEt2)2—PSiEt2Bu and (SiEt2)4P3SiEt2Bu (the butylated derivative of 22), and trace amounts of 13 are formed. A compound with the adamantane structure corresponding to compound 10 or to its precursor 11 can be excluded with certainty. 

Substitution of Cl in R(Me3Si)Pl—P2(C1)—P3(SiMe3)R with the CMe3 group occurs as the principal reaction only when R = R = Me. Under all other variations of R and R the proportion of P2-t-butylated compounds remains under 10%. Obviously, for steric reasons, transmetallation between chlorinated triphosphanes and LiCM3 at — 78°C is... 

The intent of the diversity score is to ensure that methyl-ethyl-propyl-butyl compounds won t all rank near the top and that lower scoring (on other measures) compounds that are structurally novel will be evaluated more favorably. 

Other pyrimidine substrates to be converted to A, A -dinitro derivatives by loss of N-substituents include the diacyl compounds 503 and 504, and the di-(/ftt-butyl) compound 505 <2000JOC1200>. In the case of the disulfamic acid derivative 506, O-nitration also occurred, to give the trinitro derivative 507 <2000RCB1082>. 

The reactions of 2-iodopyrazine, 2-methylsulfanyl-4-iodopyrimidine and 3-iodo-6-phenylpyridazine with lithium tributylmagnesate resulted in very efficient iodine-magnesium exchange to yield the corresponding heteroarylmagnesium species (equations 35-37)" °. The reactions with carbonyl compounds and diphenyl disulfide proceeded with good yields. The reactions proceeded smoothly, and neither the starting iodide nor any butylated compounds derived from nucleophilic addition to the heteroaromatic nuclei were observed. 

On the basis of CNDO/2 calculations on the model compounds 2.4.6-trimethyl-pyridine and 2.4.6-tri-methyl-X -phosphorin, Schweig and coworkers found that the MO sequences of pyridine and X -phosphorin do not correspond to each other. For simplicity, methyl- rather than tert-butyl groups were used in the calculations (whereas the PE and UV spectra of the tert-butyl compounds have been recorded the synthesis of the unsubstituted X -phosphorin was unknown at the... 

Butler Volmer, equation (coni.) multistep reaction. 1176. 1179 non-equilibrium, 1191 theory of diffusion, 1217 Butyl compounds, adsorption. 979... 

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