2,2 ,6,6 -tetra-t-butyl

Bipyrylium dication. 2,2, 6,6 -tetra-t-butyl-, reduction. ESR of monocation radical, 60, 90... 

CAS 118-82-1 EINECS/ELINCS 204-279-1 Synonyms Bis (2,6-di-t-butyl-4-hydroxyphenyl) methane Di (4-hydroxy-3,5-di-t-butylphenyl) methane 4,4 -Methylenebis (2,6-bis(1,1-dimethylethyl) phenol) 2,2, 6,6 -Tetra-t-butyl-4,4 -methylenediphenol Classification Sterically hindered bisphenol Empirical C29H44O2 Formula [(C4H9)2C6H2(OH)]2CH2 Properties Lt. yel. powd. insol. in water and 1.0N sodium hydroxide m.w. 424.67 dens. 0.99 (20 C) m.p. 156-158 C b.p. 289 C (40 mm)... 

Tetra-t-butyl-4,4 -methylenediphenol. See 4,4 -Methylenebis (2,6-di-t-butylphenol) Tetrabutyl orthosilicate. See Tetra-n-butoxysilane... 

Ca6H96PaPt2/ 1,1 -Bis(2,2,6,6-tetra(t-butyl)-1-platina-2,6-diphos-phacyclohexane) toluene solvate, 44B, 1081 Ca eHiooClaP4Pd2/ Bis[m-1,7-heptanediylbis(di-t-butylphosphine)]-bis-(dichloropalladium), 45B, 1370... 

C26HftOf 1/3,6,8-Tetra-t-butyl-hemi-Dewar-naphthalene, 43B, 220 C27H18/ 1/1/3,3-Bis(2,2 biphenylylene)propene, 43B, 221 C28H16O2/ Dianthronylidene, 18, 740 C28H18O2/ 10,10 Dianthronyl, 32B, 139... 

The reaction mixture is filtered through a sintered-glass funnel in a dry atmosphere such as may be maintained in a dry-box. The insoluble material is washed with 200 ml. of toluene. The washings and the filtrate are taken to dryness by distillation under reduced pressure at about 90 to 100°. The solid residue is recrystallized twice from dry carbon tetrachloride and then dried in high vacuum at 50 to 100° for a period of 6 hours. The yield of sym-N,2V7,N",N -tetra,-t-butyl-B,B, B",2 " -tetra-chloroperhydrotetrazatetraborocine is 96 g. (60%). 

The oxidative coupling of 2-halo-4,6-di-t-butylphenols with potassium hexacyanofer-rate(III) in benzene was investigated the 2-bromophenol (227) yielded l,4-dihydro-4-bromo-2,4,6,8-tetra-t-butyl-l-oxodibenzofuran (228 81%) and 2,4,6,8-tetra-t-butyldiben-zofuran (229) (81JOC3784). 

The pE spectra of cyclobutadiene 281, tetra-f-butylcyclobutadiene 282, 1,3,5-tri-f-butylpentalene 283 and aceheptylene 284, all of which are subject to second-order bond localization, have been described in the literature. Further examples are 1,3,5,7-tetra-t-butyl-5-indacene 285 (which exhibits a first double band 1,2 at 2 = 6.75 eV, followed by two bands at = 8.50 eV and Q = 9.30 eV) and the tetracyclic hydrocarbon 1,3,6,S-tetra-t-butylpentaleno[2,l-a]pentalene 286 (the first two bands of which are observed at 6.40 eV and 7.65 eV)i. ... 

From the time of van t Hoff (1) and Le Bel (2) the tetrahedral arrangement of substituents around a tetravalent carbon atom has been part of the foundation of organic stereochemistry. However, in the last 30 years, thanks to the rapid development of synthetic methods of organic chemistry as well as of experimental and theoretical methods of structure elucidation, many exciting saturated hydrocarbons with very unusual spatial structure have been synthesized. Cubane (1) was obtained as early as 1964 (3), triprismane (2) (4), a tetra-f-butyl derivative of tetrahedrane (3) (5), small-ring propellanes with structures involving inverted carbon atoms, 4-6 ([3.2.1], [4.1.1] and... 

Lithium iodide Magnesium salicylate 2,2 -Methylenebis (6-t-butyl-4-methylphenol) 2,2 -Methylenebis (4,6-di-t-butylphenyl) 2-ethylhexyl phosphite 2,2 -Methylenebis (4-methyl-6-t-butylphenol) monoacrylate 2,2, 2 "-Nitrilo [triethyl-tris (3,3, 5,5 -tetra-t-butyl-1,1-biphenyl-2,2 -diyl) phosphite] ... 

Phenyl-3,3-biphenylene-allene dimer, 40B, 142 C1HH30F2, anti-1,2-Difluoro-3,4,5,6,7,8-hexaphenyltricyclo-[4.2.0.02-5]octa-3,7-diene, 27, 786 C60H80O4 0.5 C4H10O, 3,3a ,5,5 -Tetra-t-butyl-2 -(3,5-di-t-butyl-4-hydroxyphenyl)-7 -[1 (3,5-di-t-butyl-4-hydroxyphenyl)ethylidene]-3a ,4 ,7 7a -tetrahydrospiro[cyclohexa-2,5-diene-1,1 -[IHjindene]- 4,4 -dione diethyl ether solvate, 46B, 110... 

The nucleophilicity of an hydroxy-group to be linked to the anomeric centre of sugars can be enhanced by trialkylstannylation. Thus treatment of 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl bromide with one equivalent each of tributyl-stannyl methoxide and stannic chloride in dichloromethane at 20 °C furnished an 86% yield of methyl 2,3,4,6-tetra-0-acetyl-/3-D-glucopyranoside. Orthoesters were obtained in the reactions with tributylstannyl alkoxides when the glycosyl halide was epimerized (with tetraethylammonium bromide) in situ (see p. 40). t-Butyl ethers have also been used to enhance the nucleophilicity... 

The deoxygenation of certain sterically hindered aromatic compounds has been studied, contrasting results being obtained. 2,5-Di-t-butylnitrosobenzene with TEP gives a complex mixture containing 2,5-di-t-butylaniline (127), 2,5,2, 5 -tetra-t-butyl-azobenzene (128), N-(2,5-di-t-butylphenyl)-a-t-butyl-a-2-(5-t-butylpyridyl) nitrone (129), and diethyl N-(2,5-di-t-butylphenyl)-phos-phoramidate (130), while the similar reaction of 2,4,6-tri-t-butylnitrosobenzene yielded mainly 3,3-dimethyl-5,7-di-t-butyl-dihydroindole (131) together with small amounts of 2,4,6-tri-t-butylaniline (132) and 2-(2-methylallyl)-4,6-di-t-butylaniline (133). 

Dibenzofuran, 1,2,3,4,6,7,8,9-octahydro-synthesis, 4, 693 Dibenzofuran, polychloro-occurrence, 4, 709 Dibenzofuran, 2,4,6,8-tetra-t-butyl-synthesis, 4, 682... 

A kinetic isotope effect, kH/kD = 1.4, has been observed in the bromination of 3-bromo-l,2,4,5-tetramethylbenzene and its 6-deuterated isomer by bromine in nitromethane at 30 °C, and this has been attributed to steric hindrance to the electrophile causing kLx to become significant relative to k 2 (see p. 8)268. A more extensive subsequent investigation304 of the isotope effects obtained for reaction in acetic acid and in nitromethane (in parentheses) revealed the following values mesitylene, 1.1 pentamethylbenzene 1.2 3-methoxy-1,2,4,5-tetramethyl-benzene 1.5 5-t-butyl-1,2,3-trimethylbenzene 1.6 (2.7) 3-bromo-1,2,4,5-tetra-methylbenzene 1.4 and for 1,3,5-tri-f-butylbenzene in acetic acid-dioxan, with silver ion catalyst, kH/kD = 3.6. All of these isotope effects are obtained with hindered compounds, and the larger the steric hindrance, the greater the isotope... 

Using alkyllithium compounds, a distannane with a very long Sn—Sn bond, 3.03A, and a syw-peripheral conformation122 was prepared. Thus, reaction of di-t-butyl(chloro)2,4,6-triisopropylphenyl)tin, 78, with f-butyllithium gives 1,1,2,2-tetra-f-butyl-l,2-(2,4,6-triisopropylphenyl)ditin, 79, which displays a restricted rotation about the Sn—C bond as well as the Sn—Sn bond, even at high temperatures. 

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