2.6- Di-tert-butyl-4-methoxyphenyl

Aryl Esters 2,6-Di-re/t-butyl-4-methylphenyl esters (BHT esters) and 2,6-di-tert-butyl-4-methoxyphenyl esters (BHA esters) provide steric suppression of the carboxyl reactivity so they do not react with RMgX or RLi reagents.BHT and BHA esters... 

Tomioka has also extensively investigated conjugate 1,4-additions to a,p-un-saturated BHA (2,6-di-tert-butyl-4-methoxyphenyl) esters stilbene-derived di-... 

Sterically bulkier 2,6-diisopropylphenyl (16c), 2,6-di(tert-butyl)-4-methylphenyl (16d), and 2,6-di(tert-butyl)-4-methoxyphenyl esters (16e) were more effective to protect the carboxylic acid of 16. These ester-protected styrene monomers, 16c-16e, underwent living anionic polymerization without any side reaction in THF even at -78 °C. The resulting living polymers were stable for 24 h under such conditions. Polymers with predictable molecular weights and narrow molecular weight distributions (A4w/A4n< 11) were quantitatively obtained. The success of postpolymerization and the sequential block copolymerization with tert-butyl methacrylate (tBMA) further supports the living nature of the polymerization of 16c-16e. Thus, tert-butyl and sterically bulkier phenyl esters satisfactorily protect the carboxylic acid function of 16 to enable the living anionic polymerization of their ester-protected monomers. 

Analogous results were found in hydrogen peroxide oxidation of 2.6-di-tert-butyl-4(4-methoxyphenyl)-X -phosphorin 87. The crystalline 2-hydrophosphinic acid 88, m.p. 176-178 °C, on esterification with diazomethane, leads to a mixture of two diastereoisomeric esters, 89 E and 89 Z, which could be separated by thin-layer chromatography but not crystallized. 

The BBrs reaction with 1. l-dimethoxy-2.4.6-di-tert-butyl-4-(4 -methoxyphenyl)-X -phosphorin 200 leads to cleavage of both methoxy groups in addition to the methoxy group at the phosphorus, the 4 -methoxy group is attacked. The 2-hydro-4-(4 -hydroxyphenyl)-phosphinic acid methyl ester 201 can be methylated with methyl iodide in methanol/sodium methylate at the phenolic group, leading to 202, which can also be prepared by hydrogen peroxide oxidation of 2.6-di-tert-butyl-4-(4 -methoxy phenyl)-X -phosphorin 204 to 203, followed by diazomethane methylation (see Table 13, p. 61). 

Results are selected from Reference 50. RO" is the 2,6-di-tert-butyl-4-(4 -methoxyphenyl)phenoxy radical. 

Abbreviations Ac acetyl Bn benzyl BSP 1-benzenesulfinyl piperidine BTIB bis(trifluoroacetoxy)iodobenzene DAST (diethylamino)sulfur trifluoride DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTSF dimethyl(methylthio)sulfonium tetrafluoroborate DMTST dimethyl(methylthio)sulfonium triflate DTBMP 2,6-Ai-tert-butyl-4-methylpyridine DTBP 2,6-di-tert-butylpyridine DTBPl 2,6-di-tert-butylpyridinium iodide FDCPT l-fluoro-2,6-dichloropyridinium triflate FTMPT l-fluoro-2,4,6-trimethylpyridinium triflate IDCP iodonium dicollidine perchlorate IDCT idonium dicollidine triflate LPTS 2,6-lutidinium p-toluenesulfonate LTMP lithium tetramethylpiperidide Me methyl MPBT S-(4-methoxyphenyl) benzenethiosulflnate NBS A-bromosuccinimide NIS A-iodosuccinimide NlSac A-iodosaccharin PPTS pyridinium p-toluenesulfonate TBPA tris(4-bromophenyl)ammoniumyl hexachloroantimonate Tf trifluoromethanesulfonyl TMTSB methyl-bis(methylthio)sulfonium hexachloroantimonate TMU tetramethylurea Tr trityl TTBP 2,4,6-tri-tert-butylpyrimidine. 

Stabilizers UVA 2-hydroxy-4-octyloxybenzophenone 2-(2H-benzo-triazol-2-yl)-6-dodecyl-4-methylphenol, branched linear propanedioic acid, [(4-methoxyphenyl)-methylene]-dimethyl ester HAS 1,3,5-triazine-2,4,6-triamine, N,N [1,2-ethane-diyl-bis[[[4,6-bis[butyl(1,2,6,6-pentamethyl-4-piperidinyl) amino]-1,3,5-triazine-2-yl]imino]-3,1 -propanediyl]bis[N, N -dibutyl-N ,N -bis(1,2,2,6,6-pentamethyl-4-piperidinyl)- poly[[(6-[1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl] [2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[2,2,6,6-tetramethyl-4-piperidinyl)imino]] 1,6-hexanediamine- N,N -bis(2,2,6,6-tetramethyl-4-piperidinyl)-polymer with 2,4,6-trichlo-ro-1,3,5-triazine, reaction products with N-butyl-1-butanamine an N-butyl-2,2,6,6-tetramethyl-4-piperidinamine butanedioic acid, dimethylester, polymer with 4-hydroxy-2,2,6,6-tetrameth-yl-1-piperidine ethanol Phenolic antioxidant pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) Amine benzenamine, N-phenyl-, reaction products with 2,4,4-trimethylpentene Optical brightener 2,2 -(1,2-ethyl-enediyldi-4,1-phenylene)bisbenzoxazole, C.I.F.B. 367 ... 

MePTZ = lO-methylphenothiazine 2,3-dpp = 2,3-bis (2-pyridyl)pyrazine 2,9-Me2-4,7-Ph2-phen = 2,9-dimethyl-4,7-diphenyl-l,10-phenanthrolme 2,9-Me2-phen = 2,9-dimethyl-1,10-phenanthroline 3,4,7,8-Me4-phen = 3,4,7,8-tet-ramethy 1-1,10-phenanthroline 4,4 - NH2 2-bpy = 4,4 -dia-mino-2,2 -bipyridine 4,4 -Me2-bpy = 4,4 -dimethyl-2,2 -bipyridine 4, 4 -Ph2-bpy = 4,4 -diphenyl-2,2 -bipyridine 4, 4 - Bu2-bpy = 4,4 -di-tert-butyl-2,2 -bipyridine 4,7-Me2-phen = 4,7-dimethyl-l,10-phenanthroline 4-MeOPh-HPh bpy = 4 -(4-methoxyphenyl)-6 -phenyl-2,2 -bipyridine 4-Me-phen = 4-methyl-1,10-phenanthroline 5,6-Me2-phen = 5,6-dimethyl-l,10-phenanthroline 5-Ph-phen = 5-phenyl-1,10-phenanthroline bimy = benzimidazol-2-ylidene biq = 2,2 -biquinoline bpy = 2,2 -bipyridine bpy-dvb-bpy = 1,4-bis[2-(4 -methyl-2,2 -bipyrid-4-yl)ethenyl]benzene bpy-pyrl = 4-(2-pyrrol-l-ylethyl)-4 -methyl-2,2 -bipyridine bpy-pyr2 = 4,4 -bis((3-pyrrol-l-ylpropyloxy)carbonyl)-2,2 -bipyridine BSA = bovine serum albumin BTA = bis(trimethylsilyl)acetylene chrysi = 5,6-chrysenequinone diimine COD = 1,5-cyclooctadiene DAB = 1,4-diaza-1,3-butadiene DFT = density functional theory dmb =1,8-diisocyano-/ -menthane dmb-tol = 4-methyl-4 -(iV-methyl-/ -tolylaminomethyl)-2,2 -bipyridine dmpe = l,2-bis(di-methylphosphino)ethane dmpm = bis(dimethylphosphino) methane dpmp = bis(diphenylphosphinomethyl)phenylphos-phine dppb = l,2-bis(diphenylphosphino)benzene dppe = l,2-bis(diphenylphosphino)ethane dpp-HCNN = 2,9-di-... 

Di(tert-butyl)-6-[(4-methoxyphenyl)methyl]phenol (789) sterilizes female housefly and screwworm fly species, because microsomal oxidation of 789 may produce the corresponding reactive o-quinone methide (790). Thus, the phenol 789 was submitted to AgiO-promoted oxidation in MeOH-MeiNH (reflux, 1 min) to afford an adduct 791 (60%) through the quinone methide intermediate 790 (Scheme 158). ... 

Our initial attempts at metalating hydrazones of methyl and tert-huiy pyruvate and trapping them with electrophiles were unsuccessful and led primarily to self-acylated products (scheme 12). Only after we sterically blocked the ester reactivity as the 2,6-di-t rt-butyl-4-methoxyphenyl ester was the direct manipulation of the corresponding azaenolates possible. 

Benzopyran-3-one, l,4-dihydro-6,7-dimethoxy-], 55, 45 Isocyamde, benzyl-, 55, 98 Isocyanide, butyl-, 55, 98 ISOCYANIDE, tert-butyl- [Isocyamde, 1,1-dimethylethyl-], 55, 96 Isocyamde, cyclohexyl-, 55, 98 Isocyamde, dodecanyl-, 55, 98 Isocyamde, ethyl, 55,98 Isocyamde, methyl, 55, 98 Isocyamde, phenyl-, 55, 98 (-)-2,3 4,6-Di-0-isopropylidene-2-keto-L-gulomc acid, hydrate [L-jcy/o-2-Hex-ulosomc acid, bis-<9-( 1 -mcthylcthyl-ldene)-], 55,80, 81 ISOXAZOl F, 3-(4-chlorophenv1)-5-(4-methoxyphenyl)-, 55, 39 Isoxazole,5 -(4-chloropheny l)-3-(4-me th-oxyphenyl)-, 55,42... 

OH-DPAT = 8-Hydroxy-2-(di-n-propylamine)tetralin CP93129 = 5-Hydroxy-3(4-l,2,5,6-tetrahydropyridyl)-4-azaindole LY334370 = 5-(4-fluorobenzoyl)amino-3-(l-methylpiperidin-4-yl)-l -indole fumarate SB204741 = A/-(l-methyl-5-indolyl)-/V -(3-methyl-5-isothiazolyl)urea WAY100635 = N-tert-Butyl 3-4-(2-methoxyphenyl)piperazin-l-yl-2-phenylpropanamide. 

---