4-Methylphenol, reaction with

Methylphenol is converted to 6-/ f2 -butyl-2-methylphenol [2219-82-1] by alkylation with isobutylene under aluminum catalysis. A number of phenoHc anti-oxidants used to stabilize mbber and plastics against thermal oxidative degradation are based on this compound. The condensation of 6-/ f2 -butyl-2-methylphenol with formaldehyde yields 4,4 -methylenebis(2-methyl-6-/ f2 butylphenol) [96-65-17, reaction with sulfur dichloride yields 4,4 -thiobis(2-methyl-6-/ f2 butylphenol) [96-66-2] and reaction with methyl acrylate under base catalysis yields the corresponding hydrocinnamate. Transesterification of the hydrocinnamate with triethylene glycol yields triethylene glycol-bis[3-(3-/ f2 -butyl-5-methyl-4-hydroxyphenyl)propionate] [36443-68-2] (39). 2-Methylphenol is also a component of cresyHc acids, blends of phenol, cresols, and xylenols. CresyHc acids are used as solvents in a number of coating appHcations (see Table 3). 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

BHT (2,6-di-tert-butyl-4-methylphenol), a phenolic antioxidant, on reaction with NO under neutral conditions, results in scavenging of the potentially harmful NO via radical reactions [143]. Sodium phenolate under basic conditions undergoes a Traube-type reaction at the ortho-position to produce a cupferron derivative [144]. When the ortho-positions are sterically blocked and the para-position does not bear a proton, cyclohexadienone diazeniumdiolates may be formed (Scheme 3.12) [145]. 

In a smog chamber experiment, 2-methylphenol reacted with nitrogen oxides to form nitrocresols, dinitrocresols, and hydroxynitrocresols (McMurry and Grosjean, 1985). Anticipated products from the reaction of 2-methylphenol with ozone or OH radicals in the atmosphere are hydroxynitrotoluenes and ring cleavage compounds (Cupitt, 1980). 

The metalloporphyrin-initiated polymerizations are accelerated by the presence of steri-cally hindered Lewis acids [Inoue, 2000 Sugimoto and Inoue, 1999]. The Lewis acid coordinates with the oxygen of monomer to weaken the C— O bond and facilitate nucleophilic attack. The Lewis acid must be sterically hindered to prevent its reaction with the propagating center attached to the prophyrin structure. Thus, aluminm ortho-substituted phenolates such as methylaluminum bis(2,6-di-/-butyl-4-methylphenolate) accelerate the polymerization by factors of 102-103 or higher. Less sterically hindered Lewis acids, including the aluminum phenolates without ortho substituents, are much less effective. 

The remarkably high isotope effects found in Reactions 10 and 10a are almost as embarrassing as was our discovery of an isotope effect of about 15 in the reaction with phenols referred to above. [For 2,6-di-tert-butyl-4-methylphenol in oxidizing styrene at 65°C. we obtained an isotope effect kH/kD = 10.6 (11). We have since carefully measured the isotope effect for 2,4,6-tri-ferf-butylphenol under the same conditions and have obtained a value 15. In these cases, hydrogen bonding to the solvent is relatively unimportant (6, 12). Similarly, DaRooge and Mahoney (9) have reported that for the reaction of 2,4,6-tri-tert-butylphenoxy radicals with 4-phenylphenol kH/kD 7.5.] Although... 

Reaction of 9-fluoro-7-oxo-2,3-dihydro7H-pyrido[l,2,3-de][l,4]oxa-zine-6-carboxylate and ferf-butyl (2-mercaptoethyl)carbamate in DMSO at 100 °C for 5 h gave 9-[2-(ferc-butoxycarbonylamino)ethylthio] derivative (06WOP2006/050943). The iodo atom of 9-iodo-7-oxo-2,3-dihydro-7H-pyrido[l,2,3-de][l,4]oxazine-6-carboxylic acids was coupled with 4 -0-(2-allyloxyethyl)azithromicin in MeCONMe2 in the presence of Bu3N and fra s-di-g-acetato-bis[2-(di-o-tolylphosphino)benzyl]dipalladium(II) and di(ferf-butyl)-4-methylphenol at 110-115 °C for 15-17 h to give a mixture of 9-(3-substituted prop-1- and -2-enyl) derivatives (07WOP2007/ 054296). 10-methoxy and 10-cyano-3-hydroxymethyl-2,3-dihydro-5H-pyr-ido[l,2,3-de][l,4]benzoxazin-5-ones were obtained from 10-bromo derivative by reaction with NaOMe in the presence of Cu(I)I at 140 °C in DMF,... 

Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are antioxidants that are added to foods and many other organic materials to inhibit decomposition caused by reactions with oxygen. Perhaps you have seen these compounds listed among the ingredients on your cereal box at breakfast. (The mechanism of operation for these antioxidants is described in Section 21.8.) Both of these compounds are prepared by Friedel-Crafts alkylation reactions. BHT is synthesized by the reaction of p-methylphenol with 2-methylpropene in the presence of an acid catalyst. 

Irmak et al. (2005) also utilized an analogous divided Pt/carbon-felt cell to destroy 300 cm3 of an 02-saturated 0.6 mM 4-chloro-2-methylphenol solution with Fe2+ as catalyst in H2S04 of pH 2.7 by electro-Fenton and photoelectro-Fenton at Ecat = —0.55 V vs. SCE. The solution was irradiated with UVC light of Amax = 254 nm in photoelectro-Fenton. After applying 141 C to a solution with 1.8mMFe2+ for 300 min, the photoelectro-Fenton process led to overall mineralization with total release of Cl-. This process was much faster than the comparable electro-Fenton one, as expected from the additional photolysis of complexes of Fe3+ with pollutants and the production of more OH from reaction (19.24). 

Benzyl bromides 15 derived from either salicylaldehydes or 2-methylphenols by reaction with alkyl propynoates afford 277-1 -benzopyrans on treatment with tetrahydrothiophene and K2CO3. A sulfonium ylide is proposed which initiates a Michael addition - elimination -substitution sequence. When CS2CO3 is used as the base, 477-1-benzopyrans result almost exclusively, presumably through isomerisation of the 277-1-benzopyran. The protocol thus offers access to both chromene isomers through simple variation of the reaction conditions <06OL3853>. The Cu-catalysed intramolecular O-arylation of a-(2-bromobenzyl)-P-keto esters in refluxing THF offers a useful route to 2-substituted 477-l-benzopyran-3-carboxylates <06JOC6427>. 

A powerful oxidizer. Explosive reaction with acetaldehyde, acetic acid + heat, acetic anhydride + heat, benzaldehyde, benzene, benzylthylaniUne, butyraldehyde, 1,3-dimethylhexahydropyrimidone, diethyl ether, ethylacetate, isopropylacetate, methyl dioxane, pelargonic acid, pentyl acetate, phosphoms + heat, propionaldehyde, and other organic materials or solvents. Forms a friction- and heat-sensitive explosive mixture with potassium hexacyanoferrate. Ignites on contact with alcohols, acetic anhydride + tetrahydronaphthalene, acetone, butanol, chromium(II) sulfide, cyclohexanol, dimethyl formamide, ethanol, ethylene glycol, methanol, 2-propanol, pyridine. Violent reaction with acetic anhydride + 3-methylphenol (above 75°C), acetylene, bromine pentafluoride, glycerol, hexamethylphosphoramide, peroxyformic acid, selenium, sodium amide. Incandescent reaction with alkali metals (e.g., sodium, potassium), ammonia, arsenic, butyric acid (above 100°C), chlorine trifluoride, hydrogen sulfide + heat, sodium + heat, and sulfur. Incompatible with N,N-dimethylformamide. 

A strong base. Vigorous reaction with 1,2,4,5-tetrachlorobenzene has caused many industrial explosions and forms the extremely toxic 2,3,7,8-tetrachlorodibenzodioxin. Mixmres with aluminum + arsenic compounds form the poisonous gas arsine. Potentially explosive reaction with bromine, 4-chlorobutyronitrile, 4-chloro-2-methylphenol (in storage), nitrobenzene + heat, sodium tetrahydroborate, 2,2,2-trichloroethanol, zirconium + heat. Reacts to form explosive products with ammonia + silver nitrate (forms silver nitride), N,N -bis(trinitroethyl)urea (in storage), cyanogen... 

Metal-carbon bonds in some Zn and A1 porphyrins, e.g., N-methyltetra-phenylporphinatozinc ethyl and tetraphenylporphinatoaluminium ethyl, can be activated photochemically and undergo substitution reactions with hindered phenols such as 2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-methoxy-phenol. The products are metalloporphyrins having a phenoxy-group bound to Zn or Al. Photoexcitation is thought to increase the electron density of the ethyl group bound to the central metal atom and this brings about an enhanced nucleophilicity of the metal-carbon bond. " ... 

Nitroso-2-methylphenol Coapiing with diazonium salts. Discussed in Secs. 23.17 and 24.10. (h) Ourbonation. Koibe reaction. Discussed in Sec. 24.11. 

We have discovered that 2-amino-4-methylphenol condenses with different aryl phosphorodichloridates in boiling toluene/triethylamine to produce (via suspected intermediate 1) the novel spirobis[l,3,2-benzoxazaphosphole] 2. One product was obtained from all reactions with the assumed elimination of an aryloxy moiety. Apparently the high temperature and increased basicity of the amino group (presumably held out of the ring plane to some extent by the OH group) of the starting material induced conversion of intermediate 1 to 2. 

We also have attempted to inhibit these free radical reactions with 2,6-di-t-butyl-4-methylphenol and found no effect on the formation of cyclohexanol or cyclohexanone using catalyst 4. This latter result strongly suggests that peroxyl, alkoxyl, or hydroxyl radicals are not intermediates in these reactions. The intermediacy of a putative oxo-manganese complex is further strengthened by the reaction of 1-4 with cyclohexene in the presence of TBHP or iodosylbenzene to provide cyclohexene epoxide and our proposed mechanism is shown in the Equation (2). w H... 

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