5- Bromo-3-methylphenol

Fig. 9 Synthetic pathway and FTIR spectra of acetylated 3-bromo-4-methylphenol...

Methylphenol in Hf / antimonypentafluoride treated with bromine and worked up after Ih. to give 3-bromo-4-methylphenol. 

Show reagents and conditions to convert toluene to 3-bromo-4-methylphenol. 

If t he directing effects of the two groups oppose each other, the more powerful activating group has the dominant influence, but mixtures of products often result. For example, bromination of p-methylphenol yields primarily 2-bromo-4-methylphenol because —OH is a more powerful activator than -CH3. 

In rat liver slices, evidence also supports the roles of QMs in mediating the toxicity of a series of 4-methylphenols.24 The potency correlates with rates of QM formation in the order 2-bromo-4-methylphenol > 4-methylphenol = DMP > TMP > 2-methoxy-4-methylphenol. None of these compounds contain two bulky ortho substituents, so as discussed earlier the corresponding QMs are expected to be highly reactive. The authors suggested that differences in the reactivities of these QMs determine their relative toxic potencies as electron-donating substituents on the ring stabilize the QM and thereby reduce its toxicity (e.g., 2-methoxy-4-methylphenol is less toxic than DMP) and conversely, electron-withdrawing substituents destabilize QMs and enhance toxicity (e.g., 2-bromo-4-methylphenol is more potent than DMP). 

Problem 19.9 Devise practical laboratory syntheses of the following phenols from benzene or toluene and any inorganic or aliphatic compounds (a) m-iodophenol, (b) 3-chloro-4-methylphenol, (c) 2-bromo-4-methylphenol. 

Analyte pulse perturbation-chemiluminescence spectroscopy Arthromyces rasomus peroxidase Ascorbic acid Adenosine triphosphate Avalanche photodiode 5-Bromo-4-chloro-3-indolyl 2,6-Di-ferf-butyl-4-methylphenol Bioluminescence Polyoxyethylene (23) dodecanol Bovine serum albumin Critical micelle concentration Calf alkaline phosphatase Continuous-addition-of-reagent Continuous-addition-of-reagent chemiluminescence spectroscopy Catecholamines Catechol... 

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,... 

Bromo-2-fert-butyl-6-methylphenol (isolated yield, 70%)... 

How would you prepare the following compounds from the named starting material (a) 1-methoxy-3-nitrobenzene from ben-zenesulfonic acid (b) methyl 2-hydroxybenzoate from phenol (c) 2-bromo-4-methylphenol from toluene. 

C7H6BrN02 1 -bromo-2-methyl-3-nitrobenzene 55289-35-5 538.66 47.611 2 10269 C7H6CI20 2,6-dichloro-3-methylphenol 13481-70-4 510.15 44.860 1,2... 

Generally, the reaction rates of aryl halides follow the order iodides > bromides > chlorides > fluorides. This fact can be used for the selective substimtion in polyhalogenated systems. For instance, 2-bromo -chlorotoluene gives 76% of 5-chloro-2-methylphenol by treatment with sodium hydroxide at 200 °C. Nevertheless, polyhalogenated systems which contain fluorides have a variable behaviour depending on the reaction temperature. At lower temperatures preferential hydrolysis of the fluoride takes place and at >200 °C the usual reactivity order iodides > bromides > chlorides > fluorides is observed. For instance, l,2-dibromo-3,4,5,6-tetrafluorobenzene affords 2,3-dibromo-4,5,6-trifluorophenol in 87% yield by treatment with potassium hydroxide at 85 °C. Under the same conditions, 1,4-dibromo-2,3,5,6-tetrafluorobenzene produces a 78% yield of 2,5-dibromo-3,4,6-trifluorophenol. However, 4-fluorobromobenzene with NaOH at 200 °C gives 4-fluorophenol in 70-79% yield. ... 

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