2-Methoxy-5-methyl phenol

FIGURE 10.12 Pyrogram of oak wood pyrolyzed at 600°C. Peaks 1 = acetic acid, 2 = furan carboxaldehyde, 3 = 2-methoxy -methyl phenol, 4 = 2,6-dimethoxy phenol, 5 = 2,6-dimethoxy-4-propenyl phenol. 

Photo-induced electron-transfer decarboxylation reactions have been reviewed. A variety of methyl- and methoxy-substituted phenol radical cations have been generated by either photo-induced electron transfer or photo-ionization in dry solvents such as acetonitrile. In the presence of small amounts of water the radical cations are not detected and the phenoxyl radical is the only transient species observed. The 2-methoxyphenol radical cation was found to be more reactive than the 4-methoxy radical cation. 

By careful optimization, Widdowson and coworkers were able to show that methoxy-methyl ethers of phenols are better substrates for alkyllithium-diamine controlled enan-tioselective deprotonation, and (—)-sparteine 362 is then also the best ligand among those surveyed the BuLi-(—)-sparteine complex deprotonates 447 to give, after electrophilic quench, compounds such as 449 in 58% yield and 92% ee (Scheme 180) . Deprotonation of the anisole complex 410 (see Scheme 169) under these conditions gave products of opposite absolute stereochemistry with poor ee. 

Butylmethylanisole, Butylmethoxymethylbenzene, or Butylr ethoxytoluene(ca. e. Methylhther des Methyl-butyl-phenol, Methoxy-methyl-butyl -benzol, or Butyl-kresol-methylBther in Ger), C4Hg.CgH3(CH3).OCH3. Two isomers of tert-butylmethylanisole are described in the literature... 

In the course of the previous work we have prepared compounds for comparative purposes, one of which has been reported by Gierer. He and his co-workers 15) synthesized an unsymmetrical diphenylmethane by acid-catalyzed condensation of syringyl alcohol and 2-methoxy-4-methyl-phenol and assumed substitution in the 6-position of the guaiacol nucleus. We repeated this synthesis and prepared an isomeric material by base-catalyzed condensation of the same starting materials. Our interpretation of the modes of synthesis and the NMR spectra of the two compounds is that Gierer s compound most probably is 3, 4-dihydroxy-6 -methyl-3,4, 5-trimethoxydiphenylmethane and that the compound prepared under basic conditions is 2, 4-dihydroxy-5 -methyl-3,3, 5-trimethoxydiphenylmethane, the structure claimed by Gierer. We do not, however, have unequivocal structural evidence and our data are summarized under Experimental. 

Directed metallation SEM ethers of phenols are as useful as MOM (methoxy-methyl) ethers for directed ort/io-metallation of aromatic systems, and have the added advantage of removal by fluoride ion. This group is also useful for directed lithiation of hydroxypyridines. 

Hartwig [9] et al. developed a novel ferrocene-based dialkyl-phosphine-ligand for this arylation 2-methoxy-4-methyl-phenol is arylated with 2-chloro-p-xylene in 81% yield [eq. (g)]. 

Phenol, 2-methoxy-4-methyl Phenol, 2-methoxy-4-(2-propenyl) ... 

Amberlyst-15 was also used as a catalyst for the reaction of alcohols and phenols with tetrahydropyran (Eqn. 22.33). Refluxing a mixture of an alcohol and dimethoxymethane in the presence of a Nafion-H catalyst gave the methoxy methyl ethers in very good yields (Eqn. 22.34). ° Nafion-H was also used to catalyze the conversion of diols to cyclic ethers. ... 

In the case of the rhenium-catalyzed oxidation of methoxy- and hydroxy-substituted substrates, there is some complementary work concerning the general mechanism of the arene oxidation [10b, 11]. Since the major products in the oxidation of such arenes or phenols are the quinones, the formation of intermediary epoxides seems to be a predominant reaction step. When p-substituted phenols such as 2,6-di( -butyl)-4-methylphenol are treated with the MTO/H2O2 oxidant and acetic acid as solvent, the formation of hydroxydienones is observed. This is also reported for the oxidation using dimethyldioxirane as oxidant [20]. Since an arene oxide intermediate was postulated for the dioxirane oxidation, a similar mechanism is plausible here [11], e. g., for the oxidation of l,2,3-trimethoxy-5-methylbenzene (Scheme 3) or 2,6-di(f-butyl)-4-methyl-phenol. 

On the other hand, phosphorane intermediates are not expected to be involved in the hydrolysis of phosphate monoesters, so the effective observed catalysis by the carboxyl group of salicyl phosphate 3.21 [51] (Scheme 2.26) is presumed to be concerted vith nucleophilic attack. (The hydrolysis reaction involves the less abundant tautomer 3.22 of the dianion 3.21, and the acceleration is >10 -fold relative to the expected rate for the pH-independent hydrolysis of the phosphate monoester dianion of a phenol of pK 8.52.) However, this system differs from the methoxy-methyl acetals discussed above, in that there is a clear distinction between neutral nucleophiles, which react through an extended transition structure similar to 3.16 in Scheme 2.23, and anions, which do not react at a significant rate, presumably because of electrostatic repulsion. This distinction is well-established for the dianions of phosphate monoesters with good leaving groups (p-nitrophenyl [52] and... 

Fiir die Ringspaltung von 2-Amino-l, 3-benzothiazolen wird die Verwendung von Kalilauge (35-50%ig RiickfluB 6-9 h) angegeben, z. B.965 966. Bei der Reaktion von 2-Amino-6-meth-oxy-l,3-benzothiazol und 2-Amino-6-methoxy-5-methyl-l,3-benzothiazol bei 250-260° in einer Schmelze aus Natriumhydroxid, Kaliumhydroxid und Natriumsulfid-Nonahydrat (7 min) findet gleichzeitig Dealkylierung der Methoxy-Gruppe statt (4-Amino-3-mercapto-phenol bzw. 4-Amino-3-mercapto-6-methyl-phenol)961. 

Styrene (99%, Nacalai Tesque, Japan), MMA (99%, Nacalai), and azobis(isobutyronitrile) (AIBN) (99%, Nacalai) were purified by distillation or recrystallization. 1-Phenylethyl iodide (PE-1) and 2-cyanopropyl iodide (CP-1) were prepared according to Matyjaszewski (9) and Balczewski (10), respectively. 2,2 -Azobis(2,4,4-trimethylpentane) (VRllO) (99.9%, Wako Pure Chemical, Japan), f-butyl peibenzoate (BPB) (98%, Aldrich), di(4-f-butylcyclohexyl) peroxydicarbonate (PERKADOX16) (95%, Akzo), thymol iodide (TI) (95%, Wako), 2,4,6-trimethyl phenol (2,4,6-Me) (97%, Wako), 2,6-di-f-butyl-4-methyl phenol (3,5-di-f-butyl-4-hydroxy toluene (BUT)) (98%, Wako), 2,6-di-i-butyl-4-methoxy phenol (3,5-di-i-butyl-4-hydroxy anisole (BHA)) (97%, Aldrich), phenol (99%, Wako), vitamin E (VE) (99.5%, Wako), vitamin C (VC) (99%, Tokyo Kasei, Japan), and 2,2,6,6-tetramethylpiperidinyl-l-oxy (TEMPO) (99%, Aldrich) were used as received. 

Phenol, 2-methoxy-5-propyI-Phenol, 2-methoxy-6-(1-propenyl)-, ( )-Phenol, 2-methoxy-6-(1-propenyl)-, (Z)-Phenol, 2-methoxy-6-methyl-Phenol, 2-methoxy-propyl-Phenol, 2-methoxy-trlmethyl-Phenol, 2-methyl- o-cresol ... 

Methoxymethyl ethers of phenols. Phenols can be converted into methoxy-methyl ethers (Ar0CH20CH3> in 80-95% yield by reaction with chloromethyl methyl ether under phase-transfer conditions. Adogen 464 (6, 10) has been used as catalyst. 

If the /7-position of the amine is blocked by methoxy, methyl, chlorine or bromine groups, the species is stable with respect to dimerisation and higher anodic potentials are required for its further oxidation. However, further decomposition of the tri /7-anisylamine radical cation occurs in the presence of any traces of cyanide ion present in the acetonitrile solution. Primary aromatic amines, like phenols, tend to polymerise upon oxidation unless the o and p positions are blocked. 2,4,6-tri-t-butylaniline in acetonitrile solution yields a fairly stable radical cation which in the presence of water forms 3,5-di-f-butyl-4-amino-2,5-cyclohexadienone. ° ... 

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