P-Methoxy-toluene

Fora (4-Methyl anisole, p-Cresyl methyl ether, p-Methoxy toluene or Methyl-p-Cresol), colorl... 

Side-chain substitution of aromatics is best rationalized by an ECrECn me" chanism via a radical cation 30 in Eq. (101) as intermediate 106-226-241-243. Yet side products of typical radical origin, e.g., bibenzyl in acetoxylation of toluene, have been accounted in favor of a radical chain mechanism (Eq.(99) ) 230, 244,24 5) An ECE-mechanism however has been clearly demonstrated by cyclic voltammetry for side-chain substitution of pentamethylanisole and p-methoxy-toluene 241 Eberson has proposed a modified ECrECn mechanism to account for the formation of radical coupling products 242 (Eq. (101) ) The radical cation 30, the first intermediate, can escape from the electrode surface and loose a proton to form a benzyl radical in the bulk of the solution. This benzyl radical can couple to bibenzyl or abstract hydrogen to form starting material. 

For a series of methylbenzenes, the rates decreased in the order toluene > xylenes > mesitylene > durene > hexamethylbenzene. This order of reactivity is the reverse of that expected for a mechanism involving electrophilic substitution or electron transfer. However, Bushweller598 found that electron-releasing groups facilitate the benzylic oxidation of substituted toluenes by Pd(OAc)2 in acetic acid. p-Methoxy toluene gave a 96% yield of p-methoxybenzyl acetate, and p-nitrotoluene gave only 2% p-nitrobenzyl acetate, in agreement with either an electrophilic substitution or electron transfer mechanism. More mechanistic studies are necessary to clear up these anomalies. Steric effects may play an important role in these reactions. 

SYNS p-CRESOL methyl ether p-cresyl METHYL ETHER FEMANo. 2681 p-METHOXY-TOLUENE 4-METHOXYTOLUENE 4-METHYL-l-METHOXYBENZENE 4-METHYLPHENOL METHYL ETHER METHYL-p-TOLYL ETHER p-TOLYL METHYL ETHER... 

Ammoxidation of p-methoxytoluene (protection of the OH group in the p-cresol feed by methylation) over vanadium-titanium oxide catalysts gives p-methoxy-benzonitrile in 65 % yield [81,82]. Because of the greater reactivity of p-methoxy-toluene compared with the m isomer the ammoxidation of m,p-methoxytoluene mixtures results in the formation of only p-methoxybenzonitrile and the m isomer remains mainly unreacted. This presents the possibility of reactive separation of differently substituted toluenes [82]. 

As a typical example of indirect electrooxidation of alkylbenzenes, the oxidation conditions and results on p-methoxy toluene (147) with CAN in acetic acid or methanol are shown in Scheme 59 [219]. The treatment of (147) with CAN in methanol at room temperature affords the aldehyde (148), exclusively. However, the oxidation of (147) with CAN in either aqueous 50% acetic acid... 

A mixture of K-p-methylphenoxide and methyl methacrylate containing a little hydroquinone heated 5 hrs. at 200° under Ng in a stirring autoclave p-methoxy-toluene. Y 84.5%. F. e. s. T. Kito, N. Yanai, and I. Hirao, Bull. Chem. Soc. Japan 45,3490 (1972). 

Obtained by Friedel-Crafts acylation of excess p-methoxy-toluene with 2-methoxy-5-methyl-benzoyl chloride in the presence of aluminium chloride, first at 0° for 2 h, then at r.t. overnight and at reflux for 3 h (23%) [1153],... 

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