4-Methoxyphenyl acetate

When Cl and MeO substituents are attached to the phenolic ring, the PFR may result in displacement of those substituents by the acyl moiety. An example of chlorine displacement has been given in Section I, whereas Scheme 10 shows the case of 2-methoxy-4-methylphenyl benzoate (26), where the reaction mixture contains 2-hydroxy-5-methylbenzophenone (27), a product of methoxy substim-tion [37]. Hageman also reported the substitution of MeO by acetyl in the photolysis of 4-methoxyphenyl acetate and related esters [32]. 

Magnetic field effects have been used to study the photo-Eries rearrangement of 4-methoxyphenyl acetate [49] and 1-naphthyl acetate [50], These effects can be subdivided into internal and external. 

When the reaction is run with /tara-methoxyphenol up to 44% of photoproducts correspond to substitution of the methoxy group by tert-bvXyl and acetyl (Scheme 17). This is in agreement with the observation that photolysis of 4-methoxyphenyl acetate yields, among other products, para-acetyl phenol [32]. 

An acetic acid or acetic anhydride solution of 4-methoxyphenyl tellurium triacetate, prepared from bis[4-methoxyphenyl] ditellurium and lead tetraacetate, upon irradiation with light from a high pressure mercury lamp produced 4-methoxyphenyl acetate in 14% yield4. 

A synthetic route to ( )-0,f>-dimethyltubocurarine iodide (CXXV), via the racemate of 0,0-dimethylbebeerine (CXXIII), was announced in 1959 by Tolkachev and his collaborators (94). It started by the condensation of 3-methoxy-4-hydroxyphenethylamine with 4-benzyloxy-phenylacetic acid to give the amide CXXVI. Reaction of the potassium salt of the latter with the methyl ester of 3-bromo-4-methoxyphenyl-acetic acid in the presence of copper powder gave compound CXXVII. This on condensation with 3-methoxy-4-hydroxy-5-bromophenethyl-amine afforded compound CXXVIII, which was methylated to CXXIX. The latter compound was cyclized with phosphorous oxychloride to the dihydroisoquinoline derivative CXXX. Debenzylation of CXXX followed by intramolecular Ullmann condensation yielded compound CXXXI. The latter was converted to racemic dimethylbebeerine (CXXIII) by reduction with zinc dust in acetic acid followed by methyla-tion. Finally, treatment of ( + )-CXXIII with methyl iodide furnished the dimethyl ether of ( + )-tubocurarine iodide, identified by comparison of its UV-spectrum with that of the dimethyl ether of natural tubo-curarine iodide and by melting-point determination of a mixture of the two specimens. 

A very similar phenomenon was observed for methoxychlor related compounds. Also the more polar metabolites 4,4 -dimethoxy-benzophenone and 2,2-bis(4-methoxyphenyl)acetic acid became most abundant within the bound organic fraction. 

Bis(4-methoxyphenyl)-acetic acid KJ-y HC) 227, 286 detected after methylation. Recovery and calibration data were kept from 4,4 -DDA. 

Ethyl-2-methoxyphenol Ethyl (4-methoxyphenyl)acetate Ethyl 2-methylacetoacetate AEEthyl-2-methylallylamine 5-Elhyl-5-(2-methylallyl)-2-thiobarbituricacid... 

Phthalides have an extremely high oxidative potential (2.86 V) (03GC512). Selective fluorination also takes place in the case of carbonyl-containing heterocyclic compounds. Thus mono- and difluoro derivatives of 4-(metho-xyphenyl)acetone and ethyl 4-(methoxyphenyl)acetate (87TL2359, 98JFC(87)215) and fluoroindanes (90TL3137) are produced by anodic fluorination of hydrocarbon substrates in the... 

Phenols can also be prepared by combining two reactions that you have seen previously Baeyer-Villiger oxidation and ester hydrolysis. Oxidation of p-methoxyacetophenone with trifluoroperoxyacetic acid gives 4-methoxyphenyl acetate as the major product and methyl 4-methoxybenzoate as the minor one. 

Hydrolysis of the ester group of 4-methoxyphenyl acetate gives 4-methoxyphenol. 

Tadesse and coworkers assumed that pulmonarins and synoxazolidinones share the common biosynthetic route in the organism [15]. Pulmonarin A (19) had been considered as a dibrominated form of />-hydroxybenzoylcholine, which biosynthetically derived from p-hydroxybenzyl alcohol [16, 17]. According to the proposed biosynthesis dibromo hydroxybenzyl alcohol 21 get oxidized and methylated before coupling with choline 24 (Scheme 3). The biosynthesis of pulmonarin B (20) was assumed via the coupling of known metabolites 2-(3,5-dibromo-4-methoxyphenyl)acetic acid 25 [11] and ascophylline 26 [18]. 

Measurement of kinetic isotope effects (KIE) provides valuable insight into the mechanism of the PFR. Thus, the absence of any detectable KIE in the rearrangement of C- or 0-labeled 4-methoxyphenyl acetate is in agreement with the absence of an activation energy barrier for the O—CO bond cleavage and with formation of 2-hydroxy-5-methoxyacetophenone by recombination of a caged radical pair produced from a singlet excited state [40, 41]. 

In this study, Rh2(TPA)4 (1, TPA = triphenylacetate) vkfas reacted with C-labeled methyl 2-diazo-2-(4-methoxyphenyl)acetate, and a metastable Rh2(TPA)4-carbenoid intermediate, supported by a donor-acceptor carbene fragment, was generated (Scheme 9.2). The stability of the dirhodium-carbenoid intermediate in CHClj at 0°C for 20h allowed for the determination of its physical and chemical properties for the first time. The characterization of the bonding within the [Rh-Rh] = C framework by vibrational and NMR ( C = 242 ppm,/g, c = 27 Hz)... 

Because of the uncertainty of sample delivery times, rapid/fast IPC chromatographic methods are needed to maintain an efficient analytical laboratory and plant operation.Since many samples can be generated during the process development, IPC methods should be developed and optimized for the shortest analysis time possible. The need for a fast IPC method was demonstrated by Wu et al. who redeveloped an in-process method to shorten the run time for a reaction conversion HPLC analysis from 30 to 10 min using a monolithic HPLC column.The newly developed method could also be used to determine mother liquor concentrations and perform impurity profiles for the crude product. This optimized method reduced the process cycle time for lab instrumentation. The dual purpose for an IPC method (i.e., COR, impurity profiling, and/or concentration analysis) is another opportunity to improve the process and lab efficiency. Another example of a dual-purpose method use was demonstrated by Nageswara Rao et al. who developed a 15-min RP-HPLC method that could determine the COR and impurity profile (isolated product) for two different processes for production of 4-methoxyphenyl acetic acid." The dual-purpose method is a common theme for in-process analyses. It is also important to remember that a reduction in the analysis time and overall manufacturing time can reduce the cost of the API. 

Also obtained by UV light irradiation of 4-methoxyphenyl acetate in ethyl ether, at 25° (7%) [2193],... 

Preparation by Fries rearrangement of 4-methoxyphenyl acetate with aluminium chloride without solvent at 130° (40%) [2344],... 

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