Methyl benzoate, hydrolysis preparation

It is not possible to prepare biaryls containing a free carboxyl group directly by the diazo reaction. No biaryl is formed when (a) diazotized aniline and sodium benzoate, (b) diazotized anthranilic acid and aqueous sodium benzoate, or (c) diazotized anthranilic acid and benzene are used as components in the reaction.13 On the other hand, the reaction proceeds normally if methyl benzoate is used in reaction (a) or when methyl anthranilate replaces the anthranilic acid in (b) and in (c). The success of the diazohydroxide reaction appears to lie in the ability of the non-aqueous liquid to extract the reactive diazo compound from the aqueous layer.4 However, esters and nitriles can be prepared from esters of aromatic amino acids and cyanoanilines and also by coupling with esters of aromatic acids, and from the products the acids can be obtained by hydrolysis. By coupling N-nitrosoacetanilide with ethyl phthalate, ethyl 4-phenylphthalate (VIII) is formed in 37% yield. 

Preparation by acylation of o-cresol with p-(trichloro-methyl)phenyl p-(trichloro-methyl)benzoate in methylene chloride in the presence of aluminium chloride at 0-5° over 1 h, then at r.t. for 1 h, followed by alkaline hydrolysis of the resnlting keto ester [325] (Japanese patent). 

Dibenzoylmcthane has been prepared by the hydrolysis of dibenzoyl acetic acid 1 by the slow spontaneous decomposition of acetyl dibenzoyl methane 2 by the action of metallic sodium,3 sodium ethylate,3 sodium methylate,4 alchoholic potash,4 or sodamide 5 on mixtures of acetophenone and ethyl benzoate and by the action of alcoholic potash,6 sodium methylate,7 or sodium ethylate 8 on benzalacetophenone dibromide. 

Roberts and Whiting developed a method for effecting the anhydrous hydrolysis of esters and nitriles in DMSO. A solution of sodium methylsulfinylmethide is prepared from sodium hydride and DMSO and titrated with a solution of an appropriate amount of water in DMSO, using triphenylmethane as indicator. This produces a fine suspension of sodium hydroxide which hydrolyzes ethyl benzoate very rapidly at room temperature. As compared with reactions in hydroxylic solvents, rates are enhanced by a factor of 10 -10 . Benzonitrile is hydrolyzed to benzamide. Methyl and ethyl mesitoates are hydrolyzed readily at 25°. 

The 6-(2-(subsdtuted cinnamoyl) esters 12 of methyl p-D-gluco- and -galacto-pyranoside were obtained via the tri-O-trimethylsilyl ethers 11. In the preparation of the corresponding primary monoesters 14 of methyl a-L-arabinofuranoside, on the other hand, acetyl protecting groups were employed, and the required selective hydrolysis of acetates in the presence of aromatic esters (13- 14) was achieved with 10% pyrrolidine in 95% ethanol. The preparation of mono- and diformates, -acetates, and -benzoates of etoposide is covered in Chapter 19. 

Polymethyl acrylate can be hydrolysed rapidly and completely under alkaline conditions. On the other hand, the monomer units in polymethyl methacrylate prepared and treated similarly are resistant to hydrolysis [51] although benzoate end-groups react readily [52]. Only about 9% of the ester groups in polymethyl methacrylate reacted even during prolonged hydrolysis hydrolysis of polymethyl acrylate was complete in 0.5 hours. Although only about 9% of the ester groups in methyl methacrylate homopolymers are hydrolysed in several hours reflux with alcoholic sodium hydroxide, this proportion is increased by the introduction of comonomer units into the polymer chain. Thus, saponification techniques should be applied with caution to polymeric materials. 

Preparation by hydrolysis of 2-(2-hydroxy-4,6-dimethoxy-phenyl)-2-oxoethyl benzoate in pyridine with aqueous sodium hydroxide under nitrogen atmosphere at r.t. for 1 h (80%) [5118]. Also obtained by degradation of 2-[2-(2-hydroxy-4,6-dimethoxyphenyl)-2-oxoethoxy]-2-methyl-propionic acid in refluxing mixture of concentrated hydrochloric acid/methanol (1 vol/5 vol) for 1 h (42%) [5119]. 

In our system, the acid chloride as the acylating agent was not applicable due to the basic conditions of the proposed transformation and the internal free nitrogen of the piperidyl moiety. However, the trioxifene acylation was adapted by preparing the phenyl ester of 5. Therefore, the required phenyl 4-[2-(l-piperidinyl)ethoxy]benzoate (9) was prepared by alkylating methyl 4-hydroxybenzoate with 2-(l-piperidinyl)ethyl chloride (6). Hydrolysis of the methyl ester provided the carboxylic acid that was converted to the acid chloride (8) using SOCI2 in a mixture of 1,2-dichloroethane and toluene. Acid chloride 8 was then reacted with sodium phenolate to provide 9 as a stable crystalline solid in 64% overall yield from the carboxylic acid. 

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