P-methoxybenzoate

Results of the sulfur tetrafluoride fluorination of benzenecarboxylic acids strongly depend on the nature of a benzene ring substituent Benzoic, toluic, and particularly p-methoxybenzoic acids give poor yields of the respective benzotri-... 

The benzoate ester is one of the more common esters used to protect alcohols. Benzoates are less readily hydrolyzed than acetates, and the tendency for benzoate migration to adjacent hydroxyls, in contrast to that of acetates, is not nearly as strong, but they can be forced to migrate to a thermodynamically more stable position. The p-methoxybenzoate is even less prone to migrate than the benzoate. Migration from a secondary to a primary alcohol has also been induced with AgN03, KF, Pyr, H2O at 100°. ... 

An example of a reaction series in which large deviations are shown by — R para-substituents is provided by the rate constants for the solvolysis of substituted t-cumyl chlorides, ArCMe2Cl54. This reaction follows an SN1 mechanism, with intermediate formation of the cation ArCMe2 +. A —R para-substituent such as OMe may stabilize the activated complex, which resembles the carbocation-chloride ion pair, through delocalization involving structure 21. Such delocalization will clearly be more pronounced than in the species involved in the ionization of p-methoxybenzoic acid, which has a reaction center of feeble + R type (22). The effective a value for p-OMe in the solvolysis of t-cumyl chloride is thus — 0.78, compared with the value of — 0.27 based on the ionization of benzoic acids. 

Quinoxalinediamine (172) and p-methoxybenzoic acid gave 2-p-methoxy-phenyl-17/-imidazo[4,5-/]quinoxaline (174) [neat synthon (2 equiv), 210°C,... 

In order to extend the scope of the reaction, and with the aim of designing a greener approach to the above set of reactions, we preformed the acylation of the same substrates with different acylation agents, such as maleic anhydride, p-methoxybenzoic acid and acetic acid (Scheme 48.4). Table 48.3 shows the results for acylation of benzenesulfonamide. 

Maleic anhydride p-methoxybenzoic acid Acetic acid ... 

The simplest possible use that can be made of the Hammett equation is to calculate k or K for a specific reaction of a specific compound, where this information is not available in the literature, or indeed where the actual compound has not even been prepared yet. Thus it is known that the base-catalysed hydrolysis of ethyl m -nitrobenzoate is 63-5 times as fast as the hydrolysis of the corresponding unsubstituted ester under parallel conditions what then will be the comparable rate for base-catalysed hydrolysis of ethyl p-methoxybenzoate under the same conditions Looking at the table of [Pg.374]

Kindler [Twi., 450( 1), 1926] has studied the alkaline hydrolysis of the ethyl esters of a number of substituted benzoic acids. The m-nitro compound was found to have a rate constant 63.5 times as fast as the unsubstituted compound. What relative rate constant is predicted for the reaction of p-methoxybenzoate by the Hammett equation The value based on experimental results is 0.214. 

A specific case of the carbonium ion mechanism [Eq. (5)] with reasonable plausibility is decarboxylation of metal arenoates by classic electrophilic aromatic substitution [Eq. (12)]. This mechanism would be favored by electron-donating substituents and has been invoked to explain the relative ease of decarboxylation of p-methoxybenzoic acid in molten mercuric trifluoroacetate (77) as well as the very facile decarboxylation on reaction of polymethoxybenzoic acids with mercuric acetate (18) (see below). 

Methoxybenzaldehyde, 54, 42 p-Methoxybenzaldehyde, by reduction of p-methoxybenzo-nitrile with Raney nickel alloy, 51, 22... 

Methoxychlor-DDE and p,p-dimethoxybenzophenone were formed when methoxychlor in water was irradiated by UV light (Paris and Lewis, 1973). Compounds reported from the photolysis of methoxychlor in aqueous, alcoholic solutions were p,p-dimethoxybenzophenone, p-methoxybenzoic acid, and 4-methoxyphenol (Wolfe et al., 1976). However, when methoxychlor in milk was irradiated by UV light (A. = 220 and 330 nm), 4-methoxyphenol, methoxychlor-DDE, p,p-dimethoxybenzophenone, and l,l,4,4-tetrakis(p-methoxyphenyl)-l,2,3-butatriene were formed (Li and Bradley, 1969). 

Methidathion oxon, see Methldathion Methiocarb sulfone, see Methlocarb Methiocarb sulfoxide, see Methiocarb Methionine, see Thiram Methoxyacetaldehyde, see Alachlor Methoxyacetic acid, see 1,4-Dioxane p-Methoxybenzaldehyde, see Methoxychlor p-Methoxybenzoic acid, see Methoxychlor... 

The major metabolites formed in the HC/LN and HC/HN cultures were methyl p-methoxycinnamate (11), methyl p-methoxybenzoate (11),... 

Suitable substrates for the Hunsdiecker reaction are first of all aliphatic carboxylates. Aromatic carboxylates do not react uniformly. Silver benzoates with electron-withdrawing substituents react to the corresponding bromobenzenes, while electron-donating substituents can give rise to formation of products where an aromatic hydrogen is replaced by bromine. For example the silver p-methoxybenzoate 6 is converted to 3-bromo-4-methoxybenzoic acid 7 in good yield ... 

The absolute configurations of two rigid cyclic diols, (—)-adamantane-2,6-diol and ( )-spiro[5.5]undecane-3,9-diol, have been determined by the application of the dibenzoate chirality rule to the bis(p-methoxybenzoate) derivatives195,196. 

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