Methyl phthalate, reactions

A particularly interesting case is the reaction of the enamino ketone (47), which under similar conditions gives the intermediate product (80), which then undergoes cyclization to the benzene derivative dimethyl 3-pyrrolidino-5-methyl phthalate (81). 

EM is assumed to be 109 M for all phthalate esters, and 3 x 109 M for all maleate esters m Eberson, 1964. The reaction is eighty times faster than that of methyl phthalate under these conditions (using activation energy = 23 kcal mol-1)... 

An Indian group report that the thermal cyclization of methyl a-eleo-stearate (18 3 9cll/13/) and of its 18-hydroxy-derivative (kamlolenate) in the presence of sulphur furnishes disubstituted cyclohexadienes [such as (29)], with the double-bond positions varying somewhat with the reaction temperature. The diene (29) obtained at 160 °C undergoes an interesting reaction with dimethyl but-2-ynedioate (acetylenedicarboxylic ester) since the Diels-Alder adduct is decomposed to methyl phthalate and methyl tetradec-cw-9-enoate. The results are summarized in Scheme 4. 

The mechanism of this reaction has been studied by several groups [133,174-177]. The consensus is that interaction of ester with the phenolic resole leads to a quinone methide at relatively low temperature. The quinone methide then reacts rapidly leading to cure. Scheme 11 shows the mechanism that we believe is operative. This mechanism is also supported by the work of Lemon, Murray, and Conner. It is challenged by Pizzi et al. Murray has made the most complete study available in the literature [133]. Ester accelerators include cyclic esters (such as y-butyrolactone and propylene carbonate), aliphatic esters (especially methyl formate and triacetin), aromatic esters (phthalates) and phenolic-resin esters [178]. Carbamates give analogous results but may raise toxicity concerns not usually seen with esters. 

Althongh the degradation of naphthalene-2-carboxylate by Burkholderia sp. strain JT 1500 involves the formation of 1-hydroxy naphthalene-2-carboxylate, this is not formed from the expected (l/ ,25)-di-l,2-dihydrodiol-2-naphthoate. Possibly, therefore, the reaction is carried out by a monooxygenase, or a dehydration step is involved. Subsequent reactions produced pyruvate and o-phthalate that was degraded via 4,5-dihydroxyphthalate (Morawski et al. 1997). Degradation of naphthalene carboxylates formed by oxidation of methyl groups has already been noted. 

While a carboxylate anion is a potent nucleophile in an intramolecular reaction it is not powerful enough to displace methoxide or an unprotonated amine, unless the nucleophile and the carbonyl group are held even more rigidly than in the phthalate system. Kirby and Lancaster (referred to by Kirby and Fersht, 1971) have found that such displacement can occur in disubstituted maleate monoesters and amides. The estimated rate constant for cyclization of N-methyl dime thy Imaleamic acid [equation (41)] is 16,000 times greater than that for the unsubstituted compound. Below pH 5-6 hydrolysis of the cyclic anhydride becomes rate-determining. 

The reaction of l-methyl-2-(methylmercapto)-2-pyrroline (282) with DMAD is known to give a dihydroazepine derivative (283) (Eq. (38)1. The recent report of the reaction of 1-methyl-2-pyrrolidone dimethyl-acetal (284) with DMAD to give products like 286, 287, 288, and 289 may be interpreted as essentially the reaction of the enamine system (285) (Scheme 45). Other examples of the reaction of enamines include the reaction of the pyrrolidinopentenone (290) to give the phthalate (293)... 

Chemical methods used for the determination of hydroxyl groups or alcoholic constituents in polymers are based on acetylation [16-18], phthalation [18], and reaction with phenyl isocyanate [18,19] or, when two adjacent hydroxy groups are present in the polymers, by reaction with potassium periodate [9,17]. Alcoholic hydroxyl groups may be found in the following polymers (1) poly(ethylene terephthalate) (PET) [20], (2) poly(methyl acrylate), [21], (3) poly(methyl methacrylate) [21], and (4) polyhydric alcohols in hydrolysates of poly(ester) resins [22]. 

Fig. 12. Reaction of monoalkyl monohydrogen phthalate with aniline. [Ester] = [Amine] = 0.25 M, T = 70 °C, Solvent = DMSO-d6. ( ) trifluoroethyl ester ( ) 1,3-dichloroisopropyl ester ( ) ethylglycolyl ester (A) propargyl ester (T) methyl ester...

Starting with ketones and hydrogen peroxide in the presence of a catalytic amount of acid, mixtures of up to eight components have been identified, i.e.. (1, X = OH. R3 = H), (1, X = OOH, R3 = H), (2, X = Y = OH). (2, X = Y = OOH), (2, Y = OH, Y = OOH), (3). (4), and (5). The ketone structure and reaction conditions, i.e., acid strength, reactant molar ratios, temperature, and time, determine which compounds form and predominate. Mixtures of several peroxide structures usually are present. Individual peroxides have been isolated from several ketones under different conditions (Table 5). The pure peroxides should be handled with extreme caution since most, especially those derived from the low moleculai weight ketones, ate shock- and friction-sensitive and can explode violently. Methyl ethyl ketone peroxide (MEKP) mixtures are produced commercially only as solutions containing <40 wt% MEKPs in solvents, commonly dialkyl phthalates. 

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. 

Alkyl- and aryl-substituted carboxylic acid derivatives such as ethyl 4-methoxybenzoate, diethyl phthalate,104 aryl- and alkylcarboxylic add halides or anhydrides10,2 5 8 give benzoxazinones (193). When IA was brominated in glacial acetic acid, 193 (R2 = CHBr2) was obtained.259 Anthranilic acid (4) with A-methyl IA (24) leads to 194, which cyclizes in sulfuric acid to the benzoxazinone 195134 (Scheme 33). Reaction of /V-formylanthranilic acid (196) (available from 1A and formic acid) with IA again yields the quina-zolinone 19710 260 (Eq. 19). 

Figure 8-7. Correlation between equilibrium constant for esterification and solubility of water in the solvent. Equilibrium constant was defined as [Ester]/([Alcohol].[Acid]), for reactions at fixed water activity (close to 1). Solvents are bb, butyl benzoate be, bromoethane bk, dibutyl ketone bp, dibutyl phthalate bz, benzene ca, 1,1,1-trichloroethane cf, chloroform ct, carbon tetrachloride cy, trichloroethylene ee, ethyl ether ek, diethyl ketone ep, diethyl phthalate hd, hexadecane hx, hexane me, methylene chloride mk, methyl iso-butyl ketone nm, nitromethane oc, /so-octane pe, iso-propyl ether tl, toluene. Valivety et al...

By using the principles of this classic reaction, new aromatic polyols were created, based on the reaction between dimethyl phthalate, dimethyl isophthalate and dimethylterephthalate with diethanolamine, using sodium or potassium methylate as catalyst (reactions 19.2, 19.3 and 19.4) ... 

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