Aromatic esters, synthesis

Cristiani, G., V.M. Monnet, Food micro-organisms and aromatic ester synthesis,... 

General Synthesis and Reactions of Esters Synthesis of Diesters Synthesis of Hydroxy-esters Synthesis of Keto-esters Synthesis of Unsaturated Esters Synthesis of Aromatic Esters Synthesis of Thioesters Synthesis of Vinylogous Esters... 

Isothiazole-4,5-dicarboxylic acid, 3-phenyl-dimethyl ester synthesis, S, 150 Isothiazole-5-glyoxylic acid ethyl ester reduction, 6, 156 Isothiazole-4-mercurioacetate reactions, 6, 164 Isothiazole-5-mercurioacetate reactions, 6, 164 Isothiazoles, 6, I3I-I75 acidity, 6, 141 alkylation, 6, 148 aromaticity, S, 32 6, 144-145 basicity, 6, I4I biological activity, 6, 175 boiling points, 6, I43-I44, 144 bond fixation, 6, 145 bond orders, 6, I32-I34 calculated, 6, 133 bromination, S, 58 6, 147 charge densities, 6, 132-134 cycloaddition reactions, 6, 152 desulfurization, S, 75 6, 152 deuteration, S, 70... 

The use of silylated monomers is an interesting alternative method of aromatic polyester synthesis since the silylated gaseous by-products cannot participate in the reverse reaction, shifting polyesterification toward polymer formation. Reactions between silyl esters and acetates (Scheme 2.23) and reactions between silyl ethers and acid chlorides (Scheme 2.24) have been applied to the synthesis of linear265-267 and hyperbranched wholly aromatic polyesters202,268 269 (see Section 2.4.5.2.2). 

Synthesis and characterization of ABA type copolymers containing polydimethyl-siloxane or poly(trifluoropropyl,methyl)siloxane middle blocks and aromatic ester based liquid crystalline end blocks were reported 252,253). These materials were synthesized in solution by the reaction of primary or secondary amine-terminated, di-... 

When an aromatic ring is treated with diethyl oxomalonate, (Et00C)2C=0, the product is an arylmalonic acid derivative, ArC(OH)(COOEt)2, which can be converted to an arylmalonic acid, ArCH(COOEt)2. This is therefore a way of applying the malonic ester synthesis (10-104) to an aryl group (see also 13-12). Of course, the opposite mechanism applies here The aryl species is the nucleophile. 

The authors used for the first time aromatic hydrotope solution system such as 50% sodium p-toluene sulfonate aqueous solution (NaPTSA), 40% sodium cumene sulfonate aqueous solution (NaCuS), and 20% sodium p-xy-lene sulfonate (NaXS) aqueous solution to perform Hantzsch ester synthesis. 

The reason why the acyloin synthesis is especially characteristic of aromatic aldehydes, depends on the circumstance that in the aromatic series the tertiary carbon atom in the ring does not allow of the aldol condensation, a reaction for which conditions are otherwise much more favourable. The simplest example of the acyloin condensation, moreover, was already encountered in the case of formaldehyde (p. 218) glycollic aldehyde is the simplest acyloin. Acyloin compounds are also produced, in the aliphatic series, by the action of sodium or potassium on esters, and hence are also formed as by-products in the acetoacetic ester synthesis (Bouveault, Scheibler). 

This method for preparing 2-phenyl-1-pyrroline, and assorted 2-substituted 1-pyrrolines, is one of the best currently available, particularly because it reproducibly affords clean materials. Generally, the procedure is amenable to various aromatic esters 2 it has also been applied successfully to aliphatic esters (Table I).3 An advantage of this method is the use of readily available, inexpensive N-vinyl-pyrrolidin-2-one as a key starting material. This compound serves effectively as a 3-aminopropyl carbanion equivalent. The method illustrated in this procedure has been extended to include the synthesis of 2,3-disubstituted pyrrolines. Thus, alkylation of the enolate of the intermediate keto lactam, followed by hydrolysis, leads to various disubstituted pyrrolines in good yields (see Table II).3... 

Z. D. Liu, D. Y. Liu, S. L. Lu, R. C. Hider, Synthesis, Physicochemical Properties and Biological Evaluation of Aromatic Ester Prodrugs of l-(2 -Hydroxyethyl)-2-ethyl-3-hy-droxypyridin-4-one (CP102) Orally Active Iron Chelators with Clinical Efficacy , J. Pharm. Pharmacol. 1999, 51, 555-564. 

The Sm-catalyzed synthesis of a-dike-tones from aromatic esters [571], the... 

Scheme 169 Samarium-catalyzed synthesis of diketones from aromatic esters.

While we believe our discussions of nitramine and nitrate ester synthesis to be comprehensive, it would be quite impossible to have a comprehensive discussion of aromatic nitration in this short chapter - published studies into aromatic nitration run into many tens of thousands. The purpose of this chapter is primarily to discuss the methods used for the synthesis of polynitroarylene explosives. Undoubtedly the most important and direct method for the synthesis of polynitroarylenes involves direct electrophilic nitration of the parent aromatic hydrocarbon. This work gives an overview of aromatic nitration but the discussion doesn t approach mechanistic studies in detail. Readers with more specialized interests in aromatic nitration are advised to consult several important works published in this area which give credit to this important reaction class.The use of polynitroarylenes as explosives and their detailed industrial synthesis has been expertly covered by Urbanski in Volumes 1 and 4 of Chemistry and Technology of Explosives ... 

Carboxylic acids can be alkylated in the a position by conversion of their salts to dianions [which actually have the enolate structures RCH=C(0 )21497] by treatment with a strong base such as lithium diisopropylamide.1498 The use of Li as the counterion is important, because it increases the solubility of the dianionic salt. The reaction has been applied1499 to primary alkyl, allylic, and benzylic halides, and to carboxylic acids of the form RCHjCOOH and RR"CHCOOH.1454 This method, which is an example of the alkylation of a dianion at its more nucleophilic position (see p. 368), is an alternative to the malonic ester synthesis (0-94) as a means of preparing carboxylic acids and has the advantage that acids of the form RR R"CCOOH can also be prepared. In a related reaction, methylated aromatic acids can be alkylated at the methyl group by a similar procedure.1500... 

In a similar way to that described for the synthesis of furo[2,3-6]pyrazine (Section 3.17.2.1.4, Scheme 29), the dianion of 3-methylpyrazine-2-thione reacts with aromatic esters to give side-chain acylated 3-methylpyrazine-2-thiones (367). The cyclization to thieno[2,3-f ]pyrazines (368) was effected by warming these compounds in 10% methanolic hydrochloric acid solution (Scheme 108) (78RTC81, 78RTC151). 

It turns out that we must protect the phenol as its methyl ether 127 and that 126 is best used as an amidine-ester rather than the double enamine. The synthesis is then quite short. We have barely scratched the surface of aromatic heterocyclic synthesis in this chapter but the encouraging message is that cyclisation is easy and that cyclisations to form aromatic compounds are the easiest of all. Disconnect with confidence ... 

Like the acetoacetic ester reaction, the malonie ester synthesis also proceeds via a carbanion and thus the alkyl halide should be either primary or secondary. Tertiary and aromatic halides will not work. 

In the synthesis of zearalenone, a key reaction is the formation of the aromatic ester moiety. This has been carried out in 70% yield by the ester-forming carbonylation process illustrated in equation 159906. A similar reaction has been used for the synthesis of the natural product curvulin907. 

Up to this point the discussion has been concerned with alkylene terephthalate/PTME terephthalate copolymers in which the concentration of alkylene terephthalate and the chemical structure of the alkylene groups have been varied. The next section of this report is concerned with polyether-ester copolymers in which aromatic esters other than terephthalate are used in combination with PTME glycol and various diols. The objective is the same, to correlate changes in copolymer structure with changes in copolymerization results and copolymer properties. Once again the 50% tetramethylene terephthalate/PTME terephthalate copolymer (Tables I and II) with its excellent properties and relative ease of synthesis will be used as the point of reference to which the other polymers will be compared. 

Anhydrides—Continued reduction to alcohols, 155 reduction to lactones, 535 Arenes, see Hydrocarbons, aromatic Amdt-Eistert reaction, 433, 487, 573 Aryl esters. Fries rearrangement, 344 hydrolysis, 169 preparation, 169 Aryl halides, see Halides Atyloxy acids, preparation, by aceto-acetic ester synthesis, 430 by malonic ester synthesis, 429 from atyloxy alcohols, 419 from atyloxy cyanides, 414 preparations listed in table 48, 460 Aryloxy acyl halides, preparation, 547 preparations listed in table 61, 553 Aryloxy esters, preparations listed in table 55, 516... 

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