Dicarboxylic acids, salts reactions

Many other reactions have been reported for the synthesis of polyesters, such as reactions between dicarboxylic acid salts and dialkyl halides, reactions between... 

Recently, treatment of the esters or amides of l-methylpyridinium-3,5-dicarboxylic acid salts with an alkanethiol and TEA in methylene chloride was found to give a mixture of dihydropyridines (Scheme 77) (80CC1147). These yellow adducts are particularly useful as thiolate transfer agents. Excellent yields of thioesters, for example (133), are formed by the reaction of the adducts with activated acid derivatives. 

Several special dicarboxylic acid salts were used to produce both fer-rocene and cobalticinum-containing polyesters. Ferrocene reactions to produce structure 9, were studied as a function of pH. The pK q for 1,1 -ferrocenedicarboxylic acid (FDCA) is not known but should be near 6.8. ... 

Syntheses of aliphatic polyesters and polyamides by 02 + 2 polycondensations in the melt were first studied by Carothers in the years 1930-1937 (see Chap. 3). Since that time Nylon-6,6 type aliphatic polyamides were and are prepared from equimolar monomer mixtures usually supplied in the form of diamine-dicarboxylic acid salts. In the case of aliphatic polyesters two different procedures are applicable, depending on the volatility of the reaction partners. Combinations of low boiling esters such as dimethyl succinate and low boiling dieols (e.g., ethanediol) are best polymerized in equimolar feed ratios Equimolar feed ratios are again advisable for combinations of long a,m-alkanediols and dicarboxylic acids or their... 

If two equivalents of the reagents are used, disubstitution to ECeC-CH(E)R occurs in most cases, but interestingly the reaction of LiCeCCH(Li)R with an excess of COj gives mainly the allenic dicarboxylic acids. These are probably the result of a rapid isomerization of the primary dilithium salt of the acetylenic diacid during the work-up or during the reaction of the dilithio compound with COj ... 

The first in this series to be reported was 4-oxoisoxazoline-3,5-dicarboxylic acid diethyl ester, which was formed by the reaction of nitrous acid on diethyl acetonedicarboxylate in 1891. Quilico described a number of syntheses in his 1962 review and the most general include the reaction of hydroxylamine and a-hydroxy-(or acetoxy)- 3-diketones and the conversion of 4-isoxazolediazonium salts to the hydroxy moiety (62HC(17)1, p. 3). Additional syntheses reported were the oxygenation of a 4-boric acid derivative (67JOM(9)l9) and peroxide oxidation of a 4-nitro-2-isoxazoline (Scheme 151) (79ZOR2436). 

In spirooxaziridines like (114), /3-scission proceeds with ring opening. Stoichiometric amounts of iron(II) salt in acidic solution lead to the dicarboxylic acid derivative (115). The radical undergoes some interesting reactions with added unsaturated compounds. For example, pyridine yields a mixture of 2- and 4-alkylation products in 80% yield. Catalytic amounts of iron(II) ion are sufficient here since the adduct of the radical with pyridine is oxidized by iron(III) ion to the final product (116), thus regenerating iron(II) ion (68TL5609). 

The first, and still widely used, polymer-supported ester is formed from an amino acid and a chloromethylated copolymer of styrene-divinylbenzene. Originally it was cleaved by basic hydrolysis (2 N NaOH, FtOH, 25°, 1 h). Subsequently, it has been cleaved by hydrogenolysis (H2/Pd-C, DMF, 40°, 60 psi, 24 h, 71% yield), and by HF, which concurrently removes many amine protective groups. Monoesterification of a symmetrical dicarboxylic acid chloride can be effected by reaction with a hydroxymethyl copolymer of styrene-divinylbenzene to give an ester a mono salt of a diacid was converted into a dibenzyl polymer. ... 

The reaction of diamines with dicarboxylic acids, via a nylon salt (Figure 18.1). 

Monoesterification of a symmetrical dicarboxylic acid chloride can be effected by reaction with a hydroxymethyl copolymer of styrene-divinylbenzene to give an ester a mono salt of a diacid was converted into a dibenzyl polymer." ... 

In a modified procedure the free carboxylic acid is treated with a mixture of mercuric oxide and bromine in carbon tetrachloride the otherwise necessary purification of the silver salt is thereby avoided. This procedure has been used in the first synthesis of [1.1.1 ]propellane 10. Bicyclo[l.l.l]pentane-l,3-dicarboxylic acid 8 has been converted to the dibromide 9 by the modified Hunsdiecker reaction. Treatment of 9 with t-butyllithium then resulted in a debromination and formation of the central carbon-carbon bond thus generating the propellane 10." ... 

Generally, both sodium methoxide and ethoxide are employed as basic catalysts, but sometimes potassium methoxide or sodium hydride67 is used. The alkali salts of the dicarboxylic acids are primarily formed, due to the basic reaction conditions, but after acidic workup the free acids are obtained in 20-60 % yield. Reesterification65 of the acids can be performed (see Section 2.1.4.3.). This method can also be applied to the synthesis of hetarenothiepins such as furanothiepins.67... 

Catalytic hydrogenation of dimethyl 3-methyl-3//-3-benzazepine-2,4-dicarboxylate (10) to the 1,2,4,5-tetrahydro derivative with hydrogen and a palladium-barium sulfate catalyst, followed by treatment of the reaction mixture with iodomethane in refluxing methanol, yields a mixture of the 2,4-dicarboxylic acid 11 and the methiodide salt 12.24... 

From the preceding discussion, it is easily understood that direct polyesterifications between dicarboxylic acids and aliphatic diols (Scheme 2.8, R3 = H) and polymerizations involving aliphatic or aromatic esters, acids, and alcohols (Scheme 2.8, R3 = alkyl group, and Scheme 2.9, R3 = H) are rather slow at room temperature. These reactions must be carried out in the melt at high temperature in the presence of catalysts, usually metal salts, metal oxides, or metal alkoxides. Vacuum is generally applied during the last steps of the reaction in order to eliminate the last traces of reaction by-product (water or low-molar-mass alcohol, diol, or carboxylic acid such as acetic acid) and to shift the reaction toward the... 

Hie reaction of dicarboxylic acid cesium or potassium salts with alkylene dihalides is another method of polyester preparation in relatively mild conditions... 

The paraffin wax is oxidized by air in a liquid phase process at 110-130°C. Catalysts for this radical reaction are cobalt or manganese salts [54]. The quality of the obtained mixture of homologous carboxylic acids is impaired by numerous byproducts such as aldehydes, ketones, lactones, esters, dicarboxylic acids, and other compounds. These are formed despite a partial conversion of the paraffin and necessitate an expensive workup of the reaction product [50,55]. 

High density brine completion fluids also often require the use of corrosion inhibitors (8,9). Blends of thioglycolates and thiourea alkyl, alkenyl, or alkynyl phosphonium salts thiocyanate salts mercaptoacetic acid and its salts and the reaction products of pyridine or pyrazine derivatives with dicarboxylic acid monoanhydrides have been used as high density brine corrosion inhibitors. 

The addition product of ethyl acetoacetate and methyl a-methoxyacrylate was hydrolyzed, and the resulting dicarboxylic acid was treated with dimethylamine hydrochloride and aqueous formaldehyde. The product of the Mannich reaction was decarboxylated, reesterifed, and finally treated with methyl iodide to supply quaternary salt 469 as the main product. During the above one-pot process, elimination also took place, yielding unsaturated ketone 470, which was later utilized as its hydrogen bromide adduct 471. Reaction of 3,4-dihydro- 3-car-boline either with 469 or 471 furnished the desired indolo[2,3-a]quinolizine derivative 467 as a mixture of two diastereomeric racemates. 

Oppenauer-type oxidation of secondary alcohols can be a convenient procedure for obtaining the corresponding carbonyl compounds. It was found recently [19], that Ir(I)- and Rh(I)-complexes of 2,2 -biquinoline-4,4 -dicarboxylic acid dipotassium salt (BQC) efficiently catalyze the oxidation of secondary alcohols with acetone in water/acetone 2/1 mixtures (Scheme 8.5). The reaction proceeds in the presence of Na2C03 and affords medium to excellent yields of the isolated ketones. The process is much faster in largely aqueous solutions, such as above, than in wet organic solvents in acetone, containing only 0.5 % water, low yields were observed (15 % vs. 76 % in case of cyclohexanol). 

The gas-solid neutralizations found more interest than the solid-solid variant. The quantitative reactions of gaseous ammonia with solid benzoic and related acids were interpreted by a concept of gas permeability of the crystal in order to explain anisotropic reaction fronts in single crystals [24]. Also, the ammonium salts of the aromatic or aliphatic mono- and dicarboxylic acids 16-21 (Scheme 3) formed the corresponding salts with 100% yield. The need for molecular migrations immediately upon reaction was not considered at that... 

Because template polycondensation is not very well studied at present/ general mechanism is difficult to present. Two main types of polycondensation are well known in the case of conventional polycondensation. They are heteropolycondensation and homopolycondensation. In the heteropolycondensation two different monomers take part in the reaction (e.g., dicarboxylic acid and diamine). In the case of homopolycondensation, one type of monomer molecule is present in the reacting system (e.g., aminoacid). The results published on the template heteropolycondensation indicate that monomer (dicarboxylic acid) is incorporated into a structure of the matrix (prepared from N-phosphonium salt of poly-4-vinyl pyridine) and then the second monomer (diamine) can react with so activated molecules of the first monomer. The mechanism can be represented as in Figure 2.2. 

Anhydrides are produced most commonly by the reaction of an acid chloride and a carboxylic acid or carboxylate salt (see Sections 4.3.14 and 5.5.5). Five- or six-membered cycbc anhydrides are prepared by heating dicarboxylic acids at high temperatures. 

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