Carboxylic acids preparation from

A number of (R)-thiazolidine-4-carboxylic acids prepared from cysteine and various aldehydes have been investigated [138 - 140], Nonenzymatic hy-... 

The methyl ester has also been obtained by esterification of cyclopentanecarboxylic acid.8 The acid, in turn, has been prepared by the Favorskii rearrangement,6 7 9-11 by the reaction of cyclopentyl Grignard reagent with carbon dioxide,12 by the carbonylation of cyclopentyl alcohol with nickel carbonyl13 or with formic acid in the presence of sulfuric acid,14 and by the hydrogenation of cyclopentene-1-carboxylic acid prepared from ethyl cyclopentanone-2-carboxylate 15 or from cyclopentanone cyanohydrin.16... 

Heuma nn II Process. In the Heumann II process, starting from anthranilic acid,, V-phcnylglycine-o-carboxylic acid, prepared from anthranilic acid and chloroace-tic acid, is added in the form of the alkali metal salt 13 to a KOH/NaOH melt at 200 °C to produce indoxylcarboxylic acid salt 14. After hydrolysis and decarboxylation, the product is oxidized in air to yield indigo [19],... 

Table S Carboxylic Acids Prepared from Ketones ...

Table 5 Carboxylic Acids Prepared from Ketones25...

Trifluoroacetic and triflic anhydrides can be utilized to promote acylation of aromatics with carboxylic acids without any metal catalyst. Thus, the trifluoroacetic anhydride (TFAA)-promoted cycloacylation of conveniently functionalized carboxylic acids prepared from Baylis-Hillman adducts... 

An ester of l-thiochromanone-2-carboxylic acid, prepared from thiophenol and chlorosuccinic acid, may be brominated and the product dehydrobrominated by heating with pyridine to give an ester of 1-thio-chromone-2-carboxylic acid [63], The overall yield from thiophenol is about 12 per cent. 

The most convenient laboratory method for the preparation of 2,4-dimethyl-5-carbethoxypyrrole is that given above. A cheaper method of obtaining large quantities consists in the partial hydrolysis of 2,4-dimethyl-3,5-dicarbethoxypyrrole with sulfuric acid, followed by decarboxylation. The ester has been obtained also by the alcoholysis of 5-trichloroaceto-2,4-dimethyl-pyrrole in the presence of sodium ethylate. The free acid has been obtained fronii-[2,4-dimethylpyrrole-5]-2,4-dimethylpyrrole-5-carboxylic acid and from 2,4-dimethylpyrrole-5-aldehyde. ... 

Phenylpyrido[4,3-d]pyrimidin-o(677)-ones (145) have been prepared from 7-phenylpyrano[4,3-d]pyrimidin-5(6/7)-ones (144) by treatment with ammonia, hydroxylamine, or hydrazine at room temperature. The utility of the route lies in the rapid preparation of 4-methyl-2-phenylpyrimidine-5-carboxylic acid (143) from cheap... 

Af-Ethyl-A-(3-halo-2-methylphenyl)aminomethylenemalonates (106, R = Et, R1 = Me, R2 = Hlg, R3 = H) were heated in polyphosphoric acid, prepared from phosphoric acid and phosphorus pentoxide, at 140°C for 40 min. The reaction mixture was then poured into water, and the product was hydrolyzed with 10% aqueous sodium hydroxide to give quinoline-3-carboxylic acids (696, R = Et, R1 = Me,R2 = Hlg) in 68-70% yields (80GEP3007006). 

Nakagome and co-workers effected the successful cyclization of N-ethyl-N-arylaminomethylenemalonates (749) in poly phosphoric acid, prepared from orthophosphoric acid and phosphorus pentoxide in polyphosphate ester (PPE), prepared from phosphorus pentoxide and anhydrous diethyl ether in chloroform in phosphoryl chloride on the action of boron trifluoride etherate on the action of acetic anhydride and concentrated sulfuric acid or on the action of phosphorus pentoxide in benzene [71GEP2033971, 71JHC357 76JAP(K) 18440]. Depending on the work-up process, l-ethyl-4-oxoquinoline-3-carboxylates (750, R1 = Et), l-ethyl-4-oxoquinoline-3-carboxylic acids (750, R2 = H) and 3-ethoxycarbonyl-4-chloroquinolinium iodides (751) were obtained. Only the cyclization of... 

Fig. 14. Hyperbranched polymer grafts prepared on a mercaptoundecanoic acid (MUA) self assembled monolayer confined to a gold substrate. PAAM-c-PAA represents a random copolymer of poly(acrylamide) and poly(acrylic acid) prepared from the poly(acrylic acid) carboxylic acid groups and an amine [129]...

As shown in Figure 13.2.2, the top peak of the excitation spectra of the ZnS Mn without carboxylic acid prepared in this method shifts toward higher energy by 0.06 eV, to 3.67 eV (339 nm) from 3.61 eV (344 nm), for the particles prepared by a conventional method, with their average particle size being 0.5 mm. By preparing them in the presence of AA, however, a larger blue shift by 0.16 eV with respect to the commercial particles, to 3.77 eV (330 nm), is observed. 

Ethyl 6-hydroxy-l-oxo-l//-pyrimido[l,2-a]quinoline-2-carboxylate was prepared from the 2-carboxylic acid in boiling ethanol in the presence of 3% hydrogen chloride for 4 h (77GEP2628751,77USP4031217). Heating ethyl 6-methoxy-l-oxo-l//-pyrimido[l,2-a]quinoline-2-carboxylate in ethylene glycol in the presence of triethylamine for 6 h yielded the 2-hydroxyethyl ester (75GEP2513930). 

Analogous to the use of chiral enoates (see previous section), a, -unsaturated carboxylic amides, prepared from chiral amines, may be utilized in asymmetric 1,4-additions. When Grignard reagents are added to unsaturated amides (21), derived from (-)-ephedrine (20),25 highly optically active fi-sub-stituted alkanoic acids (22 R and R = alkyl or phenyl) are obtained in a variety of cases, after hydrolysis of the initially formed adducts (Scheme 7). This method was used for the synthesis of the antibiotic (-) malyngolide and its stereoisomers.26 Recrystallization of the intermediate (saturated) amide was necess-... 

Treatment of O-acyl esters (2) with l,l-dichloro-2,2-difluoroethylene provides a,a-difluorocarboxylic acids (37) through photolysis, followed by the hydrolysis of the adducts (36) with AgN03 (eq. 8.17) [53]. Eq. 8.18 shows the preparation of a-keto carboxylic acids (40) from carboxylic acids, by means of the radical addition to ethyl acrylate, oxidation to the sulfoxides by mCPBA, the Pummerer reaction with... 

Radical nucleophile oxidation based on one-electron oxidation, known as the Minisci reaction, is employed for the functionalization of /V-heterocycles with acidic hydrogen peroxide in the presence of iron(II) salts (Figure 3.112).472 A range of A-heterocycles (pyridines, pyrazines, quinolines, etc.) which are activated towards attack by nucleophilic radicals when protonated are suited to this chemistry. The Minisci reaction is suitable for the preparation of carboxylic amides (from formamide), carboxylic esters (from pyruvic esters via a hydroxyhydroperoxide), aldehydes (from 1,3,5-trioxane) and alkylated pyridines (either from carboxylic acids or from alkyl iodides in dimethyl sulfoxide).473 The latter reaction uses dimethyl sulfoxide as the source of methyl radical (Figure 3.112). 

For example, an aldehyde prepared by the oxidation of a primary alcohol (Sec. 16.8) may very well be contaminated with the carboxylic acid this acid can be simply washed out with dilute aqueous base. The carboxylic acid prepared by oxidation of an alkylbenzene (Sec. 12.10) may very well be contaminated with unreacted starting material the carboxylic acid can be taken into solution by aqueous base, separated from the insoluble hydrocarbon, and regenerated by addition of mineral acid. 

We have seen (Sec. 18.5) that in the carboxylic acids obtained from fats we have available long straight-chain units for. .se in organic synthesis. Reduction of these acids to alcohols (either directly or as esters) is a fundamental step in the utilization of these raw materials, since from the alcohols, as we know, a host of other compounds can be prepared (Sec. 16.10). Although only acids of even carbon number are available, it is possible, of course, to increase the chain length and thus prepare compounds of odd carbon number. (For an alternative source of alcohols both of even and odd carbon number, see Sec. 32.6.)... 

Adducts (6) and (7) from amides and chlorophosphoric acid aiyl esters or dichlorophosphoric acid aryl esters respectively are well known. - The adducts are formed in a 1 1 ratio. They have been applied to the synthesis of mixed anhydrides from diarylphosphoric acids and carboxylic acids, as well as mixed substituted esters of pyrophosphoric acid. The adduct formation between primary or secondary carboxamides and dichlorophosphates has been used to prepare nitriles and isonitriles respectively. The adduct from DMF and phenyldichlorophosphate is a useful reagent for the preparation of carboxylic acid esters from the corresponding acids and alcohols, 3-lactams from imines and carboxylic acids," carboxylic acid anhydrides, carboxylic acid esters and thiol esters. Adducts of amides with ester amides or diamides of chlorophosphoric acid have been studied. ... 

Epoxides - The first indication of the synthetic utility of metalated carboxylic acids resulted from efforts to prepare steroidal aldosterone inhibitors from spiroepoxides.39 Model studies indicated that the reaction fails as a result of severe steric hindrance in either the epoxide or carboxylic acid and that monosubstitution occurs for the same reason.39 The reaction has been used in a key step of an elegant synthesis of vernolepin, 5. 40 Forcing conditions are required, and, in contrast to acid dianions, anions of unactivated esters fail to react with epoxides.39 41... 

Gancet, C Preparation of Esters of Carboxylic Acids Directly From Carboxylic Acids and Alcohols Using a Catalyst System Comprising a Sulfonic Acid and a Polymer-Bound Tertiary Amine. European Patent 1,167,337, Jan 2, 2002. 

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