Dicarboxylic add esters

Cyclizative condensations based on aldol-type reactions which conform to the llbd pattern have also been developed. Condensation of bis(alkoxycarbonylmethyl)amines or bis(cyanomethyl)amines with benzil affords 3,4-diarylpyrrole-2,5-dicarboxylic add esters or nitriles. These reactions frequently lead to partial hydrolysis of at least one of the alkoxycarbonyl substituents and if the 3,4-diarylpyrrole is the ultimate objective, work-up involving complete hydrolytic decarboxylation is appropriate (equation 119) (6lLA(639)l02, 65JOC859). 

From Pyrazines with Carbonyl Functions in the 2- and 3-Position From Pyrazine-2,3-dicarboxylic Add Esters... 

The author was the first to discover the intramolecular coordination bond, because he studied a subsidiary research subject, that is, not the main reactions of halo-dicarboxylic add esters with tinfoil but the main reactions of halo-monocarboxylic add esters with tinfoil. He was fortunate to be able to recognize a large shift in the IR spectrum, because the products contain two kinds of absorptions in carbonyl gronps in a single molecule (Eq. (2.4)). 

Gently warm a mixture of 32 g. (32 ml.) of ethyl acetoacetate and 10 g. of aldehyde-ammonia in a 400 ml. beaker by direct heating on a gauze, stirring the mixture carefully with a thermometer. As soon as the reaction starts, remove the heating, and replace it when the reaction slackens, but do not allow the temperature of the mixture to exceed 100-no the reaction is rapidly completed. Add to the mixture about twice its volume of 2A -hydrochloric acid, and stir the mass until the deposit either becomes solid or forms a thick paste, according to the quality of the aldehyde-ammonia employed. Decant the aqueous acid layer, repeat the extraction of the deposit with more acid, and again decant the acid, or filter off the deposit if it is solid. Transfer the deposit to a conical flask and recrystallise it twice from ethanol (or methylated spirit) diluted with an equal volume of water. The i,4-dihydro-collidine-3,5-dicarboxylic diethyl ester (I) is obtained as colourless crystals, m.p. 130-131°. Yield 12 5 g,... 

Azodne-6,7-dicarboxylic add, 1,2-dihydro-1-phenyl-dimethyl ester NMR, 7, 660... 

In the early stage of thiepin chemistry, Scott26) reported the synthesis of benzo-[phthalaldehyde with diethyl 3-thiapentanedioate followed by hydrolysis. Shortly after Scott s synthesis, Dimroth et al.27) found that the ester 34a was thermally more stable than the free acid... 

Kolbe electrolysis is generally useful for the formation of hydrocarbons from monocarboxylic acids and for the preparation of many difunctional compounds as well. A specific illustration is the synthesis of esters of long-chain dicarboxylic adds from monoesters of appropriate dicarboxylic acids (see p. 33). A number of these syntheses are discussed by Fichter.4 In the present preparation, a two-compartment cell is employed to avoid, or at least greatly reduce, undesired reduction of the nitro group at the cathode. It seems likely that the procedure could be adapted to the preparation of other difunctional compounds containing groups that are easily reduced. 

Diaminopyridazino[4,5-d]pyridazine is prepared by the condensation of 4,5-dicyanopyridazine with hydrazine (68JHC53). In like manner, condensation of the pyridazine-4,5-dicarboxylic esters (157) with hydrazines gives the corresponding pyridazino[4,5-d]-pyridazine-l,4-(2f/,3f/)-diones (158). These compounds can also be prepared by condensing pyridazine-4,5-dicarboxylic add anhydrides with hydrazines (75JHC95). 

The reactions of oxalic add, including the formation of normal and add salts and esters, are typical of the dicarboxylic adds class. Oxalic add, however, does not form an anhydride. 

Benzo[6]thiophene-2,3-dicarboxylic add dimethyl ester synthesis, 4, 895... 

The first in this series to be reported was 4-oxoisoxazoline-3,5-dicarboxylic add 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)19) and peroxide oxidation of a 4-nitro-2-isoxazoline (Scheme 151) (79ZOR2436). 

The hydrolysis rate of uncha d esters 7 in tlK presence of the polymer 14 was subtly smaller (ratio, 0.7—1.0) than those with NaOH, whereas, for the monoeth] esters of dicarboxylic adds 15, the polymer-catalyzed rates were greater than those with NaOH by factors of 2—5. In the presence of a similar, polymeric quaternary ammonium (PVBA-Cl) 16, the second-order rate constant of the alkali hydrolysis of... 

Sonoda, Y., Kawanishi, Y., Tsuzuki, S. and Goto, M. (2005) Crystalline-state Z,E-photoisomerization of a series of (Z,E,Z)-l,6-diphenylhexa-l,3,5-triene 4,4 -dicarboxylic add dialkyl esters. Chain length effects on the crystal structure and photoreactivity. J. Org. Chem., 70, 9755-9763. 

The hydrocarboxylation of an unsaturated fatty add ester is carried out in a single organic phase. As product, the monoester of a dicarboxylic add is formed. When this produd is treated with aqueous sodium hydroxide solution this add is converted into a water-soluble sodium salt. In the following separator the water-insoluble palladium catalyst is extracted from the aqueous phase by addition of an organic solvent. When the aqueous product phase is addified with aqueous hydrochloride solution the released carboxylic acid forms a second organic phase and can easily be separated. The catalyst-containing solvent phase passes a distillation step, thus recycling the solvent to the separator and the palladium catalyst to the reactor. 

Diethyl 4-hydroxyisoxazole-3,5-dicarboxylate (334) was prepared by the reaction of acetonedicarboxylic add ester with nitrosyl chloride (78JHC1519). Other 4-hydroxyisoxazoles have been prepared by the reaction of 2-hydroxy(or acetoxy)-l,3-diketones with hydroxylamine (34JA2190, 62HC(i7)l, p. 149), and by hydrolysis of 4-isoxazolediazonium salts (62HC(17)1, p. 149). The parent 4-hydroxyisoxazole has not yet been reported. 

Figure 8. Preparation of the a-cyclodex-trin ester of pytidine-2,5-dicarboxylic add...

S-dicarboxylic add. l-[2-phenyl-2-[(trimethyl-s3yl)oxy]ethylJ-. dimethyl ester -4,5-dicarboxylic add, l-pyrido[2,3-d]tetrazolo-[l,5-h]pyridazin-6-yl-. dimethyl ester -4,5-dkarboxyIic add. l-(2-pytidy])-, dimethyl ester... 

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