Aconitic esters

The methods of preparation of i. ost cyclojro-par.e acids involve first the preparation of tAie cyclic ester and subsequent hydrolysis to the free acid. That such hydrolysis did not change tne cyclic structure has been seen to be true ir. all tne cases tnus iar examined i o exceptions to tnis rule will now be studied,ior tney are botn 1,1,2,3 compounds. Aconitic ester and diazoacetic ester give by the usual reactions a cyclopropane ester as follows ... 

Ruhemann prepared phenylcarboxylic-aconitic ester by the action of phenylmalonic ester on chlor-fumarlc ester in the presence of sodium ethylate. This ester,OaHsO( OOOCiHs )s-J( COOCgHe ),... 

There have been a number of isolated studies of metal-ion catalyzed nucleophilic reactions of other groupings. Particularly interesting is the induced nucleophilic attack on olefins. Hydration is normally very sluggish. Enzymes can speed up such reactions. Aconitase, an iron-containing enzyme, catalyzes the isomerization of citric acid to isocitric acid, through the intermediacy of cis-aconitic acid. A possible mechanism has been suggested based on the following Co(III) model chemistry. Rapid cyclization of the maleate ester produces Ai and AS chelated malate half ester ... 

Figure 1. Total ion current of n-butyl esters of the acidic fraction from non-sterile leaf washings of C. sativa. Key 1 = oxalic acid 2 = malonic acid 3 = maleic acid 4 = succinic acid 5 = fumaric acid 6 = alpha-ketoglutaric acid 7 = cis-aconitic acid 8 = citric acid (19)-...

A number of other acylsuccinic esters can be prepared in a similar fashion from the appropriate saturated aliphatic aldehydes and maleic esters.2 3 The procedure is equally adaptable to the preparation of a-acyltricarballylic esters from aldehydes and aconitates.2 Good temperature control (80-90°) is most important for success in these reactions. 

Monoethyl ester of 0.00265 b-aras-Aconitic acid No effect... 

Aconites, commonly called wolfsbane or monkshood, are species of Aconitum (Ranunculaceae), valued ornamental herbaceous plants, grown for their showy blue or purple flowers, which are shaped like a monk s cowl. Their alkaloid content, mainly in the roots, makes them some of the most toxic plants commonly encountered. The dried roots of Aconitum napellus were once used, mainly externally for relief of pain, e.g. in rheumatism. The toxic alkaloids (0.3-1.5%) are complex diterpene-derived esters. Aconitine (Figure 6.124) is the principal component (about 30%) and is a diester of aconine with acetic and benzoic acids. Hydrolysis products benzoylaconine and aconine are also present in dried plant material. These alkaloids appear to behave as neurotoxins by acting on sodium channels. All species of Aconitum and Delphinium are potentially toxic to man and animals and must be treated with caution. 

Shikimic acid methyl ester Aconitic acid dialdehyde methyl ester 75%. 125... 

Tricarballylic acid, 1,2,3-propanetricarboxyIic acid, is produced by the reduction of aconitic acid by catalytic methods,107-111 electrolyti-cally,112-114 or by sodium amalgam.50-115 Sulfotricarballylic acid (VII), its salts, and its esters have become of interest recently due to their... 

Propargylic alcohols are less reactive than their esters, and their carbonylation has been carried out under somewhat harsh conditions (100 °C, 100 atm) [10,11]. The carbonylation products under these conditions are different from those obtained by the carbonylation of the corresponding carbonates under milder conditions. Carbonylation of propargyl alcohol (82) in methanol without using a phosphine ligand proceeded in the presence of hydrochloric acid to afford dimethyl itaconate (79) as a main product and trimethyl aconitate (83) as a minor product (Scheme 11-24). PdCl2 or Pd/charcoal is an active catalyst [11]. 

Use Conversion to aconitic acid, tributyl aconitate, and similar ester plasticizers. 

The second metabolic pathway which we have chosen to describe is the tricarboxylic acid cycle, often referred to as the Krebs cycle. This represents the biochemical hub of intermediary metabolism, not only in the oxidative catabolism of carbohydrates, lipids, and amino acids in aerobic eukaryotes and prokaryotes, but also as a source of numerous biosynthetic precursors. Pyruvate, formed in the cytosol by glycolysis, is transported into the matrix of the mitochondria where it is converted to acetyl CoA by the multi-enzyme complex, pyruvate dehydrogenase. Acetyl CoA is also produced by the mitochondrial S-oxidation of fatty acids and by the oxidative metabolism of a number of amino acids. The first reaction of the cycle (Figure 5.12) involves the condensation of acetyl Co and oxaloacetate to form citrate (1), a Claisen ester condensation. Citrate is then converted to the more easily oxidised secondary alcohol, isocitrate (2), by the iron-sulfur centre of the enzyme aconitase (described in Chapter 13). This reaction involves successive dehydration of citrate, producing enzyme-bound cis-aconitate, followed by rehydration, to give isocitrate. In this reaction, the enzyme distinguishes between the two external carboxyl groups... 

C HgOe, Mr 176.13, prisms, mp. 166 °C, sublimation. P. is formed in sugar beets and sugar maple by reduction of citric acid, on the technical scale by reduction of aconitic acid. P. esters with fatty alcohols belong to the so-called inverse fats. 

Ethyl carbonate. See Diethyl carbonate Ethyl-2-carboxyglutaconate. See Ethyl aconitate, mixed esters Ethyl carvacrol Ethyl carvacryl ether. See Carvacryl ethyl ether Ethyl Cellosolve. See Ethoxyethanol Ethylcellulose CAS 9004-57-3 INS462... 

Ethyl polysilicate. See Polydiethoxysiloxane Ethyl potassium carbonate Ethyl potassium xanthate Ethyl potassium xanthogenate. See Potassium ethyl xanthate Ethyl propanoate. See Ethyl propionate 1 -Ethyl-1 -propanol. See 3-Pentanol Ethyl 1-propene-1,2,3-tricarboxylate. See Ethyl aconitate, mixed esters Ethyl propenoate Ethyl 2-propenoate. See Ethyl acrylate Ethyl propionate... 

Ethyl 2-acetyl-3-phenylpropionate Ethyl aconitate, mixed esters Ethyl acrylate Ethyl-p-anisate Ethyl anthranilate Ethyl benzoate Ethyl benzoylacetate a-Ethylbenzyl butyrate... 

Aconitine an extremely poisonous ester and alkaloid (see Terpene alkaloids) from the roots of aconite (Aconitum napellus) and other Aconitum and Delphinium species. Between 1 and 2 mg A. causes death in adult humans by paralysing the heart and respiration. In spite of useful physiological properties, A. is rarely used clinically, due to its toxidty. A. is sometimes used internally as a tincture for rheumatism and neuralgias, and externally as a pain-killing salve. In antiquity, aconite preparations were used as arrow poisons by the Greeks and (East) Indians. Its hydrolysis products are only slightly toxic. 

The product, trimethyl ester of aconitic acid, was obtained as a mixture of Z- and E-stereoisomers. 

Wang Y, Shi L, Song F, Liu Z, Liu S (2003) Exploring the ester-exchange reaction of diester-diterpenoid alkaloids in the aconite decoction process by electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom 17 279-284... 

Aconitic acid a-Mono-Me ester, in A-70055 Aconitic acid )ff-Mono-Me ester, in A-70055 Aconitic acid y-Mono-Me ester, in A-70055... 

Phenolic acids of E. arvense include di- -caffeoyl-me50-tartaric acid methy esters of protocatechuic and caffeic acids aconitic, oxalic, malic, tannic, arahinoic, and threonic acids minerals, including silicic acid and silicates (5-8%) water soluble up to 80%, potassium, aluminum, and manganese sterols, including campesterol isocuosterol, and brassinosteroids and others. Trace amounts of nicotine have been found in E. arvense ... 

Because citric acid is considered as relatively cheap and abundant material, it was catalytically dehydrated to aconitic acid in the 120-150 °C temperature range by Umbdenstock and Bruin [61]. Aconitic acid can be readily decaiboxylated to a mixture of isomeric itaconic acids (itaconic, citraconic and mesaconic acids). These acids and their esters are nsed to produce alkyl resins and plasticizers. The mechanism of thermal rearrangement of citraconic acid to itaconic acid in aqueous solution was in a great detail investigated by Sakai [62]. In some cases, the applied catalyst caused excessive pyrolysis of citric acid and in the dehydration and decarboxylation reactions acetone dicarboxylic acid (P-ketoglutaric acid) was initially formed and from it acetone. The catalytic pyrolysis of citric acid monohydrate heated up to 140 °C to obtain itaconic and citraconic acids was reported by Askew and Tawn [63],... 

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