Tricarballylic acid

Tricarballylic acid. Place 228 g. (204 ml.) of ethyl propane-1 1 2 3-tetracarboxylate and 240 ml. of 1 1 hydrochloric acid in a 1-litre threenecked flask, fitted with a mechanical stirrer and a fractionating column with condenser set for downward distillation attach a receiver with side tube to the condenser and connect the side tube to a wash bottle containing water. Boil the mixture, with continual stirring, at such a rate that the... 

Table XXXI.—Gel Points for Polymers Containing Tricarballylic Acid ...

The addition of active methylene compounds (ethyl malonate, ethyl aceto-acetate, ethyl plienylacetate, nitromethane, acrylonitrile, etc.) to the ap-double bond of a conjugated unsaturated ketone, ester or nitrile in the presence of a basic cataljst (s ium ethoxide, piperidine, diethylamiue, etc.) is known as the Michael reaction or Michael addition. The reaction may be illustrated by the addition of ethyl malonate to ethyl fumarate in the presence of sodium ethoxide hydrolysis and decarboxylation of the addendum (ethyl propane-1 1 2 3-tetracarboxylate) yields tricarballylic acid ... 

C domains can display functions that deviate from typical amide bond formation. Several C domains are postulated to act as ester synthases, catalyzing ester formation instead of amide formation. NRPS modules containing C domains that display this activity are present in the biosynthetic pathways for the kutznerides, cryptophycins, " cereulide, valinomycin, hectochlorin, and beauvericin. Each of these C domains likely utilizes a PCP-bound a-hydroxyl acceptor in the condensation reaction. Another NRPS C domain that catalyzes ester bond formation is involved in the biosynthesis of the polyketide-derived mycotoxins known as the fiimonisins. Du and coworkers have shown that a recombinant PCP-C didomain of an NRPS involved in the biosynthetic pathway of the fnmonisins can catalyze ester bond formation between hydroxyfumonisins and the A-acetylcysteamine thioester of tricarballylic acid, even though PCP-bound tricarballylic acid is not... 

Soon after thiophene and its derivatives had been prepared by treating 1,4-dicarbonyl compounds with P2S3, Biedermann and Jacobson extended this procedure to citric and tricarballylic acids. By heating a mixture of citric acid and PjSj, they obtained a compound CJH4S2, b.p. 224°-226°, in about 1% yield. The structure 1 was ascribed to this compound, which was called thiophthene [Eq. (1)]. 

Similar results were obtained from the sodium salt of tricarballylic acid with PjSj. 

Tricarballylic acid [99-14-9] M 176.1, m 166°. Crystd from ethyl ether. 

Tricarballylic acid is readily soluble in water (requiring about twice its weight at room temperature), but may, if desired, be recrystallized from it. Dry ether may also be employed, about 50 parts by weight being necessary. 

Tricarballylic acid was originally prepared by hydrolysis of the nitrile obtained from glycerol tribromohydrin and potassium cyanide 1 it has also been obtained by the reduction of aconitic acid by sodium amalgam 2 or electrolytically.3 The hydrolysis of ethyl propanetetracarboxylate may be carried out either in acid solution (with hydrochloric acid)4 or in alkaline solution,5... 

The filtrate is now refluxed on a water bath with a sufficient quantity (40 gms.) of caustic potash, to decompose the cyanide formed, until no more ammonia is evolved. The alcohol is distilled off on a brine bath, and the cooled residue evaporated to dryness with excess nitric acid. From it, after being well dried and powdered, the tricarballylic acid may be extracted with absolute alcohol. The dark-coloured substance obtained on evaporating off the alcohol is recrystallised from hot water with the addition of animal charcoal. 

Propenyl tricyanide, the nitrile of tricarballylic acid, is obtained in a similar manner (see Preparation 62). 

C6H5 N903 mw 251.20 N 50.20% OB to C02 —73.25% yel expl oil with a heavy odor. Sol in ethanol and eth insol in w. Prepn is by reacting tricarballylic acid trihydrazide hydrochloride with a soln of Na nitrite at 0°... 

Products from the direct oxidation of lignin that give information about its structure include acetic, oxalic, and succinic acids, vanillin, vanillic acid, and dehydrodivanillin. Regarding lignin constitution, they are of only minor interest, but the yields in which they are obtained are significant. For vanillin and its derivatives the total yield is about 33% of spruce lignin (24, 36, 37, 38). Two extraordinary products of this direct oxidation deserve special attention—i.e., benzenepentacarboxylic (45) and tricarballylic acids (47), (XXIX) and (XXX). They will be mentioned later in connection with lignenolide (XXVII). 

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