ISODEHYDROACETIC ACID

ISODEHYDROACETIC ACID, 32, 57, 76 Isomerized wood rosin, 32, 2 2-Isonitrosocyclohexanone, 32, 38 Isopropyl alcohol, 31,112 Isopropyl iodide, 30, 34 31, 33 -Isopropylphenylacetamide, 32, 94 -Isopropylphenyldichlorophosphine,... 

Dimethylcoumalin has been prepared by the decarboxylation of isodehydroacetic acid in sulfuric acid or by heating. ... 

The filtrate, ca. 4 1. in volume, is extracted with three 1.5-1. portions of ether (Note 4), and the sulfuric acid mother liquors are discarded. The ether extracts are combined and used to dissolve the solid mixture of acid and ester. If necessary, more ether can be added to assist in dissolving the solid. The ether solution is washed with 50 ml. of cold water and extracted with approximately ten 100-ml. portions of saturated sodium carbonate solution until all the isodehydroacetic acid has been removed (Note 5). The combined sodium carbonate extracts are acidified with an excess of concentrated hydrochloric acid, and the finely divided acid which precipitates is redissolved by heating to the boiling point. The hot solution is filtered with the aid of suction and is cooled in an ice bath the solid is collected on a filter. The crude isodehydroacetic acid is dissolved in 400 ml. of hot water, and this solution treated with decolorizing carbon, filtered, and cooled slowly to effect crystallization. The yield of isodehydroacetic acid is 91-115 g. (22-27%) m.p. 154-155°. 

Two equations are written since isodehydroacetic acid is not esterified rapidly and its ester is not hydrolyzed rapidly under the conditions used here. 

Isodehydroacetic acid has been prepared by the action of sulfuric acid on acetoacetic ester 3 4 The ethyl ester has been prepared by the action of dry hydrogen chloride on acetoacetic ester 6 6 and by the sodium-catalyzed condensation of ethyl /3-chloroisocrotonate with ethyl acetoacetate3 The methyl ester of isodehydroacetic acid has been prepared by the thermal rearrangement of pyrazolines 7... 

The ester of isodehydroacetic acid, a derivative of a-pyrone, forms a 3-methylpyrazolin-5-one with hydrazine,407 although in certain papers a-pyrones and hydrazines are said to form 4-acylcarboxylic acid hydrazides408 and A-aminopyridones.409 A point of interest is that even nitrogenous heterocyclic compounds such as quinolin-4-ones... 

C8H10OS methyl p-tolyl sulfoxide 934-72-5 453.82 39.465 2 14030 C8H10O4 isodehydroacetic acid 480-65-9 486.15 42.555 2... 

When ethyl acetoacetate is reacted with HCl, isodehydroacetic acid (ethyl 4,6-dimethyl-2-pyrone-5-carboxylate) is formed - explain. 

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