Potassium acid acetylenedicarboxylate

Piperidine acetate, 32, 33 Potassium, 30, 19, 20 directions for safe handling of, 30, 20 Potassium acid acetylenedicarboxylate, 32, 55... 

The potassium acid salt of acetylenedicarboxylic acid is commercially obtainable from the National Aniline Division, Allied Chemical and Dye Corporation, New York, New York. Directions for the preparation of the free acid are given in earlier volumes.2-3... 

Potassium hydrogen acetylenedicarboxylate (Butynedioic acid monopotassium salt)... 

Phenyl, phenylethynyliodonium perchlorate, 3628 Poly(2,4-hexadiyne-l,6-ylene carbonate), 2665 Potassium acetylene-1,2-dioxide, 0986 Potassium ethynediolate, 0986 Potassium hydrogen acetylenedicarboxylate, 1378 5-(Prop-2-ynyloxy)-l,2,3,4-thiatriazole, 1416 Propiolaldehyde, 1082 Propiolic acid, 1083 Propioloyl chloride, 1062... 

Acetylenedicarboxylic add, HOjCC CCOzH, m.p, 175°. Suppliers Farchan, A, B, F. Preparation by reaction of a, 8-dibromosuccinic acid with methanolic potassium hydroxide, isolation of the potassium acid salt, acidification, and extraction with ether. The potassium acid salt is available from National Aniline and from Eastman. 

Dimethyl acetylenedicarboxylate, CHjOjCC COiCH,. Mol. wt. 110.11, b.p. 96-9878 mm., sp. gr. 1.10, a powerful lachrymator and vesicant. Suppliers A, E, F, MCB. Preparation from commercially available potassium acid acetylene dicarboxylate. 

Potassium hydrogen acetylenedicarboxylate, 1382 Potassium hydrogen tartrate, 1462 -Propenc-l,2,3-lricarboxylic acid, 2342 Propiolic acid, 1086 2,5-Pyridincdicarboxylic acid, 2696 Pyruvic acid, 1150... 

Diphenylquinoxaline and dimethyl acetylenedicarboxylate in methanol/ as in the phenanthridine case, combined to give a yellow pseudomethoxide (147) converted by acid into the corresponding quinoxalinium salt (148). Heating the adduct (147) with ethanolic potassium hydroxide gave 45% 2,3-diphenylquinoxaline, along with... 

The same general method has been used by the submitters to prepare diethyl acetylenedicarboxylate. In this case absolute ethanol was used, and the ether extract was dried over anhydrous magnesium sulfate. The yield of diethyl ester from 100 g. of the acid potassium salt of acetylenedicarboxylic acid was 57-59 g. (51-53%) b.p. 96-98°/8 mm. n 1.4397. 

Dimethyl acetylenedicarboxylate has been prepared by refluxing the acid potassium salt of acetylenedicarbotxylic acid with methanol and sulfuric acid.4,5 The method described here is a substantial improvement over the method of Moureu and Bongrand,6 who prepared it from acetylenedicarboxylic acid, absolute methanol, and sulfuric acid. 

The methyl esters of dicarboxylic acids88 give no dicarboxylic products only mono-carboxylic acid derivatives are formed. Dimethyl succinate, dimethyl maleate and dimethyl acetylenedicarboxylate over potassium tetrafluorocobaltate(III) at 270-350"C all give mixtures of (crude products are converted into ethyl esters) ethyl pentafluoropropanoate and ethyl... 

HETEROCYCLES Copper phcnylace-tylide. Dichlorobis(benzonitrile)palladium. N-Dichloromethylene-N,N-dimcthylammo-nium chloride. Diiminosuccinonitrile. Dimethyl acetylenedicarboxylate. Dipotassium cyanodithioimidocarbonate. Ethoxy-carbonyl isothiocyanate. Ethyldiisopropyl-amine. Ethylene oxide. Hydrogen fluoride. Isocyanomethane-phosphoric acid diethyl ester. Lead tetraacetate. Lithium aluminium hydride. Methylhydrazine. Phosphoryl chloride. Polyphosphate ester. Polyphosphoric acid. Potassium amide. Potassium hydroxide. Tolythiomethyl isocyanide. Tosylmethyl isocyanide, Trichlo-romethylisocyanide dichloride. Trimethyl-silyldiazomethane. 

The unsubstituted l,3-dithiole-2-thione (245) can be accessed, however, by the reaction of dimethyl acetylenedicarboxylate with l,3-dithiolane-2-thione (Scheme 50) <74JOC2456>, from the reaction of sodium acetylide with carbon disulfide and elemental sulfur <64CB1298>, or by a two-step synthesis from the 1,2-dichloroethyl ethylether (246) and potassium trithiocarbonate. The intermediary 4-ethoxy-l,3-dithiolone-2-thione (247) affords, upon reaction with p-toluene sulfonic acid with concomitant loss of ethanol, the unsubstituted derivative (245) <76CC920>. 

With electron-deficient acetylenes, the dithioate anions can be involved in the reactions of both 1,3-anionic cyclo- and nucleophilic additions [550], The reactions of 1,3-anionic cycloaddition are typical provided that the central atom of [S-C-S] has aromatic substituents ensuring the anion stabilization [551,552], For instance, potassium pyrrole-l-carbodithioate selectively reacts (acetonitrile, -30°C, CH3COOH) with dimethyl ester of acetylenedicarboxylic acid to form rapidly polymerizing 2-(pyrrol-l-yl)-4,5-dimethoxycarbonyl-l,3-dithiol (Scheme 2.80) [552,553]. 

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