Acetylene derivs carboxylic acids

By altering the reaction conditions, a preponderance of either product may be produced as desired. Vinyl acetate, which is used for making polymers, and ethylidene diacetate, which is an intermediate for the manufacture of acetic anhydride, are produced on a large scale. The reaction may be applied to other carboxylic adds and acetylene derivatives. Strong acids, such as sulfuric, methane di- and trisulfonic, and phosphoric acids, are catalysts. They may be used in conjunction with mercury salts. Other catalysts which have been disclosed for the reaction include boron trifiuoride and the salts of various metals, such as zinc silicate, zinc acetate, and mercuric phosphate. The addition may be effected in the vapor phase... 

For this reason, the heterocyclization of acetylenic derivatives of pyrazolecar-boxylic acids with different arrangements in the ring of the interacting groups was studied (Table XXVI). The reaction is carried out in boiling pyridine in the presence of catalytic amounts of PhC=CCu (81IZV1342). 4-Acetylenyl-l-methylpyrazole-5-carboxylic acids (Scheme 121) are fully isomerized into the pyranopyrazoles in 20 min in 62-84% yields. 

Hydrazides of vicinal acetylene-substituted derivatives of benzoic and azole carboxylic acids are important intermediate compounds because they can be used for cyclization via both a- and /3-carbon atoms of a multiple bond involving both amine and amide nitrogen atoms (Scheme 131). Besides, the hydrazides of aromatic and heteroaromatic acids are convenient substrates for testing the proposed easy formation of a five-membered ring condensed with a benzene nucleus and the six-membered one condensed with five-membered azoles. 

Tazarotene (Table 1) is an acetylenic third generation retinoid derivative. It is a poorly absorbed, nonisome-risable arotinoid, which is rapidly metabolized to its free carboxylic acid, tazarotenic acid, binding with high affinity to RARs, with the rank order of affinity being... 

Ebdon and coworkers22 "232 have reported telechelic synthesis by a process that involves copolymerizing butadiene or acetylene derivatives to form polymers with internal unsaturation. Ozonolysis of these polymers yields di-end functional polymers. The a,o>dicarboxy1ic acid telechelic was prepared from poly(S-s tot-B) (Scheme 7.19). Precautions were necessary to stop degradation of the PS chains during ozonolysis. 28 The presence of pendant carboxylic acid groups, formed by ozonolysis of 1,2-diene units, was not reported. 

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Reaction XXXIV. (c) Action of Carbon Dioxide on Sodium Acetylides in Dry Ether. (B., 12, 853 J. pr., [2], 27, 417 B., 33, 3586.)—This is an example of the great activating influence of a triple bond. When carbon dioxide is passed into a solution of the sodium derivative of an acetylenic hydrocarbon in dry ether, direct addition takes place to give the sodium salt of the next highest acetylenic carboxylic acid. For example, sodium allylene yields sodium tetrolate—... 

Oxidation of these complexes releases the apical carbon atom and its substituent in the form of an organic derivative.2 Thus ceric ammonium nitrate oxidation of an RCCo3(CO)9 complex produces the carboxylic acid, RC02H, when the reaction is carried out in aqueous acetone. Thermolysis of RCCo3(CO)9 produces acetylenes or acetylene hexacarbonyl dicobalt complexes, depending on the reaction conditions. Useful applications of these cluster complexes in organic synthesis remain to be developed. 

By the oxidation of propargyl alcohol, propinol, CH=C—CH2OH (p. 167), an acid is obtained having the constitution CH=C—COOH and known as propiolic acid or propinoic acid and also as acetylene carboxylic acid. This is the simplest acid of the ethine series and the only one we shall mention. Derivatives of it are of importance in the benzene series in Part li as will be shown later. 

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