0,7-Acetylenecarboxylic acid

Reactions of Acetylenecarboxylic Acids and Their Esters with Nitrogen-Containing Heterocyclic Compounds... 

Acetylenic esters react well witli copper-zinc compounds. Propiolic esters are especially reacive [83], but otier acetylenecarboxylic acid derivabves suci as di-nietliyl acetylenedicarboxylate or propiolaniide 118 undergo biglily stereoselecive cis addition (Scienie 2.47) [46]. 

Reactions of Acetylenecarboxylic Acids and Their Esters with Nitrogen-containing Heterocyclic Compounds R. M. Acheson, Adv. Heterocycl. Chem., 1963,1, 125-165. The Reactions of Diazomethane with Heterocyclic Compounds R. Gompper, Adv. Heterocycl. Chem., 1963, 2, 245-286. 

Methyl acetylenecarboxylate (41 R = H, R = Me) reacts with 2-mercaptocyclohexanone in the presence of a catalytic quantity of potassium er -butoxide to give methyl 4,5,6,7-tetr ahy dr obenzo [6] -thiophene-3-carboxylate (42 R = H, R = Me), together with a mixture of the cis and trans isomers of the adduct (43 R = H, R = Me).257 Substituted acetylenecarboxylic acid esters (41 R=Me or Ph, R = Et) behave analogously only the cis adducts (43) are formed in these cases. 

Acetylenecarboxylic acids and esters, reactions with AMieterocydic compounds, 1, 125... 

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