A, 3-Acetylenecarboxylic acid

Sodium methoxide a, -Acetylenecarboxylic acid amides from a, -dibromo-a-dicarboxylic acid amides Anion specificity... 

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. 

Only two reports have been found dealing with the chemistry of this ring system. In the first of these the amination of several simple pyrazine derivatives such as the dimethyl compound (1) with hydroxylamine O-sulfonic acid to give the corresponding iV-amino compounds is described. Treatment of the latter with derivatives of acetylenecarboxylic acid provides pyrazolo[l,5-a]pyrazines such as 2 in 2-10% yields. In contrast, the N-oxide of 1 gave a 41% yield of the 5-oxide 3. Condensation of the... 

Sodium hydroxide a,j -Acetylenecarboxylic acids by elimination-decarboxylation... 

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