Acetylene acidity and

Phenylpropiolic acid. This is an example of an aromatic acetylenic acid, and is made by adding bromine to the ethylenio linkage in ethyl cinnamate, and treating the resulting dibromide with alcohobc potassium hydroxide which eliminates two molecules of hydrogen bromide ... 

III. Reactions of Acetylenic Acids and Esters with Individual Nitrogen ... 

Thiophenols undergo base-catalyzed, Michael addition to acetylenic acids and esters to give trans addition products. These vinyl thioethers have been used in the synthesis of thiochromones. " Recently, Undheim and Lie have shown that thiophenol adds to DMAD with concomitant cyclization to give benzo[6]thiophenes. 

As for the unsaturated carbonyl compounds, the most significant groups are the oc,/ -unsaturated acids or esters. Some of their methods of formation are closely analogous, for example, (a) the Horner-Emmons or Wadsworth-Emmons reaction, and (b) the aldol-type reactions. Rather more specific methods are considered below for the formation of a,/ -acetylenic acids, and for the conversion of the unsaturated dicarboxylic acid, maleic acid, into its anhydride or into fumaric acid. 

Stereoselectivity was similarly increased for additions to o, -acetylenic acids and, to a lesser extent, to a,(3-acetylenic ketones. 

Only the major fatty acids are listed in this table. Other fatty acids such as ethylenic acids, acetylenic acids and substituted fatty acids (hydroxy-, polyhydroxy-, keto- and expoxy acids) occur in seed fats (for further details, see Hitchcock, 1975 [36])... 

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