Amides, acetylenic, hydration

Carboxylic esters, thiol esters, and amides can be made, respectively, by acid-catalyzed hydration of acetylenic ethers, thioethers,162 and ynamines, without a mercuric catalyst 163... 

The third approach to enamides is based on the interaction of aldehydes and ketones 7 with amides 4. This general method can be also considered as a peculiar vinylation at the nitrogen atom of the amide because the carbonyl compounds 7 are the products of hydration of the acetylenes 5 and have the same oxidation level of two17 (equation... 

The unsymmetrical acetylene (43) yields cw-(CF3)iN-CH CH-CFs with hydrogen-Raney nickel at 20 C, undergoes slow hydration in the presence of aqueous sulphuric acid and mercuric sulphate at 53 °C to give the propion-amide (CFa)jN CO-CH2 CF3, combines with methanol in the presence of sodium methoxide to yield a 96 4 mixture of (CF3)aN-C(OMe) CH CF3 and (CFj)jN CH C(OMe)-CF3, and when subjected to photochemical hydrobromination gives the 1 1 adduct (CFs)jN-CH CBr-CF3 almost quantitatively. Slow electrophilic hydrobromination of the acetylene can be achieved in the presence of aluminium bromide at 20 °C, the main product being the same as that obtained in the photochemical reaction (H trans to Br in each case) this unexpected direction of addition is suggested to result... 

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