69962-06-7Relevant academic research and scientific papers
Lithium/Ammonia Reductions of 2-Thiophenecarboxylic Acids
Blenderman, Walter G.,Joullie, Madeleine M.,Preti, George
, p. 3206 - 3213 (2007/10/02)
Lithium/ammonia reductions of 2-thiophenecarboxylic acids (1) in the absence of a proton source afforded mixtures of products.In the presence of methanol acyclic mercapto carboxylic acids (4) were the major products.Ring closure of 4 to the corresponding thiolactones (12) showed the double bonds in 4 to be of cis geometry.Attempts were made to prepare Z olefinic compounds derived from these mercapto carboxylic acids.Lithium 2-thiophenecarboxylate salts (2) afforded good yields of the corresponding 2,5-dihydro-2-thiophenecarboxylic acids (3).The presence of substituents on the ring and the ratio of metal to acid were significant factors in determining the nature of this products.A mechanism is proposed to explain the products observed.
ACTION OF ALKALI METALS IN LIQUID AMMONIA ON SUBSTITUTED THIOPHENES VII. REGIOSPECIFIC AND STEREOSPECIFIC RING OPENING IN 2-THIOPHENECARBOXYLIC ACIDS AS A METHOD FOR THE PRODUCTION OF δ-MERCAPTO β,γ-UNSATURATED ACIDS
Gol'dfarb, Ya. L.,Zakharov, E. P.,Shashkov, A. S.,Stoyanovich, F. M.
, p. 1310 - 1316 (2007/10/02)
Regiospecific and stereospecific ring opening was detected in 2-thiophenecarboxylic acids under the influence of lithium and ethanol in liquid ammonia.The reaction leads to the formation of previously unknown δ-mercapto-β,γ-Z(cis)-alkenoic acids with preparative yields.The acids were isolated as such or in the form of S-alkyl-substituted derivatives.The latter were obtained by addition of the alkylating agent to the reaction mixture after reduction.The structure of the products was established by physical methods.
