183194-06-1Relevant academic research and scientific papers
Synthesis of 2-exo-methylenepenam and 3-chloro-Δ3-cephem through a sequential reductive 1,2-elimination/S-S bond fission or chloride ion-addition/cyclization of 3,4-disubstituted 2-butenoates in metal salt/metal combinations
Tanaka,Sumida,Nishioka,Kobayashi,Tokumaru,Kameyama,Torii
, p. 3610 - 3617 (1997)
Synthesis of 2-exo-methylenepenam 1 through a sequential reductive 1,2-elimination/S-S bond fission/cyclization of 6 was performed by treatment with a PbBr2/Al (or a BiCl3/Al) combination in DMF, while that of 3-chloro-Δ3-cephem 2 through reductive 1,2-elimination/chloride ion-addition/cyclization was attained by use of an AlCl3/Al combination in N-methylpyrrolidone (NMP). The selective transformation of 6 to the allenecarboxylate 3 was also achieved by treatment with an AlBr3/Al combination in NMP. Cyclic voltammograms of 3,4-disubstituted 2-[2-oxo-3-(phenylacetamido)-4-[(phenylsulfonyl)thio]azetidin-1-yl]-2- butenoates (6) exhibit two irreversible reduction peaks responsible for reductive 1,2-elimination of the 3,4-disubstituted 2-butenoate moiety (at less negative potential) and for reductive S-S bond fission of the (phenylsulfonyl)thio moiety, suggesting that the reductive 1,2-elimination of 6 leading to allenecarboxylate 3 would occur prior to the reductive S-S bond cleavage.
