Synthesis and antibacterial activity of 2-[(methoxycarbonyl)methylene]cephalosporins
作者:C. U. Kim、P. F. Misco、U. J. Haynes、D. N. McGregor
DOI:10.1021/jm00375a026
日期:1984.9
2-[(methoxycarbonyl)methylene]-3-cephem-4-carboxylic acids with methyl or acetoxymethyl at the 3-position are described. The key step in the synthesis includes the stereospecific formation of the 2-[(Z)-(methoxycarbonyl)methylene] group by Pummerer rearrangement of the sulfoxides 3a and 3b. It was also possible to isomerize photochemically the C-2 olefin of 4a to its E isomer, 9. The new derivatives exhibited