Synthesis of 6-[1-[4-(benzoxazol-2-yl)thiobuthyl]-1,2,3-triazole-4-yl]methylenepenam as beta-lactamase inhibitors.
The 6,6-dibromopenam6 was treated with CH(3)MgBr and carbaldehyde5 to afford the 6-bromo-6-(1-hydroxy-1-methyl)penicillanate7, which was reacted with acetic anhydride to give acetoxy compound8. The deacetobromination of8 with zinc and acetic acid gave 6-exomethylenpenams, Z-isomer9 and E-isomer10, which were oxidized to sulfones11 and12 by m-CPBA. The p-methoxybenzyl compounds were deprotected by AlCl(3) and neutralized to give the sodium salts13, 14, and15.
Im
C
C
College of Pharmacy, Chung-ang University, Heuksuk-Dong, Dongjak-Ku, 156-756, Seoul, Korea.
Yim
C B
CB
Oh
J S
JS
Yoon
S B
SB