Tricyclic products from the reaction between penicillin derived thiazoloazetidinones and ethyl diazoacetate. X-Ray structure of methyl 2-[(1R, 3S, 4R, 5S, 6S, 8R)-3-benzyl-4,5-bismethoxycarbonyl-6-ethoxycarbonyl-9-oxo-7,10-diaza-2-thiatricyclo[6.2.0.03,7]decan-10-yl]-3-methylbut-2-enoate
Abstract
Treatment of methyl (2R)-2-[(1R, 5R)-3-benzyl-6-oxo-4,7-diaza-2-thiabicyclo[3.2.0]hept-3-en-7-yl]-3-methylbut-3-enoate (1; R1= PhCH2, R2= Me) and its conjugated isomer (2; R1= PhCH2, R2= Me) with an excess of ethyl diazoacetate in the presence of Cu(acac)2 gave the tricyclic adducts methyl (2R)-2-[(1R, 3S, 4R, 5S, 6S, 8R)-3-benzyl-4,5,6-trisethoxycarbonyl-9-oxo-7,10-diaza-2-thiatricyclo[6.2.0.03,7]decan-10-yl]-3-methylbut-3-enoate (3) and (5), respectively. In the presence of dimethyl fumarate the analogous 4,5-bismethoxycarbonyl adducts (4) and (6) were also obtained. The structure of methyl 2-[(1R, 3S, 4R, 5S, 6S, 8R)-3-benzyl-4,5-bismethoxycarbonyl-6-ethoxycarbonyl-9-oxo-7,10-diaza-2-thiatricyclo[6.2.0.03,7]decan-10-yl]-3-methylbut-2-enoate (6) was established by an X-ray structure determination.