10-nitrooxy-6β-phthalimido-penicillanic acid methyl ester

9-nitrooxy-6β-phthalimido-penicillanic acid methyl ester

(1R,6aS)-1-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-1,6a-dihydro-5H-4-oxa-6-thia-2a-aza-cyclobuta[a]pentalene-2,3-dione

(2R,2aR)-2-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-2,2a-dihydro-5H-6-oxa-3,4-dithia-7b-aza-cyclobuta[e]indene-1,7-dione