2,2-diethoxycarbonyl-4-hydroxy-1-(4-nitrobenzoyl)pyrrolidine

ethyl 2-acetamido-2-(ethoxycarbonyl)-4-pentenoate

水

6-bromomethyl-2-methyl-5,6-dihydro-[1,3]oxazine-4,4-dicarboxylic acid diethyl ester, hydrobromide