diethyl (3RS,4SR,5SR,6RS)-3-acetoxymethyl-6-benzyloxy-4,5-dihydroxyhexahydropyridazine-1,2-dicarboxylate

diethyl (3RS,4SR,5SR,6RS)-3-acetoxymethyl-4,5-dihydroxy-6-methoxyhexahydropyridazine-1,2-dicarboxylate

diethyl (3RS,6SR)-3-acetoxymethyl-6-benzyloxy-1,2,3,6-tetrahydropyridazine-1,2-dicarboxylate

diethyl (3RS,4SR,5SR,6RS)-3-t-butyldimethylsilyloxymethyl-4,5-dihydroxy-6-methoxyhexahydropyridazine-1,2-dicarboxylate