methyl 5-{[(5-{[(5-{[(5-amino-6-isopropoxy-2-pyridinyl)carbonyl]amino}-6-isopropoxy-2-pyridinyl)carbonyl]amino}-6-isopropoxy-2-pyridinyl)carbonyl]amino}-6-isopropoxy-2-pyridinecarboxylate

methyl 6-isopropoxy-5-(6-isopropoxy-5-nitropicolinamido)picolinate

methyl 3-isopropoxy-4-(6-isopropoxy-5-(6-isopropoxy-5-nitropicolinamido)picolinamido)benzoate

Methyl 5-{[(5-amino-6-(benzyloxy)-2-pyridinyl)carbonyl]amino}-6-isopropoxy-2-pyridinecarboxylate

5-[(6-Benzyloxy-5-nitro-pyridine-2-carbonyl)-amino]-6-isopropoxy-pyridine-2-carboxylic acid methyl ester