Synthesis of deuterium-labelled 6-[5-(4-amidinophenyl)furan-2-yl]nicotinamidine and N-alkoxy-6-{5-[4-(N-alkoxyamidino)phenyl]-furan-2-yl}-nicotinamidines
6-[5-(4-Amidinophenyl)furan-2-yl]nicotinamidine-d4 (5) was synthesized from 6-[5-(4-cyanophenyl)furan-2-yl]nicotinonitrile-d4 (3), through the bis-O-acetoxy-amidoxime followed by hydrogenation. Compound 3 was prepared from 6-(furan-2