Stereospecific synthesis of (2R,5R)-hept-6-yne-2,5-diamine: a potent and selective enzyme-activated irreversible inhibitor of ornithine decarboxylase (ODC)

Abstract

Hept-6-yne-2,5-diamine (2) and 2-methylhept-6-yne-2,5-diamine (3), while structurally related to the potent ornithine decarboxylase (ODC) inhibitor hex-5-yne-1,4-diamine (1), are stable to in vivo oxidation by monoamine oxidase (MAO). Although the methyl substitution is at a carbon relatively remote from the site of metabolic attack by ornithine decarboxylase (ODC), it has a critical influence on the potencies of these compounds as inhibitors of the enzyme. Of the four stereoisomers, (2R,5R)-(2) is the most active. Unambiguous syntheses of each isomer of (2) from the dianion of 3-trimethylsilyl-N-butoxycarbonylprop-2-ynylamine (5) are presented.