Three functional groups (2-propenyl, 2-propynyl, and 2,3-butadienyl) were introduced onto one of the terminal amino groups of spermidine. Of the six compounds synthesized, N -(3-aminopropyl)- N ′-2,3-butadienyl-1,4-butanediamine ( N 8-butadienyl Spd) and N -[3-(2,3-butadienylamino)propyl]-1,4-butanediamine ( N 1-butadienyl Spd) irreversibly inactivated human spermine oxidase (SMO) and N 1-acetylpolyamine oxidase (APAO). Interestingly, N 8-butadienyl Spd inactivated SMO far more potently than N , N ′-di-2,3-butadienyl-1,4-butanediamine (MDL 72527).