Chiral non-racemic bis(vicinal 1,2-diamines): 4,5-diamino-N-(3,4-diaminobutyl)pentanamide tetrahydrochloride, N,N'-bis[3,4-bis(t-butoxycarbonylamino)butyl]urea and N,N'-bis[3,4-bis(t-butoxycarbonylamino)butyl]hexanamide

Article abstract of DOI:10.1016/0040-4020(95)00853-Z

The reaction of (R) or (S)-N⁴,N⁵-bis(t-butoxycarbonyl)-4,5-diaminopentanoic acid (6) with (R) or (S)-N³,N⁴-bis(t-butoxycarbonyl)-3,4-diaminobutylisocyanate (8) catalyzed by 4-dimethylamino pyridine (DMAP), leads to the synthesis of (R,R), (S,S), (R,S) and (S,R) isomeric amides (11 a-d). The addition of adipic acid monomethyl ester to (R) or (S) isocyanate, followed by saponification, acidification and subsequent reaction with the second molecule of (R) or (S) isocyanate allows isolation of the (R,R), (S,S) and the meso isomers of N,N'-bis[3,4-bis(t-butoxycarbonylamino)butyl]hexanediamide (17). Removal of protecting groups with HCl/EtOH affords chiral non-racemic molecules having two free vicinal diamine units.