Novel Efficient Total Synthesis of Antiviral Antibiotic Distamycin A

Article abstract of DOI:10.1021/jo00330a022

In connection with an attempt to design a flexible synthesis of analogues of distamycin A (14) for a structure-activity study, by starting from 4-<<(tert-butyloxy)carbonyl>amino>-1-methylpyrrole-2-carboxylic acid (3) and the corresponding formyl derivative (9), the distamycin A precursor 12 was prepared.The versatility of 12 is demonstrated by direct attachment, after activation, of preformed β-aminopropionamidine dihydrobromide to give 14 in fair yield.We conclude that N- and/or ring-substituted derivatives of 3 and 9 may lead to the corresponding analogues of 12 and thus serve as useful precursors, to which the amino amidine or derivatives thereof can be attached.After hydrogenation of the corresponding nitro compound, 3 and 9 were prepared with (tert-butyloxy)carbonyl fluoride and formic anhydride, respectively.Amide bond formations were accomplished with carbodiimides, occasionally via intermediary active esters (8,13).