Convergent synthesis of Carpatamide-A: Cytotoxic arylamine derivative from marine derived Streptomyces sp.

First total synthesis of carpatamide-A 7a, cytotoxic arylamine derivative isolated from marine derived Streptomyces sp., was achieved in twelve steps with overall yield of 24% with seven longest linear steps. In the penultimate step, dienoic acid 13 and an amino-phenylpropionic acid methyl ester core 21 were coupled to synthesize methylated derivativative of carpatamide-A 22 followed by demethylation of the intermediate with BBr3 to accomplish carpatamide-A 7a. Both precursors 13 and 21 were synthesized from readily available starting materials i.e. isovaleraldehyde 8 and 2, 4-dihydroxy benzaldehyde 14.