An iterative synthesis of poly-substituted indole oligomers reveals a short effective conjugation length in eumelanin model compounds.

ABSTRACT: Eumelanin is a multifunctional biomaterial that colors the skin, hair and eyes of mammals. Despite years of effort, its molecular structure remains unknown, limiting our understanding of its biological function and the design of synthetic mimics. In an effort to address this challenge, we report an Iterative Chain Growth (ICG) of well-defined 5,6-dihydroxyindole (DHI) model compounds that provides direct, experimental evidence of a short effective conjugation length in the resulting oligomers. Our ICG highlights the C2-selective borylation of N-H indoles in complex settings, and the utility of Suzuki-Miyaura Coupling (SMC) to grow the chain. The resulting C2-C7' linkage is installed selectively with good yields, affording products with up to 5-indole units. Access to these oligomers allows

SUBMITTER: Huang H 

PROVIDER: S-EPMC11836627 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature