Facile synthesis of 6-hydroxyindole-3-acetic acid: On the structure of the aromatic subunit of nephilatoxin-1~6

Article abstract of DOI:10.1016/0040-4039(96)01583-3

A facile synthesis of 6-hydroxyindole-3-acetic acid 1a, which is the proposed aromatic subunit of NPTX-1~6, is described. Radical cyclization of isonitrile 2 successfully afforded 9 in high yield. The aromatic subunit of NPTX-1~6 was confirmed as 4-hydroxyindole-3-acetic acid 12 by comparison of the ¹H-NMR spectra with those of authentic 4- and 6-hydroxyindole-3-acetic acids.