CompX, a luciferin-related tyrosine derivative from the bioluminescent earthworm Fridericia heliota. Structure elucidation and total synthesis

A luciferin analog, CompX, was isolated from the extracts of the bioluminescent earthworm Fridericia heliota. Its structure was determined as (Z)-5-(2-carboxy-2-methoxyvinyl)-2-hydroxybenzoic acid by spectroscopic data analysis and was confirmed by total synthesis. The (Z)-configuration of the double bond was established by comparing the ROESY spectra of CompX with those of its synthetic (E)-isomer. CompX represents a tyrosine analog, not previously found in natural sources, and is probably derived from tyrosine by deamination, O-methylation of the resulting alpha-keto acid, and carboxylation at the aromatic core.