Synthesis of (+/–)-Mesocentroquinone, a Biquinone of a Novel Structural Class and Metabolite of Sea Urchins Mesocentrotus nudus and Strongylocentrotus intermedius, and Related Compounds#.

The synthesis of mesocentroquinone, a metabolite of the sea urchins Mesocentrotus nudus and Strongylocentrotus intermedius, is described. The procedure includes bromination of 2-hydroxy-6,7-dimethoxy-3-ethylnaphthazarin, dehydrobromination of the resulting 1′-bromoethyl derivative, and heterodiene condensation of the 2-oxo-3-ethylidene- and 3-vinyl-2-hydroxy-derivatives formed by this. The general nature of the proposed approach to the synthesis of 2-(1,4-naphthoquinon-2-yl)-benzo[g]-2Hbenzochromene-5,10-diones is demonstrated using two examples. [ABSTRACT FROM AUTHOR]