Pigments of marine animals. XII. The synthesis of certain substituted naphthopyrones related to crinoid pigments

Abstract

Syntheses of 5,6,8-trimethoxy-2-propyl-4H-naphtho[2,3-b]pyran-4-one, 5,6,8,10-tetramethoxy-2-propyl-4H-naphtho[2,3-b]pyran-4-one, 5,8,10-trimethoxy-2-propyl-4H-naphtho[l,2-b]pyran-4-one and 5,6,8,10-tetramethoxy-2-propyl-4H-naphtho[l,2-b]pyran-4-one are described. The products confirm the structures assigned previously to the crinoid pigments neocomantherin, comaparvin, 6-methoxycomaparvinand 6-methoxycomaparvin 5-methyl ether.