A new synthesis of dehydroluciferin [2-(6′-hydroxy-2′-benzothiazolyl)-thiazole-4-carboxylic acid] from 1,4-benzoquinone

A new synthesis of dehydroluciferin, the oxidative product of luciferin, has been realized starting from 1,4-benzoquinone. Reaction with cysteine ethyl ester, oxidation-cyclization, hydrolysis, and decarboxylation gave 6-hydroxybenzothiazole. The tert-butyl(dimethyl)silyl ether of this key intermediate was subjected to α-lithiation followed by formylation, condensation with cysteine ethyl ester, dehydrogenation, and deprotection to afford dehydroluciferin (35% overall yield from 1,4-benzoquinone).