THE DDQ MEDIATED CYCLIZATION PRODUCTS OF SOME 2-HYDROXY-3-(1′-ALKENYL)-1,4-NAPHTHOQUINONES

ABSTRACT The DDQ mediated cyclisation products derived from 2-hydroxy-3-(1′-alkenyl)-1,4-napthoquinones viz. 17 were found to be temperature dependent. At 60°C the naphthofuranquinone 19 was the predominant isomer whereas at 8°C, the naphthopyranquinone 18 was exclusively formed.