Strong acid-promoted skeletal remodeling of the aphid pigment: red uroleuconaphin to green viridaphin

Abstract

We present herein a strong acid-promoted single-step transformation of red uroleuconaphin A₁ into green viridaphin A₂. Viridaphin A₁ and bis-naphthoquinone were also obtained by performing the reaction in aqueous media. The optical properties were studied to determine the absolute stereochemistry of viridaphins A₁ and A₂ by comparison with those obtained from naturally occurring aphid pigments. The photophysical and antimicrobial activities of those green pigments were also studied.