Phthalide

Phthalide is an organic chemical compound with the molecular formula C₈H₆O₂. It is a lactone that serves as the core chemical structure for a variety of more complex chemical compounds including dyes (such as phenolphthalein), fungicides (such as tetrachlorophthalide, often referred to simply as "phthalide") and natural oils (such as butylphthalide).