Wikipedia - 2,3-pentanedione
Acetylpropionyl, also known as acetyl propionyl or 2,3-pentanedione, is an organic compound, more specifically a diketone. Uses for acetylpropionyl include:
a solvent for cellulose acetate, paints, inks, and lacquers,
a starting material for dyes, pesticides, and drugs,
and a flavor, with an odor described as "buttery, cheesy, sweet, nutty, fruity, creamy, caramel".