view 2-methyl-6-propylpyrazine burnt, butterscotch,
view 2-ethyl-3-methylpyrazine (or 3-ethyl-2-methylpyrazine) butterscotch, nutty, pleasant earthy, raw potato, roasted,
view 2,3-butanedione (diacetyl, dimethylglyoxal) butter, butterscotch, chlorine, diacetyl, penetrating, quinonic, sickly,
view 2,3-pentanedione almond, burnt, burnt butter, butter, butterscotch, diacetyl, estery apple, fruity, grain, malt, oily buttery, pungent, sickly,