mesitonic

from The Century Dictionary.

• Noting an acid, a colorless compound, (CH₃)₂C(COOH)CH₂COCH₃, prepared by the action of hydrochloric-acid gas, potassium cyanide, and alcohol on acetone. It crystallizes in small prisms or large plates, melts at 74° C., and boils at 138° C. under 15 millimeters pressure.