3-Penten-2-one, 4-methyl-oxide (141-79-7) 

MESITYL OXIDE (C6H10O)

Synonyms: 4-methyl-3-penten-2-one
Description: Oily, colorless liquid. Honey-like odor.
Uses: Manufacture of methyl isobutyl ketone; solvent; ore flotation; insect
      repellent; paint and varnish remover.
Hazards: Moderately toxic; avoid skin contact. Do not expose to heat or
        flame.
Fire fighting: Alcohol foam, CO2, dry chemical
Will explode on contact with: H2SO4, HNO3

Source:  http://www.bluemud.org/print/11914

MESITYL OXIDE
141-79-7

Source:  http://toxnet.nlm.nih.gov/cgi-bin/sis/search