description： 2-Acetyl-5-methylthiophene is a volatile organic compound formed during the reaction between L-cysteine and dihydroxyacetone in glycerine or triglyceride solvent system. It can be prepared by reacting 2-methylthiophene with acetic anhydride. 2-Acetyl-5-methylthiophene undergoes palladium-catalyzed cross-coupling reaction with aryl bromides to form C-4 arylated product. It reacts with 1,2-bis(5-formyl-2-methylthiophen-3-yl)cyclopentene via Aldol condensation to form a chalcone with photochromic property. The standard molar enthalpies of combustion, formation and vaporization of 2-acetyl-5-methylthiophene are 4341.9 ± 1.8kJ/mol, 158.0 ± 2.1kJ/mol and 62.0 ± 2.6kJ/mol, respectively. application： 2-Acetyl-5-methylthiophene may be used in the preparation of: • 2-ethyl-5-methylthiophene • (5-methylthiophen-2-yl)glyoxal • (2E)-1-(5-methylthiophen-2-yl)-3-(pyridin-3-yl)prop-2-en-1-one • ethyl 3-(5-methylthiophen-2-yl)-3-oxopropanoate