4-Methylthiazole-5-carboxylic acid is used as a reagent to synthesize thiazolylimidazolidinone compounds that act as Stearoyl-CoA desaturase-1 (SCD1) inhibitors. These SCD1 inhibitors are used in the treatment of metabolic diseases. 4-Methylthiazole-5-carboxylic acid is also used as a reagent to synthesize 4-Methyl-5-formylthiazole, an important intermediate in the synthesis of Cefditoren pivoxil (C242700).