General procedure for the synthesis of 1-(4-methyl-2-(methylamino)thiazol-5-yl)ethanone from N-methylthiourea and 3-chloro-2,4-pentanedione: 1-methylthiourea (6.00 g, 66.6 mmol) was dissolved in a mixture of methanol (130 mL) and pyridine (5 mL) and cooled in an ice bath. Subsequently, 3-chloropentane-2,4-dione (8.96 mL, 66.6 mmol) was added slowly and dropwise to this cooled solution. The reaction mixture was gradually warmed to room temperature and stirred continuously for 4 hours. Upon completion of the reaction, the resulting white solid precipitate was collected by filtration and washed with ether (20 mL) to give the final target product 1-(4-methyl-2-(methylamino)thiazol-5-yl)ethanone (8.94 g, 79% yield). The product was characterized by 1H-NMR (DMSO-d6): δ 2.39 (s, 3H, CH3), 2.49 (s, 3H, CH3), 2.91 (s, 3H, CH3), 9.12 (s, 1H, NH). Mass spectrometry (ESI) analysis showed a calculated value of 171.06 (C7H11N2OS+) for m/z [M+H]+ and a measured value of 171.06.
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