反应详情

温度

60 °C

N-(5-acetyl-4-methyl-1,3-thiazol-2-yl)-N-pyrazin-2-ylacetamide (511.2 mg; 1.85 mmol; 1 eq.) is dissolved in AcOH (10 ml). Hydrobromic acid (32 μl; 0.19 mmol; 0.10 eq.) is added, followed by a solution of bromine (95 μl; 1.85 mmol; 1 eq.) in AcOH (2 ml). The mixture is stirred 3 h at rt and 2 h at 60° C. To complete the reaction, bromine (95 μl; 1.85 mmol; 1 eq.) in AcOH (2 ml) is added and the mixture is stirred 4 h at 60° C. Solvents are evaporated and the resulting dark brown solid is suspended in THF, filtered and washed with cyclohexane, affording Intermediate 3 as yellow solid (467.7 mg; 64%). It is used in bisthiazol synthesis as HBr salt or as parent, after 5 min treatment with Amberlyst A21 in DCM/MeOH mixture. 1H NMR (DMSO-d6, 300 MHz) δ 2.60 (s, 3H), 4.64 (s, 2H), 8.24 (d, J=2.6 Hz, 1H), 8.43 (dd, J=1.5 Hz, J=2.6 Hz, 1H), 8.50 (d, J=1.5 Hz, 1H). M+ (ESI): 312.9. HPLC (Method A), Rt: 2.80 min (purity: 97%).

1. additionis added
2. stirringthe mixture is stirred 4 h at 60° C
3. customSolvents are evaporated
4. filtrationfiltered
5. washwashed with cyclohexane