Sodium Carbonate → HCID 44176976, compound

Participants

Reaction Steps

A mixture of 2,6-dichloropyrazine (0.150 g, 1.006 mmol), 5-amino-2-methylbenzothiazole (0.250 g, 1.51 mmol), BINAP (0.0137 g, 0.02215 mmol), sodium tertiary butoxide (0.136 g, 1.409 mmol) and palladium acetate (0.005 g, 0.02215 mmol) in toluene (8 mL) was heated at 85° C. for 16 h under nitrogen. CH2Cl2 was added, the reaction mixture was filtered through Celite, and the solvent was evaporated. The residue was purified by column chromatography (5% methanol in CH2Cl2 as eluent) to give 0.180 g (65%) of intermediate (6-chloro-pyrazin-2-yl)-(2-methyl-benzothiazol-5-yl)-amine. 1H NMR (CDCl3) δ 7.59-7.54 (d, J=15.6 Hz, 2H), 7.38 (s, 1H), 7.19-7.16 (d, J=8.65 Hz, 1H), 6.98-6.95 (d, J=8.41 Hz, 1H), 6.71 (brs, 1H, NH), 2.31 (s, 3H, CH3); MS (API-ES/Positive); m/z: 277 (M+H)+. A mixture of (6-chloro-pyrazin-2-yl)-(2-methyl-benzothiazol-5-yl)-amine (0.075 g, 0.271 mmol), pyridine-4-boronic acid (0.040 g, 0.326 mmol), sodium carbonate (0.143 g, 1.35 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.0156 g, 0.0135 mmol) in DME:water (3:2, 5 mL) was heated at reflux for 20 h. The reaction mixture was concentrated under reduced pressure and the residue obtained was extracted with dichloromethane. The organic layer was washed with water, brine, dried over sodium sulfate and concentrated. The crude product was purified by flash chromatography (5% methanol in CH2Cl2 as eluent) to yield 2-methyl-N-(6-pyridin-4-ylpyrazin-2-yl)-1,3-benzothiazol-5-amine (0.075 g, 86.5%) as a yellow solid. 1H NMR (CD3OD) δ 8.82 (m, 3H), 8.72 (s, 1H), 8.45-8.44 (m, 2H), 8.35 (s, 1H), 7.92-7.90 (d, J=8.67 Hz, 1H), 7.61-7.59 (dd, J=10.63, 1.94 Hz, 1H), 2.89 (s, 3H, CH3); MS (API-ES/Positive); m/z: 320 (M+H)+.

Provenance & Evidence