| 54% |
With hydrazine In ethanol; water at 20℃; for 3.50 h; |
Intermediate 4A mixture ofIntermediate 3 (3.55 g, 15.8 mmol) and 35percent aqueous hydrazine (35 ml) in ethanol (35 ml) was stirred at rt for 3.5 hours. The reaction mixture was added to ice and extracted with ethyl acetate. The organic phase was washed with brine, dried and concentrated. The residue was purified by flash column chromatography on silica gel eluting with 3:1 petrol- ethyl acetate to give an off-white coloured solid (1.71 g, 54percent). 1H NMR (400 MHz, DMSO- cfB) δ ppm 2.64 (s, 3 H), 7.63 (s, 1 H). |
| 0.74 g |
With hydrazine hydrate In ethanol at 20℃; for 40.00 h; |
To a solution of 1-(2,4,6-trichloro-pyridin-3-yl)-ethanone (1,75 gin ethanol, absolute (8,75 mL) was added hydrazinehydrate (0,76 mL). The reaction was stirred at room temperature over the weekend (40 h). The solvent was evaporated and water (10 mL) added. The aqueous phase was extracted with DCM (3 x 10 mL), the combined organic phases were dried (Na2504) and concentrated. The crude material was purified by Biotage Isolera FCC (5i02 50 g) eluting 10-30percent EtOAc in cyclohexane to give 0.74 g of product as an off white solid.Analysis: HPLC-MS: R1 = 1.15 mm (method P), M+H = 202/2041H NMR (DMSO, 500 MHz) 6 2.64 (3H, s), 7.64 (1 H, s) |