Ethanol → (S)-(1-Methylpiperidin-2-yl)methanol

関与物質

反応手順

Following the known procedure of patent EP 0 429 984 A2 (reference example 8). The resolution was identical to the procedure described above except 3 rounds of crystallization were performed. To a mixture of (±)-1-methyl-2-piperidinemethanol (95.6 g, 740 mmol) in EtOH (840 mL) was added dibenzoyl-L-tartaric acid (255 g, 711 mmol). The resulting mixture was slowly heated until a solution was obtained at which time the solution was slowly cooled with gentle stirring. After 12 h the crystals were isolated and dried to provide 79.6 g. This process was repeated: (2) EtOH (335 mL) provided 50.4 g. (3) EtOH (345 mL) provided 35 g. The resulting salt was treated with 3M HCl (134 mL) which was heated to induce it to dissolve. The still warm solution was poured into a separatory funnel and extracted with ethyl acetate. The remaining aqueous layer was adjusted to pH 10 with K2CO3. The solution was extracted with CH2Cl2, dried (MgSO4) and concentrated to give 6 g of the alcohol. This alcohol (6 g, 46.7 mmol) was suspended in CH2Cl2 (100 mL) and SOCl2 (6.8 mL, 93.3 mmol) added dropwise. After stirring for 12 h, the solvent was removed to provide a crude HCl salt. This salt (5.98 g) was dissolved in EtOH (100 mL) and treated with NH2NH2 (19.5 mL, 405 mmol) and heated to reflux for 3 h. Half the solvent was removed, the residue extracted with ether and the extracts dried and concentrated to give 4.55 g of a crude oil. This crude hydrazine (2.01 g, 14.06 mmol) was dissolved in THF (100 mL) and triphenylmethylisocyanate (4.0 g, 14.1 mmol) was added slowly. The solution was then stirred overnight and the solvent removed under reduced pressure and the residue was purified by flash chromatography (CH2Cl2/MeOH/NH4OH) to provide 350 mg of the desired product. 1H NMR (DMSO-d6) δ 1.10 (m, 2H), 1.30-1.56 (m, 4H), 1.95 (t, 1H), 2.15 (s, 1H), 2.18 (s, 3H), 2.71 (d, 1H), 3.25 (q, 1H), 3.55 (q, 1H), 4.80 (s, 2H), 7.12-7.32 (m, 15H), 8.02 (s, H). ESI-MS m/z 429.2 (100, M+H).

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