21926-00-1

Step b: Lithium aluminum hydride (6.96 g, 0.183 mol) was slowly added to a solution containing tetrahydrofuran (80 mL) at 0°C, followed by dropwise addition of tetrahydro-4H-thiopyran-4-one oxime (8 g, 0.0610 mol) to a tetrahydrofuran solution (20 mL). The reaction mixture was refluxed for about 4 hours before the reaction was burst with saturated ammonium chloride solution. The reaction solution was extracted with ethyl acetate, the organic layers were combined and dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure to give the crude tetrahydro-2H-thiopyran-4-amine in a yield of 8 g (100%).

[1] Patent: WO2008/111009, 2008, A1. Location in patent: Page/Page column 52
[2] Patent: WO2008/111010, 2008, A1. Location in patent: Page/Page column 75
[3] Patent: US2003/232847, 2003, A1. Location in patent: Page 16
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[5] Patent: WO2013/7765, 2013, A1. Location in patent: Page/Page column 110-111