Synthesis
1. cool a suspension of 1-aminocyclopentanecarboxylic acid (675 g, 5.23 mol, 1.0 eq.) in methanol (6.5 L) at -15 °C using an ice/methanol bath.
2. thionyl chloride (687 mL, 9.4 mol, 1.8 eq.) was slowly added dropwise with controlled titration rate to maintain reaction temperature.
3. after completion of the dropwise addition, the cooling device was removed and the reaction mixture was allowed to warm to room temperature and stirred overnight.
4. Upon completion of the reaction, the reaction mixture was concentrated under reduced pressure. 5.
5. The concentrated residue was treated with dichloromethane (1 L) and concentrated again under reduced pressure to give methyl 1-aminocyclopentanecarboxylate hydrochloride as a white solid (938 g, 100% yield). 6. The product was analyzed by 1H NMR.
6. The product was characterized by 1H NMR (CD3OD) and NMR (DMSO-d6) to confirm the correct structure.
7. The product obtained did not require further purification and could be used directly in the subsequent reaction steps.
References
[1] Patent: US6353006, 2002, B1. Location in patent: Page column 31
[2] Patent: WO2013/19091, 2013, A2. Location in patent: Paragraph 821-823
[3] Patent: US2014/206875, 2014, A1. Location in patent: Paragraph 0449-0451
[4] Patent: WO2003/87069, 2003, A2. Location in patent: Page/Page column 103-104
[5] Patent: WO2006/44775, 2006, A2. Location in patent: Page/Page column 35-36
