b) Synthesis of 2-(pyrrolidin-1-yl)acetic acid: ethyl 2-(pyrrolidin-1-yl)acetate (2 g, 12.7 mmol, 1.0 eq.) was dissolved in 8N HCl and the reaction was stirred for 16 hrs. at 95°C. Upon completion of the reaction, the mixture was concentrated, the reaction was quenched and extracted as in Intermediate Example 15(b). Subsequently, the solvent was removed by distillation to afford the target product 2-(pyrrolidin-1-yl)acetic acid in 91% (1.5 g) yield. The product was analyzed by LC-MS (ESI): calculated mass 129.1; measured mass 130.1 [M + H]+ (retention time: 0.26 min).
[1] Patent: WO2013/53983, 2013, A1. Location in patent: Page/Page column 40
[2] Patent: US2015/11548, 2015, A1. Location in patent: Paragraph 0161
[3] Liebigs Annalen der Chemie, 1983, # 6, p. 950 - 961