Synthesis
General procedure for the synthesis of 2-methoxyacetimidic acid ethyl ester hydrochloride as 2-methoxyacetamidine hydrochloride: ethanol (500 mL) was cooled to -15°C and anhydrous ammonia was passed through the mixture with stirring until the mixture was saturated. Ethyl 2-methoxyacetimidate hydrochloride (90 g, 585 mmol) was added and the reaction mixture was stirred at room temperature overnight. Subsequently, the mixture was cooled again to -15°C and a small amount of insoluble solid was removed by filtration. The filtrate was concentrated to dryness under reduced pressure and the residue was crystallized during standing to give 2-methoxyacetamidine hydrochloride (70 g, 96% yield). The product was characterized by 1H NMR (360 MHz, DMSO-d6): δ 3.35 (3H, s), 4.24 (2H, s), 8.85 (4H, br s).
References
[1] Journal of Medicinal Chemistry, 1998, vol. 41, # 22, p. 4251 - 4260
[2] Patent: WO2005/47279, 2005, A1. Location in patent: Page/Page column 47
[3] Patent: WO2006/44732, 2006, A2. Location in patent: Page/Page column 213
[4] Patent: WO2008/39882, 2008, A1. Location in patent: Page/Page column 212
