Synthesis
General procedure for the synthesis of 5-amino-4-chloropyrimidine from 5-amino-6-chloropyrimidine-4-thiol: The concentrated product of Example 18 (4.3 g, 26 mmol) was dissolved in EtOH (40 mL). Subsequently, NH4OH (4 mL) was added to this solution. Under stirring, an excess of Raney Nickel was added in batches. the reaction mixture was stirred overnight at room temperature and then heated at 80 °C for 2 h. The reaction was carried out at room temperature. Upon completion of the reaction, the mixture was filtered through a diatomaceous earth pad and the filtrate was concentrated. The crude product was purified by silica fast chromatography using EtOAc/hexane as eluent to give 1.6 g (47% yield) of 5-amino-4-chloropyrimidine as a yellow solid.
References
[1] Patent: US2006/13799, 2006, A1. Location in patent: Page/Page column 59
[2] Patent: WO2006/127584, 2006, A1. Location in patent: Page/Page column 61; 89
[3] Patent: WO2007/8563, 2007, A2. Location in patent: Page/Page column 88
