Synthesis
Step 3: To a 100 mL three-necked round-bottomed flask under nitrogen protection was added 5-allylpyrimidine-4,6-diol (4 g) and phosphoryl chloride (25 mL). The reaction mixture was heated to 80 °C and the reaction was stirred at this temperature for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the excess phosphoryl chloride was subsequently removed under reduced pressure. The residue was neutralized with saturated sodium bicarbonate solution and the pH was adjusted to 8-9. The aqueous layer was diluted with dichloromethane (100 mL) and extracted with dichloromethane (2 x 50 mL). The organic layers were combined, washed with saturated saline (50 mL) and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography using methanol/chloroform (0.4:9.6, v/v) as eluent to yield 5-allyl-4,6-dichloropyrimidine (2.7 g). The structure of the product was confirmed by 1H NMR (DMSO-d6): δ 3.59-3.61 (d, 2H), 5.00-5.05 (dd, 1H), 5.13-5.16 (dd, 1H), 5.85-5.94 (m, 1H), 8.8 (s, 1H).
References
[1] Chemistry of Heterocyclic Compounds, 2018, vol. 54, # 6, p. 638 - 642
[2] Khim. Geterotsikl. Soedin., 2018, vol. 54, # 6, p. 638 - 642,5
[3] Journal of Organic Chemistry, 2009, vol. 74, # 9, p. 3587 - 3590
[4] Patent: WO2010/9195, 2010, A1. Location in patent: Page/Page column 76-77
[5] Patent: WO2010/9207, 2010, A1. Location in patent: Page/Page column 45
