7-Benzyl-5,6,7,8-tetrahydro4-chloro-pyrido[3,4-d]pyrimidine hydrochloride

Synthesis

7-Benzyl-5,6,7,8-tetrahydropyrido[3,4-D]pyrimidin-4(3H)-one (3.00 g, 12.4 mmol) was used as a raw material and dissolved in toluene (40 mL) at room temperature. To this solution, phosphorus trichloride (2.28 g, 14.9 mmol) and Hunig base (1.28 g, 9.92 mmol) were sequentially added, and the reaction system was subsequently heated to 100 °C and maintained for 30 min. After completion of the reaction, it was cooled to room temperature. The reaction mixture was quenched with 200 mL of saturated aqueous sodium bicarbonate and 200 mL of crushed ice and stirred for 1 hour at room temperature. Subsequently, extraction was performed with dichloromethane (100 mL x 4). The organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 3.32 g of 7-benzyl-4-chloro-5,6,7,8-tetrahydropyrido[3,4-D]pyrimidine (69B) as a dark brown oil in about 100% yield. The product could be used in the next reaction without further purification.HPLC retention time: 0.95 min. Mass spectrum (MH+) m/z: 260.

References

[1] Patent: WO2005/42537, 2005, A1. Location in patent: Page/Page column 86
[2] Bioorganic and Medicinal Chemistry Letters, 2007, vol. 17, # 18, p. 5019 - 5024
[3] Bioorganic and Medicinal Chemistry Letters, 2016, vol. 26, # 1, p. 160 - 167
[4] Patent: WO2009/158396, 2009, A1. Location in patent: Page/Page column 67-68
[5] Patent: WO2005/66171, 2005, A1. Location in patent: Page/Page column 59-60