Hydrochloric Acid → N-(tetrahydro-2H-pyran-4-yl)-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidin-2-amine

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Reaction Steps

A round-bottom flask was charged with 26 (27.5 g, 82.2 mmol), DCM (100 mL) and MeOH (25 mL) and maintained under nitrogen. A 4N solution of HCl in dioxane (103 mL, 411 mmol) was added and the resulting solution stirred for 18 h. The reaction mixture was concentrated and re-suspended in DCM (150 mL). A methanolic NH3 solution (25 mL, 7 N) and additional DCM (100 mL) was added. The precipitated salts were filtered and the filtrate concentrated to afford a brown solid which was stirred with Et2O/MeOH (95:5) for 1 h. A fine light brown solid precipitated and recovered by filtration to afford 15 g, (99% purity, 77% yield) of N-(tetrahydro-2H-pyran-4-yl)-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidin-2-amine (28): MS m/z (APCI-pos) M+1=235.2.

Provenance & Evidence