反应详情

K2CO3 (535 mg, 3.87 mmol) and acetamidine hydrochloride (185 mg, 1.93 mmol) were added to a suspension of ethyl N—BOC-3-oxopiperidine-4-carboxylate (525 mg, 1.93 mmol) in MeOH (3 mL) and H2O (1 mL) in a 40 mL vial. The reaction was heated in an aluminum block at 70° C. for 90 minutes. LCMS analysis indicated complete consumption of the starting material. The reaction mixture was then acidified to pH 3 and extracted with DCM (3×). The combined organic extracts were dried over MgSO4, filtered and concentrated to obtain tert-butyl 4-hydroxy-2-methyl-5,6-dihydropyrido[3,4-d]pyrimidine-7(8H)-carboxylate as a yellow oil. The product was used without further purification (473 mg, 93%). MS (ESI): mass calcd. for C13H19N3O3 265.1 m/z found, 266.2[M+H]+. 1H NMR (400 MHz, CDCl3) δ 4.37 (s, 2H), 3.71-3.50 (m, 2H), 2.60 (s, 2H), 2.50-2.38 (m, 3H), 1.52-1.41 (m, 9H).

1. customconsumption of the starting material
2. extractionextracted with DCM (3×)
3. dry with materialThe combined organic extracts were dried over MgSO4
4. filtrationfiltered
5. concentrationconcentrated