反应详情

K2CO3 (563 mg, 4.07 mmol) and 1,1-dimethylguanidine sulfate (566 mg, 2.04 mmol) were added to a suspension of ethyl N—BOC-3-oxopiperidine-4-carboxylate in MeOH (2 mL) and H2O (1 mL) in a 40 mL vial. The reaction was heated in an aluminium block at 70° C. for 90 minutes. LCMS analysis showed that the reaction was complete. The mixture was acidified to pH 3 and extracted with DCM (3×). The combined organic extracts were dried over MgSO4, filtered and concentrated to obtain tert-butyl 2-(dimethylamino)-4-hydroxy-5,6-dihydropyrido[3,4-d]pyrimidine-7(8H)-carboxylate as a pale yellow solid which was used without further purification. MS (ESI): mass calcd. for C14H22N4O3, 294.3. m/z found, 295.3 [M+H]+. 1H NMR (400 MHz, MeOD) δ 4.29-4.11 (m, 2H), 3.71-3.46 (m, 2H), 3.09 (s, 6H), 2.42 (t, J=5.8 Hz, 2H), 1.58-1.38 (m, 9H).

1. extractionextracted with DCM (3×)
2. dry with materialThe combined organic extracts were dried over MgSO4
3. filtrationfiltered
4. concentrationconcentrated