Trifluoroacetic acid → 4-Phenyl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine

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Reaction Steps

To the product of Intermediate 1, step c (265 mg, 0.85 mmol) in DCM (4 mL) was added TFA (0.85 mL). After stirring 3 h, the mixture was concentrated in vacuo. The residue was dissolved in DCM and treated with saturated aqueous NaHCO3 solution. The aqueous layer was then extracted with DCM and EtOAc. The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. Chromatography on SiO2 eluting with 2 M NH3 in MeOH/DCM afforded the desired product as a dark orange oil (172 mg, 96%). MS (ESI) mass calcd. C13H13N3, 211.11. m/z found 212.1 [M+H]+. 1H NMR (500 MHz, CDCl3): 9.03 (s, 1H), 7.62-7.56 (m, 2H), 7.52-7.43 (m, 3H), 4.16 (s, 2H), 3.09 (t, J=5.7 Hz, 2H), 2.85 (t, J=5.6 Hz, 2H).

Provenance & Evidence