4-Chloroquinazoline → 4-Quinazolin-4-yl-3,6-dihydro-2H-pyridine-1-carboxylic acid benzyl ester

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Reaction Steps

To a 25 mL flask was charged 4-Trifluoromethanesulfonyloxy-3,6-dihydro-2H-pyridine-1-carboxylic acid benzyl ester (prepared from 4-Oxo-piperidine-1-carboxylic acid benzyl ester according to the literature: Wustrow, D. J. et. al. (1991), Synthesis, 993-995. 1.14 g, 3.12 mmol), 4-chloroquinazoline (0.512 g, 3.12 mmol), lithium chloride (0.397 g, 9.36 mmol), Pd(PPh3)4 (0.180 g, 0.156 mmol) and hexamethyl ditin (1.02 g, 3.12 mmol). 1,4-Dioxane (20 mL) was added and the reaction was degassed with N2 for 15 minutes. The mixture was stirred at reflux overnight. After cooling, the black suspension was poured into saturated aqueous potassium fluoride solution. The mixture was diluted with EtOAc and stirred for 2 hours. The organic phase was separated. The aqueous phase was extracted with EtOAc. The combined organic layers were washed with brine, dried and concentrated. The residue was purified by column chromatography (hexanes:EtOAc, 2:3) to give 4-Quinazolin-4-yl-3,6-dihydro-2H-pyridine-1-carboxylic acid benzyl ester (0.790 g, 73%) as a colorless oil. 1H NMR (CDCl3, 400 MHz) δ 9.27 (s, 1H), 8.19 (d, J=7.2 Hz, 1H), 8.07 (d, J=8.8 Hz, 1H), 7.91 (m, 1H), 7.62 (t, J=7.2 Hz, 1H), 7.41 (m, 6H), 6.18 (m, 1H), 5.23 (s, 2H), 4.32 (s, 2H), 3.85 (t, J=5.6 Hz, 1H), 2.80 (br s, 2H). LCMS (APCI+) m/z 346 [M+H]+; Rt=3.16 min.

Provenance & Evidence