Benzaldehyde → 1-[6-benzylamino-4-oxo-3-(2-trimethylsilanyl-ethoxymethyl)-3,4-dihydro-quinazolin-2-yl]-1H-pyrazole-4-carboxylic acid ethyl ester

Participants

Reaction Steps

A vial was charged with 1-[6-amino-4-oxo-3-(2-trimethylsilanyl-ethoxymethyl)-3,4-dihydro-quinazolin-2-yl]-1H-pyrazole-4-carboxylic acid ethyl ester (0.250 g, 0.582 mmol), benzaldehyde (59.2 μL, 0.582 mmol), and 4 Å MS (0.25 g). DCE was added (1.9 mL) and the reaction mixture was stirred at room temperature for 18 h. Sodium triacetoxyborohydride (0.308 g, 1.46 mmol) was added and the reaction mixture was stirred for a further 24 h. The reaction was quenched with saturated aqueous sodium bicarbonate (10 mL) and was then extracted with DCM (3×15 mL). The combined organic layers were washed with brine (20 mL), dried (MgSO4), and concentrated. The residue was purified by FCC (2-40% EtOAc/hexanes) to yield the titled compound (0.273 g, 90% yield). MS (ESI/Cl): mass calcd. for C27H33N5O4Si, 519.2; m/z found, 520.2 [M+H]+.

Provenance & Evidence