3-(4-Methyl-1-piperazine)propan-1-ol → 4-{6-Fluoro-7-[3-(4-methyl-piperazin-1-yl)-propoxy]-quinazolin-4-yl}-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

A solution of 1.19M KOtBu in THF (128 μL, 152 μmol) was added dropwise with stirring over 2.5 min to a 0° C. homogeneous solution of 4-(6,7-Difluoro-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester (38.1 mg, 109 μmol), as prepared in the previous step, and 3-(4-Methyl-piperazin-1-yl)-propan-1-ol (22.4 mg, 142 μmol) in THF (170 μL). The reaction was stirred at 0° C. for 1.5 hr, and was then partitioned with DCM (2 mL) and 1M NaCl (2 mL). The aq layer was back-extracted with DCM (1×2 mL), and the combined cloudy white organic layers were dried (Na2SO4) and concentrated. The residue was purified by silica flash chromatography (1:2 hex/EtOAc/3% DMEA eluent) to yield the title compound as an off-white foam (32.6 mg, 61%). NOe experiments support the assigned regioisomer. Select 1H-NMR resonances and nOes (300 MHz, CDCl3) δ 7.73 (d, J=11.4 Hz, 1H), 7.43 (d, J=8.1 Hz, 1H), 3.46 (tt, 1H). Irradiation of the diagnostic methine proton at δ 3.46 generates an nOe to the quinazoline C5 proton at δ 7.73, but not to the quinazoline C8 proton at δ 7.43. The C5 proton has a larger coupling constant than the C8 proton, indicating fluorine substitution at C6 of the quinazoline. LC/MS (ESI): calcd mass 487.3, found 488.3 (MH)+.

Provenance & Evidence