Morpholine → 4-(6-Fluoro-7-morpholin-4-yl-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

A solution of 4-(6,7-Difluoro-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester (37.8 mg, 108 μmol) (preparation in Example 205c) and morpholine (19.8 μL, 227 μmol) in THF (100 μL) and DMSO (50 μL) was heated at 100° C. for 1 hr. The crude reaction was loaded onto a flash silica cartridge (1:1 hexanes/EtOAc eluent) to provide the title compound (40.2 mg, 89%). NOe experiments support the assigned regioisomer. Select 1H-NMR resonances and nOes (300 MHz, CDCl3) δ 7.68 (d, J=13.7 Hz, 1H), 7.37 (d, J=8.4 Hz, 1H), 3.45 (tt, 1H), 3.31 (m, 4H). Irradiation of the diagnostic methine proton at δ 3.45 generates an nOe to the quinazoline C5 proton at δ 7.68, but not to the quinazoline C8 proton at δ 7.37. The C5 proton has a larger coupling constant than the C8 proton, indicating fluorine substitution at C6 of the quinazoline. Furthermore, irradiation of the C8 proton at δ 7.37 generates an nOe only to the morpholine C3 protons at δ 3.31, while irradiation of the C5 proton generates an nOe only to the methine proton at δ 3.45. These data indicate morpholine substitution at the quinazoline C7 carbon. LC/MS (ESI): calcd mass 416.2, found 417.3 (MH)+.

Provenance & Evidence