Water → 4-(6,7-Difluoro-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-(6,7-Difluoro-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (451 mg, 1.11 mmol), as prepared in the previous step, LiCl (89 mg, 2.12 mmol), water (60 μL, 3.3 mmol), and DMSO (430 μL) was stirred at 150° C. for 7.5 hrs with a reflux condenser. The reaction was then allowed to cool to rt, shaken with 1M NaCl (5 mL), and extracted with DCM (1×3 mL) and 9:1 DCM/MeOH (1×3 mL). The organic layers were combined, dried (Na2SO4), and concentrated. The residue was purified by silica flash chromatography (3:1 hex/EtOAc→2:1 eluent) to provide the title compound (151.8 mg, 39%). 1H-NMR (300 MHz, CDCl3) δ 9.22 (s, 1H), 7.90 (dd, 1H), 7.81 (dd, 1H), 4.33 (br m, 2H), 3.50 (tt, 1H), 2.96 (br t, 2H), 2.11-1.82 (m, 4H), 1.49 (s, 9H). LC/MS (ESI): calcd mass 349.2, found 368.3 (MH.H2O)+.

Provenance & Evidence