1-N-Boc-4-Piperidinecarboxylic acid methyl ester → 4-(6,7-Difluoro-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester

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Reaction Steps

A solution of piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (1.27 g, 5.23 mmol) in dry THF (2 mL) was added dropwise over 2 minutes with stirring to 1.01M LiHMDS/THF (5.75 mL, 5.81 mmol) at −78° C. under argon. After 5 min at −78° C., the cold bath was removed and the reaction was allowed to stir at “rt” for 30 min. A portion of this enolate solution (5.1 mL, ˜3 mmol enolate) was added dropwise over 2-3 min to a stirred homogeneous solution of 4-chloro-6,7-difluoroquinazoline (600 mg, 2.99 mmol) in dry THF (3 mL) at 0° C. under argon. The reaction was stirred for 30 min at 0° C., and was then quenched with 1M NaH2PO4 (50 mL) and extracted with EtOAc (1×50 mL). The organic layer was washed with 4M NaCl (1×50 mL), dried (Na2SO4), and concentrated. The residue was purified with silica flash chromatography (3:1 hexanes/EtOAc) to afford the title compound as a yellow oil (451 mg, 37%). LC/MS (ESI): calcd mass 407.2, found 408.2 (MH)+.

Provenance & Evidence