tert-Butanol → HCID 69480388, compound

Participants

Reaction Steps

A solution of 5-(4-fluorobenzyl)-2,3-pyridinedicarboxylic acid 2-ethyl ester (28 g, 92 mmol), diphenylphosphoryl azide (29.7 mL, 138 mmol) and Et3N (38.5 mL, 276 mmol) in t-BuOH (250 mL) was heated at reflux for 5 h and stored at rt for 3 d. After removal of solvent in vacuo, EtOAc was added and the mixture was washed with NH4Cl solution, NaHCO3 solution and brine, and then dried and concentrated. The crude material was purified by column chromatography on silica gel eluting with 30% EtOAc/hexanes to afford the product as the major isomer. This material contained ca. 30% of the corresponding 3-ethyl ester 2-(tert-butoxy)carbonylamino isomer. Major isomer: 1H NMR (d6-DMSO) δ 9.96 (1H, s), 8.30 (1H, d, J=2 Hz), 8.24 (1H, d, J=2 Hz), 7.27 (2H, m), 7.11 (2H, m), 4.28 (2H, q, J=7 Hz), 4.01 (2H, s), 1.43 (9H, s), 1.28 (3H, t, J=7 Hz); AP+ MS: 375 (M+H+, 100).

Provenance & Evidence