HCID 42637705, compound → HCID 42637767, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-(4-fluorobenzyl)-2,3-pyridinedicarboxylic acid (25.3 g, 92 mmol) and Ac2O (200 mL) was stirred for 3 h at 120° C. The reaction mixture was concentrated in vacuo, dissolved in toluene (200 mL) and re-concentrated in vacuo again to give 5-(4-fluorobenzyl)-2,3-pyridinedicarboxylic anhydride. This material was dissolved in EtOH (200 mL) and the mixture was heated at reflux for 3 h and then stored at rt overnight. The reaction mixture was concentrated in vacuo, dissolved in toluene and concentrated again to afford the product as the major isomer. This material contained ca. 30% of the corresponding 3-ethyl ester 2-carboxylic acid isomer. Major isomer: 1H NMR (d6-DMSO) δ 13.5 (1H, br), 8.67 (1H, d, J=2 Hz), 8.06 (1H, d, J=2 Hz), 7.31 (2H, dd, J˜9, 6 Hz), 7.11 (2H, t, J˜9 Hz), 4.25 (2H, q, J=7 Hz), 1.24 (3H, t, J=7 Hz); ES+ MS: 304 (M+H+, 80), 326 (M+Na+, 30).

Provenance & Evidence