Triphenylphosphine → 2-{3-[3-(2-Tert-butyl-1,1,3-trioxo-2,3-dihydro-1h-1lambda6-isothiazol-5-yl)-phenyl]-propoxy}-6-hydroxy-benzoic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 4.08-C (0.21 g, 0.6 mmol), methyl 2,6-dihydroxybenzoate (0.13 g, 0.8 mmol), and triphenylphosphine (0.22 g, 0.8 mmol) in tetrahydrofuran (1.5 mL) was treated with diisopropyl azodicarboxylate (0.18 mL, 0.9 mmol) dropwise at 0° C. The reaction mixture was stirred at 25° C. for 2 h. The reaction mixture was concentrated to give a crude residue which was purified using flash column chromatography (100% hexane to 25% ethyl acetate/hexane) to yield 4.08-D as a white solid (0.18 g, 60%). 1H NMR (500 MHz, CDCl3): δ 11.47 (s, 1H), 7.42 (dd, J=8.3, 8.3 Hz, 1H), 7.34–7.31 (m, 3H), 7.11–7.08 (m, 1H), 6.62 (s, 1H), 6.60 (dd, J=8.3, 1.0 Hz, 1H), 6.43 (dd, J=8.3, 1.0 Hz, 1H), 4.27–4.25 (m, 2H), 4.21–4.19 (m, 2H), 3.91 (s, 3H), 2.33–2.30 (m, 2H), 1.73 (s, 9H); LCMS found for C24H27NO8SNa (M+Na)+: m/z=512.

Provenance & Evidence