Phosphorus oxychloride → 2,3-Dioxoindoline-5-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

(16) Phosphorus oxychloride (13.2 mL, 141.6 mmol) was added to a solution of 5-isatinsulfonic acid (5), sodium salt hydrate (8.0 g, 30.0 mmol) in tetramethylene sulfone (40 mL). The mixture was heated to 60° C. for 3 h, then cooled to 0° C. The reaction mixture was poured into 150 g of ice. The solid was filtered out and washed with cold water, then the solid was dissolved in ethyl acetate (100 mL), washed with water (50 mL×2) and saturated NaCl (50 mL), and dried over Na2SO4. The ethyl acetate was evaporated in reduced pressure to afford 6.12 g (83%) of 6 as a pale yellow solid, mp 188.2-190.1° C. 1H NMR (300 MHz, DMSO) δ 11.1 (s, 1H), 7.82 (dd, J=8.4 Hz, J=1.8 Hz, 1H), 7.60 (s, 1H), 6.89 (d, J=8.1 Hz, 1H).

Provenance & Evidence