Chlorosulfonic acid → (+/-)-2-Carbamoylchroman-6-sulfonyl chloride

Participants

Reaction Steps

The compound from Example 21 (2.0 g, 11.3 mmol) was added in portions over 10 minutes to cooled (0° C.) chlorosulfonic acid (9 mL). After 75 minutes the mixture was added slowly and dropwise to ice (150 g). The mixture was filtered and the solids washed with water (3×20 mL) and dried at 50° C. in vacuo to give a colorless powder (2.29 g, 73%). Mp 147-148° C.; 1H NMR (CDCl3, 300 MHz) δ 7.82 (m, 2H), 7.08 (d, J=8.6 Hz, 1H), 6.50 (br s, 1H), 5.77 (br s, 1H), 4.68 (dd, J=9.4 Hz, 3.1 Hz, 1H), 2.95 (m, 2H), 2.52 (m, 1H), 2.16 (m, 1H).

Provenance & Evidence