Chlorosulfonic acid → 1-(chloromethyl)-3-(trifluoroacetyl)-1,2-dihydro-3H-benzo[e]indole-7-sulfonyl chloride

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Reaction Conditions

Reaction Steps

Solid 108 (1.6 g, 5.1 mmol) was gradually added to chlorosulfonic acid (6.0 mL, 90 mmol) with ice bath cooling. The mixture was then heated to 60° C. for 2 h, and the reaction was quenched by pouring slowly, with stirring, into ice-water. The precipitated solid was collected, washed with water, dried and chromatographed on silica gel. Elution with EtOAc/petroleum ether (from 1:4 to 1:1) gave 1-(chloromethyl)-3-(trifluoroacetyl)-1,2-dihydro-3H-benzo[e]indole-7-sulfonyl chloride (113) (0.53 g, 25%) as a pale yellow solid: mp (EtOAc/petroleum ether) 189-192° C.; 1H NMR (CDCl3) δ 8.70-8.64 (m, 2H), 8.13-8.08 (m, 2H), 8.00 (d, J=9.0 Hz, 1H), 4.72-4.68 (m, 1H), 4.55-4.48 (m, 1H), 4.33-4.25 (m, 1H), 3.98-3.93 (m, 1H), 3.68-3.61 (m, 1H), 13C NMR δ 154.9 (q, JC-F 38.4 Hz), 143.9, 140.7, 132.7, 131.8, 130.1, 130.0, 125.8, 124.8, 123.2, 119.6, 115.9 (q, JC-F 288 Hz), 52.8, 45.4, 42.4. Anal. (C15H10Cl2F3NO3S) C, H, N, Cl.

Provenance & Evidence