Trifluoroacetic acid → 5,6-Dihydrophenanthridine

Participants

Reaction Steps

The intermediate dihydrophenanthridine was prepared from 6-ethyl-8-fluorophenanthridine, (Example 40, Step b, 0.40 g, 1.8 mmol), by treatment with sodium borohydride (0.40 g, 10.6 mmol) and trifluoroacetic acid (0.55 mL, 7.1 mmol) in tetrahydrofuran (7 mL). In a separate, second step, the dihydrophenanthridine was treated with triethylamine (0.9 mL, 6.4 mmol) and 3-chloro-4-methoxybenzenesulfonyl chloride (0.51 g, 2.1 mmol, 2.1 equivalents) in dichloromethane (5 mL), according to the procedure and in the same manner as described in Example 32, Method A, Step d, to afford 6-ethyl-8-fluoro-5-[(3-chloro-4-methoxyphenyl)sulfonyl]-5,6-dihydrophenanthridine as a crude product, which was utilized without further purification.

Provenance & Evidence