4-Methoxybenzenesulfonyl chloride → (S)-8-Fluoro-5-(4-methoxy-benzenesulfonyl)-6-methyl-5,6-dihydrophenanthridine

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Reaction Steps

The title compound was prepared according to the procedure of Example 19, starting from the (S)-8-Fluoro-6-methyl-5,6-dihydrophenanthridine of Example 20 (38.4 g) and 4-methoxyphenylsulfonyl chloride (37.2 g). The crude product (65.6 g) was purified by filtration over a flash silica gel plug (1 Kg) eluting with 20-25% hexane-ethyl acetate to provide 54.1 (78.4% yield) of product. The material (54.1 g) was recrystallized twice from hot 30% toluene in ethanol. The solution was seeded hot and allowed to cool to room temperature. After about 3 hours the crystalline solid was collected, rinsed with 30% toluene in ethanol (1×15 mL) and with hexane (2×15 mL), and dried to provide 27.1 g (39.3% yield based on (S)-8-fluoro-6-methyl-5,6-dihydrophenanthridine) of title compound. The compound was analyzed by chiral stationary phase HPLC (Chiralpak AD-25×0.46 cm column) on a HP1100 using 90:10 hexane-isopropanol as the mobile phase with a 1 mL/min flow rate. The analysis showed the material to be a 98.7:1.3 mixture of enantiomers,

Provenance & Evidence