cis-N-[2-(4-bromophenoxy)cyclopentyl]propane-2-sulfonamide → N-[(1S,2R)-2-(4-bromo-3-fluorophenoxy)-cyclopentyl]propane-2-sulfonamide

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Reaction Steps

The title compound of Step 7 was prepared according to the general procedure for the synthesis of cis-N-[2-(4-bromophenoxy)cyclopentyl]propane-2-sulfonamide in Example 5, except that (1S,2R)-2-(4-bromo-3-fluorophenoxy)cyclopentanamine was used instead of cis-2-(4-bromophenoxy)cyclopentanamine, and the chromatographic purification was carried out with a gradient of 0% to 10% methanol in dichloromethane, to provide the title compound as an off-white solid. Yield: 4.15 g, 10.9 mmol, 54% from (1R,2R)-2-(4-bromo-3-fluorophenoxy)cyclopentyl acetate (5 steps). 1H NMR (500 MHz, CDCl3) δ 1.36 (d, J=6.7 Hz, 3H), 1.39 (d, J=6.8 Hz, 3H), 1.62-1.69 (m, 1H), 1.77-1.90 (m, 3H), 1.92-2.00 (m, 1H), 2.10-2.15 (m, 1H), 3.14 (septet, J=6.8 Hz, 1H), 3.86 (m, 1H), 4.56-4.60 (m, 2H), 6.61 (ddd, J=8.9, 2.8, 1.1 Hz, 1H), 6.70 (dd, J=10.3, 2.8 Hz, 1H), 7.43 (dd, J=8.8, 8.1 Hz, 1H). The absolute configuration of N-[(1S,2R)-2-(4-bromo-3-fluorophenoxy)cyclopentyl]propane-2-sulfonamide was assigned by analogy to the stereochemistry of compounds in Example 7 and Preparation 6.

Provenance & Evidence