Triethylamine → Methanesulfonic acid (S)-3-(4-benzyloxycarbonylamino-phenyl)cyclopentyl ester

Participants

Reaction Steps

To a solution of [4-((S)-3-hydroxy-cyclopentyl)-phenyl]-carbamic acid benzyl ester (0.44 g, 1.4 mmol) in DCM (8 mL) was added Et3N (214 mg, 0.3 mL, 2.12 mmol, 1.5 equiv.). The solution was cooled in an ice-water bath and then de-aerated by vacuum/nitrogen exchange. To this solution was transferred a solution of methanesulfonyl chloride (242 mg, 2.12 mmol, 1.5 equiv.) in DCM (2 mL). The clear solution was stirred with the ice-water bath on all the time for 1 h. TLC (50% EtOAc in heptane) indicated that the reaction was complete. The reaction was quenched by diluting with DCM (10 mL), followed by addition of NaHCO3 aq. (5 mL). The two layers were separated and the aqueous layer was extracted with DCM (2×5 mL). The combined extracts were washed successively with NaHCO3 aq. (5 mL), brine (5 mL) and dried (K2CO3). The solution was filtered through a silica gel pad, eluted with 5% MeOH in DCM. The filtrate was concentrated to dryness to obtain 510 mg (yield: 93%) of the title compound as an off-white wax-like solid material.

Provenance & Evidence