Trifluoroacetic acid → HCID 69763513, compound

Participants

Reaction Steps

A solution of 2(R)-[(N-tert-butoxycarbonylindol-5-ylmethyl)-(4-methoxybenzenesulfonyl)amino]-3-methylbutyric acid benzyl ester (2.7 g. 4.45 mmol) and trifluoroacetic acid (5 mL) in methylene chloride (15 mL) was stirred for 2 h at room temperature. The organics were removed under vacuum and the residue was dissolved in ethyl acetate (80 mL) and the ethyl acetate layer was washed with 5% sodium bicarbonate and brine. The organic layer was dried over magnesium sulfate and concentrated to give a white foamy solid which was chromatographed on a silica gel column eluting with (5-100%) ethyl acetate/hexanes. This procedure gave 2(R)-[(1H-indol-5-yl-methyl)-(4-methoxybenzenesulfonyl)amino]-3-methylbutyric acid benzyl ester (1.7 g) as a white foamy semi-solid, which was converted to 2(R)-[(1H-indol-5-ylmethyl)-(4-methoxy-benzenesulfonyl)amino]-3-methylbutyric acid by following the procedure described in Example 1, Step 6 above.

Provenance & Evidence