Bromotrimethylsilane → N-[1-Carboxy-2-(1H-indol-3-yl)-ethyl]-3-(4-phenyl-2-phosphono-butyrylamino]-succinamic acid

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Reaction Steps

The more polar peptide phosphonate of Example 159 (54 mg, 69 μmol) was dissolved in dry CH2Cl2 (2 mL) followed by the addition of TMSBr (73 μL, 552 μmol). The resulting pale yellow solution was stirred for 40 h. The volatile materials were evaporated in vacuum at room temperature and the obtained residue was suspended in a water/methanol mixture (20:1) and vigorously stirred for 2 h after which it was lyophilized to give the crude phosphonic acid intermediate. This crude product was taken up in methanol (5 mL) and treated with Pd/C powder (10%, 25 mg). The mixture was stirred under an H2 atmosphere (45 PSI) for 12 h and then the catalyst was removed by filtration through a celite pad. The resulting mixture was concentrated to give the crude title compound which was purified by HPLC.

Provenance & Evidence