Methyl 2-((s)-2-(benzyloxycarbonylamino)-3-methylbutanamido)-3-(7-bromo-1h-indol-3-yl)propanoate → methyl 2-((S)-1-(benzyloxycarbonylamino)-2-methylpropyl)-5-(7-bromo-1H-indol-3-yl)oxazole-4-carboxylate

Participants

Reaction Steps

Dichlorodicyanoquinone (340.8 g, 1,500 mmol) was added to a stirred solution of the title compound of Example 4 (361.4 g, 681 mmol) dissolved in tetrahydrofuran (15 L) and heated to reflux for 6 hours at which time HPLC indicated complete reaction. The reaction was concentrated to ¼ its volume and diluted with ethyl acetate (12 L). The resulting black solution was washed three times with saturated aqueous NaHCO3 (5.5 L). The organic layer was dried over sodium sulfate and concentrated to give the title compound as a black solid (392 g, 100% yield). 1H NMR (CDCl3): consistent with proposed structure.

Provenance & Evidence