Diisopropylethylamine → (S)-2-{[(1S,4S)-2-{(S)-1-[((S)-Cyclohexyl-methoxycarbonyl-methyl)-carbamoyl]-2-methyl-propylcarbamoyl}-4-(7-methoxy-2-phenyl-quinolin-4-yloxy)-cyclopent-2-enecarbonyl]-amino}-pentanoic acid tert-butyl ester

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Reaction Steps

The acid 11 (0.051 g, 0.087 mmol) and (2-amino-3-methyl-butyrylamino)-cyclohexyl-acetic acid methyl ester (0.054 g, 0.21 mmol) were dissolved in DMF (1.5 mL) and cooled in an ice-bath. DIPEA (16 mg, 0.12 mmol) and HATU (47 mg, 0.13 mmol) were added. After two and a half hours the mixture was co-concentrated with toluene and methanol and then purified by flash column chromatography (toluene/ethyl acetate 3:1). Further purification was performed on HPLC (90% MeOH+0.2% TEA). This gave after co-concentration the two diastereomers 19a (9.4 mg, 13%) and 19b (5.3 mg, 7%) as slightly yellow syrups. After lyophilisation 19a and 19b were collected as white powders:

Provenance & Evidence