Diisopropylethylamine → HCID 86670839, compound

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Reaction Steps

In a 50 ml round-bottomed flask, (S)-2-(methoxycarbonylamino)-3-methylbutanoic acid (813 mg, 4.64 mmol) was combined with DMF (10 ml) to give a colorless solution. HATU (1.76 g, 4.64 mmol) was added and stirred at room temperature for 10 min. Ethyl 8-oxa-2-azaspiro[4.5]decane-3-carboxylate (prepared according to the patent procedure described in WO 199808850) (900 mg, 4.22 mmol) and DIPEA (1.91 g, 2.58 ml, 14.8 mmol) were added and stirred overnight. It was diluted with H2O and extracted with EtOAc (2×100 ml). The organic layer was washed with brine and H2O, dried with MgSO4, filtered and concentrated in vacuo to afford (S)-ethyl 2-((S)-2-(methoxycarbonylamino)-3-methylbutanoyl)-8-oxa-2-azaspiro[4.5]decane-3-carboxylate as a viscous oil (1.3 g, 83.2%). ESI-LRMS m/e calcd for C18H30N2O6 [M+] 370. found 371 [M+H+].

Provenance & Evidence