Benzyl Bromide → N-(tert-Butoxycarbonyl)-3,4-dibenzyloxyphenylalanine benzyl ester

HRID 58900Notes

Reaction equation

C([O-])([O-])=O.[K+].[K+].[C:7]([NH:14][C@@H:15]([CH2:19][C:20]1[CH:27]=[C:25]([OH:26])[C:23]([OH:24])=[CH:22][CH:21]=1)[C:16]([OH:18])=[O:17])([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8].[CH2:28](Br)[C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1>C(#N)C>[CH2:28]([O:26][C:25]1[CH:27]=[C:20]([CH2:19][C@H:15]([NH:14][C:7]([O:9][C:10]([CH3:12])([CH3:13])[CH3:11])=[O:8])[C:16]([O:18][CH2:19][C:20]2[CH:27]=[CH:25][CH:23]=[CH:22][CH:21]=2)=[O:17])[CH:21]=[CH:22][C:23]=1[O:24][CH2:28][C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1)[C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1

Participants

Conditions

Temperature: 55 °C

Procedure

K2CO3 (21.0 g, 150 mmol) was added to a solution of Boc-L-dopa (10.0 g, 33 mmol) in acetonitrile (100 mL) followed by addition of benzyl bromide (21.0 g, 123 mmol). The suspension was heated at 50-60° C. for 4 h and then cooled to ambient temperature. The mixture was filtered and the filtration cake was washed with acetonitrile (50 mL). The filtrate and washings were combined and concentrated to dryness. The residue was purified by flash column chromatography on silica gel (Hexane/EtOAc=20:1) to afford (S)-benzyl 3-(3,4-bis(benzyloxy)phenyl)-2-(tert-butoxycarbonylamino)propanoate (15.3 g, yield 80%).

Workup

temperaturecooled to ambient temperature
filtrationThe mixture was filtered
washthe filtration cake was washed with acetonitrile (50 mL)
concentrationconcentrated to dryness
customThe residue was purified by flash column chromatography on silica gel (Hexane/EtOAc=20:1)

Sources & evidence

ORD record: ord-d81204e5ed364f4790ee10a56f8d230a
Source dataset: uspto-grants-2016_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09434761B2

Reaction notes

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