[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C@H:8]2[CH2:18][CH2:17][C:10]3([NH:14]C(=O)N[C:11]3=[O:16])[CH2:9]2)=[CH:4][CH:3]=1.[OH-:19].[Na+].Cl>O1CCOCC1>[NH2:14][C:10]1([C:11]([OH:19])=[O:16])[CH2:17][CH2:18][C@H:8]([C:5]2[CH:6]=[CH:7][C:2]([Br:1])=[CH:3][CH:4]=2)[CH2:9]1To (7S)-7-(4-bromophenyl)-1,3-diazaspiro[4.4]nonane-2,4-dione (I-1B, 13.9 g, 45.0 mmol) in 1,4-dioxane (40 mL) in a round bottom flask was added aqueous NaOH (2N, 100 mL, 200 mmol). The mixture was heated to 95° C. and stirred for 24 hours. Additional NaOH (25 mL, 50 mmol) was added and heating continued for another two days. The solution was cooled with an ice-bath, neutralized with 5N HCl to approximately pH 7 resulting in the formation of a white precipitate. The solids were collected by filtration and dried under high vacuum for 2 days to provide 14 g of (3S)-1-amino-3-(4-bromophenyl)cyclopentanecarboxylic acid as a white solid which was used as such for the subsequent step without further purification. HPLC retention time=0.64 min (Condition G) LC/MS M+1=284/286.
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