Diisopropylethylamine → (1R,3S,5R)-2-[2-(3-Carbamoyl-indazol-1-yl)-acetyl]-2-aza-bicyclo[3.1.0]hexane-3-carboxylic acid benzyl ester

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Reaction Steps

To a solution of (1R,3S,5R)-2-aza-bicyclo[3.1.0]hexane-3-carboxylic acid benzyl ester trifluoroacetate (3.9 g, 9.77 mmol), (3-carbamoyl-indazol-1-yl)-acetic acid (prepared as described in Part A, 2.26 g, 9.77 mmol), HBTU (5.56 g, 14.66 mmol) in CH2Cl2 (60 mL) was added DIPEA (5.12 mL, 29.3 mmol). The reaction mixture was stirred for 48 h at RT under a nitrogen atmosphere. The reaction mixture was poured into water and extracted with CH2Cl2 (×3). The combined organic extracts were dried over Na2SO4, filtered and concentrated. The crude residue was purified by flash column chromatography on silica gel (c-hexane/EtOAc 10:0 to 0:10) to afford the title compound. Rf, TLC (EtOAc)=0.85; MS (UPLC): 436.3 [M+NH4]+, 463.2 [M+HCOO]−; tR (HPLC conditions b): 1.82 min.

Provenance & Evidence