Acetic Acid → US10098902, Example 27

Temperatur

40 °C

A stirred solution of (3R,4S)-3-acetamido-N-tert-butyl-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)pyrrolidine-3-carboxamide (Example 8, step 4) (198 mg, 0.5 mmol) and N-BOC-pyrrolidine-3-one (0.185 g, 1.0 mmol) in anhydrous 1,2-dichloroethane (5 mL) was treated with anhydrous sodium sulfate (1 g) and glacial acetic acid (30 mg, 0.5 mmol), stirred at 40° C. for 2.5 h, then cooled to room temperature and treated with sodium triacetoxyborohydride (276 mg, 1.3 mmol) and stirred for 18 h. Aqueous sodium carbonate (10%, 5 mL) was added and the mixture stirred for a few minutes and extracted with ethyl acetate (30 mL, then 2×10 mL). The combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each), dried (MgSO4), and concentrated. The crude material was deprotected and isolated using the method described for example 8, step 5 to afford (3R,4S)-3-amino-4-(3-boronopropyl)-1,3′-bipyrrolidine-3-carboxylic acid (160 mg, 81%) as an amber solid. NMR (D2O) δ 4.25-4.35 (m, 1 H), 4.00 (dd, J1=12 Hz, J2=5 Hz, 1 H) 3.70-3.95 (m, 3 H), 3.25-3.60 (m, 4 H), 2.45-2.65 (m, 2 H), 2.15-2.25 (m, 1 H), 1.50-1.65 (m, 1 H), 1.15-1.35 (m, 3 H), 0.60-0.70 (m, 2 H). MS (m+1): 286.1; MS (m−H2O+1): 268.3.

1. temperaturecooled to room temperature
2. stirringstirred for 18 h
3. stirringthe mixture stirred for a few minutes
4. extractionextracted with ethyl acetate (30 mL
5. washThe combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each)
6. dry with materialdried (MgSO4)
7. concentrationconcentrated
8. customisolated

ORD-Eintrag

ord-9e542c44bc924576a853d4ac124a19a3

Quelldatensatz

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09440995B2