Hydrochloric Acid → (S)-2-amino-6-borono-2-ethylhexanoic acid hydrochloride

A solution of (S)-methyl 2-(tert-butoxycarbonylamino)-2-ethyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (0.283 g, 0.709 mmol) in 6 N HCl (5 mL) was heated to a gentle reflux for 16 h. After cooling to room temperature, the reaction mixture was transferred to a separatory funnel, diluted with deionized water (5 mL) and washed with dichloromethane (3×10 mL). The aqueous layer was concentrated to give an off-white solid that was dissolved in deionized water (3 mL) and passed through a C-18 Isolute SPE column (20 g) eluted with 10% methanol in deionized water (200 mL). The fractions containing product were concentrated under reduced pressure, redissolved in deionized water (5 mL), frozen in liquid nitrogen and lyophilized to give (S)-2-amino-6-borono-2-ethylhexanoic acid hydrochloride as an white foam (0.096 g, 67%). 1H NMR (D2O, 300 MHz) δ□ (m, 4H), 1.31-1.17 (m, 3H), 1.13-0.97 (m, 1H), 0.794 (t, J=7.6 Hz, 3H), 0.63 (t, J=7.8 Hz, 2H); ESI-LCMS m/z calcd for C8H18BNO4: 203.1. found 204.1 (M+1)+.

1. temperaturea gentle reflux for 16 h
2. customthe reaction mixture was transferred to a separatory funnel
3. washwashed with dichloromethane (3×10 mL)
4. concentrationThe aqueous layer was concentrated
5. customto give an off-white solid
6. washeluted with 10% methanol in deionized water (200 mL)
7. additionThe fractions containing product
8. concentrationwere concentrated under reduced pressure
9. dissolutionredissolved in deionized water (5 mL)
10. temperaturefrozen in liquid nitrogen

ORD record

ord-aa6b9cddd15541619ace7fc8c276958f

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09040703B2