Diethyl Ether → HCID 86755664, compound

To a solution of (1S,2R,3R,5R,6S)-2-azido-3-hydroxy-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 2-benzyl ester 6-ethyl ester (VII-1) (200 mg, 0.58 mmol) in MeOH (5.8 mL) and a few drops of chloroform at 0° C. was added NiCl2.6 H2O (661 mg, 2.78 mmol) was dissolved in acetone (45 mL) and H2O (4.5 mL), NaN3 (720 mg, 11.1 mmol) and stirred for 10 min at 0° C. Upon cautious addition of NaBH4 (175 mg, 4.62 mmol) the reaction mixture turned immediately black, stirring was continued at 0° C. for 10 min and then hydrolyzed with water and ether. After additional stirring for 10 min at 0° C., the reaction mixture was extracted with ether, washed with brine (2×50 mL) and dried over Na2SO4 and filtered through celite. The solvent was removed under vacuum, the residue was purified by silica gel column chromatography with ethyl acetate/MeOH 95:5 (+0.6% Et3N) to give (1S,2R,3R,5R,6S)-2-amino-3-hydroxy-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 2-benzyl ester 6-ethyl ester (VIII) (106 mg, 57%) as a yellow oil. 1H-NMR (250 MHz, CDCl3) □1.25 (3H, t, J=7.1 Hz), 1.75 (1H, t,J=3.5 Hz), 1.97 (1H, m), 2.12 (1H, dd,J=7, 3.5 Hz), 2.14-2.28 (4H, m), 2.33 (1H, dd,J=12.5, 7 Hz), 3.65 (1H, dd, J=8, 7 Hz), 4.10 (2H, q, J=7.1 Hz), 5.22 (1H, d, J=12.5 Hz), 5.27 (1H, d, J=12.5 Hz), 7.38 (5H, m); MS[ISP] 320 (M+H+); □D20 -0.56° (c=0.89, CHCl3).

1. stirringAfter additional stirring for 10 min at 0° C.
2. extractionthe reaction mixture was extracted with ether
3. washwashed with brine (2×50 mL)
4. dry with materialdried over Na2SO4
5. filtrationfiltered through celite
6. customThe solvent was removed under vacuum
7. customthe residue was purified by silica gel column chromatography with ethyl acetate/MeOH 95:5 (+0.6% Et3N)

ORD record

ord-f8aca118f67f4caa8a4d1b4c7a23ebc0

Source dataset

uspto-grants-2000_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06107342