Lithium Chloride → 2-Isobutyl-succinic acid-4-t-butyl ester

Cyanoester 2 (0.76 g, 3.91 mmol), water (0.14 mL, 7.82 mmol) and lithium chloride (0.66 g, 15.6 mmol) were heated to 150° C. in DMSO (40 mL) for 22 hours. The mixture was allowed to cool, diluted with water (150 mL), and extracted with ether (3×50 mL). The combined ether fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane-ethyl acetate, 95:5) to give the cyanide 3 (0.21 g, 44%) as a 60:40 mixture of diastereoisomers; Rf(heptane-ethyl acetate, 9:1) 0.44; νmax(film)/cm−1 2238 (CN); Major diastereoisomer: δH (400 MHz; CDCl3) 2.97 (1H, m), 2.87 (2H, m), 2.32–2.18 (2H, m), 2.10–1.96 (3H, m), 1.92–1.78 (2H, m), 1.48–1.38 (1H, m); Minor diastereoisomer: δH (400 MHz; CDCl3) 3.13 (1H, m), 2.87 (2H, m), 2.32–2.18 (2H, m), 2.10–1.96 (3H, m), 1.92–1.78 (2H, m), 1.48–1.38 (1H, m).

1. temperatureto cool
2. extractionextracted with ether (3×50 mL)
3. washThe combined ether fractions were washed with brine
4. dry with materialdried (MgSO4)
5. customthe solvent was evaporated under reduced pressure
6. customThe residue was chromatographed (SiO2, heptane-ethyl acetate, 95:5)

ORD record

ord-5dc6fe038f7c46fcb43c08d3d9814651

Source dataset

uspto-grants-2006_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07138542B2