Diisopropylamine → HCID 14158038, compound

Temperature

0 °C

A 1.6 M solution of butyllithium in hexane (7.8 ml) was added to a stirred solution of diisopropylamine (1.26 g) in dry THF (10 ml) at 0° C. under an atmosphere of argon. The temperature was maintained at 0° C. for 30 minutes, and then a solution of iso-valeric acid (0.63 g) in dry THF (5 ml) was added. The solution was heated at 35° C. for 30 minutes and then cooled to ambient temperature. Hexamethylphosphoramide (HMPA) (1.11 g) was added followed by a solution of (5R,4S)-3-benzyloxycarbonyl-4-cyclohexylmethyl-5-iodomethyl-2,2-dimethyl-1,3-oxazolidine (obtained as described in J.Med.Chem., 1988, 31, 1839) (589 mg) in dry THF (5 ml). The solution was stirred for 2 hours and was then added to saturated ammonium chloride solution (50 ml). The mixture was extracted with ethyl acetate (3×30 ml). The combined extracts were washed with water (30 ml), saturated sodium chloride solution (30 ml) and dried (MgSO4). The solvent was removed by evaporation to give crude (2RS)-2-[(4S,5S)-3-benzyloxycarbonyl-4-cyclohexylmethyl-2,2-dimethyl-1,3-oxazolidin-5-yl]methyl-3-methylbutanoic acid (I), as a clear oil (551 mg), which was used without further purification. For the purposes of characterisation a sample was purified by flash chromatography eluting with ethyl acetate/hexane (1:4 v/v); NMR (CDCl3): 0.8-2.1 (complex m, 28H), 2.3, 2.6 (both m, integration ratio 1:1, total 1H). 3.75 (m, 1H). 3.9 (m, 1H), 5.1 (m, 2H), 7.4 (m, 5H).

1. temperatureThe solution was heated at 35° C. for 30 minutes
2. temperaturecooled to ambient temperature
3. extractionThe mixture was extracted with ethyl acetate (3×30 ml)
4. washThe combined extracts were washed with water (30 ml), saturated sodium chloride solution (30 ml)
5. dry with materialdried (MgSO4)
6. customThe solvent was removed by evaporation

ORD record

ord-853013f5f2b14ae98ceecad5faa0f74a

Source dataset

uspto-grants-1992_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05091425