Triethylamine → [3,3-dimethyl-1(S)-(4-methyl-2,6,7-trioxabicyclo[2.2.2]oct-1-yl)butyl]carbamic acid benzyl ester

To a solution of 2(S)-benzyloxycarbonylamino-4,4-dimethylpentanoic acid 3-methyl-oxetan-3-ylmethyl ester (21.5 g, 59 mmol) in dry DCM (50 ml) was added BF3.Et2O (0.4 ml, 3.2 mmol). After 5 h, triethylamine (0.9 ml, 6.4 mmol) was added and stirring was continued for 30 min at room temperature. The solvent was evaporated using a rotavap and the resulting oil was redissolved in ethyl acetate and was washed with 50 ml of 3% NH4Cl solution followed by brine. The ethyl acetate layer was dried over MgSO4, the solvent was evaporated and the residue was purified with column chromatography using silica gel and 20:80 EtOAc:Hexane as eluent to give [3,3-dimethyl-1(S)-(4-methyl-2,6,7-trioxabicyclo[2.2.2]oct-1-yl)butyl]carbamic acid benzyl ester (15.5 g).

1. waitwas continued for 30 min at room temperature
2. customThe solvent was evaporated
3. dissolutionthe resulting oil was redissolved in ethyl acetate
4. washwas washed with 50 ml of 3% NH4Cl solution
5. dry with materialThe ethyl acetate layer was dried over MgSO4
6. customthe solvent was evaporated
7. customthe residue was purified with column chromatography

ORD record

ord-2f239e58a85a4ff5b338967acd59a687

Source dataset

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08013186B2