Acetic Acid → 1-Benzyl 3-ethyl 4-oxopyrrolidine-1,3-dicarboxylate

Temperature

0 °C

To a suspension of potassium t-butoxide (2.52 g, 22.4 mmol, 1.4 equiv.) in toluene (50 mL) at 0° C. under nitrogen, was added diester 70 (5.41 g, 16 mmol) in toluene (10 mL) over a 10 min period. The solution was stirred for 30 min at 0° C. and 2 mL of glacial acetic acid was added, immediately followed by 10 g of NaH2PO4.H2O in 100 mL of ice-cold water. The resultant mixture was extracted with chloroform (3×150 mL), and the combined organic extracts were washed twice with phosphate buffer (2×25 mL, pH=7.0), dried over anhydrous sodium sulfate and evaporated to dryness. The residue was dissolved in toluene (200 mL), cooled to 0° C., and extracted with cold pH 9.5 carbonate buffer (3×150 mL). The aqueous extracts were converted to pH 3 with phosphoric acid, and extracted with chloroform (5×125 mL) which were combined, dried, and evaporated to a afford keto ester 71 (2.2 g, 42%).

1. extractionThe resultant mixture was extracted with chloroform (3×150 mL)
2. washthe combined organic extracts were washed twice with phosphate buffer (2×25 mL, pH=7.0)
3. dry with materialdried over anhydrous sodium sulfate
4. customevaporated to dryness
5. dissolutionThe residue was dissolved in toluene (200 mL)
6. temperaturecooled to 0° C.
7. extractionextracted with cold pH 9.5 carbonate buffer (3×150 mL)
8. extractionextracted with chloroform (5×125 mL) which
9. customdried
10. customevaporated to a afford keto ester 71 (2.2 g, 42%)

ORD record

ord-3978ecbf793a4f2090f6c9042e7abec0

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09394540B2