Dimethyl Sulfoxide → 1-(p-nitrobenzyloxycarbonyl)-4-oxo-L-proline p-methoxybenzyl ester

A solution of 0.35 ml of dimethyl sulfoxide in 1 ml of dried methylene chloride was added dropwise to a solution of 0.2 ml of oxalyl chloride in 5 ml of dried methylene chloride at -60° to -70° C. Ten minutes later, 10 ml of a dried methylene chloride solution of 860 mg of trans-1-(p-nitrobenzyloxycarbonyl)-4-hydroxy-L-proline p-methoxybenzyl ester was added dropwise to the above mixture at a temperature of -50° C. or less, followed by stirring for 15 minutes. 1.01 g of triethylamine was then added dropwise thereto, and the resulting mixture was warmed to room temperature. The mixture was diluted with methylene chloride, washed with dilute hydrochloric acid aqueous solution and dried over sodium sulfate. The solvent was removed by distillation, and the residue was purified by silica gel column chromatography to yield 1-(p-nitrobenzyloxycarbonyl)-4-oxo-L-proline p-methoxybenzyl ester.

1. washwashed with dilute hydrochloric acid aqueous solution
2. dry with materialdried over sodium sulfate
3. customThe solvent was removed by distillation
4. customthe residue was purified by silica gel column chromatography

ORD record

ord-ac269d1fac6c4d10bdbd5349a81f09fd

Source dataset

uspto-grants-1992_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05122604