Dimethylformamide → 88043-21-4

Participants

Reaction Steps

To a solution of trans-N-Boc-4-hydroxy-L-proline methyl ester (7) in pyridine and dry DCM at 0° C. is added 4-methyl-benzenesulfonyl chloride. After adding, the mixture is refluxed overnight. The solvent is evaporated and then the residue is dissolved in CH2Cl2. After removal of solvent, the crude 4-(toluene-4-sulfonyloxy)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester is obtained, which is used in the following reaction without further purification. To a solution of 4-(toluene-4-sulfonyloxy)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester thus obtained above in dry DMF is added NaN3 in one portion, and the reaction mixture is stirred at about 50° C. for 5 h. The resulting mixture is purified to give 4-azido-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (8).

Provenance & Evidence