(4-oxo-4-(2-oxo-1-pyrrolidinyl)butanoyl]-L-prolinol → (4-oxo-4-(2-oxo-pyrrolidinyl)butanoyl]-L-prolinal

Reaction equation

[O:1]=[C:2]([N:14]1[CH2:18][CH2:17][CH2:16][C:15]1=[O:19])[CH2:3][CH2:4][C:5]([N:7]1[CH2:13][CH2:12][CH2:11][C@H:8]1[CH2:9][OH:10])=[O:6]>C1C=CC=CC=1.CS(C)=O.C(N(CC)CC)C>[O:1]=[C:2]([N:14]1[CH2:18][CH2:17][CH2:16][C:15]1=[O:19])[CH2:3][CH2:4][C:5]([N:7]1[CH2:13][CH2:12][CH2:11][C@H:8]1[CH:9]=[O:10])=[O:6]

Participants

Procedure

N-[(4-Oxo-4-(2-oxo-1-pyrrolidinyl)butanoyl]-L-prolinol (105 mg) was dissolved in a mixed solvent of benzene (0.25 ml), DMSO (0.79 ml) and triethylamine (0.25 ml), and sulfur trioxide pyridine complex (285 mg) was added thereto under ice-cooling. After 0.5 hour's stirring at a temperature of 10°-15° C., the reaction mixture was poured into ice water, and extracted with chloroform. The organic layer was washed with a saturated aqueous solution of sodium bicarbonate and saturated brine in sequence. The organic layer was dried over magnesium sulfate, followed by concentration. The residue was purified by PLC (chloroform:methanol=49:1) using silica gel to give 65 mg of N-[(4-oxo-4-(2-oxo-pyrrolidinyl)butanoyl]-L-prolinal.