(S)-2-Hydroxy-2-(6-(hydroxymethyl)-5-oxo-2,3-dihydro-5H-spiro[indolizine-1,2'-[1,3]dioxolan]-7-yl)-N-((S)-1-phenylethyl)butanamide → (4S)-4-Ethyl-7,8-dihydro-4-hydroxy-1H-pyrano(3,4-f)indolizine-3,6,10(4H)-trione
Reaction equation
[CH2:1]([C@:3]([OH:31])([C:15]1[CH:23]=[C:22]2[N:18]([CH2:19][CH2:20][C:21]32OCC[O:24]3)[C:17](=[O:28])[C:16]=1[CH2:29][OH:30])[C:4](N[C@H](C1C=CC=CC=1)C)=[O:5])[CH3:2]>FC(F)(F)C(O)=O>[CH2:1]([C@:3]1([OH:31])[C:15]2[CH:23]=[C:22]3[N:18]([CH2:19][CH2:20][C:21]3=[O:24])[C:17](=[O:28])[C:16]=2[CH2:29][O:30][C:4]1=[O:5])[CH3:2]Participants
3
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
Three hundred milligrams of the compound (VII) obtained in the above procedure (1) were dissolved in 80% trifluoroacetic acid solution and the resulting mixture was stirred at room temperature for 2 hours under a nitrogen gas stream. The reaction mixture was concentrated to dryness and the residue was purified by column chromatography on silica gel (10 g). A colorless oily substance was obtained from a 98:2 eluate of chloroform and methanol. The oily substance was crystallized from a mixed solvent of ethanol and petroleum ether to obtain 170 mg of the title compound as colorless needle-like crystals.
Workup
- concentrationThe reaction mixture was concentrated to dryness
- customthe residue was purified by column chromatography on silica gel (10 g)
- customA colorless oily substance was obtained from a 98:2 eluate of chloroform and methanol
- customThe oily substance was crystallized from a mixed solvent of ethanol and petroleum ether
Sources & evidence
- ORD record
- ord-af3463de5c3049afa97c6e8c001aff25
- Source dataset
- uspto-grants-1988_10
- Patent number
- US04778891
Reaction notes
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