Reaktion #630389

Reaktionsgleichung

DMSO

DMSO

THF

6-Hydroxy-2(S)-phthalimidohexanoic acid

Pyridinium dichromate

→

5-Formyl-2(S)-phthalimidopentanoic acid

Lösungsmittel

CH2Cl2

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONBy addition
2. 2
   Filtrationto 200 ml of ethyl acetate and filtration, chromium salts
3. 3
   Sonstigewere removed
4. 4
   EinengenThe filtrate was concentrated under vacuum
5. 5
   workup.DISSOLUTIONThe residue was redissolved in 250 ml of ethyl acetate
6. 6
   Sonstigeto remove trace amounts of chromium salts
7. 7
   Einengenconcentrated
8. 8
   Sonstigeto afford a white solid, 0.475 g

Vorschrift

6-Hydroxy-2(S)-phthalimidohexanoic acid (1.94 g) was dissolved in 145 ml of CH2Cl2 containing 2.26 ml of pyridine. Pyridinium dichromate (1.95 g) was added and the mixture stirred overnight under nitrogen. By addition to 200 ml of ethyl acetate and filtration, chromium salts were removed. The filtrate was concentrated under vacuum. The residue was redissolved in 250 ml of ethyl acetate and the solution refiltered. The filtrate was finally passed through a MgSO4 pad to remove trace amounts of chromium salts and concentrated to afford a white solid, 0.475 g; m.p. 219°-22°; [α]D25° =-41.6° (THF, c=1.5). Tlc on silica (4:1 ethyl acetate:acetic acid) indicated a single spot at Rf =0.79. 'H NMR spectrum (d6 -DMSO) showed triplets at δ9.65 (1H) and δ4.85 (1H, J=7.5 Hz), a singlet at δ7.95 (4H), and a broad multiplet at δ0.9-2.50 (6H) ppm. 13C NMR spectrum (d6 -DMSO) showed single absorptions at 202.9, 170.5, 167.5, 134.9, 131.3, 123.5, 51.7, 42.4, 27.8, and 18.7 ppm.

Quelle