Trifluoroacetic acid → (+)-12-Oxocalanolide A

HRID 1457430

Reaktionsgleichung

Reaktionsgleichung von HRID 1457430
[CH3:1][C:2]1([CH3:25])[O:7][C:6]2[C:8]3[C:13]([CH2:14][CH2:15][CH3:16])=CC(=O)O[C:9]=3[C:18]([C:21](=[O:24])[CH2:22][CH3:23])=[C:19]([OH:20])[C:5]=2[CH:4]=[CH:3]1.[CH2:26](OC(OCC)C)[CH3:27].F[C:35](F)(F)[C:36]([OH:38])=[O:37]>C(OCC)(=O)C>[CH3:16][CH2:15][CH2:14][C:13]1[C:8]2[C:6]3[O:7][C:2]([CH3:1])([CH3:25])[CH:3]=[CH:4][C:5]=3[C:19]3[O:20][C@H:26]([CH3:27])[C@@H:22]([CH3:23])[C:21](=[O:24])[C:18]=3[C:9]=2[O:38][C:36](=[O:37])[CH:35]=1

Komponenten

5

Edukt 3

HCID 6422Trifluoroacetic acidHCID 7765AcetalHCID 54948815-Hydroxy-2,2-dimethyl-6-propionyl-10-propyl-2H,8H-pyrano[2,3-f]chromen-8-one

Produkt 1

HCID 463613(+)-12-Oxocalanolide AAusbeute 30 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 8857Ethyl AcetateLösungsmittel

Reaktionsbedingungen

Temperatur
140 °C

Versuchsvorschrift

A solution containing chromene 4 (344 mg, 1.0 mmol), acetaldehyde diethylacetal (473 mg, 4.0 mmol), trifluoroacetic acid (1.5 mL, 19.4 mmol) and anhydrous pryidine (0.7 mL) was heated at 140° C. under N2. The reaction was monitored by TLC analysis. After 4 hours, the reaction mixture was cooled to room temperature, diluted with ethyl acetate and washed several times with 10% aqueous NaHCO3 and brine. The organic layer was separated and dried over Na2SO4. The solvent was removed in vacuo and the crude product was purified by silica gel column chromatography eluting with ethyl acetate/hexane (2:3). Chromanone 7 (10,11-trans-dihydro-6,6,10,11-tetramethyl-4-propyl-2H,6H,12H-benzo[1,2-b:3,4-b':5,6-b"]-tripyran-2,12-dione) (110 mg, 30% yield) was obtained m.p. 176°~177° C. (Lit.5 130°~132° C.). 1H-NMR5 (CDCl3) δ 1.02 (3H, t, J=7.5 Hz, CH3); 1.21 (3H, d, J=6.8 Hz, CH3); 1.51 (3H, d, J=7.0 Hz, CH3); 1.55 (6H, 2s, 2 CH3); 1.63 (2H, sextet, J=7.0 Hz, CH2); 2.55 (1H, dq, J=6.9 Hz, J=11.0 Hz, H11); 2.88 (2H, t, J=7.6 Hz, CH2); 4.28 (1H, dq, J=6.3 Hz, J=11.0 Hz, H10); 5.60 (1H, d, J=9.9 Hz, H8); 6.04 (1H, s, H3); 6.65 (1H, d, J=11.8 Hz, H7); MS (CI): 369 (100, M+1).

Aufarbeitung

  1. temperaturethe reaction mixture was cooled to room temperature
  2. washwashed several times with 10% aqueous NaHCO3 and brine
  3. customThe organic layer was separated
  4. dry with materialdried over Na2SO4
  5. customThe solvent was removed in vacuo
  6. customthe crude product was purified by silica gel column chromatography
  7. washeluting with ethyl acetate/hexane (2:3)

Quellen und Nachweise

ORD-Eintrag
ord-79185ef148c945cf972845d442fc1a75
Quelldatensatz
uspto-grants-1998_12
Patentnummer
US05847164

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