Trifluoroacetic acid → (+)-12-Oxocalanolide A

HRID 363832

Reaktionsgleichung

Reaktionsgleichung von HRID 363832
[CH3:1][CH:2]1OC(C)OC(C)O1.[CH3:10][C:11]1([CH3:34])[O:16][C:15]2C3C(CCC)=[CH:21][C:20](=[O:26])[O:19][C:18]=3[C:27]([C:30](=[O:33])[CH2:31][CH3:32])=[C:28]([OH:29])[C:14]=2[CH:13]=[CH:12]1.CC1C=CC(S([O-])(=O)=O)=CC=1.[CH:46]1[CH:51]=[CH:50][NH+]=[CH:48][CH:47]=1.C(C(O)=O)(F)(F)F.C([O-])(O)=O.[Na+]>ClCCCl>[CH3:48][CH2:47][CH2:46][C:51]1[C:50]2[C:15]3[O:16][C:11]([CH3:34])([CH3:10])[CH:12]=[CH:13][C:14]=3[C:28]3[O:29][C@H:1]([CH3:2])[C@@H:31]([CH3:32])[C:30](=[O:33])[C:27]=3[C:18]=2[O:19][C:20](=[O:26])[CH:21]=1

Komponenten

7

Edukt 5

HCID 6422Trifluoroacetic acidHCID 31264Paraldehyde3×HCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)2×HCID 516892Sodium BicarbonateHCID 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 27 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 111,2-DichloroethaneLösungsmittel

Versuchsvorschrift

Paraldehyde One-Step Reaction: To a stirring solution of chromene 4 (350 mg, 1.0 mmol) and PPTS (250 mg, 1.0 mmol) in 1,2-dichloroethane (2 mL) at ambient temperature under N2 was added 3 mL paraldehyde (22.5 mmol). The resulting mixture was refluxed for 7 h. Then, CF3CO2H (1 mL), an additional equivalent of PPTS and 1 mL of paraldehyde were added; the mixture was refluxed overnight. The reaction mixture was neutralized with saturated aqueous NaHCO3 and extracted with ethyl acetate (50 mL×3). The crude product obtained by evaporation under reduced pressure was washed with hexane. The residue was purified by column chromatography eluting with ethyl acetate/hexane (1:2) to afford 100 mg (27% yield) of chromanone 7 and 30 mg (8% yield) of 7a. 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) obtained by this method was identical with an authentic sample by comparison of TLC, HPLC and spectroscopic data.

Aufarbeitung

  1. temperatureThe resulting mixture was refluxed for 7 h
  2. temperaturethe mixture was refluxed overnight
  3. extractionextracted with ethyl acetate (50 mL×3)
  4. customThe crude product obtained by evaporation under reduced pressure
  5. washwas washed with hexane
  6. customThe residue was purified by column chromatography
  7. washeluting with ethyl acetate/hexane (1:2)

Quellen und Nachweise

ORD-Eintrag
ord-ea6f25205d0d462b9e680b508233e7c0
Quelldatensatz
uspto-grants-1999_02
Patentnummer
US05874591

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