Hydrochloric Acid → 3,4-Dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyran-6-carboxaldehyde

HRID 798

Reaktionsgleichung

Reaktionsgleichung von HRID 798
Br[C:2]1[CH:3]=[C:4]([CH3:15])[C:5]2[S:10][CH2:9][CH2:8][C:7]([CH3:12])([CH3:11])[C:6]=2[C:13]=1[CH3:14].C([Li])CCC.CN(C)[CH:23]=[O:24].Cl>C(OCC)C>[CH3:11][C:7]1([CH3:12])[C:6]2[C:13]([CH3:14])=[C:2]([CH:23]=[O:24])[CH:3]=[C:4]([CH3:15])[C:5]=2[S:10][CH2:9][CH2:8]1

Komponenten

6

Edukt 4

HCID 313Hydrochloric AcidHCID 6228DimethylformamideHCID 129936856-Bromo-3,4-dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyranHCID 178418339Butyllithium

Produkt 1

HCID 196938673,4-Dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyran-6-carboxaldehyde

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 3283Diethyl EtherLösungsmittel

Versuchsvorschrift

6-Bromo-3,4-dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyran (19.8 g, World Patent Application 95/04054) was dissolved in diethyl ether (350 mL) and treated with n-butyllithium (2.5N in hexanes, 42 mL). The mixture was stirred at room temperature for 1 h and then cooled in a dry-ice/acetone bath. Dimethylformamide (16 mL) was added over a period of several minutes and the reaction bath was allowed to warm to -40° C. Hydrochloric acid (1N aqueous, 100 mL) was added and the mixture was allowed to warm to 23° C. The organic phase was separated and washed with saturated aqueous sodium bicarbonate solution (100 mL). The organic phase was dried over magnesium sulfate, filtered, and evaporated under reduced pressure. The residue was subjected to chromatography on silica gel using hexanes/ether (9:1) as eluent to afford the desired compound as a yellow semi-solid (7.7 g). 1H NMR(CDCl3): δ 1.5 (6H), 2.0 (2H), 2.3 (3H), 2.8 (3H), 3.0 (2H), 7.4 (1H), 10.2 (1H).

Aufarbeitung

  1. temperaturecooled in a dry-ice/acetone bath
  2. temperatureto warm to -40° C
  3. temperatureto warm to 23° C
  4. customThe organic phase was separated
  5. washwashed with saturated aqueous sodium bicarbonate solution (100 mL)
  6. dry with materialThe organic phase was dried over magnesium sulfate
  7. filtrationfiltered
  8. customevaporated under reduced pressure

Quellen und Nachweise

ORD-Eintrag
ord-415b27028875405d86f41fbc30253639
Quelldatensatz
uspto-grants-1998_03
Patentnummer
US05723411

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