Water → β,ψ-Carotene, 3′,4′-didehydro-1′,2′-dihydro-1′-hydroxy-2′-oxo-

HRID 265821Notes

Reaction equation

HRID 265821 reaction equation
[CH3:1][C:2]1[CH2:7][CH2:6][CH2:5][C:4]([CH3:9])([CH3:8])[C:3]=1/[CH:10]=[CH:11]/[C:12](/[CH3:36])=[CH:13]/[CH:14]=[CH:15]/[C:16](/[CH3:35])=[CH:17]/[CH:18]=[CH:19]/[CH:20]=[C:21](/[CH:23]=[CH:24]/[CH:25]=[C:26](/[CH:28]=[CH:29]/[CH:30]=[C:31](/[CH:33]=O)\[CH3:32])\[CH3:27])\[CH3:22].[OH-:37].[K+].[OH2:39]>C(O)CC>[CH3:1][C:2]1[CH2:7][CH2:6][CH2:5][C:4]([CH3:9])([CH3:8])[C:3]=1/[CH:10]=[CH:11]/[C:12](/[CH3:36])=[CH:13]/[CH:14]=[CH:15]/[C:16](/[CH3:35])=[CH:17]/[CH:18]=[CH:19]/[CH:20]=[C:21](/[CH:23]=[CH:24]/[CH:25]=[C:26](/[CH:28]=[CH:29]/[CH:30]=[C:31](/[CH:33]=[CH:4]/[C:3]([C:2]([OH:39])([CH3:7])[CH3:1])=[O:37])\[CH3:32])\[CH3:27])\[CH3:22]

Participants

5

Reactant 3

HCID 962WaterHCID 14797Potassium HydroxideHCID 442240335056-12-22×

Product 1

HCID 87443362β,ψ-Carotene, 3′,4′-didehydro-1′,2′-dihydro-1′-hydroxy-2′-oxo-Yield 97.8%

Reagents, catalysts & solvents 1

HCID 10311-PropanolSolvent2×

Conditions

Temperature
70 °C

Procedure

10.12 g of β-apo-4'-carotenal are suspended in 50 ml of n-propanol under argon in a 350 ml sulphonation flask fitted with a stirrer, thermometer, cooler and dosage pump. Then, 9.6 ml of 50% potassium hydroxide solution are added. The red-violet, thin suspension is now heated to 70° C. internal temperature. Then, a solution of 7.72 g of cyclocarbonate in 20 ml of n-propanol is dosed in using the dosage pump within one hour at 70° C. The mixture is stirred at 70° C. for 5 hours under control by thin-layer chromatography and HPLC. Almost all of the β-apo-4'-carotenal has reacted after this time according to HPLC. 70 ml of water are added to the mixture and the red-brown, thin reaction mixture is heated to reflux and stirred at an internal temperature of 89.3° C. Thereafter, the oil bath is removed and the mixture is cooled to 22° C. using a water bath and stirred for 30 minutes. The crystals are subsequently filtered off under suction and washed in succession twice with 50 ml of n-propanol each time and three times with 50 ml of water each time. After filtering off the crystals these are dried for 16 hours at 50° C. under reduced pressure. In this manner there are obtained 11.09 g (97.8% of theory) of 2'-dehydroplectaniaxanthin as brown crystals.

Workup

  1. customfitted with a stirrer
  2. customwithin one hour
  3. customat 70° C
  4. temperaturethe red-brown, thin reaction mixture is heated
  5. temperatureto reflux
  6. stirringstirred at an internal temperature of 89.3° C
  7. customThereafter, the oil bath is removed
  8. temperaturethe mixture is cooled to 22° C.
  9. stirringstirred for 30 minutes
  10. filtrationThe crystals are subsequently filtered off under suction
  11. washwashed in succession twice with 50 ml of n-propanol each time and three times with 50 ml of water each time
  12. filtrationAfter filtering off the crystals
  13. customthese are dried for 16 hours at 50° C. under reduced pressure

Sources & evidence

ORD record
ord-04e770a1b5a44300b68e5640b4d31f31
Source dataset
uspto-grants-1997_07
Patent number
US05648550

Reaction notes

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