Formaldehyde → (-)-1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid

HRID 2185665Notes

Reaction equation

HRID 2185665 reaction equation
[NH2:1][C@H:2]([C:10]([OH:12])=[O:11])[CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[CH2:13]=O.S(=O)(=O)(O)O>Cl>[CH2:13]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH2:3][C@@H:2]([C:10]([OH:12])=[O:11])[NH:1]1

Participants

5

Reactant 3

HCID 712FormaldehydeHCID 1118Sulfuric AcidHCID 6140L-Phenylalanine

Product 1

HCID 2733226(-)-1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

5.0 g (30.27 mmol) of L-phenylalanine are dissolved in 50 ml of concentrated hydrochloric acid and 4.0 g of para-formaldehyde and 1 ml of concentrated sulphuric acid are added. This solution is maintained at reflux for two days. After cooling and filtration, the resulting solid is dissolved in a 1/1 (v/v) hot water/ethanol mixture and aqueous NH4OH (30%) is added until a pH 7.0 is reached. The crystals which have precipitated after cooling the solution are recovered by filtration, washed with ethanol and dried. The desired product is thus obtained.

Workup

  1. temperatureThis solution is maintained
  2. temperatureat reflux for two days
  3. temperatureAfter cooling
  4. filtrationfiltration
  5. dissolutionthe resulting solid is dissolved in a 1/1 (v/v) hot water/ethanol mixture and aqueous NH4OH (30%)
  6. additionis added until a pH 7.0
  7. customThe crystals which have precipitated
  8. temperatureafter cooling the solution
  9. filtrationare recovered by filtration
  10. washwashed with ethanol
  11. customdried

Sources & evidence

ORD record
ord-17df20052b3748889aff4fafcb5168a1
Source dataset
uspto-grants-2002_06
Patent number
US06403561B1

Reaction notes

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