Hydrochloric Acid → (S)-7-methoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid

HRID 654233Notes

Reaction equation

HRID 654233 reaction equation
C[C@@H](N)C1C=CC=CC=1.[CH3:10][O:11][C:12]1[CH:21]=[C:20]2[C:15]([CH2:16][CH2:17][CH:18]([C:22]([OH:24])=[O:23])[CH2:19]2)=[CH:14][CH:13]=1.Cl>CC(C)=O.O>[CH3:10][O:11][C:12]1[CH:21]=[C:20]2[C:15]([CH2:16][CH2:17][C@H:18]([C:22]([OH:24])=[O:23])[CH2:19]2)=[CH:14][CH:13]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 6431891-Phenethylamine, (+)-HCID 147228197-Methoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid

Product 1

HCID 10632089(S)-7-methoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 180AcetoneSolventHCID 962WaterSolvent

Procedure

(R)-(+)-α-methylbenzylamine (25.8 ml, 0.2 mol) is added to a solution of 7-methoxy-1,2,3,4-tetrahydronaphthalen-2-carboxylic acid racemate (41 g, 0.2 mol) in acetone (800 ml) and after 2 hours at room temperature the obtained salt is recovered by filtration (45.2 g) and crystallized twelve times from acetone until a product with constant [α] of -20.5° (c=1.4%, CHCl3) is obtained. This product is then taken up in water (30 ml) and the obtained solution is made acidic by the addition of concentrated HCl and extracted with ethyl ether. The organic phase is dried and evaporated to dryness and the obtained residue is crystallised from benzene (20 ml) affording 0.9 g of 7-methoxy-1,2,3,4-tetrahydronaphthalen-2(S)-carboxylic acid; m.p. 133°-135° C.; [α]=-45.1° (c=1.4%, CHCl3). To determine its absolute configuration, the thus obtained product is converted into the corresponding 2-amino-7-methoxy-1,2,3,4 -tetrahydronaphthalene by the Curtius reaction.

Workup

  1. filtrationis recovered by filtration (45.2 g)
  2. customcrystallized twelve times from acetone until a product with constant [α] of -20.5° (c=1.4%, CHCl3)
  3. customis obtained
  4. extractionextracted with ethyl ether
  5. customThe organic phase is dried
  6. customevaporated to dryness
  7. customthe obtained residue is crystallised from benzene (20 ml)

Sources & evidence

ORD record
ord-69d10011a78945b6ac48d5d10eb3cb88
Source dataset
uspto-grants-1992_07
Patent number
US05130339

Reaction notes

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