Brucine → (R)-1',2',3',4'-tetrahydro-2'-hydroxy-5',8'-dimethoxyspiro[1,3-dithiolane-2,4'-naphthalene]-2'-carboxylic acid

HRID 280909Notes

Reaction equation

HRID 280909 reaction equation
[OH:1][C:2]1([C:20]([OH:22])=[O:21])[CH2:11][C:10]2([S:15][CH2:14][CH2:13][S:12]2)[C:9]2[C:4](=[C:5]([O:18][CH3:19])[CH:6]=[CH:7][C:8]=2[O:16][CH3:17])[CH2:3]1.COC1C=C2[C@@]34[C@@H]5C[C@H]6C(CN5CC3)=CCO[C@H]3CC(=O)N([C@H]4[C@@H]63)C2=CC=1OC>C(OCC)(=O)C>[OH:1][C@@:2]1([C:20]([OH:22])=[O:21])[CH2:11][C:10]2([S:15][CH2:14][CH2:13][S:12]2)[C:9]2[C:4](=[C:5]([O:18][CH3:19])[CH:6]=[CH:7][C:8]=2[O:16][CH3:17])[CH2:3]1

Participants

4

Reactant 2

HCID 442021BrucineHCID 132641391',2',3',4'-Tetrahydro-2'-hydroxy-5',8'-dimethoxyspiro[1,3-dithiolane-2,4'-naphthalene]-2'-carboxylic acid

Product 1

HCID 13264140(R)-1',2',3',4'-tetrahydro-2'-hydroxy-5',8'-dimethoxyspiro[1,3-dithiolane-2,4'-naphthalene]-2'-carboxylic acidYield 35.7%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

A suspension of 3.42 g of rac-1',2',3',4'-tetrahydro-2'-hydroxy-5',8'-dimethoxyspiro[1,3-dithiolane-2,4'-naphthalene]-2'-carboxylic acid in 168 ml of ethyl acetate and 4.0 g of brucine was heated under reflux until a clear solution was obtained. After seeding, the solution was left to cool slowly to room temperature. The crystalline precipitate (3.6 g) was collected after 2 days. The precipitate was dissolved in 1500 ml of boiling ethyl acetate, the solution was concentrated to 600 ml and left to cool slowly. The crystalline product [2.7 g [α]D20 =-46.6°, c=0.5% in dimethylformamide] was suspended in 150 ml of ethyl acetate and shaken with three 10 ml portions of 5-M hydrochloric acid and with two 100 ml portions of brine. After drying over magnesium sulphate, the solvent was evaporated to give a colourless oil which was crystallised from diethyl ether to yield 1.22 g of (R)-1',2',3',4'-tetrahydro-2'-hydroxy-5',8'-dimethoxyspiro[1,3-dithiolane-2,4'-naphthalene]-2'-carboxylic acid in the form of colourless crystals of melting point 147°-149° C.; [α]D20 =+13.8° (c=0.5% in dioxan).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux until a clear solution
  3. customwas obtained
  4. waitthe solution was left
  5. customThe crystalline precipitate (3.6 g) was collected after 2 days
  6. dissolutionThe precipitate was dissolved in 1500 ml of boiling ethyl acetate
  7. concentrationthe solution was concentrated to 600 ml
  8. waitleft
  9. temperatureto cool slowly
  10. customThe crystalline product [2.7 g [α]D20 =-46.6°, c=0.5% in dimethylformamide]
  11. dry with materialAfter drying over magnesium sulphate
  12. customthe solvent was evaporated
  13. customto give a colourless oil which
  14. customwas crystallised from diethyl ether

Sources & evidence

ORD record
ord-b9100c9995484081bd93b084114f2698
Source dataset
uspto-grants-1986_05
Patent number
US04591636

Reaction notes

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