p-Toluenesulfonic acid → Pseudomonic acid C

HRID 1395639Notes

Reaction equation

HRID 1395639 reaction equation
[CH3:1][C@@H:2]([C@@H:33]([OH:35])[CH3:34])[C@@H:3]1O[C@H:4]1[CH2:6][C@@H:7]1[C@@H:12]([OH:13])[C@@H:11]([OH:14])[C@H:10]([CH2:15]/[C:16](/[CH3:32])=[CH:17]/[C:18]([O:20][CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][C:29]([OH:31])=[O:30])=[O:19])[O:9][CH2:8]1.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)(O)[O-].[K+].[Se-]C#N.[K+].C(O)(CC)(C)C.O>COC(OC)(C)C.C(OCC)(=O)C>[CH3:1][C@@H:2]([C@@H:33]([OH:35])[CH3:34])/[CH:3]=[CH:4]/[CH2:6][C@@H:7]1[C@@H:12]([OH:13])[C@@H:11]([OH:14])[C@H:10]([CH2:15]/[C:16](/[CH3:32])=[CH:17]/[C:18]([O:20][CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][C:29]([OH:31])=[O:30])=[O:19])[O:9][CH2:8]1

Participants

8

Reactant 5

HCID 6101p-Toluenesulfonic acidHCID 76960Potassium selenocyanateHCID 446596MupirocinHCID 516893Potassium BicarbonateHCID 129645095HCID 129645095, compound

Product 1

HCID 10413058Pseudomonic acid CYield 58%

Reagents, catalysts & solvents 2

HCID 64952,2-DimethoxypropaneSolventHCID 8857Ethyl AcetateSolvent

Procedure

Pseudomonic acid A (500 mgs) was dissolved in 2,2-dimethoxypropane (20 ml) and ethyl acetate (20 ml) then p-toluene sulphonic acid (few crystals) added. The solution was stirred for 1 hour then washed with brine and dried (MgSO4). After evaporation of the solvent in vacuo, the residue was dissolved in water-methanol (1:1, 20 ml) and potassium bicarbonate (100 mgs, 1 eq) added. The solvents were removed in vacuo and potassium selenocyanate (432 mgs, 3 eq), tert-amyl alcohol-water (9:1, 15 ml) added and the reaction refluxed for 4 days. After filtering the solution was evaporated to dryness, water (20 ml) added and solution adjusted to pH2 (5 M-HCl) under a layer of ethyl acetate (20 ml). The organic layer was separated and the aqueous layer further extracted with ethyl acetate (3×20 ml). The combined extracts were dried (MgSO4) and evaporated to an oil which was redissolved in 80% acetic acid (10 ml) and stirred at room temperature overnight. The solution was evaporated to dryness and the residual oil chromatographed on silica (10 g) eluting with 0 to 6% methanol-chloroforom. Fractions containing pure product (tlc) were combined and evaporated to give pseudomonic acid C (280 mgs, 58%).

Workup

  1. washthen washed with brine
  2. dry with materialdried (MgSO4)
  3. customAfter evaporation of the solvent in vacuo
  4. dissolutionthe residue was dissolved in water-methanol (1:1, 20 ml)
  5. additionadded
  6. temperaturethe reaction refluxed for 4 days
  7. filtrationAfter filtering the solution
  8. customwas evaporated to dryness, water (20 ml)
  9. additionadded
  10. customThe organic layer was separated
  11. extractionthe aqueous layer further extracted with ethyl acetate (3×20 ml)
  12. dry with materialThe combined extracts were dried (MgSO4)
  13. customevaporated to an oil which
  14. dissolutionwas redissolved in 80% acetic acid (10 ml)
  15. stirringstirred at room temperature overnight
  16. customThe solution was evaporated to dryness
  17. customthe residual oil chromatographed on silica (10 g)
  18. washeluting with 0 to 6% methanol-chloroforom
  19. additionFractions containing pure product (tlc)
  20. customevaporated

Sources & evidence

ORD record
ord-84bb4a214ced43c684d7ae15f67553c6
Source dataset
uspto-grants-1980_05
Patent number
US04205002

Reaction notes

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