Ethyl 2-cyclopentyl-4,5-dihydrothiazole-4-carboxylate → Ethyl 2-cyclopentylthiazole-4-carboxylate

HRID 446412Notes

Reaction equation

HRID 446412 reaction equation
[CH:1]1([C:6]2[S:7][CH2:8][CH:9]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[N:10]=2)[CH2:5][CH2:4][CH2:3][CH2:2]1>C(#N)C.[O-2].[O-2].[Mn+4]>[CH:1]1([C:6]2[S:7][CH:8]=[C:9]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[N:10]=2)[CH2:2][CH2:3][CH2:4][CH2:5]1

Participants

4

Reactant 1

HCID 57989100Ethyl 2-cyclopentyl-4,5-dihydrothiazole-4-carboxylate

Product 1

HCID 57989290Ethyl 2-cyclopentylthiazole-4-carboxylate

Reagents, catalysts & solvents 2

HCID 178418406HCID 178418406, compoundCatalystHCID 6342AcetonitrileSolvent

Procedure

Manganese dioxide (24 g) was added to a solution of ethyl 2-cyclopentyl-4,5-dihydrothiazole-4-carboxylate [Carboxylic Acid 2, step b] (3.2 g) in acetonitrile (100 mL) and the resulting mixture heated at reflux overnight. The reaction was allowed to cool and filtered through a pad of Celite. The filter pad was washed with acetonitrile (2×100 mL) and the combined filtrate and washings evaporated. The residue was purified by silica gel chromatography eluting with 9:1 isohexane:ethyl acetate. The fractions containing the product were combined, evaporated and redissolved in ethanol (20 mL). A slurry of palladium on carbon (5%, 0.66 g) in water (0.5 mL) was added and the resulting suspension stirred under an atmosphere of hydrogen at 5 bar pressure for 2 h. The mixture was filtered through a pad of Celite which was washed with ethanol (3×50 mL). The combined filtrate and washings were evaporated to give the subtitled compound as a clear oil. Yield 0.9 g.

Workup

  1. temperaturethe resulting mixture heated
  2. temperatureat reflux overnight
  3. temperatureto cool
  4. filtrationfiltered through a pad of Celite
  5. washThe filter pad was washed with acetonitrile (2×100 mL)
  6. customthe combined filtrate and washings evaporated
  7. customThe residue was purified by silica gel chromatography
  8. washeluting with 9:1 isohexane
  9. additionThe fractions containing the product
  10. customevaporated
  11. dissolutionredissolved in ethanol (20 mL)
  12. additionA slurry of palladium on carbon (5%, 0.66 g) in water (0.5 mL) was added
  13. filtrationThe mixture was filtered through a pad of Celite which
  14. washwas washed with ethanol (3×50 mL)
  15. customThe combined filtrate and washings were evaporated

Sources & evidence

ORD record
ord-595135ff06904b6191af2b690c250d1d
Source dataset
uspto-grants-2013_07
Patent number
US08476265B2

Reaction notes

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