Sulfuric Acid → tert-Butyl(2S)-cyclopentyl-(4-methylphenyl)acetate

HRID 877193Notes

Reaction equation

HRID 877193 reaction equation
[CH:1]1([C@@H:6]([C:10]2[CH:15]=[CH:14][C:13]([CH3:16])=[CH:12][CH:11]=2)[C:7]([OH:9])=[O:8])[CH2:5][CH2:4][CH2:3][CH2:2]1.S(=O)(=O)(O)O.[CH3:22][C:23]([CH3:25])=[CH2:24]>ClCCl>[CH:1]1([C@@H:6]([C:10]2[CH:15]=[CH:14][C:13]([CH3:16])=[CH:12][CH:11]=2)[C:7]([O:9][C:23]([CH3:25])([CH3:24])[CH3:22])=[O:8])[CH2:5][CH2:4][CH2:3][CH2:2]1

Participants

5

Reactant 3

HCID 1118Sulfuric Acid2×HCID 8255Isobutylene2×HCID 28293121(2S)-Cyclopentyl-(4-methylphenyl)acetic acid

Product 1

HCID 54452340tert-Butyl(2S)-cyclopentyl-(4-methylphenyl)acetate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

160 g (732.9 mmol) of (2S)-cyclopentyl-(4-methylphenyl)acetic acid were initially charged in 480 ml of dichloromethane, and 2.1 ml of sulfuric acid and 172 ml (1722.4 mmol) of condensed 2-methylprop-1-ene were added at 10° C. The mixture was stirred at RT overnight. If required, the addition of sulfuric acid and 2-methylprop-1-ene was repeated until all the starting material had been consumed. After the reaction had ended, 21 g of potassium carbonate were added and the mixture was stirred for another 2-3 h (evolution of gas). The mixture was then diluted with 700 ml of water and extracted with ethyl acetate. The organic phase was dried over sodium sulfate, filtered and concentrated on a rotary evaporator. The crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 4:1). This gave 172 g (85% of theory) of the title compound.

Workup

  1. additionwere added at 10° C
  2. customhad been consumed
  3. addition21 g of potassium carbonate were added
  4. stirringthe mixture was stirred for another 2-3 h (evolution of gas)
  5. additionThe mixture was then diluted with 700 ml of water
  6. extractionextracted with ethyl acetate
  7. dry with materialThe organic phase was dried over sodium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated on a rotary evaporator
  10. customThe crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 4:1)

Sources & evidence

ORD record
ord-e2b5a3091f3d4d1fbcdb3950a28152c8
Source dataset
uspto-grants-2015_03
Patent number
US08987256B2

Reaction notes

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