(+-)-Pantolactone → 4-Methoxy cinnamic acid

HRID 1762714Notes

Reaction equation

HRID 1762714 reaction equation
C[C:2]1([CH3:9])[CH:7](O)[C:5](=[O:6])[O:4]C1.[CH3:10][O:11][C:12]1[CH:22]=[CH:21]C(C=CC(Cl)=O)=[CH:14][CH:13]=1.N1C=CC=CC=1>C(Cl)Cl>[CH3:10][O:11][C:12]1[CH:22]=[CH:21][C:9]([CH:2]=[CH:7][C:5]([OH:4])=[O:6])=[CH:14][CH:13]=1

Participants

5

Reactant 3

HCID 989(+-)-PantolactoneHCID 1049PyridineHCID 534017724-Methoxycinnamic acid chloride

Product 1

HCID 132454-Methoxy cinnamic acidYield 92.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

16.3 g of <R>-pantolactone (0.125 mol) and 28 g of 4-methoxycinnamic acid chloride (about 0.14 mol) are placed in 170 ml of CH2Cl2 while gassing with argon in a 350 ml 4-necked sulphonation flask provided with a thermometer, a reflux condenser, a magnetic stirrer as well as a 20 ml dropping funnel. A solution of 11 g (0.139 mol) of pyridine in 30 ml of CH2Cl2 is now added dropwise within 30 minutes, whereby the temperature rises slowly. The reaction mixture is finally heated to reflux temperature for 3 hours. The reaction mixture is washed with 150 ml of water, 2× with 40 ml of 5% HCl, 2× with 40 ml of 5% NaHCO3 and 1× with 100 ml of water. The organic phase is separated and dried over Na2SO4. The solvent is removed on a rotary evaporator. The thus-obtained crude product is recrystallized from 100 ml of ethyl acetate/hexane (60:100). There are obtained 33.6 g of white crystals of the <R>-pantolactone ester of p-methoxycinnamic acid (yield 92.6%).

Workup

  1. customwhile gassing with argon in a 350 ml 4-necked sulphonation flask
  2. customprovided with a thermometer, a reflux condenser, a magnetic stirrer as well as a 20 ml
  3. temperatureThe reaction mixture is finally heated
  4. temperatureto reflux temperature for 3 hours
  5. washThe reaction mixture is washed with 150 ml of water, 2× with 40 ml of 5% HCl, 2× with 40 ml of 5% NaHCO3 and 1× with 100 ml of water
  6. customThe organic phase is separated
  7. dry with materialdried over Na2SO4
  8. customThe solvent is removed on a rotary evaporator
  9. customThe thus-obtained crude product
  10. customis recrystallized from 100 ml of ethyl acetate/hexane (60:100)

Sources & evidence

ORD record
ord-72dcfe508bf64797a46cdf4dd9d8b42c
Source dataset
uspto-grants-1989_05
Patent number
US04833259

Reaction notes

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