Sodium Methoxide → Methyl 4-ethoxy-2-mercaptobenzoate

HRID 4151Notes

Reaction equation

HRID 4151 reaction equation
C[O-].[Na+].CN(C)C([S:8][C:9]1[CH:18]=[C:17]([O:19][CH2:20][CH3:21])[CH:16]=[CH:15][C:10]=1[C:11]([O:13][CH3:14])=[O:12])=O>CO>[CH2:20]([O:19][C:17]1[CH:16]=[CH:15][C:10]([C:11]([O:13][CH3:14])=[O:12])=[C:9]([SH:8])[CH:18]=1)[CH3:21]

Participants

4

Reactant 2

HCID 10942334Sodium MethoxideHCID 13987869Methyl 2-[(dimethylamino)carbonylthio]-4-ethoxybenzoate

Product 1

HCID 13987870Methyl 4-ethoxy-2-mercaptobenzoateYield 86.7%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Methanolic sodium methoxide (4.9M, 22.4 mL, 0.11 mol) was added via syringe to a solution of methyl 2-[(dimethylamino)carbonylthio]-4-ethoxybenzoate (crude, ca. 28.3 g, 0.10 mol) in methanol (100 mL) under nitrogen. The reaction mixture was heated at reflux for 30 minutes, then cooled with the aid of a water bath. Rotary evaporation yielded a solid. This was partitioned between dichloromethane (100 mL) and water (100 mL). The aqueous layer was washed with dichloromethane (3×40 mL), acidified to pH <1 with concentrated hydrochloric acid, and then extracted with dichloromethane (3×40 mL). These dichloromethane extracts were combined, dried (Na2SO4), and filtered. Rotary evaporation yielded methyl 4-ethoxy-2-mercaptobenzoate as an oil (18.4 g) that on standing formed a crystalline solid melting at 42°-44° C. PMR (CDCl3, 200 MHz): δ7.97 (d, 1H, H ortho to CO2CH3); 6.78 (d, 1H, H ortho to SH); 6.64 (dd, 1H, H para to SH); 5.06 (s, 1H, SH); 4.05 (q, 2H, OCH2CH3); 3.88 (s, 3H, CO2CH3); 1.42 (t, 3H, OCH2CH3). IR (Nujol): 1686 (vs, C=O) cm-1.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for 30 minutes
  3. temperaturecooled with the aid of a water bath
  4. customRotary evaporation
  5. customyielded a solid
  6. customThis was partitioned between dichloromethane (100 mL) and water (100 mL)
  7. washThe aqueous layer was washed with dichloromethane (3×40 mL)
  8. extractionextracted with dichloromethane (3×40 mL)
  9. dry with materialdried (Na2SO4)
  10. filtrationfiltered
  11. customRotary evaporation

Sources & evidence

ORD record
ord-f3c65c892c17444ab3d7195abd66c222
Source dataset
uspto-grants-1988_02
Patent number
US04724039

Reaction notes

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