Hydrochloric Acid → 2,5-Dimethylbenzoyl chloride

HRID 2165874Notes

Reaction equation

HRID 2165874 reaction equation
Cl.[CH3:2][C:3]1[CH:11]=[CH:10][C:9]([CH3:12])=[CH:8][C:4]=1[C:5](O)=[O:6].S(Cl)([Cl:15])=O>>[CH3:2][C:3]1[CH:11]=[CH:10][C:9]([CH3:12])=[CH:8][C:4]=1[C:5]([Cl:15])=[O:6]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 118922,5-Dimethylbenzoic acidHCID 24386Thionyl Chloride

Product 1

HCID 123518852,5-Dimethylbenzoyl chloride

Procedure

Part A. A 500-mL, three-necked, round bottomed flask equipped with an addition funnel, reflux condenser, and a nitrogen sweep to an HCl gas scrubber was charged with 2,5-dimethylbenzoic acid (50.0 g, 332.9 mmol). The apparatus was cooled in an ice bath and thionyl chloride (125 mL, 1714 mmol) was added over a period of about 5 minutes. After complete addition, the ice bath was removed and the reaction mixture was warmed to about 50° in order to completely dissolve the 2,5-dimethylbenzoic acid. The reaction mixture was allowed to gradually cool with stirring to room temperature overnight. The excess thionyl chloride and the HCl and SO2 reaction side-products were removed by vacuum distillation to afford 2,5-dimethylbenzoyl chloride as an oil, which was used without further purification. This material was transferred immediately to an addition funnel and added dropwise with stirring to a commercial 40% dimethylamine solution (188 mL, 1670 mmol) which was maintained between -5° and 5° by periodic immersion in a dry ice-acetone bath. After complete addition, the reaction mixture was stirred at room temperature for 1 hour. The reaction mixture was diluted with water and extracted with ether. The combined organic extracts were washed with water, dried, and concentrated. The resulting pale yellow oil was distilled under vacuum to afford N,N,2,5-tetramethylbenzamide (29.1 g, 164.2 mmol, 49% yield) as a clear, colorless oil: bp 100° (1.0 torr); IR(CHCl3) 1637 cm-1 ; MS m/e 178(M+ +H); 1H NMR(CDCl3) δ 7.00-7.13(m,2H), 6.90-7.00(m,1H), 3.13(s,3H), 2.84(s,3H), 2.31(s,3H), 2.23(s,3H). Anal. Calcd for C11H15NO: C,74.54; H,8.53; N,7.90. Found: C,74.30; H,8.77; N,7.73.

Workup

  1. customA 500-mL, three-necked, round bottomed flask equipped with an addition funnel
  2. temperaturereflux condenser
  3. temperatureThe apparatus was cooled in an ice bath
  4. additionAfter complete addition
  5. customthe ice bath was removed
  6. temperaturethe reaction mixture was warmed to about 50° in order
  7. dissolutionto completely dissolve the 2,5-dimethylbenzoic acid
  8. temperatureto gradually cool
  9. customThe excess thionyl chloride and the HCl and SO2 reaction side-products
  10. customwere removed by vacuum distillation

Sources & evidence

ORD record
ord-d63f23479734412795a20f5f5e16a3f7
Source dataset
uspto-grants-1990_07
Patent number
US04942163

Reaction notes

Loading…