Hydrochloric Acid → 5-Chloro-2-methylbenzoyl chloride

HRID 2165873Notes

Reaction equation

HRID 2165873 reaction equation
Cl.[Cl:2][C:3]1[CH:4]=[CH:5][C:6]([CH3:12])=[C:7]([CH:11]=1)[C:8](O)=[O:9].S(Cl)([Cl:15])=O>>[Cl:2][C:3]1[CH:4]=[CH:5][C:6]([CH3:12])=[C:7]([CH:11]=1)[C:8]([Cl:15])=[O:9]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 24386Thionyl ChlorideHCID 820095-Chloro-2-methylbenzoic acid

Product 1

HCID 148392195-Chloro-2-methylbenzoyl chloride

Procedure

Part A. A 100-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 5-chloro-2-methylbenzoic acid (10.00 g, 58.62 mmol). The apparatus was cooled in an ice bath, and thionyl chloride (40 mL, 550 mmol) was added in one portion. The ice bath was removed and the reaction mixture was warmed to about 50° for about 45 minutes in order to completely dissolve the 5-chloro-2-methylbenzoic 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. The residue was distilled under vacuum to afford 5-chloro-2-methylbenzoyl chloride as an oil: bp 65° (0.2 torr). This material was transferred immediately into an addition funnel and added dropwise with stirring to a commerical 40% dimethylamine solution (50 mL, 445 mmol) in water (150 mL). After complete addition, the reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was extracted with ether, washed with water, dried, and concentrated. The resulting oil was distilled under vacuum to afford 5-chloro-N,N-2-trimethylbenzamide (10.40 g, 52.65 mmol, 90% yield) as an oil: bp 95°-101° (0.15 torr); IR(neat) 1650 cm-1 ; 1H NMR(CDCl3) δ 7.07-7.53(m,3H), 3.12(s,3H), 2.84(s,3H). Anal. Calcd for C9H12ClNO: C,60.76; N,6.12; Cl,17.94; N,7.12. Found: C,60.57; N,6.06; Cl,17.84; N,6.86.

Workup

  1. customA 100-mL, three-necked, round-bottomed flask equipped with an addition funnel
  2. temperaturereflux condenser
  3. temperatureThe apparatus was cooled in an ice bath
  4. customThe ice bath was removed
  5. temperaturethe reaction mixture was warmed to about 50° for about 45 minutes in order
  6. dissolutionto completely dissolve the 5-chloro-2-methylbenzoic acid
  7. temperatureto gradually cool
  8. customThe excess thionyl chloride and the HCl and SO2 reaction side-products
  9. customwere removed by vacuum distillation
  10. distillationThe residue was distilled under vacuum

Sources & evidence

ORD record
ord-6cff60b1bace40dd85311a231e56f86b
Source dataset
uspto-grants-1990_07
Patent number
US04942163

Reaction notes

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