Formaldehyde → 4,4'-Bis(ethylmethylamino)benzophenone

HRID 1018179Notes

Reaction equation

HRID 1018179 reaction equation
[CH2:1]([NH:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[CH3:2].[CH2:10]=O.[CH2:12]([N:14]([CH3:21])[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)[CH3:13].[C:22](Cl)(Cl)=[O:23].[OH-].[Na+]>C(O)(C)C.O>[CH3:10][N:3]([CH2:1][CH3:2])[C:4]1[CH:9]=[CH:8][C:7]([C:22]([C:18]2[CH:19]=[CH:20][C:15]([N:14]([CH3:21])[CH2:12][CH3:13])=[CH:16][CH:17]=2)=[O:23])=[CH:6][CH:5]=1

Participants

8

Reactant 5

HCID 712FormaldehydeHCID 6371PhosgeneHCID 7670N-EthylanilineHCID 11956Benzenamine, N-ethyl-N-methyl-HCID 14798Sodium Hydroxide

Product 1

HCID 109353434,4'-Bis(ethylmethylamino)benzophenone

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 3776IsopropanolSolvent

Conditions

Temperature
55 °C

Procedure

Ethyl-aniline is methylated by reductive alkylation with formaldehyde using isopropyl alcohol as a solvent at 100° C. under 120 psi of H2. After the solvent is stripped the product ethylmethylaniline (NEMA) is purified by distillation at 120° C. at a pressure of 21 mm mercury (Hg). NEMA (80 g, 0.59 mol) is charged to a vessel fitted with a dry-ice condenser and is heated to 50-60° C. Phosgene is transferred from a cylinder to a calibrated trap placed in dry-ice. After condensing 10 mL (14.3 g, 0.145 mol), the trap was connected to the vessel containing NEMA and the phosgene was added over 1 hour. After the addition was complete, the mixture was heated to 120° C. and held at this temperature for 1 hour. The mixture was cooled to 50-60° C. before 11 g (0.275 mol) of NaOH dissolved in 100 mL of water was added to hydrolyze the unreacted acid chloride. The resulting mixture was then extracted with two 100 mL portions of toluene. The product 4,4′-bis(methylethylamino)benzophenone (MEAB) was purified by chromatography on silica gel using toluene as an eluent followed by recrystallization from methylene chloride/hexane. Several grams of highly pure MEAB were obtained. No impurities were detectable by NMR; m.p. 122-124° C. NMR, IR and mass spectra were consistent with the proposed structure.

Workup

  1. customat 100° C.
  2. distillationis purified by distillation at 120° C. at a pressure of 21 mm mercury (Hg)
  3. additionNEMA (80 g, 0.59 mol) is charged to a vessel
  4. customfitted with a dry-ice condenser
  5. customPhosgene is transferred from a cylinder to a calibrated trap
  6. customAfter condensing 10 mL (14.3 g, 0.145 mol)
  7. additioncontaining NEMA
  8. additionAfter the addition
  9. temperaturethe mixture was heated to 120° C.
  10. additionwas added
  11. extractionThe resulting mixture was then extracted with two 100 mL portions of toluene
  12. customThe product 4,4′-bis(methylethylamino)benzophenone (MEAB) was purified by chromatography on silica gel
  13. customfollowed by recrystallization from methylene chloride/hexane

Sources & evidence

ORD record
ord-5642d8c464714fa7afcbf197d44e0e74
Source dataset
uspto-grants-2002_11
Patent number
US06479706B1

Reaction notes

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