Phthalic Anhydride → Dihydrochloride trihydrate

HRID 27011Notes

Reaction equation

HRID 27011 reaction equation
[C:1]1(=[O:11])[O:6][C:4](=[O:5])[C:3]2=[CH:7][CH:8]=[CH:9][CH:10]=[C:2]12.[CH3:12][N:13]([CH3:23])[C:14]1[CH:19]=[CH:18][CH:17]=[C:16]([N:20]([CH3:22])[CH3:21])[CH:15]=1.[Cl:24]C1C=CC=CC=1>[Cl-].[Zn+2].[Cl-]>[CH3:21][N:20]([CH3:22])[C:16]1[CH:15]=[C:14]([N:13]([CH3:23])[CH3:12])[CH:19]=[CH:18][C:17]=1[C:4]([C:3]1[CH:7]=[CH:8][CH:9]=[CH:10][C:2]=1[C:1]([OH:6])=[O:11])=[O:5].[OH2:5].[OH2:5].[OH2:5].[ClH:24].[ClH:24]

Participants

6

Reactant 3

HCID 6811Phthalic AnhydrideHCID 7964ChlorobenzeneHCID 897151,3-Benzenediamine, N1,N1,N3,N3-tetramethyl-

Product 2

HCID 18760762Dihydrochloride trihydrateHCID 202872122-(2,4-Bis(dimethylamino)benzoyl)benzoic acid

Reagents, catalysts & solvents 1

HCID 3007855ZincchlorideCatalyst

Procedure

A mixture of phthalic anhydride (5.92 g.), N,N,N',N'-tetramethyl-m-phenylenediamine (6.56 g.), zinc chloride (5.40 g.) and chlorobenzene (70 ml.) was heated under reflux for three hours. The chlorobenzene was decanted and the residue was air-dried. A solution of the residue in dilute hydrochloric acid (10%, 20 ml. plus 20 ml. of water) was diluted with more water (20 ml.), affording 2-(2,4-bis-(dimethylamino)benzoyl)benzoic acid (II: Y'2 =Y'4 =(CH3)2N, Z4 =Z'5 =Z'6 =Z7 =H) dihydrochloride trihydrate (4 g., m.p. 136°-141° C.; after recrystallization from ethanol, m.p. 140°-141° C.). In another preparation the free base (m.p. 165°-168° C.) was obtained under less acidic conditions (pH 4-6).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for three hours
  3. customThe chlorobenzene was decanted
  4. customthe residue was air-dried
  5. additionA solution of the residue in dilute hydrochloric acid (10%, 20 ml. plus 20 ml. of water) was diluted with more water (20 ml.)

Sources & evidence

ORD record
ord-d1c2a84a75f940b4858cb02ecc076c17
Source dataset
uspto-grants-1980_09
Patent number
US04220357

Reaction notes

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