3-Bromotoluene → bis(3-methylphenyl)phosphinic acid

HRID 1086009Notes

Reaction equation

HRID 1086009 reaction equation
Br[C:2]1[CH:3]=[C:4]([CH3:8])[CH:5]=[CH:6][CH:7]=1.[Mg].C(N(CC)[P:13](Cl)([O-:15])=[O:14])C.[Cl-].[NH4+]>C(OCC)C>[C:4]1([CH3:8])[CH:5]=[CH:6][CH:7]=[C:2]([P:13]([C:2]2[CH:3]=[C:4]([CH3:8])[CH:5]=[CH:6][CH:7]=2)(=[O:14])[OH:15])[CH:3]=1

Participants

6

Reactant 4

HCID 115603-BromotolueneHCID 25517Ammonium ChlorideHCID 5462224MagnesiumHCID 20059535HCID 20059535, compound

Product 1

HCID 262047bis(3-methylphenyl)phosphinic acidYield 34.4%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

In 250 ml of dehydrated diethyl ether, 102.6 g (0.6 mole) of m-bromotoluene was reacted with 15.3 g (0.64 mole) of metallic magnesium to prepare a Grignard reagent. To the resulting Grignard reagent was added dropwise 57 g (0.3 mole) of N,N-diethylamidochlorophosphate at 37° to 38° C. over a period of 2 hours. After the reaction mixture was heated at reflux for 4.5. hours, 400 ml of ice-water and 150 ml of saturated aqueous ammonium chloride were added thereto to decompose the salt. After liquid separation, 400 ml of concentrated hydrochloric acid was added to the ether layer under ice-cooling, followed by heating to remove the ether by distillation. To the residue was further added 100 ml of concentrated hydrochloric acid, and a reaction was conducted at 100° to 110° C. for 5 hours. The formed oily substance was separated from the aqueous layer, and 50 ml of a 20% aqueous solution of sodium hydroxide was added thereto to form a uniform solution. The insoluble matter was removed by extraction with toluene, and 20% sulfuric acid was added to the solution to neutralize and further to make it acidic. The precipitate thus formed was collected by filtration, washed with water, and dried to obtain 27 g of a crude product. Recrystallization from methanol yielded 25.4 g (percent yield: 34%) of di-(m-tolyl)phosphinic acid as a colorless solid having a melting point of 171.5° C.

Workup

  1. temperatureAfter the reaction mixture was heated
  2. temperatureat reflux for 4.5
  3. customAfter liquid separation, 400 ml of concentrated hydrochloric acid
  4. additionwas added to the ether layer under ice-
  5. temperaturecooling
  6. temperatureby heating
  7. customto remove the ether
  8. distillationby distillation
  9. customThe formed oily substance was separated from the aqueous layer, and 50 ml of a 20% aqueous solution of sodium hydroxide
  10. additionwas added
  11. customto form a uniform solution
  12. customThe insoluble matter was removed by extraction with toluene, and 20% sulfuric acid
  13. additionwas added to the solution
  14. customThe precipitate thus formed
  15. filtrationwas collected by filtration
  16. washwashed with water
  17. customdried
  18. customto obtain 27 g of a crude product
  19. customRecrystallization from methanol

Sources & evidence

ORD record
ord-a590fa3b945741c996fd145d3d4160c3
Source dataset
uspto-grants-1991_04
Patent number
US05012002

Reaction notes

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