Phosgene → 2,5-Dimethoxybenzyloxycarbonyl chloride

HRID 1658559Notes

Reaction equation

HRID 1658559 reaction equation
[CH3:1][O:2][C:3]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[CH:7][C:4]=1[CH2:5][OH:6].[C:13](Cl)([Cl:15])=[O:14]>C1C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[CH:7][C:4]=1[CH2:5][O:6][C:13]([Cl:15])=[O:14]

Participants

4

Reactant 2

HCID 6371PhosgeneHCID 1184952,5-Dimethoxybenzyl alcohol

Product 1

HCID 215280122,5-Dimethoxybenzyloxycarbonyl chloride

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent2×

Procedure

A 50% solution of 2,5-dimethoxybenzyl alcohol and dry benzene was added dropwise to an ice-cold stirring solution of 12.5 wt. % phosgene in benzene (1 mole of alcohol per 2 moles phosgene). The resulting solution was maintained at 0° for 1 hour and then stirred an additional 2 hours at room temperature. Excess phosgene, byproduct hydrogen chloride and a small amount of benzene was removed in vacuo at room temperature to provide crude 2,5-dimethoxybenzyloxycarbonyl chloride solution. The crude product was added dropwise to a 50 wt. % solution of p-aminobenzoic acid in dry tetrahydrofuran containing 2 moles of pyridine per mole of acid. An additional two equivalents of pyridine was added dropwise simultaneously with the carbonyl chloride addition. Upon completion of the addition (25-40 mins.), the resulting mixture was added dropwise with stirring to ice-cold 5% aqueous hydrochloric acid (10 volumes of acid per final volume of reaction solution). The product was collected by filtration, dried and purified by recrystallization from acetone. m.p. 124-25.

Workup

  1. temperatureThe resulting solution was maintained at 0° for 1 hour
  2. customExcess phosgene, byproduct hydrogen chloride and a small amount of benzene was removed in vacuo at room temperature

Sources & evidence

ORD record
ord-84da3cd781564a3f9c6f1b402af61b86
Source dataset
uspto-grants-1976_06
Patent number
US03965144

Reaction notes

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