Clopyralid → 3,6-Dichloro-2-(chloromethyl)pyridine

HRID 436689Notes

Reaction equation

HRID 436689 reaction equation
[Cl:1][C:2]1[C:3]([C:9](O)=O)=[N:4][C:5]([Cl:8])=[CH:6][CH:7]=1.[BH4-].[Na+].[Cl:14]C1C(CO)=NC(Cl)=CC=1.S(Cl)(Cl)=O.Cl.N1C=CC=CC=1>O.CO>[Cl:1][C:2]1[C:3]([CH2:9][Cl:14])=[N:4][C:5]([Cl:8])=[CH:6][CH:7]=1

Participants

8

Reactant 5

HCID 15553ClopyralidHCID 24386Thionyl ChlorideHCID 4311764Sodium borohydrideHCID 10176127Pyridinium chlorideHCID 20366200(3,6-Dichloropyridin-2-yl)methanol

Product 1

HCID 203661743,6-Dichloro-2-(chloromethyl)pyridine

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

The haloalkylpyridine reactants employed as starting materials in the present invention are readily available or can be prepared according to known procedures or procedures analogous thereto. For example, the 3,6-dichloro-2-chloromethyl pyridine is prepared by converting the methyl ester of 3,6-dichloropyridine carboxylic acid to the corresponding alcohol by reaction with NaBH4 and methanol in the presence of water. The 3,6-dichloro-2-hydroxymethylpyridine product is then reacted with thionyl chloride in the presence of a catalytic amount of pyridine hydrochloride at temperatures of about 65° C. for a period of from about 15 to about 20 minutes. The thionylchloride is then removed by evaporation and the residue cooled, mixed with ice and then extracted with hexane. The desired 3,6-dichloro-2-chloromethyl pyridine reactant is obtained as a light yellow oil. Other haloalkyl pyridine starting materials can be prepared in an analogous manner.

Workup

  1. customcan be prepared
  2. customThe thionylchloride is then removed by evaporation
  3. temperaturethe residue cooled
  4. additionmixed with ice
  5. extractionextracted with hexane

Sources & evidence

ORD record
ord-8ae8fd92d6404fe59dd0db4b1383ea3b
Source dataset
uspto-grants-1977_06
Patent number
US04028092

Reaction notes

Loading…