Phosphorus oxychloride → 8-Chloro-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine

HRID 1863941Notes

Reaction equation

HRID 1863941 reaction equation
[F:1][C:2]([F:14])([F:13])[C:3]1[N:7]2[CH:8]=[CH:9][N+:10]([O-])=[CH:11][C:6]2=[N:5][N:4]=1.P(Cl)(Cl)([Cl:17])=O>>[Cl:17][C:11]1[C:6]2[N:7]([C:3]([C:2]([F:14])([F:13])[F:1])=[N:4][N:5]=2)[CH:8]=[CH:9][N:10]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 685205933-(Trifluoromethyl)[1,2,4]triazolo[4,3-a]pyrazine 7-oxide

Product 1

HCID 102201268-Chloro-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine

Procedure

A suspension of 40 mg (0.196 mmol) of 3-(trifluoromethyl)[1,2,4]triazolo[4,3-a]pyrazine 7-oxide in 0.9 mL of phosphorus oxychloride was stirred at reflux for 2.5 h. The cooled solution was concentrated to dryness. Purification of the residue by preparative HPLC (C18 reverse phase column, 10-70% acetonitrile in water containing 0.05% trifluoroacetic acid) and then by flash chromatography on silica gel (10-30% ethyl acetate in hexanes) yielded the title compound as a white solid. LC-MS 223 (M+1).

Workup

  1. temperatureat reflux for 2.5 h
  2. concentrationThe cooled solution was concentrated to dryness
  3. customPurification of the residue by preparative HPLC (C18 reverse phase column, 10-70% acetonitrile in water containing 0.05% trifluoroacetic acid) and then by flash chromatography on silica gel (10-30% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-03b46a109e0345c6a9a9f75bcbd98013
Source dataset
uspto-grants-2009_12
Patent number
US07625888B2

Reaction notes

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