Picolinic acid → 2-(2-Pyridinyl)benzothiazole

HRID 1287828Notes

Reaction equation

HRID 1287828 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[SH:8].[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[C:15](O)=O>C(Cl)(Cl)Cl>[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[C:15]1[S:8][C:3]2[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=2[N:1]=1

Participants

4

Reactant 2

HCID 1018Picolinic acidHCID 87132-Aminothiophenol

Product 1

HCID 128562-(2-Pyridinyl)benzothiazole

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a solution of polyphosphoric acid ethyl ester (PPE) 360 g in 600 ml of CHCl3 is added o-aminothiophenol 36.9 g, 0.30 mole and picolinic acid 55.5 g, 0.45 mole. The resulting solution is heated at reflux for 1 hour. The solvent is removed in vacuo, and the residue poured onto 1500 cc of ice-water. The pH of the aqueous mixture is adjusted to 10, and it is then extracted three times with 500 cc portions of CHCl3. The extracts are dried (MgSO4); filtered; and concentrated to dryness. Recrystallization from acetonitrile yields 47.4 g of the title A compound in the form of white needles, m.p. 133°-134°.

Workup

  1. temperatureThe resulting solution is heated
  2. temperatureat reflux for 1 hour
  3. customThe solvent is removed in vacuo
  4. additionthe residue poured onto 1500 cc of ice-water
  5. extractionis then extracted three times with 500 cc portions of CHCl3
  6. dry with materialThe extracts are dried (MgSO4)
  7. filtrationfiltered
  8. concentrationand concentrated to dryness
  9. customRecrystallization from acetonitrile
  10. customyields 47.4 g of the title A compound in the form of white needles, m.p. 133°-134°

Sources & evidence

ORD record
ord-9e1661c1426045679227e9be26ab5cbc
Source dataset
uspto-grants-1976_10
Patent number
US03985885

Reaction notes

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