Phosphorus oxychloride → 2-Chloro-3-methyl-5-nitropyridine

HRID 2079509Notes

Reaction equation

HRID 2079509 reaction equation
[CH3:1][C:2]1[C:3](O)=[N:4][CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1.O=P(Cl)(Cl)[Cl:14]>>[Cl:14][C:3]1[C:2]([CH3:1])=[CH:7][C:6]([N+:8]([O-:10])=[O:9])=[CH:5][N:4]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178428770HCID 178428770, compound

Product 1

HCID 896482-Chloro-3-methyl-5-nitropyridineYield 92%

Procedure

3-Methyl-5-nitropyridin-2-ol (134 g, 0.872 mol) (J. Org. Chem. 1949, 14, 328-332) was divided into 3 portions and placed in three 1-L round bottom flasks. POCl3 (200 mL) was added to each flask and the mixtures were heated to reflux for 2 h. The solutions were cooled and the excess POCl3 was removed in vacuo. The residues were poured into ice water (1 L) with stirring and the precipitates were collected by filtration and air dried for 20 min. The combined products were recrystallized from 10% ethyl acetate in hexanes (300 mL) and air dried to give 2-chloro-3-methyl-5-nitropyridine (139 g, 92% yield) as a white solid which was used in the next step without further purification: 1H NMR (300 MHz, CDCl3) δ 9.04 (d, J=2.5 Hz, 1H), 8.33 (d, J=2.2 Hz, 1H), 2.50 (s, 3H).

Workup

  1. temperaturethe mixtures were heated
  2. temperatureto reflux for 2 h
  3. temperatureThe solutions were cooled
  4. customthe excess POCl3 was removed in vacuo
  5. additionThe residues were poured into ice water (1 L)
  6. filtrationthe precipitates were collected by filtration and air
  7. customdried for 20 min
  8. customThe combined products were recrystallized from 10% ethyl acetate in hexanes (300 mL) and air
  9. customdried

Sources & evidence

ORD record
ord-63dee04bf1624730bb7cc7fc9edf56f5
Source dataset
uspto-grants-2011_04
Patent number
US07932256B2

Reaction notes

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