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

HRID 386497

Reaction equation

HRID 386497 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-8a6ff12d02d241dc832a504c5b0d1204
Source dataset
uspto-grants-2013_02
Patent number
US08372847B2

Linked notes

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