Phosphorus oxychloride → 5,8-Dichloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine

HRID 1833344Notes

Reaction equation

HRID 1833344 reaction equation
[Cl:1][C:2]1[N:16]=[CH:15][C:5]2[C:6](=O)[NH:7][C:8]3[N:9]([N:10]=[C:11]([CH3:13])[CH:12]=3)[C:4]=2[CH:3]=1.P(Cl)(Cl)([Cl:19])=O>>[Cl:19][C:6]1[C:5]2[CH:15]=[N:16][C:2]([Cl:1])=[CH:3][C:4]=2[N:9]2[N:10]=[C:11]([CH3:13])[CH:12]=[C:8]2[N:7]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 1360252228-chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-5(4H)-one

Product 1

HCID 213891765,8-Dichloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine

Procedure

23.5 g. of 8-chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-5(4H)-one of Example 1b are refluxed in 100 ml. of phosphorus oxychloride for 12 hours. The excess phosphorus oxychloride is distilled off in vacuo and the oily residue is poured on ice. After standing for 1 hour, 5,8-dichloro2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off, yield: 17 g. (67%); m.p. 203.4° (ethyl acetate).

Workup

  1. distillationThe excess phosphorus oxychloride is distilled off in vacuo
  2. additionthe oily residue is poured on ice
  3. filtration5,8-dichloro2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off

Sources & evidence

ORD record
ord-7e2fc4a868fb42398ae8234a58fe9b1c
Source dataset
uspto-grants-1978_01
Patent number
US04066645

Reaction notes

Loading…