Phosphorus oxychloride → 2-Butylamino-5-chloro-pyrido[2,3-d]pyridazine-3-carboxylic acid, ethyl ester

HRID 27757Notes

Reaction equation

HRID 27757 reaction equation
[CH2:1]([NH:5][C:6]1[C:7]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:8][C:9]2[C:10]([N:16]=1)=[CH:11][N:12]=[N:13][C:14]=2O)[CH2:2][CH2:3][CH3:4].P(Cl)(Cl)([Cl:24])=O>>[CH2:1]([NH:5][C:6]1[C:7]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:8][C:9]2[C:10]([N:16]=1)=[CH:11][N:12]=[N:13][C:14]=2[Cl:24])[CH2:2][CH2:3][CH3:4]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178448851HCID 178448851, compound

Product 1

HCID 867372142-Butylamino-5-chloro-pyrido[2,3-d]pyridazine-3-carboxylic acid, ethyl ester

Procedure

5.8 g of 2-butylamino-5-hydroxy-pyrido[2,3-d]pyridazine-3-carboxylic acid, ethyl ester (0.02 mol) are treated with 20 ml of phosphorous oxychloride for 5 days at room temperature with permanent stirring. The excess of phosphorous oxychloride in distilled off in vacuo and the remaining residue is extracted with 20 ml of hot ethyl acetate. 2-butylamino-5-chloro-pyrido[2,3-d]pyridazine-3-carboxylic acid, ethyl ester crystallizes on cooling. Yield 5.5 g (83%); m.p. 126.7° C. (ligroin).

Workup

  1. distillationThe excess of phosphorous oxychloride in distilled off in vacuo
  2. extractionthe remaining residue is extracted with 20 ml of hot ethyl acetate
  3. custom2-butylamino-5-chloro-pyrido[2,3-d]pyridazine-3-carboxylic acid, ethyl ester crystallizes
  4. temperatureon cooling

Sources & evidence

ORD record
ord-86dd28c376a44cd49296409c9c25bede
Source dataset
uspto-grants-1980_09
Patent number
US04223142

Reaction notes

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