Water → HCID 11807407, compound

HRID 1032254Notes

Reaction equation

HRID 1032254 reaction equation
[C:1]1(=O)[CH2:6][CH2:5][C:4](=[O:7])[CH2:3][CH2:2]1.[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[N:15]1[CH2:20][CH2:19][NH:18][CH2:17][CH2:16]1.C1(C)C=CC(S(O)(=O)=O)=CC=1.O>C1(C)C=CC=CC=1.Cl.CC(C)=O>[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[N:15]1[CH2:16][CH2:17][N:18]([CH:1]2[CH2:2][CH2:3][C:4](=[O:7])[CH2:5][CH2:6]2)[CH2:19][CH2:20]1

Participants

8

Reactant 4

HCID 962WaterHCID 6101p-Toluenesulfonic acidHCID 125111,4-CyclohexanedioneHCID 944591-(2-Pyridyl)piperazine

Product 1

HCID 11807407HCID 11807407, compound

Reagents, catalysts & solvents 3

HCID 180AcetoneSolventHCID 313Hydrochloric AcidSolventHCID 1140TolueneSolvent

Procedure

A solution of 1,4-cyclohexanedione monoethyleneketa (50.0 g), 1-(2-pyridyl)piperazine (52.16 g), and p-toluenesulfonic acid (0.5 g) in 500 ml of toluene is refluxed with a Dean-Stark trap until the theoretical amount of water is collected (about four hours). The solvent is evaporated in vacuo and the residue is dissolved in 750 ml of methanol. This solution is cooled in an ice bath and sodium cyanoborohydride (30.1 g) is added in small portions over a two-minute period. The resulting suspension is stirred mechanically and over the next 30 minutes enough concentrated hydrochloric acid solution is added dropwise to the reaction mixture to maintain a pH of about 4. The solvent is removed in vacuo to leave a semisolid residue which is dissolved in 300 ml of a 10% solution of hydrochloric acid in a well ventilated fume hood. This solution is diluted with an equal volume of acetone and refluxed for two hours. The volatile components of the mixture are removed in vacuo and the residue is cooled in an ice bath and made basic with concentrated ammonium hydroxide. The white solid which forms is recrystallized from ethyl acetate-heptane to give 52.4 g of the title compound; mp 142°-144° C.

Workup

  1. customis collected (about four hours)
  2. customThe solvent is evaporated in vacuo
  3. dissolutionthe residue is dissolved in 750 ml of methanol
  4. temperatureThis solution is cooled in an ice bath
  5. additionsodium cyanoborohydride (30.1 g) is added in small portions over a two-minute period
  6. additionis added dropwise to the reaction mixture
  7. temperatureto maintain a pH of about 4
  8. customThe solvent is removed in vacuo
  9. customto leave a semisolid residue which
  10. temperaturerefluxed for two hours
  11. customThe volatile components of the mixture are removed in vacuo
  12. temperaturethe residue is cooled in an ice bath
  13. customThe white solid which forms is recrystallized from ethyl acetate-heptane

Sources & evidence

ORD record
ord-72d21876a7744d4baba0815d308b0db1
Source dataset
uspto-grants-1990_09
Patent number
US04957921

Reaction notes

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