Phosgene → 4,5-dihydro-5-methyl-6-[p-(prop-2-ynyloxycarbonylamino)-phenyl]-3(2H)-pyridazinone

HRID 1649100Notes

Reaction equation

HRID 1649100 reaction equation
[CH2:1]([OH:4])[C:2]#[CH:3].[C:5](Cl)(Cl)=[O:6].[NH2:9][C:10]1[CH:15]=[CH:14][C:13]([C:16]2[CH:17]([CH3:23])[CH2:18][C:19](=[O:22])[NH:20][N:21]=2)=[CH:12][CH:11]=1>CCOCC.O1CCCC1>[CH3:23][CH:17]1[C:16]([C:13]2[CH:14]=[CH:15][C:10]([NH:9][C:5]([O:4][CH2:1][C:2]#[CH:3])=[O:6])=[CH:11][CH:12]=2)=[N:21][NH:20][C:19](=[O:22])[CH2:18]1

Participants

6

Reactant 3

HCID 6371PhosgeneHCID 7859Propargyl alcoholHCID 161928Ici 109,081

Product 1

HCID 128050434,5-dihydro-5-methyl-6-[p-(prop-2-ynyloxycarbonylamino)-phenyl]-3(2H)-pyridazinoneYield 41.3%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Procedure

2.8 g (49.9 millimoles) of prop-2-ynol are added dropwise to a stirred solution of 9.9 g (100 millimoles) of phosgene in 100 ml of absolute ether at -10° C. and the reaction solution is then stirred for 1 hour at the same temperature. Thereafter it is stirred for one hour at room temperature and the excess phosgene is then removed by means of a dry stream of nitrogen, after which the ether is removed under reduced pressure at room temperature. The prop-2-ynyl chloroformate which remains (5.2 g) is added, at room temperature, to a solution, prepared by the method described in Example 31, of 5.0 g (24.6 millimoles) of 6-(p-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone in 150 ml of absolute tetrahydrofuran. The reaction mixture is then refluxed for 1 hour and concentrated to about 70 ml. Water is added and the product is filtered off and recrystallized first from ethanol/water, then from acetone/water and finally from ethanol, giving 2.9 g (41% of theory) of 4,5-dihydro-5-methyl-6-[p-(prop-2-ynyloxycarbonylamino)-phenyl]-3(2H)-pyridazinone as colorless crystals, of melting point 204°-205° C.

Workup

  1. stirringThereafter it is stirred for one hour at room temperature
  2. customthe excess phosgene is then removed by means of a dry stream of nitrogen
  3. customafter which the ether is removed under reduced pressure at room temperature
  4. additionis added, at room temperature, to a solution
  5. customprepared by the method
  6. temperatureThe reaction mixture is then refluxed for 1 hour
  7. concentrationconcentrated to about 70 ml
  8. additionWater is added
  9. filtrationthe product is filtered off
  10. customrecrystallized first from ethanol/water

Sources & evidence

ORD record
ord-758f1ae1c36a403cb43a0c40137849ea
Source dataset
uspto-grants-1983_11
Patent number
US04415571

Reaction notes

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