Semicarbazide hydrochloride → 6-chloro-2H,3H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

HRID 1362901Notes

Reaction equation

HRID 1362901 reaction equation
[Cl:1][C:2]1[N:3]=[N:4][C:5](Cl)=[CH:6][CH:7]=1.Cl.[NH2:10][NH:11][C:12](N)=[O:13]>Cl.C(O)C.O>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]2[N:4]([C:12](=[O:13])[NH:11][N:10]=2)[N:3]=1

Participants

5

Reactant 2

HCID 11236Semicarbazide hydrochlorideHCID 673313,6-Dichloropyridazine

Product 1

HCID 64071826-chloro-2H,3H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidCatalystHCID 19096565Water ethanolSolvent

Procedure

To a stirring solution of 3 g (20 mmol) of 3,6-dichloropyridazine and 4.5 g (40 mmol) semicarbazide hydrochloride in 100 mL of a 3:1 mixture of ethanol/water was added 5 drops of concentrated hydrochloric acid. The resulting solution was heated to reflux for 24 h under nitrogen then evaporated in vacuo and the resulting solid was recrystallized from ethanol to yield the title compound as a yellow crystalline solid. A similar route to this compound is described in the literature (P. Francavilla, et. al. J. Heterocyclic Chem., 1971, 8, 415-419). LC/MS 171.2 (M+1).

Workup

  1. temperatureThe resulting solution was heated
  2. temperatureto reflux for 24 h under nitrogen
  3. customthen evaporated in vacuo
  4. customthe resulting solid was recrystallized from ethanol

Sources & evidence

ORD record
ord-ded1073530714bd4850061d678556a91
Source dataset
uspto-grants-2011_02
Patent number
US07884104B2

Reaction notes

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