Ammonia → 1-(4-Bromophenyl)-1,2-dihydro-3H-1,2,4-triazol-3-one

HRID 378966Notes

Reaction equation

HRID 378966 reaction equation
Cl.[Br:2][C:3]1[CH:8]=[CH:7][C:6]([NH:9][NH2:10])=[CH:5][CH:4]=1.NC(N)=O.O.N.[CH3:17][N:18]1CCC[C:19]1=[O:23]>>[Br:2][C:3]1[CH:8]=[CH:7][C:6]([N:9]2[CH:17]=[N:18][C:19](=[O:23])[NH:10]2)=[CH:5][CH:4]=1

Participants

6

Reactant 5

HCID 222AmmoniaHCID 962WaterHCID 1176UreaHCID 121574-Bromophenylhydrazine hydrochlorideHCID 13387N-methyl-2-pyrrolidone

Product 1

HCID 234341921-(4-Bromophenyl)-1,2-dihydro-3H-1,2,4-triazol-3-one

Procedure

A mixture of 4-bromophenylhydrazine hydrochloride (5.g, 22.4 mmol) and urea (8.1 g, 134 mmol) was heated to 80° C. overnight in 1-methyl-2-pyrrolidinone (25 mL). The reaction was poured into water (250 mL) and concentrated ammonia was added until basic pH. The solution was cooled on an ice bath and the semicarbazone filtered off. The semicarbazone (1.0 g, 4,4 mmol) was stirred in triethyl orthoformiate (B mL) at 90° C. for three days. The reaction mixture was cooled to room temperature and the crude material filtered off. Re-crystallisation from methanol afforded the desired product.

Workup

  1. additionwas added until basic pH
  2. temperatureThe solution was cooled on an ice bath
  3. filtrationthe semicarbazone filtered off
  4. filtrationthe crude material filtered off

Sources & evidence

ORD record
ord-d3746f40c06a40568812a835fdf25ed4
Source dataset
uspto-grants-2001_10
Patent number
US06297261B1

Reaction notes

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