Reaction #2348108

Reaction equation

(4-Bromo-5-chloro-2-methoxyphenyl)hydrazine

(4-bromo-5-chloro-2-methoxyphenyl)hydrazine

Intermediate 2

(4-bromo-5-chloro-2-methoxyphenyl)hydrazine

2-(5-bromothien-2-yl)glyoxylic acid

Triethylamine

diphenylphosphorylazide

→

2-(4-bromo-5-chloro-2-methoxyphenyl)-2,4-dihydro-5-(5-bromothien-2-yl)-3H-1,2,4-triazol-3-one

Yield 75.0%

Solvents

acetonitrile

Conditions

Workup

1. 1
   Temperaturethe reaction was heated
2. 2
   Temperatureat reflux 3-18 hours
3. 3
   TemperatureAfter cooling to room temperature
4. 4
   Filtrationsolids were filtered
5. 5
   Washwashed with acetonitrile and ether

Procedure

(4-Bromo-5-chloro-2-methoxyphenyl)hydrazine (Intermediate 2) (5.0 g) and 2-(5-bromothien-2-yl)glyoxylic acid (4.7 g) were refluxed in acetonitrile (15-25 ml/mmol starting material) for 30-60 minutes. The reaction was cooled to room temperature. Triethylamine (2.22 g) and diphenylphosphorylazide (6.05 g) were added, and the reaction was heated at reflux 3-18 hours. After cooling to room temperature, solids were filtered and washed with acetonitrile and ether to yield (75%) 2-(4-bromo-5-chloro-2-methoxyphenyl)-2,4-dihydro-5-(5-bromothien-2-yl)-3H-1,2,4-triazol-3-one (Intermediate 3).

Source