but-2-ynoic acid

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.5 g (35 millimoles) of 1-(2,6-difluorophenyl)ethyl azide and 2.45 g (35 millimoles) of propinecarboxylic acid in 50 ml of toluene are heated for 24 hours to 60°-70° C. The cooled reaction mixture is extracted with 100 ml of 1N sodium hydroxide solution and the extract is acidified with hydrochloric acid to give 1-[1-(2,6-difluorophenyl)ethyl-1H-1,2,3-triazole-4-carboxylic acid with a melting point of 135°-138° C. (dec.). 7.1 g (26.6 millimoles) of 1-[1-(2,6-difluorophenyl)ethyl]-1H-1,2,3-triazole-4-carboxylic acid, 150 ml of ethanol and 1 ml of sulfuric acid are heated for 10 hours to reflux. Working up gives ethyl 1-[1-(2,6-difluorophenyl)ethyl]-1H-1,2,3-triazole-4-carboxylate with a melting point of 118°-121° C. The cooled reaction mixture is extracted with 100 ml of 1N sodium hydroxide solution

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 27.5 g (0.15 mole) of 6-chloro-2-fluorobenzyl azide and 10.5 g (0.15 mole) of propinecarboxylic acid in 300 ml of toluene are heated for 3 hours to 90° C. After cooling, the crystals are filtered with suction and recrystallised from acetonitrile to give 1-(6-chloro-2-fluorobenzyl)-1H-1,2,3-triazole-4-carboxylic acid with a melting point of 182° C. (dec.). After cooling the crystals are filtered with suction recrystallised from acetonitrile

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The starting material may be prepared as follows: A solution of 50 g (0.33 mole) of o-fluorobenzyl azide, 23.1 g (0.33 mole) of propinecarboxylic acid and 400 ml of toluene is stirred for 24 hours at 70° C. After the reaction mixture has cooled to room temperature, the precipitated product is filtered with suction and washed first with toluene and then with diethyl ether, affording 1-(o-fluorobenzyl)-1H-1,2,3-triazole-4-carboxylic acid with a melting point of 151° C. (dec.). The starting material may be prepared the precipitated product is filtered with suction washed first with toluene