Triethylamine hydrochloride → methyl 3-(2H-1,2,3,4-tetrazol-5-yl)benzoate

Participants

Reaction Steps

To a solution of 3-cyanobenzoic acid (12.3 g, 0.083 mol) in toluene (300 mL) were added sodium azide (16 g, 0.25 mol) and triethylamine hydrochloride (34 g, 0.25 mol) respectively. The reaction mixture was refluxed for 4 hours, cooled to room temperature, and diluted with water (300 mL). The organic phase was separated and the aqueous portion was acidified (pH=1) using concentrated HCl. The precipitate was collected by filtration and oven-dried to give 14 g (89%) of the tetrazole as a white solid. CI-MS: C8H6N4O2 [M+1] 191.0. The product obtained (14 g, 0.074 mol) was suspended in anhydrous methanol followed by the addition of gaseous HCl over a period of 20 minutes. The warm solution was stirred at room temperature for overnight, then concentrated in vacuo. The resulting residue was triturated with diethyl ether and collected by filtration to yield 12.1 g (81%) of the methyl ester intermediate 2. CI-MS: C9H8N4O2 [M+1] 205.2

Provenance & Evidence