5-(3-Pyridyl)-1H-tetrazole is used as a pharmaceutical intermediate. The Pyridine,3-(2H-tetrazol-5-yl)- acts as reactant with 1-(4-bromo-phenyl)-3-piperidino-propan-1-one, hydrochloride, and obtain the 1-(4-bromo-phenyl)-3-(5-pyridin-3-yl-tetrazol-2-yl)-propan-1-one. This reaction needs the solvent of dimethylformamide. The yield is 31%. In addition, this reaction should be taken for 8 hours at the temperature of 150°C.
The general procedure for the synthesis of 5-(3-pyridinyl)-1H-tetrazole from 3-cyanopyridine was as follows: 3-cyanopyridine (2 mmol), sodium azide (2.4 mmol, 1.2 eq.), and tetrabutylammonium bromide (2.4 mmol, 1.2 eq.) were added to a vial with a screw cap. The reaction mixture was stirred at 105 °C and the progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was cooled to room temperature and dissolved in deionized water (5 mL). Subsequently, the aqueous solution was acidified with 1 M hydrochloric acid to pH = 3. If precipitate formation was observed, the suspension was filtered and the filter cake was washed with deionized water to obtain a pure product. If no precipitate formation was observed, the aqueous solution was extracted with ethyl acetate (3 x 4 mL). The organic phases were combined, washed with 1 M hydrochloric acid (3 x 4 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the pure product.
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