Benzyl Isocyanide Oxidation of 5-Aminotetrazoles

Submitted by Gerhard Hofle and Bernd Lanoe Checked by Orville L. Chapman and Thomas C. Hess 

Caution This preparation should be conducted in an ejficient hood because of the obnoxious odor of the isocyanide. 

5-Benzylaminotetrazole. Freshly distilled benzaldehyde (21.2 g, 0.2 mol) is added in one portion to a warm (50°C) solution of 5-ami-notetrazole (17.2 g, 0.2 mol) (Note 1) and triethylamine (20.2 g, 0.2 mol) in 100 mL of absolute methanol. After 15 min the reaction mixture is cooled to room temperature, transferred to an autoclave, and hydrogenated with agitation at room temperature over Pd (10%) on carbon (1 g) for 18 hr at 500 psi of hydrogen. The catalyst is removed by filtration and all volatile material is removed at 60°C under aspirator pressure. The gummy tan solid is triturated with 250 mL of hot water, Aqueous 20% HCl is added until pH 3 is reached. The mixture is cooled to room temperature and the solid collected, washed with water, and dried over- 

5-Aminotetrazole monohydrate is available from Aldrich Chemical Company, Inc. it was dehydrated by heating over P2O5 at 100°C under reduced pressure (100 p.) for 4 hr. 

During addition of the NaOBr solution the mixture warms to 20°C. The reaction is virtually instantaneous and can be monitored by the liberated nitrogen. 

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BENZYL ISOCYANIDE OXIDATION OF 5-AMINOTETRAZOLES (Benzene, isocyanomethyl)... 

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