sodium hydroxide in water refluxing (5-10 min), cooling to 5 to 7°C; ppt. filtration off, washing (hot pentane), Fe-compd. obtaining from pentane extracts by drying, tetrazole remaining in the solid residue;

sodium hydroxide in water refluxing (5-10 min), cooling to 5 to 7°C; ppt. filtration off, washing (hot pentane), Fe-compd. obtaining from pentane extracts by drying, tetrazole remaining in the solid residue;