The destruction of isonicotinic acid hydrazide in the presence of haemin

Abstract

Hemin destroys isoniazid by catalyzing its oxidation in air at pH 7.5 even in the absence of tubercle bacilli to give 1:2- diisonicotinoylhydrazine and isonicotinic acid. The oxidation takes place in the absence of hemin, but is slower. An improved synthesis of diisonicotinoyl-hydrazine is given. While susceptible strains of tubercle bacilli contain hemin, and resistant strains do not, the above products are much less toxic than isoniazid, so that the mode of action of isoniazid is unknown.