Isonicotinyl hydrazide

Hydrazines. The hydrazines have only historic significance. The entire group of MAOIs was discovered through the euphoric side effect of isoniazid (8.36, isonicotinyl-hydrazide), a successful antituberculotic drug introduced in 1952. Iproniazid (8.37) is the corresponding isopropyl derivative. All of the hydrazides are highly hepatotoxic, and are no longer available. 

Isonicotinyl hydrazide (INH), one of the most effective drugs against tuberculosis, is inhibitory to pyridoxal kinase, the enzyme that converts pyridoxal to PLP.C Apparently, the drug reacts with pyridoxal to form a hydrazone which blocks the enzyme. Pyridoxal kinase is not the primary target of INH in mycobacteria. However, patients on long-term isonicotinyl hydrazide therapy sometimes suffer symptoms of vitamin B6 deficiency. ... 

Isonicotinyl hydrazide, an inhibitor of enzymes that are dependent on pyridoxal phosphate, also prevents the formation of pigment in illuminated, etiolated maize, but the inhibition is reversed by pyruvate or serine.9 This supports the previously held view that the C-2—C-3 fragment of serine can give rise to acetyl-CoA in young, greening tissue. However, the significance of this pathway in mature plants has yet to be ascertained. 

Mn2Cl(isonicotinyl hydrazide)3(H20)3]3+, 64 Mn2C19H25N19S4 Mn2(NCS)4(4-metriazole)5, 21 Mn2C2oH26N4016... 

A development of the ligands derived from a-substituted pyridines is the potentially quadridentate ligand (156). It is suggested that the anhydrous cream-white [MnCljL] compound is polymeric with each N—O pair of the ligand binding to a different Mn" atom. This tendency to polymerization is ably demonstrated in the X-ray structure (157) of the compound [Mn2(31L3(H20)3]Clj Lo5 (L = isonicotinyl hydrazide) " , and in the possible structure of di(bis[A -phenylaminomethyl]pho-sphinato)manganese(II) (158). 

Acylhydrazones from azomethines. 5-Hydroxymethylfurfurylideneanilide added rapidly to a hot soln. of isonicotinyl hydrazide, and heated briefly to boiling -> 5-hydroxymethylfurfurylideneisonicotinyl hydrazide. Y 97%. F. e. and reactions s. F. Knotz, M. 89, 718 (1958). 

---