The review surveys the present state of research on the conformation, isomerism, and intramolecular interactions of molecules of the immense class of organic compounds containing a hydrazone group. A list of 221 references is included.
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442Russian Chemical Reviews, 39 (6), 1970 convenience we shall henceforward term the nitrogen atom in the azomethine group the imine nitrogen, and the other atom the amine nitrogen.The triatomic hydrazone group is characteristic of a large number of organic compounds of the typewhere R, R', X, and Υ can vary widely. We will use the term "hydrazones" as a general name for compounds having the structure (Π). When R' = Υ = Η we have "unsubstituted hydrazones"; when R' = Alk(Ar, Az) and Υ = H, "alkyKaryl, acyl)hydrazones", and when R' = Alk (Ar, Alk, Alk) and Υ = Alk(Ar, Ar, Az) "dialkyl(diaryl, alkylaryl, acylalkyl, etc.)hydrazones"; and also with X = Η we have an "aldehyde hydrazone", with X = Alk, Ar, Az a "ketone hydrazone", and so on. If R' = NH 2 CO the compounds (II) are semicarbazones, and if R' = NH 2 CS they are thiosemicarbazones. Dihydrazones of a-dicarbonyl compounds are usually termed "osazones". Where X = Hal, NO 2 , OAlk, OAr, the compounds are α-halogeno-hydrazonest or Q!-nitro(alkoxy, aryloxy)hydrazones; when X = Ν: NR they are formazans, X = NHNHR hydrazidines, X = NH 2 , NHR, NRR' amidrazones; and with X = OH, SH hydrazides and thiohydrazides are formed. Furthermore, R' and Υ may together constitute the residue of a carbonyl compound, in which case the structure (II) acquires the form (ΙΠ), and compounds of this class are termed "azines":
