Macrocycles from hydrazine

A wide range of nucleophiles has been shown to attack coordinated carbonyl compounds. The products depend upon the fate of the tetrahedral hydroxy intermediate formed. In the reaction of carbonyl compounds and amines the loss of water results in the formation of imines, and this methodology has widespread synthetic application. A novel sexidentate macrocyclic ligand (26) has been prepared by template methods. The formation of the hydrazone from hydrazine and... 

The reaction of the nickel(II) perchlorate complex (89) with acetone and related ketones yields simple hydrazone complexes rather than macrocyclic complexes resulting from a Curtis-type reaction. Acetylacetone also fails to bridge the bis(hydrazine) and instead yields a pyrazole derivative (Scheme 37).197 198 In contrast to this result, 1,4-dihydrazinophthalazine undergoes a template reaction with 2,2-dimethoxypropane, a source of acetone, in the presence of nickel(II) fluoroborate and a trace of fluoroboric acid (Scheme 38).199... 

The 14-membered macrocycle prepared from 2,6-diacetylpyridine and hydrazine 2,2 -Bipyrimidine Acetylacetone... 

In 1994 Cava and coworkers reported the synthesis of the tetrathiophene-containing systems 4.183 and 4.184. The first of these was the non-conjugated tetrathiaporphyrinogen-(2.1.2.1) 4.183. This species was isolated in remarkably high yield (78%) from the reductive McMurry coupling of dialdehyde 4.182 (Scheme 4.5.5). Dehydrogenation of this macrocycle was effected by treatment with DDQ, followed by hydrazine. This afforded the neutral aromatic tetrathia[22]porphyrin-(2.1.2.1) systems 4.184 in 82% yield. 

Polynuclear iron(II) and cobalt(III) oximehydrazonates have arisen from the template macrocyclization of the initial nonmacrocyclic tris-complexes with polydentate ligands resulting from the condensation of the corresponding diketones and their monooximes with hydrazine [193]. The tris-complexes formed have... 

The first example of the crab-like cyclization reaction for the formation of macrocycles was in the synthesis of hydrazino-crown ethers (Bradshaw et al., 1988b). The hydrazine-containing crab-like starting material was prepared from A, /V -diethylhydrazine and chloroacetyl chloride. 

Fig. 3 Electrocatalytic activity of different metal macrocyclic compounds for the oxidation of hydrazine in 0.1 mol NaOH as a function of the number of d-electrons [30, 42]. Adapted from Fig. 1...

Fig. 5 Volcano plot for oxidation of hydrazine in 0.1 mol NaOH on graphite modified electrode with several iron macrocyclic complexes. Data taken from Ref. [56]...

Volcano correlations indicate that the ability of the MN4 macrocyclic compound to bind the hydrazine molecule is related to the electronic structure of the metal in the phthalocyanine, because drainage of electrons from one of the lone pairs of one of the nitrogen atoms of hydrazine, toward the metal, occurs when N2H4 interacts with the metal center. 

---