Azomethine compounds

Scheme 1 Routes to 1,2-diamines from azomethine compounds...

Addition of Carbon Nucleophiles to Chiral a-Amino Azomethine Compounds... 

Double asymmetric induction operates when the azomethine compound is derived from a chiral a-amino aldehyde and a chiral amine, e.g., the sulfin-imine 144 [70]. In this case, the R configuration at the sulfur of the chiral auxihary, N-tert-butanesulfinamide, matched with the S configuration of the starting a-amino aldehyde, allowing complete stereocontrol to be achieved in the preparation of the diamine derivatives 145 by the addition of trifluo-romethyl anion, which was formed from trifluoromethyltrimethylsilane in the presence of tetramethylammonium fluoride (Scheme 23). The substituents at both nitrogen atoms were easily removed by routine procedures see, for example, the preparation of the free diamine 146. On the other hand, a lower diastereoselectivity (dr 80 20) was observed in one reaction carried out on the imine derived from (it)-aldehyde and (it)-sulfinamide. 

By an analogous route, the cyclization of chiral (z-amino imines 197, bearing the proper tw-functionality in the o -alkyl chain, will lead to 3-substituted 1,2-diaminocycloalkanes 198. The intermolecular and intramolecular addition of allylic silicon and tin compounds to a-amino azomethine compounds should also be investigated. 

Progress in the Asymmetric Synthesis of 1,2-Diamines from Azomethine Compounds... 

Sakaki S (2005) Theoretical Studies of C-H s-Bond Activation and Related by Transition-Metal Complexes. 12 31-78 Satoh T, see Miura M (2005) 14 1-20 Satoh T, see Miura M (2005) 14 55-84 Savoia D (2005) Progress in the Asymmetric Synthesis of 1,2-Diamines from Azomethine Compounds. 15 1-58 Schmalz HG, Gotov B, Bbttcher A (2004) Natural Product Synthesis. 7 157-180 Schmidt B, Hermanns J (2004) Olefin Metathesis Directed to Organic Synthesis Principles and Applications. 13 223-267... 

There is another structure which, although it does not represent a typical azomethine compound, is synthesized from nickel complexes of the anilide of di-imino butyric acid (35). 

Commercially available azo and azomethine metal complex pigments cover the spectral range from considerably greenish to reddish yellow and yellowish orange. Compared to their parent structures (the corresponding azo and azomethine compounds), azomethine metal complexes frequently exhibit a distinctly duller shade. Formation of the metal complex often shifts the color of an originally yellow material in the greenish yellow direction. 

The chiral azomethine compounds (111) were synthesized by condensation of (S)-valinol with benzaldehyde and substituted benzaldehydes, respectively125). The... 

Thus, o,o -dihydroxyazo (8), o.o -hydroxyaminoazo (9), o,o -carboxyhydroxy-azo (10), o,o -dihydroxyazomethine (11), and o,o -carboxyhydroxy azomethine (12) residues yield with metals stable annelated 5,6- and 6,6-membered ring systems, respectively (Scheme 2.13). The residues in the azo compounds are in most cases benzene, naphthalene, pyrazolone or open-chain enol-keto systems, while in the azomethine compounds they are mostly benzene systems. 

From the viewpoint of stereochemistry the most interesting metal complexes are the octahedrally coordinated 1 2 chromium and cobalt complex dyes, which are medially metallized azo and azomethine compounds with functional groups in the o- and o -positions. Three types of isomerism can be discriminated geometrical, N-a, 3, and that arising from azo-hydrazone tautomerism. 

The interaction of that same ligand, type 521 (R = Me), this time with Fe3(CO)12, leads to some complexes amongst which a detellurized metal-cyclic compound 523 is found [916]. At the same time [reaction (2.14)], benzoisotelluroazole 524 forms, together with Fe3(CO)12, the azomethinic compound 525 [916] ... 

Hydroxyisoindolines (217) are polarographically reducible226 as would be expected because they are derivatives of an aromatic aldehyde. As other hydrated derivatives of carbonyl or azomethine compounds they must lose water before electrons can be accepted the reduction proceeds through a radical. 

The reduction of azomethine compounds depends on their structure and the experimental conditions, but most of the reactions can be described by relatively few schemes. In acidic solutions, compounds of the type RR C=N-Y are reduced with saturation of the double bond if Y is carbon, but if Y is a heteroatom (oxygen or nitrogen), the reduction follows Eqs. (1) through (3) [1] ... 

In alkaline solution many of the azomethine compounds are not reducible but if the azomethine group is conjugated with suitable groups, the carbon-nitrogen double bond may be reduced. 

A review on the electrochemistry of azomethine compounds gives leading references up to early 1968 [5] the reduction of oximes [6] and hydrazones has been reviewed more recently [7,8]. In this chapter the azomethine compounds are treated in four sections according to whether they are derivatives of ammonia, hydrazine, hydroxylamine, or a diazoalkane. 

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