Schiff bases also

Schiff bases, also known as imines, ate formed by the condensation of carbonyl compounds with ammonia or primary amines. Hydrogenation of the resulting Schiff bases forms amines, such as benzylamine and dibenzylamine. 

The C=N double bond in Schiff bases also reacted with butadiene to give 3,6-divinylpiperidones (116) (102). For this reaction, Pd(N03)2 and PPh3(l 3) were used as a suitable catalyst ... 

Doebner-von Miller reaction is a variant of the Skraup quinoline synthesis (page 545). Therefore, the mechanism for the Skraup reaction is also operative for the Doebner-von Miller reaction. An alternative mechanism shown below is based on the fact that the preformed imine (Schiff base) also gives 2-methylquinoline ... 

Historically, the amine was an aromatic amine but is now generalized to any amine. A Schiff base, also called an aldimine, is formed in the pyridoxal 5-phosphate-dependent aminotransferase reactions. 

Schiff bases also react with unsaturated 5(477)-oxazolones and afford different products depending on the substituent at C-2. With 2-methyl-5(477)-oxazolones 545 as starting materials, 2-styryl-l-substituted imidazolones 546 are obtained (Scheme 7.172). ° Selected examples are shown in Table 7.43 (Fig. 7.54). 

Chiral iminopyridines catalyse nitro aldol reactions with good ees in the pres- ence of copper(II) acetate, without the need for exclusion of air or moisture.143 A (g) phenylalanine-derived Schiff base - also complexed to copper(II) - is also effective, with the advantage that product configuration is easily reversed (by using the enantiomeric phenylalanine).144... 

The general structure is that of (4) in Prob. 8.5(b), namely, a Schiff base (also called a ketimine). 

Many vanadium(V) complexes with Schiff bases also are known.23... 

Nonplanar or highly substituted Schiff bases also confer steric protection upon their rhodium(II) complexes. By contrast relatively simple thio ligands such as... 

Schiff bases also add Grignard reagents via a process utilizing only 50% of the available R groups easily (81), the process involving second-order kinetics and a four-center transition state. The reaction of Grignard reagents with weak acids, such as acetonitrile and alkynes has also been studied 84, 82). 

H-C [Yb(CH2Bu)3(thf)2]. A few complexes of bulky Schiff bases also exhibit this coordination number (3). 

Transimination (interconversion of Schiff bases), also called transaldimination or trans-Schiffization, denotes the reaction of an imine with a primary amine so that the original imine is converted to a new imine and a primary amine or ammonia is liberated (Scheme 19). Chemically it is a symmetrical and reversible process. 

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