1.1- Diamines azomethines

Triplet energy transfer measurements from porphyrin and phthalocyanine sensitizers give the triplet energies of six (Z)-A4,A4-diethyl-2-(alkyl, aryl)-A1-(3-phenyl-77/-pyrazolo[5,l-r-][l,2,4]triazol-7-ylidene)benzene-l,4-diamine azomethine dyes 154 with adsorption maxima in ethanol at 546-633 nm to lie in the range of 115-88 kJmoF1 <2003PPS563> (Figure 24). 

Keywords Azomethine compoimds 1,2-Diamines Organometallic compounds Reduction Stereoselectivity... 

Scheme 1 Routes to 1,2-diamines from 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. 

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 Compoimds. 15 1-58 Schmalz HG, Gotov B, Bottcher A (2004) Natmal Product Synthesis. 7 157-180 Schmidt B, Hermanns J (2004) Olefin Metathesis Directed to Organic Synthesis Principles and Applications. 13 223-267... 

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

Novel fluorine-containing aromatic poly(azomethine)s are prepared by the reaction of hexafluoroisopropylidene-unit-containing aromatic diamines, 2,2-bis[4-(4-aminophenoxy)phenyl]-l,l,l,3,3,3-hexafluoropropane (17) and 2,2-bis(4-aminophenyl)-l, 1,1,3,3,3-hexafluoropropane (18) with terephthalaldehyde (19) or isophthalaldehyde (20)20 (Scheme 11). 

The cast films ofpoly(azomethine)s are transparent but pale to deep yellow in color. The water contact angles of fluorine-containing poly(azomethine)s films from diamine (17) are 80° for terephthalaldehye (19) and 75° for isophthalalde-hyde (20) as dialdehyde component (Table 9.9).20 These low values of water contact angles are attributed to the lower fluorine content in these polymers. 

The asymmetric reduction of C=N double bonds in prochiral oximes afforded a maximum of 18% ee [380, 384, 385]. Prochiral azomethines were reduced to the corresponding 1,2-diamines and secondary amines using 36 optically active supporting electrolytes. The dimers were optically inactive, while the monomers showed low optical inductions (<11% ee). The effect of electrolyte, substrate concentration, temperature, pH, and cathode potential on the induction was studied. It was proposed that the enantioselectivity... 

Cis- and rranx-cyclopropane-1,2-diamines (both primary and secondary) react with a range of aldehydes, R CHO, to give pyrroles under very mild conditions. NMR has been used to identify the intermediates. The key steps involve ring expansion of the monoiminium ion (22), via an azomethine ylid (23), to yield a dihydropyrrolium ion (24). 

The corresponding azomethine polymers (LIX) have been synthesized by the reaction of the appropriate diamine and dialdehyde [Farcas and Grigoras, 2001 Gutch et al., 2001 Morgan et al., 1987]. 

Finally, enantiomerically pure sulfinimines have also been used as precursors of chiral imidazolidines by 1,3-dipolar cycloaddition with azomethine ylids [181]. Reactions of different arylsulfinimines 245 with dipoles 246 are highly stereoselective, mainly affording diastereoisomer 247 (absolute configuration unequivocally established by X-ray studies), which was readily transformed into vicinal diamine 248 (Scheme 111). 

An antimicrobial base solacasine has been found in the flowers of S. pseudocapsiaum. In its mass spectrum it showed peaks at m/z 56 and 82, associated with 33-amino-steroids. An azomethine linkage is responsible for its ir-absorption at 1660 cm." on reduction (NaBHi,) a primarysecondary diamine structure results, convertible into a trimethyl derivative on Eschweiler-Clark methylation. Structure (65) has been advanced and confirmed by the formation of dihydrosolacasine by methanolysis of solano-capsine (L. A. Mitscher et al., Experientia, 1976, 415). 

The authors did not discuss the mechanism. Perhaps the intermediate diamine (tetramine) formed from the nitro compound reacts with benzaldehyde to give an azomethine and then a dihydroimidazole. The latter may be oxidized to IP by the nitro compound not yet reduced the low yield of the reaction product supports this assumption. 

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