Ketimines reaction with

Other modifications of the polyamines include limited addition of alkylene oxide to yield the corresponding hydroxyalkyl derivatives (225) and cyanoethylation of DETA or TETA, usuaHy by reaction with acrylonitrile [107-13-1/, to give derivatives providing longer pot Hfe and better wetting of glass (226). Also included are ketimines, made by the reaction of EDA with acetone for example. These derivatives can also be hydrogenated, as in the case of the equimolar adducts of DETA and methyl isobutyl ketone [108-10-1] or methyl isoamyl ketone [110-12-3] (221 or used as is to provide moisture cure performance. Mannich bases prepared from a phenol, formaldehyde and a polyamine are also used, such as the hardener prepared from cresol, DETA, and formaldehyde (228). Other modifications of polyamines for use as epoxy hardeners include reaction with aldehydes (229), epoxidized fatty nitriles (230), aromatic monoisocyanates (231), or propylene sulfide [1072-43-1] (232). 

The synthesis of vinylaziridines through reactions between allylic carbenoid reagents and imines (i.e., Darzen-type reactions) was first reported by Mauze in 1980 [13]. Treatment of aldimines or ketimines 16 with gem-chloro(methyl)allyllithium (17) afforded N-substituted vinylaziridines 18 (Scheme 2.6). Similarly, 2,3-trans-N-diphenylphosphinyl-2-vinylaziridines 21 were prepared with good stereoselectivities (trans cis= 10 1 Scheme 2.7) by treatment of a-bromoallyllithium (20) with N-diphenylphosphinyl aldimines 19 in the presence of zinc chloride [14]. 

Recent efforts in the development of efficient routes to highly substituted yS-ami-no acids based on asymmetric Mannich reactions with enantiopure sulfmyl imine are worthy of mention. Following the pioneering work of Davis on p-tolu-enesulfmyl imines [116], Ellman and coworkers have recently developed a new and efficient approach to enantiomerically pure N-tert-butanesulfmyl imines and have reported their use as versatile intermediates for the asymmetric synthesis of amines [91]. Addition of titanium enolates to tert-butane sulfmyl aldimines and ketimines 31 proceeds in high yields and diastereoselectivities, thus providing general access to yS -amino acids 32 (Scheme 2.5)... 

Intramolecular addition of trialkylboranes to imines and related compounds have been reported and the main results are part of review articles [94, 95]. Addition of ethyl radicals generated from Et3B to aldimines affords the desired addition product in fair to good yield but low diaster control (Scheme 40, Eq. 40a) [96]. Similar reactions with aldoxime ethers [97], aldehyde hydrazones [97], and N-sulfonylaldimines [98] are reported. Radical addition to ketimines has been recently reported (Eq. 40b) [99]. Addition of triethylborane to 2H-azirine-3-carboxylate derivatives is reported [100]. Very recently, Somfai has extended this reaction to the addition of different alkyl radicals generated from trialkylboranes to a chiral ester of 2ff-azirine-3-carboxylate under Lewis acid activation with CuCl (Eq. 40c) [101]. 

Prior to imide formation, the imide-aryl ether ketimine copolymers were converted to the imide-aryl ether ketone analogue by hydrolysis of the ketimine moiety with para-toluene sulfonic acid hydrate (PTS) according to a literature procedure [51,52,57-59]. The copolymers were dissolved in NMP and heated to 50 °C and subjected to excess PTS for 8 h. The reaction mixtures were isolated in excess water and then rinsed with methanol and dried in a vacuum oven to afford the amic ester-aryl ether ether ketone copolymer, 2e (Scheme 8.)... 

In addition, we investigated a nonlinear-like effect (NLE), activity, temperature dependence, and kinetics of hydroxy[2.2]paracyclophane ketimine ligands with the 1,2-addition reaction of diethylzinc to cyclohexylcarbaldehyde. A linear correlation between the enantiomeric excess of AHPC ketimine ligands bearing a phenylethyl side group and the product was observed with 0.5 mol% of catalyst loading. When the catalyst loading of (Sp,S)/(Rp,R)-4a was increased to 4 mol%, a precipitate of the inactive heterochiral species was formed and resulted in a positive nonlinear like effect (Fig.2.1.3.6), while a linear behavior is observed with 5b (Fig. 2.1.3.7). The enantiomeric ratio was found to have linear temperature dependence. [16]... 

Inspired by the recent observation that imines are reduced with Hantzsch esters in the presence of achiral Lewis or Brpnsted acid catalysts (Itoh et al. 2004), we envisioned a catalytic cycle for the reductive amination of ketones which is initiated by protonation of the in situ generated ketimine 10 from a chiral Brdnsted acid catalyst (Scheme 13). The resulting iminium ion pair, which may be stabilized by hydrogen bonding, is chiral and its reaction with the Hantzsch dihydropyridine 11 could give an enantiomerically enriched amine 12 and pyridine 13. 

Iminocoumarins are formed in high yield from the Cu-catalysed multicomponent reaction of salicylaldehyde, alkynes and sulfonyl azides. It is considered that an initially formed ketimine reacts with the salicylaldehyde hydroxy function and an intramolecular nucleophilic addition to the aldehyde moiety completes the sequence (Scheme 29) <06OL4517>. 

Thermal elimination of COj and formation of a perfluorinated ketimine have been found when pentafluorophenyl isocyanate was treated with HFA at 150°C in dimethylformamide (82), in analogy to the reaction with imino sulfoxides (296) mentioned earlier. 

It has also been demonstrated that ketimines may participate in reactions with nitrostyrenes providing fused pyrroles, as shown by the preparation of the system 311. The series of events leading to this outcome were suggested to involve a Michael-type addition of the enamine tautomer of the substrate 312 to the olefin, followed by annulation with concomitant elimination of the nitro functionality (Equation 92) <1999TL4177>. In addition, solid-state reactions of enamine esters or ketones with ( )-l,2-dibenzoylethene induced by milling gave excellent yields of pyrroles <1999AGE2896>. 

The deprotonated aldimine is reprotonated at carbon-4 by reaction with a histamine residue to form the pyridoxamine phosphate ketimine. Hydrolysis of this complex yields the free oxoacid (oxaloacetate), leaving pyridoxamine phosphate at the catalytic site (Ivanov and Karpeisky, 1969). 

Various phenyl-substituted imines react with (26) in a maimer that depends on the substituents present but in all cases, elimination of the aUcyne is observed. The imine PhN=CMePh affords the -complex (35). On the contrary, with the ketimine HN=CPh2, complex (36) is generated by hydrogen transfer. Two molecules ofthe aldimine PhN=CHPh are coupled to give a five-membered diamido complex (37). An unusual reaction with 2-vinylpyridine takes place starting from (26) or (28). Monoazadienes (38) are formed, in which the aromaticity of the pyridine ring has been lost. 

Figure 24.9. Amino Acid Biosynthesis by Transamination. Within a transaminase, the internal aldimine is converted into pyridoxamine phosphate (PMP) by reaction with glutamate. PMP then reacts with an a-ketoacid to generate a ketimine. This intermediate is converted into a quinonoid intermediate, which in turn yields an external aldimine. The aldimine is cleaved to release the newly formed amino acid to complete the cycle.

Whitesell and Whitesell" have tabulated some of the many types of electrophilic reagents that C-al-kylate metallated imines. These are potent nucleophiles and undergo substitution reactions even with weakly electrophilic species such as epoxides and oxetanes. Lithiated ketimines and aldimines have been frequently used in reactions with alkylating agents containing latent 2-keto (or aldehydo) groupsor 3-keto (or aldehydo) groups. ... 

Finally, imidoyl chloride can be transformed into the corresponding ketimines via palladium complex catalyzed cross-coupling reactions with alkynyltins (equation 16). ... 

Asymmetric hydrosilylation of ketimines in the presence of a chiral titanocene difluoride is improved by a nucleophilic additive (e.g., isobutylamine) which serves to release the chiral amine products and thereby generates less hindered amido complexes which are susceptible to reaction with the hydrosilane. ... 

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