Imine bonds

Keywords Catalyst, Alkylation, Allylation, Arylation, Mannich reaction, Carbon-nitrogen double bond, Imine, Nitrone, Aldimine, Organozinc reagents, Silyl ketene acetal, Silyl enol ether, Amine, (3-Amino acid... 

Few 7r-bonded imine complexes have been prepared and investigated structurally. The only complexes of nonbridging 7r-bonded C=N investigated structurally are a substituted ketenimine complex (XLIV), an iminium complex (XLV), and a complex of the azine [(CF3)2C=N—)2 (XLVI) (see Table I). 

In the covalent approach, the print molecules are covalently coupled to polymerisable molecules prior to polymerisation (see Chapter 4). The covalent bonds have to be relatively easy to break to allow cleavage of the print molecules after polymerisation. Print molecules have been coupled to monomers through the formation of boronic, carboxylic and phosphonic ester bonds, amide bonds, imines and ketals. After copolymerisation with a high degree of cross-linker, the print molecules are cleaved from the polymer. A representative example of the covalent approach is shown in Fig. 17.1. 

IV. Compounds With C=N Double Bond Imines, Oximes, Hydrazones, Semicarbazones, Formazanes, Amidines, and Ketimines... 

IV. COMPOUNDS WITH C = N DOUBLE BOND IMINES, OXIMES,... 

Many types of reactive molecules are well known to medicinal chemists acyl halides, aldehydes, aliphatic esters, aliphatic ketones, alkyl halides, anhydrides, alpha-halocarbonyl compounds, aziridines, 1,2-dicarbonyl compounds, epoxides, halopyrimidines, heteroatom-heteroatom single bonds, imines, Michael acceptors and (l-heterosubstituted carbonyl compounds, perhalo ketones, phosphonate esters, thioesters, sulfonate esters, and sulfonyl halides, to name a few [14]. This is not to say that these functionalities are not useful - some even appear in approved drugs -but all of these can react covalently with proteins, and thus should be regarded with suspicion. However, molecules can react covalently with proteins even if they do not contain functionalities that raise alarm. Jonathan Baell has referred to these as pan assay interference compounds, or PAINS, and has published a list of moieties to watch out for, as well as strategies to detect them [15, 16]. 

Although pyridoxal phosphate is involved in a wide variety of reactions the processes are all related mechanistically by the electron withdrawal toward the cationic or hydrogen-bonded imine nitrogen and into the electron sink of the pyridine/pyridinium ring. 

There slxqFTIR spectra of synthesized samples of individual PAn, nano-TiO -zS and their composites on the Fig. 2. The form of FTIR spectrum 7 in the 400-4000 cm interval and set observed characteristic bands, namely at 3400-2880, 1560, 1470, 1290, 1110 and 793 cm , corresponds to polyaniline [28], In particular, the peak at 3400-2880 cm corresponds to so-called H-band which is a visualization of H-bonding imine- (-NH-) and protonated imine-group (-NH+-) polyaniline macromolecules between itself [46. Two characteristic bands at the 1560 and 1470 cm are connected with vibrations of quinoid and benzenoid rings and they are characteristic features of the polyaniline. Intensive peaks at 1290, 1110 and 793 cm", corresponds to the emeraldine salt and indicated on the high doping degree of PAn [46. ... 

Enantiomerically pure aldehydes 287 were obtained by DIBAL reduction of the corresponding o-alanine methyl esters. Coupling with t-butyl glycinate quantitatively gave the ( )-imines 288 (Scheme 85). Peracid oxidation did not allow the isolation of oxaziridines 289 which spontaneously decomposed to give complex mixtures of products [156]. This was probably due to a deprotonation a to the ester group accompanied by cleavage of the weak N-O bond. Imines 290, derived from aldehydes 287 and P-alanine esters, could be indeed oxidised into stable oxaziridines 291 which were isolated as mixtures of two dia-stereoisomers (Scheme 86) [157]. 

Figure 1 Example of target molecule (L-histidinyl-L-cysteine-amide) containing a variety of functional elements. The molecule may potentially form several noncovalent bonds (hydrogen bonds, ionic interactions, metal coordinations), as well as reversible covalent bonds (imines, disulfides).

A short review examines nucleophilic trifluoromethylation of C=N bonds imines, hydrazones, and nitrones, together with iminium cations and azomethine imines, mainly focusing on the Ruppert-Prakash reagent, TMS-CF3. ... 

Keywords Adaptation Constitutional dynamic chemistry Constitutional networks Dynamic materials Hydrogen bonding Imine formation Supramolecular chemistry... 

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