Formation and Reactions of Nitrogen Derivatives

Two theoretical investigations of the condensation of formaldehyde and methylamine to form A -methylmethanimine (H2C=NMe) have examined the reaction in the gas phase, and also considered the addition of discrete numbers of water molecules. 

Various methods have been employed to quantify solvation-free energies for formation 

The factors involved in the attack of nitrogen nucleophiles on carbonyl compounds, 

Several cyclopropylimines have been synthesized and their reactions with a range of nucleophiles have been investigated. Mild hydrolysis of diimine (16) produces, amongst other products, the /3-ketoimine (17), stabilized by intramolecular hydrogen bonding. 

The binding of pyridoxal 5 -phosphate (vitamin Be) to enzymes has been modelled using homo- and co-polypeptides containing L-lysine as a source of reactive amino groups. This has now been extended to reaction of pyridoxal with polyallylamine, with the polymer acting as a control that cannot provide amido -CO- or -NH- functions to stabilize the Schiff base products, as occurs in enzymes and polypeptides. Rate constants for the formation and hydrolysis of the imines have been measured and interpreted in terms of formation of the carbinolamine (in its neutral or zwitterionic form). 

Propanal reacts with ammonia in acetonitrile to give a hexahydrotriazine (17 R = Et) chloroethanal (17 R = CH2CI) reacts similarly, but in lower yield.24 The reactions proceed via carbinolamines, but increasing chloro substitution (17 R = CHCI2/CCI3) stabilizes the intermediate and disfavours trimerization. hi the case of propanal, forward and reverse rate and equilibrium data are reported, with dehydration of the carbinolamine rate determining. The course of the reactions with some primary amines is also reported. 

A kinetic study of the Schiflf base condensation of m-toluidine with salicylaldehyde has examined the effects of proton, hydroxide, general base, and transition metal catalysts, and also solvent effects.25 

Rates of [l,3]-proton shift isomerization in imines derived from PhCH COCFs have been measured, with electron-withdrawing ring substituents in /V-bcnzylimincs being particularly activating.26 

Semiempirical calculations have been used to calculate kinetic, transition-state, thermodynamic, and physicochemical parameters for acridin-9-amine (18a) and its tautomer, acridin-9( 10//)-iminc (18b).27 

Hydrolysis of Schiff bases derived from benzidine (4,4 -diaminobiphenyl) and from substituted benzaldehydes has been studied in aqueous ethanol 34 attack of water molecules on the protonated substrates is suggested as the rate-determining step. 

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Another class of pyrrole derivative may be obtained by the interaction of l-amino-l-deoxy-2-ketoses or 2-amino-2-deoxyaldoses with a jQ-dicarbonyl compound. Unlike the previous type (which is N-substituted), these pyrrole derivatives have a tetrahydroxybutyl group in the a- or /8-position with respect to the nitrogen atom of the ring, in addition to other groups arising from the dicarbonyl compound used in the condensation. The formation and reactions of this type of pyrrole derivative have been discussed in detail in two articles in this series48,49 they will, therefore, only be treated briefly. 1-Amino-l-deoxy-D-fructose (53) reacts with 2,4-pentanedione to give50 pyrrole derivative 54a similar pyrroles were obtained with ethyl acetoace-tate,50,51 which yields 54b. 

The Beckmann rearrangement is one of the typical reactions of oxime derivatives and the N-substituted nitrilium ion intermediates have been widely exploited as synthetic intermediates for the preparation of nitrogen-containing heterocycles, " while few examples have been reported for the nucleophilic substitution on the sp nitrogen atom of oximes. Even though, in some of them, carbon-nitrogen bond formation is realized, these reactions have not been well generalized as synthetic tools. ... 

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