Amine nitrogen atom

Mattox and Kendall have suggested that loss of bromide from the initially formed hydrazone of the a-halo ketone is facilitated by participation of the electron pair on the amine nitrogen atom. The same group has shown that semicarbazones are often superior to 2,4-dinitro-phenylhydra-zones since they can be obtained in higher yields and undergo cleavage more... 

Classify each of the amine nitrogen atoms in the following substances as primary, secondary, or tertiary ... 

Keywords Facial selection. Orbital phase, Secondary orbital interaction. Orbital unsymmetrization. Ketones, Olefins, Diels-Alder dienophiles, Diels-Alder dienes, Michael acceptor. Amine nitrogen atom... 

While the protonation of an out-nitrogen atom occurs at a rate comparable to the protonation of other amine nitrogen atoms, the protonation of the m-nitrogen atoms is extremely retarded. The activation barriers for the formation of the (j i) [from (ii)] and (i" / ) [from (i O] eonformers are c.ll0kJmol Almost the same value was determined for the deprotonation of to give (i" i). From these rates, the pK values for the... 

When one of the substituents on the amine nitrogen atom is ready to trap a radical formed by treatment of iV-(a-aminoalkyl)benzotriazole with Sml2, cyclization may occur. Such a situation is depicted in Scheme 102. Thus, (4-penten-l-yl)amine derivative 652 is reduced to radical 653 that is then rapidly trapped by the alkenyl group and... 

The structure of [Fe(salten)(4-methyl-pyridine)]BPh4 has been determined at 293 K [194]. The Fe(III) ion is in a pseudo-octahedral environment in which the basal plane is formed by two salicylideneiminate entities (average Fe-0= 1.885 A, Fe-N= 1.987 A) oriented in trans geometry. The two axial positions are occupied by the secondary amine nitrogen atom of the di(3-aminopropyl) moiety of the ligand (Fe-N=2.035(7) A) and the nitrogen... 

The second way of making medazepam consists of the initial reduction of the carbonyl group by lithium aluminum hydride into 7-chloro-5-phenyl-2,3-dihydro-17f-l,4-benzodi-azepin-2-one (5.1.1)—the first intermediate product in the synthesis of diazepam—which is synthesized by the cyclocondensation of 2-amino-5-chlorobenzophenone with glycine ethyl ester into 7-chloro-2,3-dihydro-5-phenyl-17/-l,4-benzodiazepine (5.1.41), and the subsequent methylation of the secondary amine nitrogen atom of the resulting product by methyliodide, using sodium hydride as a base [41,42]. 

Hence, despite the theoretical and solvent-related difficulties outlined above, it may be concluded that any increase in electronic charge at amine nitrogen atoms translates into a downfield chemical shift. 

In this review, acids and bases [8] (benzoic acids, pyridines and 1,10-phenanthrolines) will be discussed as functional groups (light bulbs). They have been incorporated into bimacrocyclic structures by bis-a- or bis-orrlio-substitu-tion of the acids or bases 2,6-disubstituted benzoic acids and pyridines, and 2,9-disubstituted 1,10-phenanthrolines were used. For the construction of the lamp shade , attention had to be paid to the components. They had to be unreactive in order not to interfere with the reactive light bulbs . Therefore, for instance amine nitrogen atoms cannot be used as bridgeheads because they may act as bases. 

In this way, a monster such as 5,a,N-TTBT becomes, quite obviously, a tryptamine with three tert-butyl groups attached, one at the 5-position, one at the alpha-carbon next to the amine, and one on the amine nitrogen atom itself. 

The lone pair of the tertiary amine nitrogen atom (N7) capping the trigonal antiprism is, directed ut the center of a trigonal antipnsmatic face and thus interacts directly with the [Pg.265]

At the same time the bond angles (C—N—C) at the N7 position vary from 112 (-fp3 as expected for an amine ligand) in the manganese complex (where repulsion is least) up to a maximum value of 120 in the iron complex with maximum repulsions. The tertiary amine nitrogen atom (N7) corresponds to a three-ribbed umbrella that has been inverted by the wind (the handle is the lone pair directed at the metal). As the a, and If levels fill, the repulsions increase, the metal-nitrogen distance increases, and the umbrella begins to flatten ... 

A frequently used method for the construction of the 2-amino-2-thiazoline ring (60) involves the reaction between thiourea and 2-bromoethylamine hydrobromide.122-124 If the amine nitrogen atom is... 

Involvement of two nucleophilic nitrogen atoms is thus typical for the amino heterocycles. The mutual disposition of the pyridine and amine nitrogen atoms allows the formation of chelate structures for the cobalt complexes of purine, 221 and 222. Structures with the N, iV -five-membered metal cycles were proven for the tri- and tetranuclear complexes of silver ) with 8-aminoquinoline (223) (92IC4370), and polymeric copper- and rhodium-acetate clusters (224). Another coordination mode can be found in the complexes of 4-amino-3,5-bis(pyridin-2-yl)-l,2,4-triazole, (225 or... 

Figure 7-18. A view of the actual diastereomer of A-[Co(sep)]3+ which is formed from the reaction of A-[Co(en)3]3 with formaldehyde and ammonia. The methylene hydrogen atoms have been omitted for clarity, and the amine nitrogen atoms are shown in black. The cation is oriented in the same way as the A-enantiomer in Fig. 7-17...

Increases in the steric demands of the substituent on the amine nitrogen atom in the series R1 = Me < Et < i-Pr < f-Bu shift the equilibria 63A... 

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