Bearings Nitrogen

There are only few reactions known introducing substituents to the H-bearing nitrogen of oxaziridines. (V-Alkylation of l-oxa-2-azaspiro[2.5]octane (3,3-pentamethylene-oxaziridine 52) with r-butyl chloride to give (53) was carried out for structure proof of (52). This reaction is of no preparative importance, since N-alkylated oxaziridines are easily obtained by ring synthesis. 

This chapter embraces quinoxalines bearing nitrogenous substituents that are joined to the quinoxaline nucleus through their nitrogen atom. However, isocyano-, isocyanato-, and isothiocyanatoquinoxalines will be found in Chapter 7 to ensure that they are adjacent to quinoxalinecarbonitriles. 

Table 5 Tetra- and penta-coordinate double-bond compounds between heavier group 14 and 16 elements bearing nitrogen substituents...

Metathesis of enyne 115 bearing nitrogen or oxygen on alkyne smoothly proceeded to give cyclized compound 116 having an enamide or an enol ether moiety in the molecule. These compounds can be converted into various functionalized compounds ... 

Anodic oxidation of organosilicon compounds bearing heteroatoms and its synthetic applications have been studied intensively. The oxidation potentials of organosilicon compounds bearing nitrogen, sulfur and phosphorus atoms at the a-, ji- and /-positions were shown in Table 512-21-23. it should be noted that the silyl group a to the heteroatom decreases appreciably the oxidation potential. 

This chapter covers 1,5-naphthyridines bearing nitrogenous substituents that are joined to the nucleus through their nitrogen atoms. 

This chapter covers pyrazines bearing nitrogenous substituents that are joined directly or indirectly to the nucleus through their nitrogen atom exceptionally, any isocyanato- or isothiocyanatopyrazines are relegated to Chapter 8 in order to be close to pyrazinecarbonitriles and the like. 

The importance of the electronic effect is most evident in pyridine systems bearing nitrogen at the 2 and 4 positions, which activate the rearrangement by protonation, as exemplified by 0-2-pyridyl thiocarbamate (Scheme 8) [6]. The activation is such that the reaction occurs at room temperature. In contrast, where nitrogen is at the 3 position the temperature at which rearrangement occurs is lowered by 60 °C, from 210 to 150 °C in the case of phenyl. 

In the course of our studies on organic and macromolecular syntheses with lanthanoid alkoxide, we have foimd that a lanthanoid complex, formed by the addition of a lanthanoid isopropoxide (LnlUPrla) to a heterocumulene bearing nitrogen atom (R-N=C=X isocyanates and carbodiimides), served as a novel COj carrier for the rapid carboxylation of active methylene compounds (Y-CHj-Z) under mild conditions such as room temperatxue and atmospheric pressure (Scheme 1). 

Two-electron oxidation of the NH-group of a diaziridine results in ring opening opposite to the H-bearing nitrogen and formation of 129, which... 

Conversion of 2-aroylquinoxaline into its phenylhydrazone and heating this in ethanolic hydrogen chloride results in annulation of the phenyl-bearing nitrogen to a ring-carbon. 

Figure 3. Phylogenetic comparison of proportion of marine-invertebrate derived substances which bear nitrogen reported during the period 1977 to 1992 (3-12).

Optically active salicylaldimine coppcr(II) complexes bearing nitrogen ligands with den-drimeric structure can also be used as cyclopropanation catalysts122. However, the enantiose-lectivities in the reaction of ethyl diazoacetate with phenylethene does not exceed 51 % ee. The same transformation is promoted with up to 62% ee when an optically active copper(I) tctrakis(campherpyrazolyl)borate complex is employed as catalyst123. 

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