Azanaphthalene

Little is known quantitatively about substituent effects in the nitration of derivatives of azanaphthalenes. In preparative experiments 4-hydroxy-quinoline, -cinnoline, and -quinazoline give the 6- and 8-nitro compounds, but with nitric acid alone 4-hydroxyquinoline and 2,4-di-hydroxyquinoline react at With nitric acid, 4-hydroxycinnoline... 

Benzimidazole (viii) and indazole (ix) differ from the azanaphthalenes in being nitrated at the / -position [C(g)] of the carbocyclic ring. ... 

In the [3,2-c ] series the spectra of the parent compound and some closely related analogues have been compared with those predicted from MO calculations of electron densities. The results confirm the predicted occiurence of a considerable degree of bond localization in these compounds <80KGS54l), as was previously found in their deaza (cinnoline) analogues <67JCS(B)1243). Other comparisons of NMR values with those expected from MO calculations for a series of azanaphthalenes have included some results with pyridopyridazines <75MI21500). 

MO calculations of electronic spectra have been performed and compared with observed values in the [2,3-d] and [3,4-d] systems (69MI21502). Good agreement was observed, as it was in a wider study of such calculations in a large series of azanaphthalenes, including several pyridopyridazines (66JSP(19)25). 

Apart from the general study by Wait and Wesley on azanaphthalenes, including most of the pyridopyridazines (66JSP(19)25), more specialized studies have attempted to relate charge density calculations to various chemical and physical properties, with greater success in the latter case. 

The pyridopyrimidines discussed in this review are derived by the ortho fusion of the pyridine and pyrimidine rings through ring carbon atoms. There are four such compounds for which the nomenclature and numbering of Chemical Abstracts (1-4) will be used. Alternative names used in the literature are 1,3,8-triazanaphthalene (1), 1,3,5-tri-azanaphthalene (2), 1,3,7-triazanaphthalene or copazoline (3), and 1,3,6-triazanaphthalene (4). There has been no previous review of the... 

Following these discoveries, we have made an extensive exj)eri-mental study of covalent hydration and find it is very common, not only in the pteridine series but also in several simpler families of poly-azanaphthalenes. The methods used to diagnose this phenomenon, its... 

The information on intranuclear and irdemuclear activations in bieyelie azines and nitronaphthalenes is summarized here. In the transition states for azanaphthalenes and their nitronaphthyl analogs illustrated in Sehemes II-IV, the leaving group position is kept eonstant in each comparison and it is assigned either the 2- or the 4-position only, for reasons diseussed under the aetivation-numbering system later in this subseetion. 

Scheme II. Intemuclear Activation in 2-Substituted (Le) 5-, 6-, 7-, and 8- Azanaphthalenes and in the Nitronaphthalene Analogs...

Scheme V. Predicted Reactivity in Azanaphthalenes (Using the Activation-Numbering System)...

The terms intranuclear and internuclear refer to activation within the same ring and from the adjoining ring, respectively they are preferable to homonuclear and heteronuclear which are vmambiguous when applied to naphthalenes598 but not when applied to azanaphthalenes.599... 

Aspirin, a56 Azabenzene, p257 Azacyclopentane, p280 Azacyclopropane, el46 1-Azanaphthalene, q3 Azelaic acid, n93... 

Our next step was to assess whether the methodology used to calculate hydration free energy differences for simple carbonyl-containing compounds9 was suitable for heteroaromatic bases. Since our drug design strategy entailed analysis of purine riboside hydration, a series of azanaphthalenes was initially selected for analysis in part because of their structural similarity to purines and in part because of the extensive... 

Stevens et al. (58JCS3067) found that when quinolizinium iodide was treated with silver oxide, or when it was warmed with ION NaOH, there was no evidence of the C-hydroxyla-tion (pseudobase formation) that is characteristic of the methiodides of the azanaphthalenes. Their suggestion that this resistance of the quinolizinium ion is understandable, in that C-hydroxylation would destroy the aromaticity of both rings, is probably correct. 

The second approach for endocyclic N-PACs is to use replacement nomenclature, in which the term aza is a prefix to the corresponding PAH. The position of the N-atom in the fused-ring system of the PAH precedes the term aza. Thus, for example, quinoline is 1-azanaphthalene. We generally use this convention for three or more ring N-PACs with endocyclic nitrogen heteroatoms. 

The chemistry of the quinoline heterocycle has already been discussed in Chapter 4. Any alkaloid that possesses a quinoline, i.e. 1-azanaphthalene, 1-benzazine, or benzo[b]pyridine, skeleton is known as a quinoline alkaloid, e.g. quinine. Quinoline itself is a colourless hygroscopic liquid with strong odour, and slightly soluble in water, but readily miscible with organic solvents. Quinoline is toxic. Short term exposure to the vapour of quinoline causes irritation of the nose, eyes, and throat, dizziness and nausea. It may also cause liver damage. 

The CD signs of the ICD of P-CDx complexes with mono-, di-, and triazanaphthal-enes in aqueous solutions depend on the polarization directions of these azanaphthal-enes. The polarization assignments come from the CNDO/S-CI calculation 165) coupled with the MCD data of these azanaphthalenes 165). In the first place, the origin of the coordinates was choosen in the center of a ring of P-CDx that is assumed to have a 7-fold symmetry axis. Next, ep which is put at the origin of the p-CDx-fixed Cartesian coordinates, is expressed by the spherical polar coordinates (Fig. 23). 

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