Azanone

An isomeric mixture of the pyridotriazine derivatives 129 and 130 was obtained in the reaction of 2-aminopyridine with perfluoro-5-azanon-4-ene 128 in the presence of triethylamine in acetonitrile. Compounds 129 and 130 were isolated in 40% and 13% yield, respectively, beside some side products (Equation 16) <2000JFC(103)105>. 

Interaction of iV-pentafluorophenylcarbonimidoyl dichloride with benzonitrile and aluminium trichloride leads to l-pentafluorophenyl-4,6-diphenyl-13 -triazin-2-one along with urea derivatives . Reaction of perfluoro-5-azanon-4-ene with a range of bidentate nitrogen nucleophiles (urea, substituted amidine hydrochlorides and guanidine), in the presence of triethylamine or potassium hydroxide, effectively provides fluorinated 1,3,5-triazines 16-19 <00JFC(103)105>. 

In this case, however, 1-isopropyl-4,4-difluoro-2-hexafluoroethyl-3-tri-fluoromethyl-li/-azetine is formed, which points to a direct reaction of olefin 1 with isopropylamine. This suggests that steric factors play a definite role in this reaction. Indeed, the interaction between olefin 1 and ethylamine is the second route of this reaction. If, however, no isomerization of perfluorolefin takes place under the action of the starting alkylamine, or if a symmetrically substituted structure is formed, then only one heterocyclic compound is obtained. This is realized for perfluoro-5-azanon-4-ene. Irrespective of the character of the nucleophilic reagent, diazete derivative 20 is produced. 

The interaction between perfluoro-5-azanon-4-ene and arylhydrazines in the presence of triethylamine in tetrahydrofuran under very mild conditions forms 1 -aryl-3,5-bis(heptafluoropropyl)-1 H-[ 1.2.4]triazoles (01ZOR1693, 01IZY457). 

When hydrazine hydrate reacts with perfluoro-5-azanon-4-ene in acetic acid, the product of cyclization is triazole[1.3.4] 69 (yield 42%) (01ZOR1693). For thermodynamic reasons, the formation of the triazole ring is preferable to the formation of the [1.2.4]triazole derivative. 

Thus reactions of perfluoro-2-methylpent-2-ene and perfluoro-5-azanon-4-ene with urea in the presence of triethylamine in dipolar aprotic solvents (MeCN, DMF) form 6-fluoro-4-pentafluoroethyl-5-trifluoro-methyl-l//-pyrimidin-2-one 93 and an s-triazine derivative, respectively (00JFC(103)105, 80/82JAP(K)85377). 

It was established (01IZV457) that the products of the reaction of per-fluoro-2-methylpent-2-ene and perfluoro-5-azanon-4-ene with guanidine hydrochloride in the presence of triethylamine are 4-fluoro-6-pentafluoro-ethyl-5-trifhioromethyl-pyrimidin-2-ylamine 101, whose structure was confirmed by X-ray analysis (Fig. 4) and compound 102, respectively. 

Note that in the case of the reaction of guanidine hydrochloride with perfluoro-5-azanon-4-ene one obtains a mixture of products 102 and 103. Compound 103 is the product of further reaction of perfluoro-5-azanon-4-ene with 102. It may be assumed that 103 is formed according to the following scheme ... 

The interaction of perfluoro-5-azanon-4-ene with amidines and 2-amino-benzimidazole occurs with formation of a six-membered heterocycle, giving 2,4-bis(heptafluoropropyl)-6-phenyl-[l,3,5]triazine, 2,4-bis(hep-tafhioropropyl)-6-methyl-[l,3,5]triazine, and a tricyclic compound—2,4-bis(heptafhioropropyl)benz-[4,5]imidazo[l,2-tf][l,3,5]triazine (01IZY457). 

It was shown (00JFC( 104)263) that perfluoro-2-methylpent-2-ene and perfluoro-5-azanon-4-ene smoothly react with two moles of aniline, 4-fluoroaniline, and 4-methoxyaniline in the presence of three moles of Et3N in acetonitrile, forming derivatives of quinoline and quinazoline. 

In the reaction of perfluoro-5-azanon-4-ene with 2,6-dimethylaniline, the attack at the carbon atom of the new N=C bond forms a six-membered heterocycle derived from dihydroquinazoline (00JFC(104)263). If the 2,6-positions of the benzene ring of aniline contain electron-donor substituents... 

Me, MeO), then cyclization by the C-anion center is possible. Thus the reactions of perfluoro-2-methylpent-2-ene and perfluro-5-azanon-4-ene with 2,6-dimethylaniline form dihydroquinoline and dihydroquinazoline derivatives, respectively. 

Seven-membered heterocycles 138-140 are formed when perfluoro-5-azanon-4-ene reacts with monoethanol derivatives and ethylenediamine. 

Reaction of perfluoro-5-azanon-4-ene with the amino alcohols 296 in the presence of base affords a convenient route to the oxadiazepine derivatives 297a,b [01JFC11]. 

The reaction of 1 with perfluoro(5-azanon-4-ene) leads, depending on the reaction temperature, to f)erfluoro(3-propyl-4-azaocla-2,4-dicnc) (4) or perfluoro(4-ethyl-5-azanona-3.5-diene) (5). The transfer of the trifluorovinyl fragment to the azamethine molecule presumably results in the initial formation of the products of allyl and vinyl fluorine substitution. ... 

Thus, reaction of the silane, in the presence of cesium fluoride in acetonitrile, with per-fluoro(3-azapent-2-ene) and perfluoro(5-azanon-4-ene) gave phenylazaalkenes 9. 

Azanone Detection with Metalloporphyrins and Heme Proteins 129... 

A. Colorimetric Detection of Azanone with Manganese Porphyrins 129... 

B. Electrochemical Detection of Azanone with a Cobalt Porphyrin 131... 

Keywords HNO NO Nitroxyl Azanone Nitroxyl anion Nitrosyl Porphyrin Heme Iron Manganese Ruthenium Cobalt Reductive nitrosylation Kinetics Oxidation Protein Myoglobin NOS. 

Azanone (HNO), also called nitroxyl (1), is a highly reactive compound. Although nowadays it is accepted that singlet HNO is the most stable form, triplet NOH is also a viable molecule, and both have been observed. The energy gap between these species is estimated to be relatively low, around 20kcalmol (2-4). 

Another endogenous suggested soimce of azanone stems from the reduction of NO to HNO by Mn or Fe superoxide dismutases (25) or by xanthine oxidase O) (22). Although both tsq>es of enzymes have been reported as capable of HNO production, the corresponding works relied on indirect methods for HNO detection which are sometimes difficult to interpret or imreliable. 

HNO and NO are, as will be shown in next chapters, very reactive molecules. One of the key reactions is the reaction of HNO with itself (i.e., dimerization) to yield hyponitrous acid (H2N2O2) at nearly diffiisional rate, which decomposes to water and N2O. Therefore, nitroxyl solutions are not stable and HNO, if not produced continuously, readily disappears. Also, HNO cannot be isolated in the sohd state, NO is even more imstable, and its reactivity is less understood. To overcome these problems, working with HNO (or NO ) has always rehed on the use of azanone... 

Rate Constants and Reduction Potentials foe Reactions of Azanone, Azanone Anion, and Nitric Oxide with Biologically Relevant Small Molecules... 

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