N-Amination

3-Methyl- and 6-methoxy-3-methylpyridazine are aminated at N-2, while 3-methoxy-pyridazine reacts at N-1. 

Few examples of N-amination of azines have been reported. The use of such reagents as 0-mesitylenesulfonylhydroxylamine has led to the direct synthesis of /V-aminopyridazinium, -pyrimidinium, and -pyrazinium salts (80CPB2676), and 1-aminobarbituric acids (72CPB1814), while 0-(2,4-dinitrophenyl)hydroxylamine was a useful amino-transfer reagent in the direct synthesis of 1 -amino-6-methylthio-1,2,4-triazin-4( 17/)-ones from 2-methylthio-1,2,4-triazin-5( 1H)-ones (82JHC1583). 

The N-amination of 3-aminopyridazines occurs next to the amino function (75JHC107 81T1787), while 3-methylpyridazine and its 6-methoxy derivative followed the trend of N-alkylation being aminated at N-2 (72CPB1814). 3-Methoxypyridazine gave the 1-amino salt as expected (71CPB2106). 

Eichenberger, A. Staehelin, and J. Druey, Helv. Chim. Acta 37,837 (1954). 

Nishizawa, Chem. Pharm. Bull. 8, 1021 

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The functional group ia collectors for nonsulfide minerals is characterized by the presence of either a N (amines) or an O (carboxyUc acids, sulfonates, etc) as the donor atoms. In addition to these, straight hydrocarbons, such as fuel oil, diesel, kerosene, etc, are also used extensively either as auxiUary or secondary collectors, or as primary collectors for coal and molybdenite flotation. The chain length of the hydrocarbon group is generally short (2—8 C) for the sulfide collectors, and long (10—20 C) for nonsulfide collectors, because sulfides are generally more hydrophobic than most nonsulfide minerals (10). 

N-Amination of indazole affords a mixture of 60% (271) and 40% (272), which compares with the 55 45 ratio obtained in methylation (Section 4.04.2.1.3(viii)). A camphopyrazole derivative (a mixture of tautomers 275 and 276) when treated with hydroxylamine O-sulfonic acid yields exclusively the (4S,7i )-4,7-methano-2-amino-7,8,8-trimethyl-4,5,6,7-tetrahydro-2H-indazole (277) (79YZ699). 

Hydroxylamine-O-sulfonic acid for N-amination of pyridine, 43, 1 Hydroxylation of indene, 41, 53 2-Hydroxy-3-methylbenzoic add, oxidation to 2-hydroxyisophthalic acid by lead dioxide, 40, 48 Rydroxymethyleerrocene. 40, 52... 

Pyrido[l,2-3][l,2,4]triazinium salts 132 could be obtained from 131 with benzil either in the presence of TEA <2001CPH(266)77> or sulfuric acid <2003ARK155> (for example, diaminopyridines 131 are generally available from 2-aminopyridines 120 via N-amination with tosyl hydroxylamine (Scheme 14) <2003ARK155>). 

The N-6 atom of the pyrimido[l,6,5- 0 ][l,4]benzoxazine 312 has been N-aminated with NH2OH <2001W02001/ 053273>. 

A novel natural product has been isolated from the Micronesian sponge Dysidea herbacea. This material is the zwitterionic pyrroloimidazopyridine 293 and is claimed to be the first example of a simple peptide with an N,N-aminal linkage <2004JOC1180>. 

Sharif, A.K.M., A.I. Mustafa, M.N. Amin, and S. Safiullah. 1993. Trace element concentrations in tropical marine fish from the Bay of Bengal. Sci. Total Environ. 138 223-234. 

N-Amination of amines by hydroxyl-amine-O-sulfonic add, 43, 1 p-Aminoacetanilide, oxidation to 4,4 -diaminoazobenzene, 40, 18 2-Amino-5-bromo-3-nitropyridine, 44,... 

An alternative route to furyl compounds of similar structure was reported by Yao et al. <2005BML511> the same starting amine 409 was N-aminated to the 1,2-diaminopyrazinium mesylate 412, which was ring-closed by treatment with furylaldehyde to yield 413 in rather poor yield. The synthesis of the pyrrolidinylcarbonyl derivative 415 in a cyclocondensation reaction of 414 by use of polyphosphoric acid was reported by Giardina et al. <1995FA405>. 

N(amine)/Co ratio which decreases from 2.7 to 0.7 as the solution pH is increased from 4 to 10. The N(amine)/Co ratio represents an upper limit for ammonia coordinated to cobalt Ill) for the adsorbed complex, since it is likely that ammonia coordinated to cobalt Ill) and ammonia sorbed on Na-birnessite would have very similar N Is binding energies, and thus, could not be easily distinguished. The greater surface concentration of protonated amine compared to non-protonated amine at low pHs indicates that the solution pH plays a role in determining the extent of ammonia protonation. However,... 

The XPS results for cobalt at pH 4, particularly the Co 2p splitting (15 eV) and the absence of shake-up satellite structure, are indicative of cobalt(III). However, the N(amine)/Co atomic ratio of 2.7 indicates that some ammonia ligands have been displaced. Since it is known (22) that hydrolysis rates for cobalt(III) complexes are very slow, the presence of cobalt with a low number of coordinated amines, suggests that hydrolysis is induced via an interaction with the birnessite surface. The cobalt to manganese ratios for bulk and surface measurements are equivalent within experimental error, a result which is consistent with a reaction process occurring primarily at the surface. It is... 

XPS results are very similar. The Co 2p splitting values 15.5 0.1 eV are equal within experimental error, the N(amine)/Co atomic ratios are 1.7 and 1.3, respectively, and the individual Co/Mn surface and bulk ratios are approximately equal at each pH. This latter result indicates that the sorption process occurs predominately on the surface at pH 6 and 7. The Co 2p splitting results are intermediate between values measured for Co(III) and Co(II)-containing compounds. To account for the Co 2p splitting result, a cobalt material with such an intermediate splitting or a mixture of the two cobalt oxidation states must be present. A survey of representative cobalt-containing materials (19,24,26) reveals that Co 2p splittings at about 15.5 eV are not common. 

Figure 26 X-Ray structure of complex [MnL]. Average bond lengths Mn-N(amidej = 1.95 A Mn-N(amine) = 2.04 A Mn-0 = 1.84 A...

Ni" forms square-planar bis-complexes with the amidate anions of L-Val, L-Phe, and L-Pro. The structure of bis(Gly)-bis(imidazole)nickel(ii) has been reported and the configuration around the metal atom is cis-O(carboxyl), cis-N(amine), cis-N(imidazole). Tetra- and penta-peptide complexes of nickel(ii) consume oxygen in neutral solutions as the metal ion catalyses peptide oxidation to give a number of products, including amides of amino-acids and peptides, oxo-acids, and C02- ... 

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