3- Methyl-4-nitropyridine N-oxide

POM (3-methyl-4-nitropyridine-N-oxide) 53) is the only commercially available organic crystal for SHG, other... 

Methyl-4-nitropyridine N-oxide, 2310 A-Methyl-A-nitrosourea, 0871 Methylnitrothiophene, 1844... 

Hypervalent Cl Sn—Cl bridges are also typical for pentacoordinate tin atoms. For example, the crystal structure of 20 and 21 comprise dimeric pairs of molecules bridged by weak intermolecular Cl Sn interactions. The Cl —Sn distances in 20 (2.475 A ), 21 (average 3.869 A ) and in MeSn(Ar)Cl2 (Ar = 3-methyl-4-nitropyridine-N-oxide) (3.934 A ) are longer than in most comparable structures The Sn NMR resonance (—285.7 ppm) for 21 suggests that it possesses a five-coordinate structure in solution . 

Methyl-4-nitropyridine AAoxide, 2310 N-Methylmorpholine oxide, 1991 iV-Methylpiperidine —N /i-oxide, 2522... 

Halo-4-nitropyridines and their A -oxides react at the C-nitro group when treated with bases or alkoxides to give XII-357 or MI-358 (X = Cl, Br, I). However, 3-fluoro-4-nitropyTidine and its 1-oxide form 4-nitro-3-pyridinols and 4-nitro-3-alkoxypyridines, respectivelyThe 3-alkoxy-4-nitropyridine-l-oxides have been converted to 3,4-dialkoxypyridine-l-oxides. Because of this marked reactivity of the 3-fluoro substituent, these studies have been extended to 3-fluoro-5-methyl-4-nitropyridine-l-oxide, 3-fluoro-2-methyl-4-nitropyri-dine-l-oxide, and 2,6-dimethyl-3-fluoro-4-nitropyridine-l-oxide. Several of these fluoronitropyridines have been extensively studied as potential reagents for formation of amino acid derivatives. 2-Fluoro-3,5-dinitropyridine, a typical example, is hydrolyzed by hot water and reacts with hot alcohols to form 2-alkoxy-3,5-dinitropyridines and reacts with amino acids and their derivatives to give well-defined products. The reactions of a number of fluoronitropyridines and their N-oxides have been summarized by Talik and Talik and the relative reactivities toward simple nucleophiles have been observed, as shown on p. 689. 

Tile same methodology as mentioned for the preparation of (9) was applied for the synthesis of 8-nitro-l,6-naphthyridines. Heating diethyl N- 3-nitropyridin-4-yl)aminomethylenemalonate (12) in diphenyl ether yields ethyl 8-nitro-l,6-naphthyridin-4(lH)-one 3-carboxylate (13) (63JCS4237, 30%) and acid treatment of 4-( y, y-diethoxypropylamino)-5-nitro-2-(/3,/3 -trifluoroethoxy)-pyridine (14) gives in a similar way 8-nitro-5-(/3, /3-triflu-oroethoxy)-l,2-dihydro-l,6-naphthyridine (15, 76%). Subsequent oxidation with chloranil, acid hydrolysis, and methylation with methyl iodide gives 8-nitro-6-methyl-l,6-naphthyridin-5(6H)-one (16,63%) (81JHC941). 

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