4-Ethoxy-3-nitropyridine

Methoxy-5-nitropyridine (126) reacts readily with Af,/V-dimethyl-ethylenediamine in boiling water to give 89% of 127 (85EUP136730). Analogously, 4-ethoxy-3-nitropyridine-hydrochloride (128), is heated at reflux for 8.5 hr with an aqueous solution of ammonium acetate to afford 87% of 3-nitro-4-aminopyridine (129) (85EUP149537). 

Diarylmethylation of nitroarenes can be performed efficiently via VNS, using carbanions of benzhydryl aryl sulfides [92]. Similarly, the VNS reaction of 4-ethoxy-3-nitropyridine with carbanion of 9-chlorofluorene results in incorporation of the... 

Alkoxy groups in the 2- or 4-positions of alkoxynitropyiidines are easily replaced by ammonia, alkylamines, or dialkylamines. Thus, 4-methylamino-3-nitropyridine (DC-43) is obtained in near quantitative yield by heating 4-ethoxy-3-nitropyridine hydrochloride in an autoclave with aqueous methyl-... 

Nucleophilic replacement of hydrogen is presumably being observed when reduction of a 3-nitropyridine to a 3-aminopyridine by stannous chloride and concentrated hydrochloric acid is accompanied by nuclear chlorina-tion so, 241a, 772-4, Thus, 4-amino-3-nitropyridine gives 3,4-diamino-2-chloropyridine soa and 4-ethoxy-3-nitropyridine yields 5-amino-2-chloro-4-ethoxypyridine24ia. Clearly, the pyridinium cations must be involved. 

C7H7N04 2-methoxy-5-nitrophenoi 636-93-1 25.00 1.3375 2 10828 C7H8N203 3-ethoxy-2-nitropyridine 74037-50-6 20.00 1 2089 2... 

Very mobile nitro groups can be replaced directly by chlorine or bromine, a reaction that has preparative importance for bromo- and chloro-pyridine and -quinoline derivatives. 5-Ethoxy-2-nitropyridine gives 2-bromo-5-ethoxy-pyridine when heated with HBr in glacial acetic acid in a sealed tube for 3 hours at 130°,1260 and 2-bromo-3-ethoxypyridine is obtained from the corresponding nitro compound and boiling 48% HBr.1261 It is particularly easy to introduce Cl or Br in place of a 4-nitro group in pyridine 1-oxide or quino-... 

Examples are known of the conversion of 2-nitropyridines into 2-halogeno-pyridines by reaction with halogen hydracids 185, 240, 847 Thus, 3-ethoxy-2-nitropyridine with hydrobromic in acetic acid gives 2-bromo-3-ethoxy- or 2-bromo-3-hydroxy-pyridine, according to conditions, whilst... 

Alkaline cleavages are rare. 3-Ethoxy-6-nitropyridine is very sensitive to alkali , but the result of the reaction is obscured by decomposition. What is happening in the conversion of 5-methoxy-l,2-dimethyl-4-pyridone into 5-hydroxy-l,2-dimethylpyrid-4-one by sodium and amyl alcohol i is not clear. 

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