Reactions of 3-R-5-nitropyridines with nucleophiles: Nucleophilic substitution vs conjugate addition

Nucleophilic Functionalization of 2-R-3-Nitropyridines as a Versatile Approach to Novel Fluorescent Molecules

“…The possibility of the substitution of the non-activated nitro group in pyridines was studied recently by our group [ 12 ]. In 3-nitro-5-Cl(Br)-pyridines, 3-NO 2 was found to be more nucleofugal than halogen in position 5.…”

“…The introduction of the nitro group into the pyridine ring facilitates its functionalization in different ways. Recently, we investigated reactions of 3-R-5-nitropyridines with various types of nucleophiles [ 12 ]. It was found that in the case of anionic S-, N- and O-nucleophiles, the substitution of the non-activated nitro group occurred while carbon nucleophiles underwent dearomatization of the pyridine ring with the formation of 1,2- or 1,4-addition products.…”

“…It was found that in the case of anionic S-, N- and O-nucleophiles, the substitution of the non-activated nitro group occurred while carbon nucleophiles underwent dearomatization of the pyridine ring with the formation of 1,2- or 1,4-addition products. As a result, a number of novel or hardly accessible pyridines and their dihydro derivatives were synthesized [ 12 ].…”

Synthesis and Facile Dearomatization of Highly Electrophilic Nitroisoxazolo[4,3-b]pyridines

“…At the same time, dearomatization as a method of converting accessible, cheap, and simple aromatic compounds into more saturated, inaccessible and promising intermediates of greater molecular complexity is a very important approach in modern organic chemistry [36,37]. This work is part of our ongoing research on highly electrophilic systems and the application of the dearomatization strategy in the synthesis of new polyfunctional azaheterocycles [38][39][40][41][42][43][44][45][46][47][48]. We have previously shown that nitropyridines fused with π-deficient heterocycles (furoxan A, selenadiazole B), Scheme 1, react with neutral nucleophiles with the formation of 1,4-addition productsdihydropyridine derivatives [45,46,48].…”

Synthesis of 2-Methyl-3-nitropyridines, 2-Styryl-3-nitropyridines and Their Reactions with S-Nucleophiles

“…In our previous work [7] we have shown that 5-substituted 3-nitropyridines readily react with various anionic O,n,S-nucleophiles, so thiolate anions were chosen as model nucleophiles to test reactivity of 2-methylpyridines 1a,c and 2-styrylpyridines 3a-d in SNAr reactions (Figure 3). More reactive 2-methyl-3,5-dinitropyridine 1a reacted with BnSH to give monosubstituted product the same way as 3,5-dinitropyridine, but presence of 2-methyl group brings possibility of 2 different isomers.…”