Side-chain prototropic tautomerism of 4-hydroxyfuroxans in methylation reactions

Nitro-, Cyano-, and Methylfuroxans, and Their Bis-Derivatives: From Green Primary to Melt-Cast Explosives

“…For the synthesis of 3-nitrofuroxans, we used our recently developed approach based on the cascade one-pot reactions of aldoximes. This approach includes the chlorination of initial aldoximes, the acylation of intermediate chloroximes with a dinitromethane sodium salt with a subsequent nitrosation of dinitromethyl derivatives, and in situ intramolecular cyclization [ 38 , 39 , 40 ]. 3-Nitrofuroxans 2 , 4 – 7 were obtained in high yields in one synthetic step and did not require additional purification ( Scheme 2 ).…”

“…3-Nitrofuroxans 2, 4-7 were obtained in high yields in one synthetic step and did not require additional purification (Scheme 2). The isomerization of the corresponding 3-nitrofuroxans afforded 4-nitro isomers 8 and 9 in quantitative yields [39,41]. The compound 8 was additionally nitrated to afford a dinitrophenyl derivative 10 in a yield of 91% (Chart 3).…”

“…3-Methylfuroxan 15 was prepared via nucleophilic substitution of the nitro group in compound 1 by hydride-anion under the action of NaBH4 [46]. The oxidative N-N coupling of aminofuroxans The isomerization of the corresponding 3-nitrofuroxans afforded 4-nitro isomers 8 and 9 in quantitative yields [39,41]. The compound 8 was additionally nitrated to afford a dinitrophenyl derivative 10 in a yield of 91% (Figure 3).…”

Five-Membered Hetarene N-Oxides: Recent Advances in Synthesis and Reactivity

“…However, in some cases, this electronic feature may be advantageous to access structurally diverse libraries of furoxan derivatives. For example, the nitro group in 4-nitrofuroxans 42 can be easily substituted by various C-, 43 S-, 44 and O-nucleophiles 45 under rather mild conditions. Also using this approach, a series of 4fluorofuroxans 43 was prepared in good to high yields (Scheme 15).…”

Lewis acid-catalyzed Wolff cyclocondensation in the synthesis of (1H-1,2,3-triazolyl)furoxans

“…[13][14][15][16][17][18][19] Our last developments resulted in new, effective one-pot approaches for the synthesis of a series of hybrid heterocyclic systems incorporating furoxan ring connected with various pharmacophoric and/or energy rich poly-nitrogen (nitrogen-oxygen) heterocycles (isomeric 1,2,3-and 1,2,4-triazoles, 1,2,4-and 1,3,4-oxadiazoles, tetrazole, pyridines, tetrahydroisoquinoline, indenopyridine, etc.). [20][21][22][23][24][25][26][27][28] Among synthesized compounds (1,2,3-triazol-1-yl)furoxan derivatives 1 attract special attention due to a wide variety of their pharmacological activity. The 1,2,3-triazole nucleus is found in a large number of compounds with agrochemical and pharmaceutical uses, 29 shows anti-HIV, 30 antimicrobial, 31 antibacterial, 32 and antitumor 33 properties and has also found many applications in chemical industries.…”