Direct di- and triamination of polyfluoropyridines in anhydrous ammonia

Kusov, Soltan Z.; Rodionov, Vladimir; Vaganova, T. A.; Shundrina, Inna K.; Malykhin, E. V.

doi:10.1016/j.jfluchem.2009.02.005

Cited by 23 publications

(8 citation statements)

References 24 publications

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“…9 At room temperature or mild warming (50 °C), pyridine 7 readily reacted with ammonia, dimethylamine, and hydrazine to afford the corresponding 4-amino, 4-dimethylamino, and 4-hydrazino derivatives in 85-86% yield. 9,10 This literature data suggested that triazidation of pyridine 7 might be a more difficult task than triazidation of fluoropyridines 1b and 1h. The reaction of trifluoropyridine 7 or 8 with excess sodium azide was carried out in dimethyl sulfoxide at room temperature for 10 hours.…”

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confidence: 99%

Synthesis of 2,4,6-Triazidopyridine and Its 3,5-Diiodo Derivative

Чапышев

Chernyak

2012

Synthesis

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2,4,6-Trifluoropyridine was diiodinated with a mixture of potassium iodide and periodic acid in sulfuric acid at 55 °C to give 2,4,6-trifluoro-3,5-diiodopyridine in 85% yield. Both the starting trifluoropyridine and its 3,5-diiodo derivative readily react with excess sodium azide in dimethyl sulfoxide at room temperature to afford 2,4,6-triazidopyridine and 2,4,6-triazido-3,5-diiodopyridine in high yields. In the 15 N NMR spectra of the triazides, the N α atoms of the α-and γ-azido groups show very differing chemical shifts, which indicates the different reactivity of these groups in 1,3-dipolar cycloaddition, phosphorylation, reduction, thermolysis, and photolysis reactions.2,4,6-Triazidopyridines are widely used as starting compounds in organic synthesis 1 and for the photochemical preparation of high-spin nitrenes. 2 In addition, some triazides are of interest as primary explosive materials and as precursors of nitrogen-rich carbon nanomaterials. 3 2,4,6-Triazido-3,5-dibromopyridine (2a) was the first representative of this class of compounds, obtained by triazidation of pentabromopyridine (1a) with sodium azide in dimethyl sulfoxide at room temperature in 86% yield. 4 Later, triazides 2b-h were synthesized by triazidation of the corresponding perhalogenated pyridines 1b-h, using similar protocols (Scheme 1). 5 Owing to the nonequivalence of the azido groups, such triazides underwent selective 1,3-dipolar cycloaddition, reduction, phosphorylation, thermolysis, and photolysis reactions to form, for example, compounds 3-6 (Scheme 2). 1 On the other hand, the photolysis of triazides 2b-d in cryogenic matrices gave the corresponding septet 2,4,6-trinitrenopyridines that were of considerable interest as models for organic molecular magnets. 2 Amongst the variations in substitution of pyridines 2a-j (Scheme 1), only triazides 2i and 2j remained unexplored. Both these triazides were considered as the most interesting model systems for photochemical studies.Triazides 2i and 2j were synthesized from commercially available 2,4,6-trifluoropyridine (7) (Scheme 3). It was reported that boiling pyridine 7 in a mixture of iodine and fuming nitric acid for 12 hours affords 3,5-diiodopyridine 8 in 55% yield. 6 However, the spectroscopic characteristics of compound 8 were not reported. Nowadays, iodination of strongly electron-deficient arenes is usually conducted using a mixture of potassium iodide, sulfuric acid, and a strong oxidative agent such as HIO 4 or H 5 IO 6 . 7 Thus, for example, diiodination of 1,3,5-trifluoro-2-nitrobenzene with mixture of potassium iodide, sulfuric acid, and periodic acid at 50 °C for 3.5 hours gave 1,3,5-trifluoro-4,6-diiodo-2-nitrobenzene in 89% yield. 8 Using a similar approach, we synthesized 3,5-diiodopyridine 8 from pyridine 7 in 85% yield. Compound 8 was obtained as a white solid with mp 79 °C. Its 13 C NMR spectrum displays characteristic signals at δ = 172.3, 163.0, and 60.6, corresponding to the carbon atoms in the α-, γ-, and β-positions of the pyridine ring, respectively. In the 19 F ...

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confidence: 99%

Synthesis of 2,4,6-Triazidopyridine and Its 3,5-Diiodo Derivative

Чапышев

Chernyak

2012

Synthesis

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“…Figure 1 depicts schematically the various amination reactions examined (as previously noted, the majority from the Malykhin group [7][8][9][10]). Since all of the reactions are aminations, we have made an important modification to our standard calculational approach: instead of using the fluoride ion as a generic attacking nucleophile we specifically use NH 2 − .…”

Section: Resultsmentioning

confidence: 97%

“…This use of liquid ammonia has been pioneered primarily by the Malykhin group at Novosibirsk State University in Russia. They have published a number of papers from 2007 onwards involving amination of polyfluorinated benzenes and pyridines [7,8], perfluorobiphenyl [7], perfluoronaphthalene [9] and tetrafluorophthalic acid [10]. Additionally, Page and coworkers have found that liquid ammonia aminates 1-nitro-2,4-difluorobenzene dominantly in the 2-position [11].…”

Section: Open Accessmentioning

confidence: 99%

Further Successes of the Meisenheimer Model

Baker

Muir

2012

Applied Sciences

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“…Polyhalogenated aminopyridines 1-5 and hydroxypyridine 6 were synthesized and purified using the procedures described in ref. [26][27][28] and references therein. The spectra and melting points of all compounds agreed with the published data: 4-aminotetrafluoropyridine (1), mp 84-85 1C, 26 4-amino-3-chloro-2,5,6-trifluoropyridine (2), mp 118-120 1C, 27 4-amino-3,5-dichloro-2,6-difluoropyridine (3), mp 113-114 1C, 26 2-amino-3,5,6-trifluoropyridine (4), mp 98-99 1C, 26 2-amino-4-chloro-3,5,6-trifluoropyridine (5), mp 124-126 1C, 26 4-hydroxy-2,3,5,6-tetrafluoropyridine (6), mp 95-97 1C.…”

Section: Methodsmentioning

confidence: 99%