Thermal cyclization of 4‐azido‐3‐nitropyridines to furoxanes

Stadlbauer, W.; Fiala, Werner; Fischer, Michaela; Hojas, Gerhard

doi:10.1002/jhet.5570370537

Cited by 22 publications

(9 citation statements)

References 14 publications

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“…Recently, we published a series of electrocyclization reactions of hetaryl azides with reactive ortho‐substituents such as acyl or nitro groups . Acetyl‐pyridocarbazolone 5 has as precursor of one of these structure elements an acetyl group, together with a hydroxy group in ortho‐position.…”

Section: Resultsmentioning

confidence: 99%

“…As described earlier, electrocyclization reactions of hetaryl azides take place also with reactive ortho‐substituents such as nitro groups . When 5‐nitro‐pyridocarbazolone 13 as starting material was brought to reaction with phosphoryl chloride to obtain as reactive intermediate 4‐chloro‐5‐nitropyridocarbazolone 22 , again this reaction was hindered by hydrogen bondings between the nitro and hydroxy groups, similarly as observed with the acetyl group in 5 .…”

Section: Resultsmentioning

confidence: 99%

“…The thermolysis of nitro compounds with ortho‐azido groups is known to lead to furoxanes. However, the thermal conditions must be carefully selected; otherwise, decomposition reactions take place . The thermal conditions for the cyclization of the azide in structure 23 to the furoxane in 24 were again determined by DSC .…”

Section: Resultsmentioning

confidence: 99%

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5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses, Substitution, and Cyclization Reactions

Stadlbauer

Dang

Guttenberger

2014

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).The synthesis of the 5-unsubstituted pyrido[3,2,1-jk]carbazol-6-one 4 can be achieved by the reaction of carbazole (1) and malonate derivatives, either in a three-step synthesis via 5-acetyl-pyridocarbazolone 3 or in a one-step reaction from 1 and malonic acid/phosphoryl chloride. The 5-acetyl derivative 5 can be transformed via a tosylate intermediate to 4-azido-pyridocarbazolone 11, which cyclizes by thermal decomposition to the isoxazolo-pyrido[3,2,1-jk]carbazolone 12. The thermolysis conditions were investigated by DSC. Nitration of pyridocarbazolone 4 and subsequent introduction of azide leads to azido derivative 23, which cyclizes on thermolysis to furazan-oxide derivative 24. Again, the thermolysis conditions were investigated by DSC. 5-Chloro-5-nitro-pyrido[3,2,1-jk]carbazole-4,6-dione, obtained from 4 by subsequent nitration and chlorination, forms by exchange of both 5-substituents 5,5-dihydroxy-pyridocarbazoledione 17, which acylates phenol to give 5-hydroxy-5-(p-hydroxyphenyl)-pyridocarbazoledione 20. Acid-catalyzed cyclodehydration of 20 forms a highly fused benzofuropyridocarbazole 21. Another C-C coupling at position 5 starts from 4-chloro-5-nitro-pyridocarbazolone 22 and diethyl malonate 2a, which forms the diethyl (nitrocarbazolyl)malonate 25. With dimethyl malonate 2c, the intermediate dimethyl (nitrocarbazolyl)malonate gives on thermolysis the (nitrocarbazolyl)acetate 27 by loss of one ester group.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses, Substitution, and Cyclization Reactions

Stadlbauer

Dang

Guttenberger

2014

Journal of Heterocyclic Chem

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“…Chlorination of cyanopyridone 1 with phosphoryl chloride similar to earlier results [ 17 ] gave only a poor yield of impure chlorination products. The addition of triethylamine to the phosphoryl chloride reagent, however, accelerated the reaction rate [ 18 ] and afforded 6-chloro-4-methyl-2-phenyl-5-pyridinecarbonitrile ( 3 ) in good yield, after 4 hours. Compound 3 with a vicinal chloro and cyano groups was envisaged as a potential starting material for the synthesis of fused heterocycle systems.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a New Series of Pyridine and Fused Pyridine Derivatives

Al-Issa

2012

Molecules

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The reaction of 4-methyl-2-phenyl-1,2-dihydro-6-oxo-5-pyridine- carbonitrile (1) with arylidene malononitrile afforded isoquinoline derivatives 2a,b. 6-Chloro-4-methyl-2-phenyl-5-pyridinecarbonitile (3) obtained by chlorination of compound 1 with phosphoryl chloride was converted into 6-amino-4-methyl-2-phenyl-5-pyridinecarbonitrile (4) and 6-hydrazido-4-methyl-2-phenyl-5-pyridinecarbonitrile (5) in good yield, through reactions with ammonium acetate and hydrazine hydrate, respectively. Treatment of 4 with ethyl acetoacetate, acetic anhydride, formic acid, urea and thiourea gave the corresponding pyrido [2,3-d] pyrimidine derivatives 7–10a,b. A new series of 6-substituted-4-methyl-2-phenyl-5-pyridine carbonitriles 11–13 has been synthesized via reaction of 4 with phenyl isothiocyanate, benzenesulphonyl chloride and acetic anhydride. Treatment of 4 with malononitrile gave 1,8-naphthyridine derivative 14. The reactivity of hydrazide 5 towards acetic acid, phenylisothiocyanate and methylacrylate to give pyrazolo-[3,4-b]-pyridine derivatives 15–17 was studied. Treatment of 5 with acetic anhydride, phthalic anhydride and carbon disulphide gave pyridine derivatives 18,19 and 1,2,4-triazolo-[3,4-a]-pyridine derivative 20.

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“…Firstly, TAL was converted into HMPO through the direct aminolysis with ammonia, and the preparation procedure was shown in supporting information (Figure S1) [18] . Then, the catalytic transformation of HMPO to MP was performed over different catalysts.…”

Section: Methodsmentioning

confidence: 99%

Production of Piperidine and δ‐Lactam Chemicals from Biomass‐Derived Triacetic Acid Lactone

et al. 2021

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Piperidine and δ‐Lactam chemicals have wide application, which are currently produced from fossil resource in industry. Production of this kind of chemicals from lignocellulosic biomass is of great importance, but is challenging and the reported routes give low yield. Herein, we demonstrate the strategy to synthesize 2‐methyl piperidine (MP) and 6‐methylpiperidin‐2‐one (MPO) from biomass‐derived triacetic acid lactone (TAL) that is produced microbially from glucose. In this route, TAL was firstly converted into 4‐hydroxy‐6‐methylpyridin‐2(1H)‐one (HMPO) through facile aminolysis, subsequently HMPO was selectively transformed into MP or MPO over Ru catalysts supported on beta zeolite (Ru/BEA‐X, X is the molar ratio of Si to Al) via the tandem reaction. It was found that the yield of MP could reach 76.5 % over Ru/BEA‐60 in t‐BuOH, and the yield of MPO could be 78.5 % in dioxane. Systematic studies reveal that the excellent catalytic performance of Ru/BEA‐60 was closely correlated with the cooperative effects between active metal and acidic zeolite with large pore geometries. The related reaction pathway was studied on the basis of control experiments.

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Thermal cyclization of 4‐azido‐3‐nitropyridines to furoxanes

Cited by 22 publications

References 14 publications

5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses, Substitution, and Cyclization Reactions

5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses, Substitution, and Cyclization Reactions

Synthesis of a New Series of Pyridine and Fused Pyridine Derivatives

Production of Piperidine and δ‐Lactam Chemicals from Biomass‐Derived Triacetic Acid Lactone

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