Syntheses of gem-dinitro heterocyclic compounds, their ring-opening reactions and transformations into indoles, indazoles and benzoxazinones

Bergman, Jan; Bergman, Solveig; Brimert, Thomas

doi:10.1016/s0040-4020(99)00570-0

Cited by 24 publications

(16 citation statements)

References 38 publications

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“…Our data for the hardly known [32], [44] double oxyfunctionalization of 3H-pyrazol-3-ones 1, isoxazol-5(4H)-ones 2, and barbituric acids 4 by the malonyl peroxides 5 a and 5c-d are summarized in Table 4 for the derivatives 1 h, 2 f and 4 a. The respective oxidation products 6 ha, 6 hd, 7 fa, 7 fd, and 9 ac -9 ad were obtained in fair to good yields (42-72 %).…”

Section: Supporting Information)mentioning

confidence: 99%

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

et al. 2017

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Oxidative functionalization of 3H‐pyrazol‐3‐ones, isoxazol‐5(2H)‐ones, pyrazolidine‐3,5‐diones, and barbituric acids by malonyl peroxides results exclusively in C−O coupling products. Traditional hydroxylation, formation of carbonyl groups, or oxidative destruction of the heterocyclic ring are not observed. Under optimized reactions conditions – fluorinated alcohols as activating medium and at room temperature (20 – 25 °C) – the selective C−O coupling proceeds in high yields (up to 94 %). The oxidative insertion into the enolizable C−H bond of the substrate is mechanistically viewed as a nucleophilic attack by the heterocycle onto the electrophilically activated malonyl peroxides. For heterocyclic substrates with an active methylene group ‐ 3H‐pyrazol‐3‐ones, isoxazol‐5(2H)‐ones, and barbituric acids ‐ both C−H bonds are oxidized to afford double oxidative C−O coupling products in good yields (up to 72 %).

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Section: Supporting Information)mentioning

confidence: 99%

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

et al. 2017

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“…The absolute configuration of 9 was subsequently proven by anomalous X‐ray diffraction techniques thus also establishing the absolute configuration of product 7 a . We assume that the epimerization is due to the intermediacy of isocyanate 10 18 during the methylation protocol. The absolute configuration at the sulfoxide sulfur atom is retained as proven by the enantiopurity of both products.…”

Section: Influence Of the Ligand Configuration On The Enantioselectivmentioning

confidence: 99%

Synergistic Stereocontrol in the Enantioselective Ruthenium‐Catalyzed Sulfoxidation of Spirodithiolane‐Indolones

Zhong

Pöthig

Bach

2015

Chemistry A European J

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A chiral ruthenium catalyst was developed for the enantioselective sulfoxidation of the title compounds. The catalyst combines two elements of chirality, a chiral pybox ligand and a chiral bicylic lactam unit, to which the ligand is attached. The latter unit was shown to improve significantly the performance of the catalyst by exposing one of the two enantiotopic sulfur atoms to the active site via hydrogen-bond mediated coordination. Ten differently substituted substrates were converted into the respective sulfoxides in yields of 52-71 % and with ≥90 % ee.

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“…However, in these studies, the nitro derivatives were not fully characterized and the yields of the products were not given. In most cases, the pyrazolin‐5‐ones were nitrated by using nitric acid or a HNO 3 /H 2 SO 4 mixture under heating (Scheme c) . The disadvantages of these procedures are harsh acidic conditions and low selectivity.…”

Section: Introductionmentioning

confidence: 99%

“…However,i n these studies, the nitro derivatives weren ot fully characterized and the yields of the products were not given.I nm ost cases, the pyrazolin-5-ones were nitrated by using nitric acid or a HNO 3 /H 2 SO 4 mixture under heating (Scheme 1c). [36][37][38][39][40] The disadvantages of these procedures are harsh acidic conditions and low selectivity.T hus, in the case of phenyl-substitutedp yrazolin-5-ones, nitrationo fb oth the phenyla nd pyrazolone rings occurred. [38] One of the main problems encountered in the selectiveo xidative functionalization of pyrazolin-5-ones, especially 4-substituted derivatives, is their tendency to undergo hydroxylation [41,42] and oxidative dimerization.…”

Section: Introductionmentioning

confidence: 99%

Mild Nitration of Pyrazolin‐5‐ones by a Combination of Fe(NO₃)₃ and NaNO₂: Discovery of a New Readily Available Class of Fungicides, 4‐Nitropyrazolin‐5‐ones

Krylov

Budnikov

Lopat’eva

et al. 2019

Chemistry A European J

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4‐Nitropyrazolin‐5‐ones have been synthesized by the nitration of pyrazolin‐5‐ones at room temperature by employing the Fe(NO3)3/NaNO2 system. The method demonstrated selectivity towards the 4‐position of pyrazolin‐5‐ones even in the presence of NPh and allyl substituents, which are sensitive to nitration. It was shown that other systems containing FeIII and nitrites, namely Fe(NO3)3/tBuONO, Fe(ClO4)3/NaNO2, and Fe(ClO4)3/tBuONO, were also effective. Presumably, FeIII oxidizes the nitrite (NaNO2 or tBuONO) to form the NO2 free radical, which serves as the nitrating agent for pyrazolin‐5‐ones. The synthesized 4‐nitropyrazolin‐5‐ones were discovered to be a new class of fungicides. Their in vitro activities against phytopathogenic fungi were found comparable or even superior to those of commercial fungicides (fluconazole, clotrimazole, triadimefon, and kresoxim‐methyl). These results represent a promising starting point for the development of a new type of plant protection agents that can be easily synthesized from widely available reagents.

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Syntheses of gem-dinitro heterocyclic compounds, their ring-opening reactions and transformations into indoles, indazoles and benzoxazinones

Cited by 24 publications

References 38 publications

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

Synergistic Stereocontrol in the Enantioselective Ruthenium‐Catalyzed Sulfoxidation of Spirodithiolane‐Indolones

Mild Nitration of Pyrazolin‐5‐ones by a Combination of Fe(NO₃)₃ and NaNO₂: Discovery of a New Readily Available Class of Fungicides, 4‐Nitropyrazolin‐5‐ones

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Syntheses of gem-dinitro heterocyclic compounds, their ring-opening reactions and transformations into indoles, indazoles and benzoxazinones

Cited by 24 publications

References 38 publications

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

Selective Oxidative Coupling of 3H‐Pyrazol‐3‐ones, Isoxazol‐5(2H)‐ones, Pyrazolidine‐3,5‐diones, and Barbituric Acids with Malonyl Peroxides: An Effective C‐O Functionalization

Synergistic Stereocontrol in the Enantioselective Ruthenium‐Catalyzed Sulfoxidation of Spirodithiolane‐Indolones

Mild Nitration of Pyrazolin‐5‐ones by a Combination of Fe(NO3)3 and NaNO2: Discovery of a New Readily Available Class of Fungicides, 4‐Nitropyrazolin‐5‐ones

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Mild Nitration of Pyrazolin‐5‐ones by a Combination of Fe(NO₃)₃ and NaNO₂: Discovery of a New Readily Available Class of Fungicides, 4‐Nitropyrazolin‐5‐ones