ChemInform Abstract: REACTION OF PROPARGYL BROMIDES WITH SILVER AND SODIUM NITRITES. NEW METHOD FOR THE SYNTHESIS OF NITROISOXAZOLES

Mechkov, Ts. D.; Sulimov, I. G.; Usik, N. V.; Mladenov, Iväılo M.; Perekalin, V. V.

doi:10.1002/chin.198041189

Cited by 3 publications

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“…The use of secondary propargyl bromides provided the synthesis of a series of 4nitroisoxazoles as a mixture with the corresponding propargyl alcohols; these were separated via chromatography (Scheme 11). 77,78 Scheme 8 Regioselective cycloaddition of nitrile oxides to 'push-pull' alkenes [63][64][65]…”

Section: Heterocyclization Of Acetylene Derivatives By Treatment Withmentioning

confidence: 99%

“…Scheme 11 Heterocyclization of propargyl bromides by treatment with sodium nitrite 77,78 The authors propose that the nucleophilic substitution of bromine by ambident nitrite anion gives a mixture of Nand O-alkylation products, nitroacetylene I and nitroso ester of propargyl alcohol II, the reaction of which with excess sodium nitrite leads to 4-nitroisoxazole and the byproduct propargyl alcohol, respectively.…”

Section: Short Review Syn Thesismentioning

confidence: 99%

“…The interaction of primary propargyl bromides with sodium nitrite results in 3-nitroisoxazoles (Scheme 20). 78,101 The reaction proceeds through the formation of acetylenenitrolic acid, which undergoes further intramolecular cyclization giving a 3-nitroisoxazole.…”

Section: Heterocyclization Of Acetylene Derivatives or 13-dihalogenomentioning

confidence: 99%

“…The synthesis of 3-nitroisoxazoles via 1,3-dipolar cycloaddition requires the use of the unstable and hardly available nitroformonitrile oxide (NFNO) as the 1,3-dipole. There are two reported methods for the generation of NFNO in situ: 1. the treatment of dinitromethane potassium salt Scheme 20 Heterocyclization of propargyl bromides by treatment with sodium nitrite 78,101…”

Section: 3-dipolar Cycloadditionsmentioning

confidence: 99%

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Synthetic Approaches to Nitro-Substituted Isoxazoles

et al. 2019

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Nitro-substituted isoxazoles are of utmost interest both as versatile intermediates for targeted organic synthesis and as perspective bioactive compounds for drug development. Nevertheless, the existing approaches to them usually lack generality and strongly depend on the position of the nitro group and on the presence of other substituents in the isoxazole ring. This review provides the first systematization of all available data concerning synthetic approaches to 3-, 4-, and 5-nitroisoxazoles. There are a number of preparative approaches to 4-nitroisoxazoles based on classical heterocyclization reactions of nitro-substituted compounds and the nitration of isoxazoles. 3-Nitro- and, especially, 5-nitroisoxazoles are much less readily available. A few methods affording 3-nitroisoxazoles have been reported, often employing the heterocyclization of unsaturated compounds by treatment with sodium nitrite. The sole general preparative method for 5-nitroisoxazoles, containing a variety of functional groups, employs the heterocyclization of electrophilic alkenes by treatment with tetranitromethane activated with triethylamine.1 Introduction2 Synthesis of 4-Nitroisoxazoles2.1 Nitration of Isoxazoles2.2 Condensations of α-Nitro Ketones or Their Oximes2.3 1,3-Dipolar Cycloaddition of Nitrile Oxides to Acetylenes and Their Synthetic Equivalents2.4 Heterocyclization of Acetylene Derivatives by Treatment with Sodium Nitrite2.5 Heterocyclization of Nitro Derivatives of 1,3-Diketones and Their Synthetic Equivalents2.6 Miscellaneous Methods3 Synthesis of 3-Nitroisoxazoles3.1 Heterocyclization of Acetylene Derivatives or 1,3-Dihalogenoalkenes by Treatment with Sodium Nitrite3.2 Heterocyclization of Morita–Baylis–Hillman Acetates by Treatment with Sodium Nitrite3.3 1,3-Dipolar Cycloadditions4 Synthesis of 5-Nitroisoxazoles4.1 1,3-Dipolar Cycloadditions4.2 Synthesis Using Polynitro Compounds5 Conclusion

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Section: Heterocyclization Of Acetylene Derivatives By Treatment Withmentioning

confidence: 99%

Section: Short Review Syn Thesismentioning

confidence: 99%

Section: Heterocyclization Of Acetylene Derivatives or 13-dihalogenomentioning

confidence: 99%

Section: 3-dipolar Cycloadditionsmentioning

confidence: 99%

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Synthetic Approaches to Nitro-Substituted Isoxazoles

et al. 2019

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“…Despite this, the first example of the alkynylation of nitroalkenes was reported as early as 1978 by Mechkov, who carried out the addition of phenylethynylmagnesium bromide to nitroethene, nitrostyrene and 1-nitropentene in 32-51% yields. 63 Later, in 1989, Pecunioso described the alkynylation of several cyclic and acyclic nitroalkenes by means of ether-free diethylalkynylalanes, which had been prepared in hexane solutions by adding either an alkynyllithium to Et 2 AlCl or a suitable alkyne to Et 3 Al (Scheme 62). 64…”

Section: Conjugate Alkynylation Of Nitroalkenesmentioning

confidence: 99%

Conjugate Alkynylation of Electrophilic Double Bonds. From Regioselectivity to Enantioselectivity

2018

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This review surveys the historical efforts addressed toward the development of the conjugate alkynylation reaction. The regio- and enantioselective conjugate alkynylation of electron-deficient double bonds, most commonly unsaturated carbonyl compounds, has been an elusive reaction for a long time. Intensive research during the last decades has resulted in the identification of a number of effective reagents and catalysts to perform this reaction. Non-stereoselective conjugate alkynylation of unsaturated carbonyl compounds was first achieved by using preformed alkynyl organometallics and later with terminal alkynes under catalytic conditions. These methods paved the way for the development of enantioselective procedures. After initial methods requiring stoichiometric amounts of chiral material, the findings by Corey on Ni-catalyzed addition of alkynylalanes and, particularly, by Carreira on Cu-catalyzed addition of terminal alkynes boosted the research on the development other asymmetric procedures catalyzed by Cu, Zn, Rh, Co, Ru and Pd complexes. The alkynylation of electrophilic alkenes conjugated with groups other than carbonyl and the alkynylation of extended conjugated systems are also discussed in the last part of this review.1 Introduction2 Non-Stereoselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds3 Enantioselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds4 Non-Stereoselective and Enantioselective Alkynylation of Other Electrophilic Alkenes5 γ-Alkynylation of α,β-Unsaturated Amides and δ-Alkynylation of Electrophilic Dienes6 Alternative Enantioselective Procedures7 Conclusion and Outlook

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Unexpected Heterocyclization of Electrophilic Alkenes by Tetranitromethane in the Presence of Triethylamine. Synthesis of 3-Nitroisoxazoles

et al. 2010

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Novel reaction of tetranitromethane (TNM) with electrophilic alkenes in the presence of triethylamine yielding substituted 3-nitroisoxazoles was found and studied. Triethylamine increases the reactivity of TNM toward electrophilic alkenes promoting their heterocyclization, and the reactions proceed in an unusual way. A variety of alpha,beta-unsaturated aldehydes, ketones, esters, amides, phosphonates, and nitro and sulfur compounds was involved in the heterocyclization reaction, and a wide range of functionalized 3-nitroisoxazoles was obtained in good to high yields. The scope and limitations of the reaction and the mechanistic aspects are discussed.

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ChemInform Abstract: REACTION OF PROPARGYL BROMIDES WITH SILVER AND SODIUM NITRITES. NEW METHOD FOR THE SYNTHESIS OF NITROISOXAZOLES

Cited by 3 publications

References 0 publications

Synthetic Approaches to Nitro-Substituted Isoxazoles

Synthetic Approaches to Nitro-Substituted Isoxazoles

Conjugate Alkynylation of Electrophilic Double Bonds. From Regioselectivity to Enantioselectivity

Unexpected Heterocyclization of Electrophilic Alkenes by Tetranitromethane in the Presence of Triethylamine. Synthesis of 3-Nitroisoxazoles

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