Rates and products from thermolysis of 5-azidoisoxazoles in solution

L'abbé, G.; Dyall, LK; Meersman, Kathleen; Dehaen, Wim

doi:10.1039/p29960002111

Cited by 6 publications

(8 citation statements)

References 19 publications

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“…Azidoisoxazole 1 was purified by silica gel column chromatography eluted with 5% ethyl acetate in hexane. Recrystallized azidoisoxazole 1 crystals (diethyl ether; 50 mg, 17% yield) were characterized using 1 H-NMR and IR spectroscopy, and the obtained spectra corresponded well with the reported data [12]. 1…”

Section: Preparation Of Azidoisoxazolesupporting

confidence: 72%

“…Azidoisoxazole 1 was synthesized by following the previously reported procedure [12]. Sodium hydride (0.041 g, 1.7 mmol) was placed a 25 mL round bottom flask, washed three times with hexane (2 mL) and once with dichloromethane (2 mL), and then vacuum dried for 1 h. Dry THF (3 mL) was added to the round bottom flask and the reaction was cooled to −30 • C using a xylene-dry ice bath.…”

Section: Preparation Of Azidoisoxazolementioning

confidence: 99%

“…Kumar et al and later L'Abbé and Godts studied the thermal decomposition of 4-azidoisoxazole derivatives and demonstrated that they undergo facile cleavage to form cyano products, as shown in Scheme 1 [9,10], presumably through a concerted reaction mechanism. In comparison, the thermal activation of 3-azidoisoxazole derivatives results in the formation of both isoxazoloisoxazole and hydroxypyrrole products (Scheme 2) [11,12]. L'Abbé and co-workers proposed that these products are formed by different reaction mechanisms, with the hydroxypyrroles formed through nitrosoalkene intermediates and the isoxazoloisoxazoles obtained from nitrene intermediates [12].…”

Section: Introductionmentioning

confidence: 99%

“…In comparison, the thermal activation of 3-azidoisoxazole derivatives results in the formation of both isoxazoloisoxazole and hydroxypyrrole products (Scheme 2) [11,12]. L'Abbé and co-workers proposed that these products are formed by different reaction mechanisms, with the hydroxypyrroles formed through nitrosoalkene intermediates and the isoxazoloisoxazoles obtained from nitrene intermediates [12]. The thermal decomposition of a 5-azidoisoxazole in the presence of 2,3-dimethyl buta-1,3-diene yields the corresponding oxazine derivative (Scheme 3) [12].…”

Section: Introductionmentioning

confidence: 99%

“…L'Abbé and co-workers proposed that these products are formed by different reaction mechanisms, with the hydroxypyrroles formed through nitrosoalkene intermediates and the isoxazoloisoxazoles obtained from nitrene intermediates [12]. The thermal decomposition of a 5-azidoisoxazole in the presence of 2,3-dimethyl buta-1,3-diene yields the corresponding oxazine derivative (Scheme 3) [12]. Therefore, it was concluded that the thermal activation of 5-azidoisoxazole yields the corresponding nitrosoalkene, which can be trapped with dienes.…”

Section: Introductionmentioning

confidence: 99%

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Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

et al. 2020

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To enhance the versatility of organic azides in organic synthesis, a better understanding of their photochemistry is required. Herein, the photoreactivity of azidoisoxazole 1 was characterized in cryogenic matrices with IR and UV-Vis absorption spectroscopy. The irradiation (λ = 254 nm) of azidoisoxazole 1 in an argon matrix at 13 K and in glassy 2-methyltetrahydrofuran (mTHF) at 77 K yielded nitrosoalkene 3. Density functional theory (DFT) and complete active space self-consistent field (CASSCF) calculations were used to aid the characterization of nitrosoalkene 3 and to support the proposed mechanism for its formation. It is likely that nitrosoalkene 3 is formed from the singlet excited state of azidoisoxazole 1 via a concerted mechanism or from cleavage of an intermediate singlet nitrene that does not undergo efficient intersystem crossing to its triplet configuration.

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Section: Preparation Of Azidoisoxazolesupporting

confidence: 72%

Section: Preparation Of Azidoisoxazolementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

et al. 2020

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A New and Productive Route to 1‐Heteroarylcyclopropanols

Belov¹,

Savchenko²,

Соколов³

et al. 2003

Eur J Org Chem

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(E/Z)‐2‐(1‐Allyloxycyclopropyl)‐3‐methoxyacrylonitrile (4‐All) was designed and prepared in five steps (58% overall yield) from ethyl cyclopropylidenacetate as a valuable precursor to various 1‐heteroarylcyclopropanols. Its condensation with amidines, guanidine, hydrazine, and methyl thioglycolate and subsequent removal of the allyl protecting group yields 1‐heteroarylcyclopropanols such as 1‐OH (36% over 2 steps), a very potent NO‐independent stimulator of soluble guanylate cyclase. Direct cleavage of the allyl ether protecting group [by palladium‐catalyzed substitution with lithium p‐toluenesulfinate in AcOH or treatment with c‐HexMgBr/Ti(OiPr)4] gives highly functionalized, sterically congested 1‐heteroarylcyclopropanols 29, 30, and 34 with intact amino and ester groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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Mass spectrometric studies of anomeric glycopyranosyl azides

Dinya¹,

Benke²,

Györgydeák³

et al. 2001

J. Mass Spectrom.

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We studied the mass spectrometric behaviour of peracetylated and underivatized anomeric hexopyranosyl azides and 5-thioglucopyranosyl azides by means of different mass spectrometric techniques. The unstable molecular ions fragment predominantly by losing either N3 radical or N2 molecule. Loss of N2 molecule and the protonation of the derived nitrene were characteristic of the studied compounds. The presence of BF3.Et2O in the ion source is favorable for producing the protonated nitrene form. The protonated nitrene shows a new type of ring expansion rearrangement. The abundances of the [M + H - N2]+ ion makes it possible to identify the anomeric configuration of the azido group.

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Rates and products from thermolysis of 5-azidoisoxazoles in solution

Cited by 6 publications

References 19 publications

Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

A New and Productive Route to 1‐Heteroarylcyclopropanols

Mass spectrometric studies of anomeric glycopyranosyl azides

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