Azodioxy-carbonyl compounds by oxidation of cyclic imines with m-CPBA

Perrone, Serena; Pilati, Tullio; Rosato, Francesca; Salomone, Antonio; Videtta, Valeria; Troisi, Luigino

doi:10.1016/j.tet.2011.01.054

Cited by 9 publications

(8 citation statements)

References 30 publications

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“…The other method is oxidation of 2‐oxazoline with 2 equiv. of MCPBA, which was prepared by acid‐catalyzed reaction between aliphatic carboxylic acid and 2‐amino‐2‐methyl‐1‐propanol, as illustrated in Scheme . Several nitroso esters, such as 2‐methyl‐2‐nitrosopropyl butanoate (MNPB), 2‐methyl‐2‐nitrosopropyl hexanoate (MNPH), 2‐methyl‐2‐nitrosopropyl undecanoate (MNPU), were prepared by this method with various carboxylic acids.…”

Section: Resultsmentioning

confidence: 99%

“…2‐Methyl‐2‐nitrosopropyl alkyl esters were synthesized according to the published procedure . Undecanoic acid, hexanoic acid, and butyric acid were used.…”

Section: Methodsmentioning

confidence: 99%

“…For the synthesis of aliphatic nitroso alkanes, oxidation of amine without α‐hydrogen under mild condition is an easy method. For one‐pot synthesis of aliphatic nitroso compounds containing ester group, oxidation of 4,4‐dimethyl dihydro‐1,3‐oxazine or 4,4‐dimethyl 2‐oxazoline with m ‐chloroperoxybenzoic acid (MCPBA) is a convenient method …”

Section: Introductionmentioning

confidence: 99%

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Radical addition-coupling polymerization with various nitroso compounds

Wang

2013

J. Polym. Sci. Part A: Polym. Chem.

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Four nitroso esters were prepared by oxidation of 4,4-dimethyl dihydro-1,3-oxazine or 4,4-dimethyl-2-oxazoline with two equiv of m-chloroperoxybenzoic acid. All of them can be applied in radical addition-coupling polymerization to produce periodic polymer together with introduction of ester group at side chain. Compared with 2-methyl-2-nitrosopropane, 2-nitroso-2-methyl-4-acetoxypentane and 2-methyl-2-nitrosopropyl hexanoate present good stability at high temperature up to 70 C and can result polymer with high molecular weight. KEYWORDS: atom transfer radical polymerization; functionalization of polymers; nitroso ester; radical addition-coupling polymerization; step-growth polymerization INTRODUCTION Radical addition-coupling polymerization (RACP) has been proposed for synthesis of periodic polymer with regular monomer sequence. [1][2][3] As shown in Scheme 1, the polymerization involves consecutive addition of carboncentered radical to N@O of C-nitroso compound followed by cross-coupling of carbon-centered radical and in situ formed nitroxyl radical, which produces copolymers with high molecular weight and unimodal molecular weight distribution from saturated and unsaturated monomers. The key step of RACP is the formation of intermediate nitroxyl radical, which is stable enough to take cross-coupling reaction with relatively active carbon-centered radical based on persistent radical effect. 4 The N@O double bond plays an essen-

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Section: Resultsmentioning

confidence: 99%

“…2‐Methyl‐2‐nitrosopropyl alkyl esters were synthesized according to the published procedure . Undecanoic acid, hexanoic acid, and butyric acid were used.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radical addition-coupling polymerization with various nitroso compounds

Wang

2013

J. Polym. Sci. Part A: Polym. Chem.

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“…Furthermore, on heating 4c in toluene (80°C), 4d was obtained (yield 80%, Scheme 3). 12 Continuing our studies on the oxidation of imines with MCPBA we have discovered outcomes strongly dependent on the C=N bond substituents. Due to the lower basicity of the nitrogen in 5-7 with respect to compounds 1-4, the second oxygen transfer on oxaziridines 5a-7a, formed on initial oxidation, did not take place.…”

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confidence: 81%

On the Oxidation of Different Iminic Bonds by Excess of 3-Chloroperbenzoic Acid

Troisi

Carrozzo

Citti

et al. 2012

Synlett

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Abstract:In the present work the behavior of different substituted iminic bonds toward the oxidative action of 3-chloroperbenzoic acid is reported. The C=N bond was or was not oxidized to oxaziridines, amides, oximes, nitroso-, nitro-, and azodioxy compounds depending on the substituents at the iminic group and on the imine/MCPBA stoichiometric ratio. Key words: imines, oxidation, oxaziridines, C-nitroso compound, oximesAlthough the reduction 1 and hydrolysis 2 of imines has been largely studied, only a few publications report its behavior toward oxidizing agents. It has been reported that benzylidene alkylamines lead to the corresponding oxaziridines by stoichiometric oxidation with peracids, 3 urea hydrogen peroxide, 4 and cobalt-mediated molecular oxygen 5 (Scheme 1). Scheme 1 Synthetic methodology for oxaziridine generationA number of thermally stable oxaziridines, obtained by oxidation of benzylidene alkylamines, 6 have been employed both as oxygenating and/or aminating agents of nucleophilic species 7 and as reagents in cycloaddition reactions with heterocumulenes, 8 alkenes, 9 alkynes, 10 and nitriles. 11 Reports of reactions of imines with excess MCPBA are scarce. Previously, we have reported that the oxidation of benzylidene alkylamines 1-3 by 1.1 mmol of MCPBA in CH 2 Cl 2 solution led to oxaziridines 1a-3a in good yields (>90%), 12 while nitroso compounds 1b-3b rapidly dimerized to azodioxy compounds 1c-3c and were obtained employing 2.2 mmol of MCPBA (Scheme 2). Furthermore compounds 2b, 3b, 2c, and 3c, having a hydrogen at the α position of R 1 , undergo isomerization into oximes 2d and 3d by heating in toluene solution.Moreover, the azodioxy dimer 3c was obtained in quantitative yield by reaction of 1.1 mmol MCPBA with the isolated oxaziridine 3a.The same result was obtained on oxidizing the cyclic imine 3,4-dihydro-2H-pyrrole 4 with 1.1 mmol of MCPBA; the condensed oxaziridine 4a (yield 98%) was obtained in this case. Product 4a was subsequently oxidized into nitroso compound 4b that rapidly dimerized to azoxydimer 4c when a further 1.1 mmol of MCPBA were added. Furthermore, on heating 4c in toluene (80°C), 4d was obtained (yield 80%, Scheme 3). 12 Continuing our studies on the oxidation of imines with MCPBA we have discovered outcomes strongly dependent on the C=N bond substituents. Due to the lower basicity of the nitrogen in 5-7 with respect to compounds 1-4, the second oxygen transfer on oxaziridines 5a-7a, formed on initial oxidation, did not take place. Instead, N,N-diarylamides 8-10 were obtained both with 1.1 mmol or 2.2 mmol of peracid, after a carbon-nitrogen migration of the aryl group (Scheme 4). Amides were also obtained in reactions of imines with sodium perborate 13 or with MCPBA and BF 3 ·OEt 2 . 14 A further decrease of basicity of the imine nitrogen as in oximes 11, isoxazolines 12, benzothiadiazines 13, and osazones 14 (Figure 1), due to the presence of a heteroatom on the nitrogen atom, diminished the reactivity towards C=N oxidation, and starting materials were recovered even ...

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“…11,12 More recently, our research group has developed a synthetic strategy to oxidize cyclic imines to azodioxy-carbonyl compounds by the action of 3-chloroperoxybenzoic acid (MCPBA). 13 Starting from the proposed racemization mechanism (Scheme 1), (±)-7-chloro-3-methyl-3,4dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (IDRA21, 1), was oxidized with MCPBA.…”

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confidence: 99%