Oxaziridines. I. The Irradiation Products of Several Nitrones<sup>1</sup>

Splitter, Janet S.; Calvin, Melvin

doi:10.1021/jo01021a038

Cited by 113 publications

(47 citation statements)

References 3 publications

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“…19,20 The photoirradiation studies on nitrones can be primarily summarized into 2 important observations; the cis-trans isomerization reactions of nitrones occur thermally or through triplet excited states in presence of photosensitizers, 21,22 while their normal photo-excitation involves singlet excited states which subsequently forms oxaziridines and other photo-products, such as amides. 19,20 The photoirradiation studies on nitrones can be primarily summarized into 2 important observations; the cis-trans isomerization reactions of nitrones occur thermally or through triplet excited states in presence of photosensitizers, 21,22 while their normal photo-excitation involves singlet excited states which subsequently forms oxaziridines and other photo-products, such as amides.…”

Section: Introductionmentioning

confidence: 99%

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

Saini

Chattopadhyay

2015

RSC Adv.

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This comprehensive spectroscopic analysis of a-(2-naphthyl)-N-methylnitrone has proposed its photochemical oxaziridine formation and thermal E-Z isomerization mechanisms. The activation energy for the conversion of the unstable non-planar E isomer to the stable planar Z-isomer is found to be 23.7 kcal mol À1 at the CASSCF/6-31G* level of calculation. A transition state with a negative frequency of 350 cm À1 is likely to be responsible for this process. Both CASSCF and ONIOM-based studies have revealed that the nitrone-oxaziridine photochemical conversion involves non-radiative decay channels which include biradicaloid conical intersection (CI) points through Hula-twist and terminal one-bond-flip motions, situated at 35-40 kcal mol À1 below the first excited singlet state (S 1 ). Following the directions of their gradient-difference vectors, the optimized oxaziridine geometries are obtained. The nature of the low-lying singlet-singlet transitions of these a-naphthyl N-methylnitrones is found to be similar to that of the conjugated non-polar polyenes, and differs appreciably from our previously studied longchain conjugated nitrone systems. The fluorescent S 1 state with a radiative lifetime of nanosecond order is populated by the weak upward S 0 -S 1 transition (transition moment: 0.3 Debye) and through the decay of the S 2 state, which eventually gets involved in the S 0 /S 1 conical intersections.

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Section: Introductionmentioning

confidence: 99%

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

Saini

Chattopadhyay

2015

RSC Adv.

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“…According to our recent studies on the behaviour of polymeric six-membered mesoions 9,10) , it is apparent that nitrones are also potential candidates to produce photosensitive materials yielding less polar oxaziridines [11][12][13] (Scheme 1). In analogy to mesoionic polymers, nitrones are also highly polar and photosensitive.…”

Section: Introductionmentioning

confidence: 99%

Polymeric nitrones, 1. Synthesis and modification of polymeric nitrones derived from polymerizable aldehydes

Heinenberg

Ritter²

1999

Macromol. Chem. Phys.

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SUMMARY: The model compound N,C-diphenylnitrone [N-(benzylidene)aniline-N-oxide] (3) was prepared by condensation of benzaldehyde with phenylhydroxylamine to study its thermal stability. X-ray diffraction analysis of a single crystal established the conformation of the nitrone group. A new monomer 4-(methacryloyloxy)benzaldehyde-phenylnitrone (8) was also prepared and could not be polymerized with 2,29-azobisisobutyronitrile (AIBN) as initiator at 70 8C. Under these conditions the nitrone reacted exclusively in an intermolecular 1,3-dipolar cycloaddition to give oligomeric tetrahydro-1,2-oxazoline derivates. The kinetics of the cycloaddition was investigated. Additionally, different (meth)acryl-and styryl-substituted aldehyde monomers were synthesized: (20) and 4-(3-methacryloyloxypropoxy)benzaldehyde (25). These new monomers were homo-and copolymerized with MMA radically at 70 8C using AIBN as initiator. The resulting polyaldehydes 26 -30 were reacted with phenylhydroxylamine to obtain the polynitrones 31 -35 in yields of up to 95%. The obtained highly polar polynitrones 31 -32 were modified by irradiation with UV-light.

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“…One of these is represented in Scheme I1 and concerns the initial preparation of the N-tert-butylbenzaldimine ( 4 ) , its oxidation to 2-tert-butyl-3-phenyloxazirane ( 5 ) and at the end the ring opening to PBN (1) (9). Another difficulty involved in step ii), the preparation of 2-tert-butyl-3-phenyloxazirane ( 5 ) , is its inclination toward fast hydrolysis producing the starting benzaldehyde ( 2 ) and Ntert-butyl-hydroxylamine (3) (9)(10)(11)(12). This collateral behaviour G. Angelini, F. Carnavalerti and F. Piccinini can be partially avoided employing particular reaction conditions, such as neutral condition and short purification time.…”

Section: Results Discussionmentioning

confidence: 99%

Synthesis of [¹⁴C]‐labeled N‐tert‐butyl‐α‐phenylnitrone. A potential spin‐trapping agent

Angelini

Carnevaletti

Piccinini

1992

Labelled Comp Radiopharmac

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Oxaziridines. I. The Irradiation Products of Several Nitrones¹

Cited by 113 publications

References 3 publications

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

Polymeric nitrones, 1. Synthesis and modification of polymeric nitrones derived from polymerizable aldehydes

Synthesis of [¹⁴C]‐labeled N‐tert‐butyl‐α‐phenylnitrone. A potential spin‐trapping agent

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Oxaziridines. I. The Irradiation Products of Several Nitrones1

Cited by 113 publications

References 3 publications

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

A comprehensive spectroscopic investigation of α-(2-naphthyl)-N-methylnitrone: a computational study on photochemical nitrone–oxaziridine conversion and thermal E–Z isomerization processes

Polymeric nitrones, 1. Synthesis and modification of polymeric nitrones derived from polymerizable aldehydes

Synthesis of [14C]‐labeled N‐tert‐butyl‐α‐phenylnitrone. A potential spin‐trapping agent

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Resources

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Oxaziridines. I. The Irradiation Products of Several Nitrones¹

Synthesis of [¹⁴C]‐labeled N‐tert‐butyl‐α‐phenylnitrone. A potential spin‐trapping agent