Photochemistry of o-tolualdehyde: photoenolization and photobenzoin condensation

Findlay, David M.; Tchir, Morris F.

doi:10.1039/c39740000514

Cited by 23 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The photoproduct was isolated and established to be the cyclobutenol 7b (eq 1). , As the reactions in solid state are most often topochemically controlled, − the regiochemistry of the photoproduct must be 7b as demanded by the molecular structure of its precursor aldehyde 2b in the solid state (vide infra). Interestingly, photolysis of its benzene solution (0.1 M) for 12 h in a Rayonet reactor (λ max = 350 nm) led to a highly intractable mixture of products; 1 H NMR (400 MHz) analysis of the mixture indicated no evidence for the cyclobutenol . Thus, the solid-state photolysis in the present instance leads to a product that is regioselective and also inaccessible from solution-phase photolysis.…”

mentioning

confidence: 73%

Solid-State Photochromism and Photoreactivity of o- and p-Anisaldehydes. Remarkable Stabilization of o-Xylylenols

et al. 2001

View full text Add to dashboard Cite

[reaction: see text] All of the crystalline o-anisaldehyde derivatives 1 and 3 change to brick-red color upon brief exposure to UV-vis radiation. The red color, attributed to (E)-xylylenol, is remarkably persistent for hours (ca. 10 h) in the case of 1c; such a long lifetime for the reactive o-xylylenols is unprecedented. In contrast, the p-anisaldehydes 2 undergo cyclization. Solid-state photolysis of 2b affords the benzocyclobutenol 7b regioselectively, which is not accessible from solution-phase photolysis.

show abstract

mentioning

confidence: 73%

Solid-State Photochromism and Photoreactivity of o- and p-Anisaldehydes. Remarkable Stabilization of o-Xylylenols

et al. 2001

View full text Add to dashboard Cite

show abstract

“…Similar processes are well known in a number of ortho-substituted aromatic systems. 16 Photostability of 2 also provides a handle for estimating the lower concentration limit for 1 at which the rearrangement pathway begins to operate (ca. 6 X 10-3 M in ethanol and ca.…”

Section: Resultsmentioning

confidence: 99%

Photoinduced rearrangement and related reactions of ethyl N-phenylcarbamate

Masilamani¹,

Hutchins²,

OHR³

1976

J. Org. Chem.

View full text Add to dashboard Cite

“…Support for this interpretation comes from the similarity in the activation energy (AE31) of ~ 1200 cm -1 determined from the phosphorescence lifetime data and the activation energy of 1400 cm -1 determined by Migirdicyan for photoenol formation. It is well known [27,29] that photoenol formation proceeds very efficiently in those orthomethyl substituted aldehydes with lowest 3nzr* states. However, there is evidence from similar systems that the intramolecular photoenol is not very stable and readily reverts to the aldehyde [27,28].…”

Section: Identification Of Triplet Species and Connection With Known mentioning

confidence: 99%

Primary photophysical and photochemical processes of 2,4,5-trimethylbenzaldehyde in crystalline durene

et al. 1977

View full text Add to dashboard Cite

The temperature dependence (10-160 K) of the phosphorescence lifetimes and intensities of 2,4,5-trimethylbenzaldehyde (TMB) in crystalline durene have been investigated. Two phosphorescence bands (407"5 and 411'2 nm) are observed to grow in with increasing temperature, reach a maximum intensity, and decrease in intensity at higher temperatures. Exponential phosphorescence decays are observed in the 10 to 95 K and 110 to 160 K ranges, while non-exponential decays are observed in the 95 to 110 K region. Ultra-violet photolysis, particularly at higher temperatures, is seen to decrease the intensity of the infra-red carbonyl stretching band at 1703 cm -x, but not the one at 1684 cm -1. A model in which two inequivalent sets of TMB molecules in the durene lattice undergo their own unique photochemical and photophysical processes is suggested to explain the results. It is proposed that within each site the lower, predominantly Z~rrr* state of the anti TMB conformer is in thermal equilibrium with the higher-lying 3nrr* state of the syn conformer which is formed by out-of-plane rotation of the aldehyde group in the excited state. In one site, intramolecular photoenol formation occurs via thermal activation from the 3nr* of the syn conformer, while in the other site intermolecular hydrogen abstraction occurs, leading to the simultaneous production of a photoenol and a duryl radical. This model is shown to be consistent with previous knowledge of the primary photochemical processes of TMB in durene.

show abstract

Photochemistry of o-tolualdehyde: photoenolization and photobenzoin condensation

Cited by 23 publications

References 0 publications

Solid-State Photochromism and Photoreactivity of o- and p-Anisaldehydes. Remarkable Stabilization of o-Xylylenols

Solid-State Photochromism and Photoreactivity of o- and p-Anisaldehydes. Remarkable Stabilization of o-Xylylenols

Photoinduced rearrangement and related reactions of ethyl N-phenylcarbamate

Primary photophysical and photochemical processes of 2,4,5-trimethylbenzaldehyde in crystalline durene

Contact Info

Product

Resources

About