The Photochemical Reactions of Alkyl Phenylglyoxalates in Alcohols<sup>1</sup>

Huyser, Earl S.; Neckers, Douglas C.

doi:10.1021/jo01025a004

Cited by 44 publications

(33 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Solvents that are potential hydrogen-radical sources can interfere with the desired Norrish type-II fragmentation by H-transfer to the intermediate diradical, resulting in the formation of dimers or photoreduction products [4] [6] [7]. Comparison of the irradiation results of citronellyl keto esters 3, 4, and 7 ± 11 in different solvents (Table 1) shows the formation of citronellal to be roughly independent of the solvent.…”

Section: Photoirradiations Of A-keto Esters In Undegassed Solutions Amentioning

confidence: 99%

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Rochat

Minardi

Laumer

et al. 2000

HCA

View full text Add to dashboard Cite

Alkyl or aryl a-keto esters of primary or secondary alcohols decompose upon irradiation at 350 ± 370 nm from the intermediate triplet state into aldehydes or ketones in polar, as well as apolar solvents. The use of these keto esters as delivery systems for the controlled release of perfumery aldehydes and ketones was investigated by photoirradiation in the presence of oxygen with a Xe or UV lamp, as well as outdoor sunlight. Systematic GC/ MS analysis of the irradiated solutions showed that, under these conditions, the desired Norrish type-II fragmentation of the ester side chain is the predominant reaction pathway in most of the cases. g-H Abstraction from the alkyl side chain of alkyl keto esters, as well as an intramolecular PaternoÁ-Büchi reaction or epoxidation of the alkene function in different citronellyl a-keto esters were identified as the most important side reactions. Some of the experimental findings have been rationalized on the basis of ab initio and density-functional calculations. (Cyclohexyl)oxoacetates and oxo(phenyl)acetates were found to be the most suitable precursors for the desired perfumery applications.1. Introduction. ± Aldehydes and ketones are important classes of fragrances that are present in all kinds of perfumes. However, many of them are very volatile and can, after application, only be perceived over a relatively short period of time. Furthermore, as constituents of perfumes for a variety of different bodycare or household applications, such as shampoos, soaps, all purpose cleaners, fabric softeners, or detergent powders, they are often too hydrophilic and thus easily carried away by water during various rinsing processes instead of staying on substrates like hair, skin, or fabrics.To prolong the desired odor perception of this class of compounds, we have prepared a series of photolabile, hydrophobic, non-volatile fragrance precursors as potential delivery systems for the controlled release of perfumery aldehydes and ketones in typical bodycare and household applications. In this publication, we describe the fragrance release from a-keto esters upon irradiation with artificial light sources, as well as natural sunlight in the presence of O 2 [1]. Some interesting fragrances for release in functional perfumery are depicted in Fig. 1 [2].The photolysis of alkyl or aryl a-keto esters of primary or secondary alcohols has been intensively studied since the early sixties [3 ± 7]. It was found that these esters decompose from their intermediate triplet state into aldehydes or ketones upon irradiation at 350 ± 370 nm in polar, as well as apolar solvents [7 ± 11]. Most of the photoirradiations described in the literature were carried out in degassed solutions in the absence of O 2 . The relatively good yields of the fragmentation process have allowed the use of a-keto esters as intermediates for the transformation of primary or secondary alcohols to aldehydes and ketones, respectively [12].

show abstract

Section: Photoirradiations Of A-keto Esters In Undegassed Solutions Amentioning

confidence: 99%

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Rochat

Minardi

Laumer

et al. 2000

HCA

View full text Add to dashboard Cite

show abstract

“…From the known behaviour of other n n * carbonyl compounds (9), the most likely pathway of reaction [5] is the Norrish Type I1 process, i. e.…”

Section: Frc 6 Arrhenius Plot For the Intramolecular Hydrogen Abstrmentioning

confidence: 99%

“…The only reported rate constant has been given by Zanocco et al in a communication on the photolysis of methyl benzoylfonnate (4). The product distribution and product quantum yield in the photolysis of aliphatic esters of benzoylfonnic acid are extremely dependent both upon the solvent (1) and temperature (5). In solvents bearing labile hydrogen atoms the main products have been rationalized by a mechanism involving keto ester photoreduction (1).…”

mentioning

confidence: 99%

Photochemistry of alkyl esters of benzoylformic acid

Encinas¹,

Lissi²,

Zanocco³

et al. 1984

Can. J. Chem.

View full text Add to dashboard Cite

The photodecomposition of several alkylbenzoylformates has been examined using quantum yield and laser flash photolysis techniques. The Norrish Type II reaction is a major triplet deactivation path in all substrates having γ-hydrogen atoms. Representative triplet lifetimes are 670, 500, and 310 ns, for the methyl, ethyl, and isopropyl esters, respectively, in 1:4 chlorobenzene: n-heptane at 298 K. Product studies suggest that several competing reactions are involved in the decay of the 1,4-biradical; some of these lead to highly absorbing (and presumably quenching) products, that make it essential to extrapolate quantum yields to "zero conversion" conditions.

show abstract

“…16,17 The solution-phase photochemistry of several a-keto esters has been studied by several investigators. [18][19][20] In alcoholic solvents at room temperature, both ethyl pyruvate and ethyl benzoylformate are efficiently photoreduced to the corresponding pinacols. [19][20][21] In an inert solvent such as benzene, a-keto esters photodecarbonylate with subsequent hydrogen transfer to yield the aldehyde or ketone derived from the alcohol portion.…”

Section: Introductionmentioning

confidence: 99%

“…[18][19][20] In alcoholic solvents at room temperature, both ethyl pyruvate and ethyl benzoylformate are efficiently photoreduced to the corresponding pinacols. [19][20][21] In an inert solvent such as benzene, a-keto esters photodecarbonylate with subsequent hydrogen transfer to yield the aldehyde or ketone derived from the alcohol portion. 18 Zinc oxide has attracted the attention of many researchers during recent years because of its many interesting properties.…”

Section: Introductionmentioning

confidence: 99%

In vitro Photo‐Oxidation of Pyruvate to Acetyl: A Main Source for the Formation of Acetyl Coenzyme A in the Citric Acid Cycle to Perform Biochemical Reactions

Farrukh

Naz

2013

J Chinese Chemical Soc

View full text Add to dashboard Cite

The kinetics of photooxidation of pyruvate was investigated in presence of zinc oxide catalyst under illumination of visible light. The influence of different parameters such as concentrations of reactants, amount of catalyst and irradiation time was studied on the redox reaction under pseudo-first order conditions. The results indicated that amount of catalyst, presence of electron accepter in solution and irradiation time was the key factors influencing the efficiency of photo-oxidation of pyruvate to acetyl.

show abstract

The Photochemical Reactions of Alkyl Phenylglyoxalates in Alcohols¹

Abstract: Huyser and NeckersVol. 29 iaojervine triacetate IVb (lack of contribution of 17,17a-double bond); 5.79 (s), 5.86 (s), 5.93 (a), 6.11 (a), 8.08 (s) µ. For analysis the material was lyophilized from benzene and dried at 56°( 2 mm.) for 3 hr.

Cited by 44 publications

References 0 publications

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Photochemistry of alkyl esters of benzoylformic acid

In vitro Photo‐Oxidation of Pyruvate to Acetyl: A Main Source for the Formation of Acetyl Coenzyme A in the Citric Acid Cycle to Perform Biochemical Reactions

Contact Info

Product

Resources

About

The Photochemical Reactions of Alkyl Phenylglyoxalates in Alcohols1

Abstract: Huyser and NeckersVol. 29 iaojervine triacetate IVb (lack of contribution of 17,17a-double bond); 5.79 (s), 5.86 (s), 5.93 (a), 6.11 (a), 8.08 (s) µ. For analysis the material was lyophilized from benzene and dried at 56°( 2 mm.) for 3 hr.

Cited by 44 publications

References 0 publications

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Controlled Release of Perfumery Aldehydes and Ketones by Norrish Type-II Photofragmentation of -Keto Esters in Undegassed Solution

Photochemistry of alkyl esters of benzoylformic acid

In vitro Photo‐Oxidation of Pyruvate to Acetyl: A Main Source for the Formation of Acetyl Coenzyme A in the Citric Acid Cycle to Perform Biochemical Reactions

Contact Info

Product

Resources

About

The Photochemical Reactions of Alkyl Phenylglyoxalates in Alcohols¹