Preparazione di ulteriori α‐cheto‐γ‐lattoni e scissione termica degli α‐cheto‐γ‐lattoni con sostituenti alchilici in posizione γ

Schinz, H.; Rossi, A

doi:10.1002/hlca.19480310711

Cited by 8 publications

(1 citation statement)

References 23 publications

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“…CH2CH3 CH3 CH2CH2CH3 (Ill) (IV) The Cs homologue, a-keto-&ethyl-y-enantholactone (IV), has been synthesized in this laboratory by the method of Monnin (1957), and it had a flavor much weaker than, and different in character from, that of the C, compound. Although the literature on other a-keto-r-lactones--carrying alkyl groups in the & or y-positions-is quite extensive (Schinz et al, 1947 ;Schinz et al, 1948 ;Monnin, 1957)) no reports on their flavor have been made. The correlation between structure and organoleptic quality of compounds within this group should constitute a fruitful area for further study.…”

Section: Resultsmentioning

confidence: 98%

A Probable Flavoring Principle in Vegetable‐Protein Hydrolysates

Sulser¹,

DePIZZOL²,

Bühi³

1967

Journal of Food Science

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SUMMARY— The characteristic seasoning flavor of hydrolyzed vegetable proteins has previously been attributed to α‐ketobutyric acid formed from threonine under the conditions of acid‐hydrolysis. However, pure α‐ketobutyric acid is virtually odorless and tasteless, and it develops the characteristic flavor only upon ageing. The true flavoring principle is probably α‐hydroxy‐β‐methyl‐Δ.α,β‐γ‐hexenolactone, which is formed from the acid by dimerization, lactonization, and decarboxylation. This conversion occurs spontaneously, but is greatly accelerated under acidic conditions.

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Section: Resultsmentioning

confidence: 98%

A Probable Flavoring Principle in Vegetable‐Protein Hydrolysates

Sulser¹,

DePIZZOL²,

Bühi³

1967

Journal of Food Science

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The fragmentation of isotetronic acids under electron impact

Bonini

Iavarone

Trogolo

et al. 1980

Org. Mass Spectrom.

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The mass spectral fragmentation of eleven or-hydroxybutenolide compounds (isotetronic acids) are reported. The main features are carboxyl and consecutive carbon monoxide expulsions. Masses were determined using high resolution techniques, metastable transitions were detected by defocusing experiments, and pathways were further documented by isotopic labelling experiments. INTRODUCGONIsotetronic acids (3-hydroxy-2-(5H)-furanones) possess the a-hydroxy-y-lactone structure 1 and havebeen isolated from a variety of natural sources.'-3 Properties leading to their use as flavouring agents,' anti-depressants4 and perfumes' have been described, and analgesic6 and antifunga17 activity has been tested.Although the closely related tetronic acids8 (2) (Bhydroxy-y-lactone) and the parent y -1actones' have been studied by mass spectrometry, n o detailed reports on the fragmentation of isotetronic acids have appeared. We have thus synthesized several representative isotetronic acids and have examined their electron impact induced fragmentations. In the following text the common features of these fragmentations, supported by high resolution (data were obtained on all peaks in the spectra of compounds 1, 2, 5, 8 and 91, metastable ion peak and isotopic labelling data, will be discussed. RESULTS AND DISCUSSION Fragmentation 1: elimination of XO,H from ringUnlike the tetronic acids,' the isotetronic acids studied here (see below) fragment primarily by loss of -CO,H to produce ions a at [M-45]+. This fragmentation may occur in two ways; the first may involve transfer of the 3-hydroxyl proton to the carbonyl group, followed by C-2-C-3 and 0-1-C-5 bond scission and t Authors to whom correspondence should he addressed. .CO,H loss (see Scheme l), while the second could involve loss of the 3-hydroxyl and carbonyl group, with the ring oxygen (0-1) being retained in the charged fragment. Labelling studies suggest that both processes are involved, with the former pathway predominating.* Second field free region metastables that were detected are indicated in the Schemes. For the first field free region metastables, see Experimental.Scheme 1. Fragmentation 1 : Elimination of .CO,H from the ring.

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Synthesis of some 3‐deoxy‐heptulosonic acids

Paerels

Geluk

1970

Recl. Trav. Chim. Pays‐Bas

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The detailed syntheses of 3-deoxy-~-arobifto-and 3-deoxy-~-lyxo-heptulosonic acids are described. The arabiito isomer was purified by LLC on cellulose. In the arabirto series an enolized 2-keto-I ,4-lactone and in both the arabino and lyxo series 2-keto-imido-1 ,rl-lactones were isolated. The chemical and spectroscopic properties of these compounds are discussed. A number of other derivatives are described. The UV spectra of the semicarbazones of 2-ketoacids and their lactones or esters are discussed. The structure of a quinoxaline derivative of the 3-deoxy-~-arabirzo-heptulosonic acid has been studied. The intermediates 1Va and IVb were obtained by treatment of IlIa and lIIb with H2O at IOO", but not by treatment with dilute HCI, as this led to acidic syrups in which the 3-deoxy-heptulosonic acids Va and Vb,

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Preparazione di ulteriori α‐cheto‐γ‐lattoni e scissione termica degli α‐cheto‐γ‐lattoni con sostituenti alchilici in posizione γ

Abstract: A. Durch Kondensation von Na‐oxalessigester mit n‐Butyraldehyd und Önanthaldehyd und nachfolgende Ketonspaltung wurden γ‐n‐Propyl‐ und γ‐n‐Hexyl‐α‐keto‐γ‐lacton hergestellt.

Cited by 8 publications

References 23 publications

A Probable Flavoring Principle in Vegetable‐Protein Hydrolysates

A Probable Flavoring Principle in Vegetable‐Protein Hydrolysates

The fragmentation of isotetronic acids under electron impact

Synthesis of some 3‐deoxy‐heptulosonic acids

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