Series Of Lactones Research Articles

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VII

A series of lactones and lactams have been examined by matrix isolation Fourier transform infrared spectrometry. The values for the carbonyl absorption bands fall between those reported for the same compounds in the vapor phase and solid state. Multiple absorption bands are found in the region of carbonyl absorption for compounds examined under the matrix isolation phase. Ring strain has a dramatic effect on simplifying the complexity of the spectra. Little or no aggregation effects are observed for either the lactones or lactams under accepted operating parameters. The effects of substituents on these systems are comparable to those found in the vapor-phase and solid-state data.

Radical reactions of carbohydrates. Part 6. An electron spin resonance. Study of the reaction of the hydroxyl radical with some lactones derived from sugars and with ascorbic acid

For a series of lactones derived from sugars it is shown that reaction of ˙OH (from the TiIII–H2O2 couple) takes place preferentially at C(2) to give the appropriate carboxy-conjugated radical. Radicals formed by abstraction of C(3)–H in the γ-lactones are shown to react readily both by ring-opening [via fission of the C(β)–O(acyloxy) bond] and by rapid oxidation with H2O2, evidently to give enediols related to ascorbic acid. Oxidation of the latter with ˙OH is suggested to proceed both via direct electron transfer (at pH >5) and, at lower pH, addition to the enolic double bond followed by either acid-or base-catalysed elimination of water.

The Reaction of Hmpa With Lactones: Unsaturated Amide Formation

Abstract A series of lactones have been reacted with HMPA at elevated temperatures. In most of the examples studied, unsaturated amides were produced in relatively good yields.

Synthetic studies in the tetranorditerpene lactone series. I. The total synthesis of dihydro-8-epi-acrostalidic acid

The total synthesis of dihydro-8-epi-acrostalidic acid ( 8b ) and other related tetranorditerpene lactones are described.

Isolement et analyse structurale du collybolide, nouveau sesquiterpene extrait de Collybia maculata alb. et sch. ex fries (basidiomycetes)

From Collybia maculata Alb. et Sch. ex. Fries two sesquiterpenes of a new type have been isolated, collybolide 1 and isocollybolide 2, artefacts resulting from carboxylic acid precursors as yet not isolated. The structure of collybolide is established by correlation with that of isocollybolide, already known, and their reactivity has been studied. NMR spectra allow the conformational analysis of all products isolated. A series of lactones (β-, γ-, σ- and ϵ-lactones) in various solvents has been studied through 13C NMR spectroscopy. The chemical shift of the carbonyl carbon appears characteristic of the type of lactone. The distinction is particularly clear between γ-lactones (+13·5 to +16 ppm/CS 2) and σ-lactones (+20 to +22 ppm).

Keten. Part VIII. The Adducts of Dimethylketen with Substituted Cinnolines

Dimethylketen forms two types of adduct with cinnolines, both having oxadiazinocinnolinone structures. Cinnolines with no substituent in the 3 position form exclusively the [1,3,4]oxadiazino[4,3-a]cinnolinones (I) resulting from nucleophilic attack on the keten by N-2. 3-Alkylcinnolines form predominantly the [1,3,4]oxadiazino[3,4-a]cinnolinones (II) arising from nucleophilic attack by N-1. Hydrolysis of these adducts gives the normal amido-acids, which form different series of lactones with electrophiles. An unusual N-1 de-alkylation of a substituted tetrahydrocinnoline by polyphosphoric acid has been observed.

357. The alkaloids of the amaryllidaceae. Part XII. The aromatic oxygenation patterns and stereochemistry of some trioxyaryl alkaloids of the hemiacetal and lactone series

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