Search results for "Lactone"

Production de gamma-decalactone par bioconversion

1993

Qualitative and quantitative study of the mixture of two odorous compounds of wine

2003

National audience

Biocontrol of the parasitic plant species Phelipanche ramosa, using rapeseed rhizosphere fungi or phytotoxic metabolites they produce.

2019

Phelipanche ramosa (L.) Pomel, branched broomrape, is a major root-holoparasitic damaging weed with a large host range besides a strong adaptation to rapeseed. Broomrape seed germination is necessarily triggered by host root exudates. This ensures that they germinate close to a host root where they attach and establish a vascular connection to take up water and nutrients. No efficient broomrape management technique has been validated yet. Biocontrol could be an alternative but there is currently no biological control agent on the market. Indeed tripartite interactions between the host plant, the parasitic plant and a pathogenic agent of the latter are complex and poorly understood. The obje…

Biosynthesis of scarab beetle pheromones. Enantioselective 8-hydroxylation of fatty acids

1999

Chemical communication in scarab beetles (Coleoptera: Scarabaeidae) is achieved with a wide variety of pheromones, but one typical structure is the γ‐lactone having a long unsaturated hydrocarbon chain. Several species utilize (R,Z)‐5‐(–)‐(oct‐1‐enyl)‐oxacyclopentan‐2‐one (buibuilactone), (R,Z)‐5‐(–)‐(dec‐1‐enyl)‐oxacyclopentan‐2‐one and (S,Z)‐5‐(+)‐(dec‐1‐enyl)‐oxacyclopentan‐2‐one [(R)‐japonilure and (S)‐japonilure]. Using deuterated precursors, we have demonstrated that these compounds are biosynthesized from fatty acids. (9,10‐d4)‐Palmitic acid, (9,10‐d4)‐stearic acid, (9,10‐d2)‐palmitoleic acid, (9,10‐d2)‐oleic acid, (9,10‐d2)‐8‐hydroxypalmitoleic acid and (9,10‐d2)‐8‐hydroxyoleic acid…

The mechanism of formation of 3H,9H-Pyrano[3,4-b]indol-3-ones from 3-indolalkanoic acids

1991

The mechanism of the formation of 1-methyl-3H,9H-pyrano[3,4-b]indol-3-one (4) from the corresponding 3-indolacetic acid 1 is discussed. The suggested mechanism is substantiated by the isolation of a stable intermediate 2 and its transformations in the presence of acetic anhydride and/or Lewis acids.

Antibacterial performance of solvent cast polycaprolactone (PCL) films containing essential oils

2013

Abstract The increase of consumer demand for higher quality and longer shelf-life in foods, while reducing the use of non-compostable packaging materials, has encouraged research on biopolymers incorporating natural antimicrobial compounds. Cinnamaldehyde (CNMA) and allyl isothiocyanate (AITC) were incorporated into polycaprolactone (PCL) films by solvent casting. The release study was carried out by means of ATR and transmission FTIR spectroscopy and showed high volatility of the essential oils during the film forming process. While only negligible quantities of AITC were retained in the polymer matrix after film curing, the release of CNMA was prolonged for at least 50 h at room temperatu…

Synthetic Studies towards Pectenotoxin-2: Synthesis of the Nonanomeric 10-epi-ABCDE Ring Segment by Kinetic Spiroketalization

2011

The synthesis of the nonanomeric 10-epi-ABCDE ring system of pectenotoxin-2 has been achieved by using a kinetic spiroketalization reaction. The synthesis of the spiroketalization precursor was achieved through a cross-metathesis/hydro-genation sequence. The formation of the epi-C10 isomer resulted from an unexpected anti-Felkin selective addition of organometallic nucleophiles to the advanced CDE ring precursor. This addition reaction was investigated with differently protected α,β-dioxygenated model aldehydes, which displayed similar anti-Felkin selectivities with organometallic nucleophiles.

β-Alkyl- und β-Alkyl-α-hydroxycarbonsäure-Derivate über radikalische oder ionische 1,4-Addition von Dialkylaluminiumchloriden an α,β-ungesättigteN-Ac…

1991

Synthesis of Spirovetivane Sesquiterpenes from Santonin. Synthesis of (+)-Anhydro-?-rotunol and All Diastereomers of 6,11-Spirovetivadiene.

2005

The synthesis of the spirovetivane sesquiterpenes (+)-anhydro-beta-rotunol and all the diastereomers of 6,11-spirovetivadiene in enantiomerically pure form has been achieved starting from santonin. The key step is the silicon-guided acid-promoted rearrangement of a 1-trimethylsilyl-4,5-epoxyeudesmane prepared from santonin in several steps involving lactone reductive opening, conjugate addition of TMSLi-CuCN, deoxygenation of a carbonyl group, and epoxidation. Rearrangement of the epoxide gave a spiro[4,5]decanediol which was used as a synthetic intermediate. From this compound, (+)-anhydro-beta-rotunol was prepared after elimination of the primary hydroxyl group in the side chain, followed…

Semisynthesis of new tetrahydrofuranic alkyl ester and furano-pyrone derivatives as inhibitors of the mitochondrial complex I

2002

Abstract Methoxymethylation of altholactone ( 1 ) led to the corresponding O -methoxymethyl derivative ( 3 ) in addition to the unexpected 6,7-dihydro-7-methoxy analogue ( 4 ), and two original tetrahydrofuranic (THF) alkyl esters ( 5 , 6 ). Moreover, when we accomplished a new method for the preparation of the furano-pyrone goniofupyrone ( 7 ) through 7-hydroxylation of 1 in acid medium, a minor compound ( 8 ) with an identical skeleton to that of compounds 5 and 6 was identified. Careful examination of the published spectral data of the reported styryl-lactones with an heptolide skeleton reveals that those structures possess also a THF alkyl ester skeleton. The revision of those structure…