999-40-6Relevant academic research and scientific papers
New neryl esters from Helichrysum italicum (Roth) G. Don (Asteraceae) essential oil
?or?evi?, Miljana R.,?ivkovi? Sto?i?, Milena Z.,Aksi?, Jelena M.,Gen?i?, Marija S.,Mladenovi?, Marko Z.,Radulovi?, Niko S.
supporting information, (2020/11/02)
Helichrysum italicum (immortelle) is a dwarf aromatic shrub native to the Mediterranean region. The typical subspecies (italicum) produces an essential oil rich in neryl acetate and characteristic β-diketones, italidiones, highly valued in the perfume industry. As esters are an important group of aroma-active volatiles, herein the composition of the ester fraction of this immortelle chemotype essential oil was studied in detail. Chromatographic separation of Corsican immortelle essential oil enabled the discovery of numerous potentially olfactory-interesting esters of nerol and/or angelic acid, undetectable by direct GC-MS analyses of the unfractioned oil. Four esters of nerol and medium-chain branched fatty acids represent new natural products, while several other esters have a rather restricted occurrence in the Plant Kingdom.
A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases
Lozano, Pedro,Bernal, Juana M.,Navarro, Alicia
, p. 3026 - 3033 (2013/01/15)
A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL-1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.
STEREOSELECTIVE LIPASE-CATALYSED ACYLATION OF TERPENIC ALLYLIC ALCOHOLS BY FATTY ACID ANHYDRIDES
Foumeron, Jean-Dominique,Chiche, Melissa,Pieroni, Gerard
, p. 4875 - 4878 (2007/10/02)
Lipase from pancreatic powder preferentially catalyses the acylation of the E isomer of terpenic allylic alcohols using fatty acid anhydrides as the acylating agent.The course of the reaction can be described by a first-order equation.
