730-46-1Relevant articles and documents
W(OTf)6-Catalyzed Synthesis of Γ-Lactones by Ring Contraction of Macrolides or Ring Closing of Terminal Hydroxyfatty Acids in Ionic Liquid
Xie, Zhong-Yu,Deng, Jin,Fu, Yao
, p. 2332 - 2339 (2018/07/31)
γ-Lactones are an important class of fine chemical products and are widely used in perfumes, medicines, pesticides, dyes, and other fields. Herein, a new method for γ-lactones preparation based on ring contraction was developed. Starting from macrolides, W(OTf)6 was used to catalyze the ring-opening polymerization then depolymerization. The depolymerization step was not a common ring-closing process, and the carbon number of the ring was reduced one by one by rearrangement to form the most thermodynamically stable five-membered ring compounds. γ-Caprolactone (180 °C for 10 h) was obtained in a yield of 94 % when [EMIM]OTf was used as the solvent, and the yield of isolated product was up to 85 %. The interaction of various components and the reaction mechanism were studied by FTIR spectroscopy and 1H NMR spectroscopy, respectively. Furthermore, γ-lactones could be produced when the substrate was extended to terminal hydroxyfatty acids. Unexpectedly, the catalyst was poisoned by 1 equivalent of H2O added during the process and thus the yield decreased greatly. The reaction is green and simple, and proceeds in one pot with high atom economy (100 % for macrolides and with water as the only byproduct for terminal hydroxyfatty acid), which provides a promising approach to synthesizing γ-lactones.
Silver triflate-catalysed synthesis of γ-lactones from fatty acids
Goossen, Lukas J.,Ohlmann, Dominik M.,Dierker, Markus
supporting information; experimental part, p. 197 - 200 (2011/02/27)
A silver(i)-based catalytic system was found to efficiently promote the double-bond isomerization of unsaturated fatty acids and at the same time to mediate the intramolecular addition of the carboxylate group to the isomerized double bond under selective formation of five-ring lactones. The resulting one-step isomerization-γ-lactonization process allows the direct conversion of unsaturated fatty acids into the corresponding γ-lactones in good yields.
Sensory-directed identification of creaminess-enhancing volatiles and semivolatiles in full-fat cream
Schlutt, Birgit,Moran, Noelia,Schieberle, Peter,Hofmann, Thomas
, p. 9634 - 9645 (2008/03/17)
Aimed at defining the chemical nature of creaminess-related flavor compounds in dairy products on a molecular level, a full-fat cream was analyzed for sensorially active volatiles and semivolatiles by means of activity-guided screening techniques. Application of the aroma extract dilution analysis on an aroma distillate prepared from pasteurized cream (30% fat) revealed δ-decalactone, (Z)-6-dodeceno-γ-lactone, γ-dodecalactone, δ-dodecalactone, and 3-methylindole with by far the highest flavor dilution (FD) factors among the 34 odor-active volatiles identified. Using a complementary approach involving silica column chromatography and fractionated high-vacuum distillation combined with sensory experiments enabled the additional identification of δ-tetradecalactone, δ-hexadecalactone, γ-tetradecalactone, γ-hexadecalactone, and δ-octadecalactone as semivolatile flavor components in the cream fat. Although a series of lactones is present in dairy cream, spiking of cream samples with individual lactones revealed that only the δ-tetradecalactone is able to enhance the typical retronasal creamy flavor of the product when added in amounts above its theshold level of 66 μmol/kg. Rather than contributing to the retronasal aroma of cream, first evidence was found that, particularly, γ- and δ-octadecalactones and γ- and δ-eicosalactones are able to influence the melting behavior of cream in the oral cavity.
Formation of isomeric monohalo-n-alkanoic acids in the reactions of γ- and δ-n-alkanolactones with hydrogen halides
Granata, Alessandro,Perlin, Arthur S.
, p. 864 - 871 (2007/10/02)
In 57percent hydriodic acid or 48percent hydrobromic acid, under reflux, n-alkanoic γ- or δ-lactones of form 5 to 18 carbon atoms undergo facile ring opening to monohalo-n-alkanoic acids.With both reagents the ratio of acid to lactone at equilibrium varies widely, ranging from about 1:3 for γ-valerolactone (C5) to 3:1 or more for γ-octanolactone and the larger members of the series.Extemsive scrambling of the halogen atoms accompanies the formation of the haloacids, whereby mixtures of monohalo isomers substituted at all positions from C-4 to the penultimate carbon are found.In an 18 h reaction with HBr, for example, γ-caprolactone was converted into a 1:3 mixture of 4- and 5-bromohexanoic acids, and γ-decanolactone into 1:1.4:1.4:1.4:2.3:2.3 mixture of 4-, 5-, 6-, 7-, 8-, and 9-bromodecanoic acids.By contrast, the γ-lactones containing 14 or 16 carbon atoms gave only 10:1 mixtures of the 4- and 5-bromoacids, and at the level of 18 carbon atoms rearrangement was was no longer evident; i.e., γ-octadecanolactone afforded only 4-bromooctadecanoic acid.Similar isomer distributions were obtained for the iodoacid homologs.Hydrochloric acid (37percent) was far less effective in opening the lactone rings, and also in inducing rearrangement of the chlorine atoms introduced.Differences in entropy and in solvation appear to be the main factors contributing to the variations observed among isomeric lactones.
