Academic literature on the topic 'Oak lactones'

The influence of the addition of oak chips and barrel ageing on basic wine parameters and volatile compounds of Chardonnay wines has been studied. Chardonnay wines were obtained by the traditional wine-making process. Oak chips (4 g/L—non-toasted and light toasted) were added at the final stage of the winemaking process for ageing 1, 2 and 3 months, respectively. Also, the control wine was aged in non-toasted barrels for the same period of time. Following Liquid-liquid extraction-gas chromatography-mass spectrometry analysis, alcohols, esters, fatty acids, lactones, and phenolic compounds were identified and quantified. The light toasted wine was clearly separated by phenolic compounds (vanillin, p-vinyl guaiacol and acetovanillone). The floral aroma supplied by 2-phenylethanol was slowly increased by ageing with odor activity values (OAV) higher in aged samples than control wine (1.07). The vanilla scent could be easily perceived in all aged samples, mainly for light toasted chip-treated samples with OAV values between 2.30 and 2.37. After 3 months, the volatile compounds of wine from non-toasted medium (chips and barrels) were almost similar from the volatile profile point of view. This could have economic and vinification management implications since oak barrels are expensive and the wine oak barrel aging is a long process. All wines studied in this research can provide a viable alternative to young varietal wines.

The aim of this work was to compare the variations of alcohols compounds in white wine Muscat Ottonel variety aged in the presence of untoasted oak chips, toasted oak chips and untoasted barrel, considering three ageing periods—30, 60, and 90 days. The liquid-liquid extraction and gas chromatography coupled to mass spectrometry were used to compare the concentrations of the volatile constituents of Muscat Ottonel wines. A total of 51 volatile compounds were quantified. Alcohols, terpenic and carboxylic acids decreased with ageing time, whereas esters, lactones, and phenolic compounds increased due esterification processes. The chips toast level, method, and duration of ageing, significantly influenced the content of aromatic compounds. Partial least squares regression (PLS-R) clearly discriminated the initial wine and also the wines aged with toasted and untoasted medium. The compounds (alcohols and terpenes) that impart distinctive aroma of Muscat Ottonel were enhanced by untoasted medium. Light toasted oak chips enhanced wood volatile components (acetovanillone and p-vinyl guaiacol). This study provides important scientific results on the ageing of Muscat Ottonel wines with practical economic benefits to winemakers. Alternative less expensive ageing methods and improved control on the wood components extraction process, may contribute to obtaining high-quality wines.

In the present study we aimed to investigate the volatile organic compounds (VOCs) that may potentially be responsible for specific descriptors of Madeira wine providing details about Madeira wine aroma notes at molecular level. Moreover, the wine aroma profile, based on the obtained data, will be a starting point to evaluate the impact of grape variety (Malvasia, Bual, Sercial, Verdelho and Tinta Negra), type (sweet, medium sweet, dry and medium dry), and age (from 3 to 20 years old) on Madeira wine sensorial properties. Firstly, a comprehensive and in-depth Madeira wine volatile profiling was carried out using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS–SPME/GC–qMS). Secondly, a relation among the varietal, fermentative and aging aroma compounds, and their aroma descriptors with the Madeira wine sensorial properties was assessed. A total of 82 VOCs, belonging to different chemical families were identified, namely 21 esters, 13 higher alcohols, ten terpenic compounds, nine fatty acids, seven furanic compounds, seven norisoprenoids, six lactones, four acetals, four volatile phenols and one sulphur compound. From a sensorial point of view, during the aging process the wine lost its freshness and fruitiness odor related to the presence of some varietal and fermentative compounds, whereas other descriptors such as caramel, dried fruits, spicy, toasty and woody, arose during ageing. The Maillard reaction and diffusion from the oak were the most important pathways related with these descriptors. A relationship-based approach was used to explore the impact of grape variety, wine type, and age on Madeira wine sensorial properties based on shared number of VOCs and their odors.

Many modern alcoholic beverages are subjected to ageing processes during which compounds extracted from wood contribute decisively to the overall beverage character. Wines represent a perfect example of beverage in which ageing is a crucial technological manufacturing step. During winemaking, producers accelerate chemical changes in wine composition by traditional and alternative methods, such as the use of oak wood barrels and/or oak wood chips. Our research aimed to investigate the overall volatile composition and sensory quality of red wines aged for two timeframes, namely, 1.5 and 3 months, and with two technological variants, i.e., American and French oak wood chips. Red grapes from the Fetească neagră (Vitis vinifera) variety were harvested from a vineyard in the North-East region of Romania. Stir bar sorptive extraction and gas chromatography coupled with mass spectrometry (SBSE–GC–MS) was used to extract minor aromas present in wine samples. The results showed clear differences between wines treated with American and French oak chips. Furthermore, ageing for 3 months increased the concentration of cis-whiskey lactone and guaiacol in American oak-treated wine samples. For wines aged with French oak chips, we observed higher concentrations of furfural, 5-methylfurfural, 4-vinylguaiacol, and trans-whiskey lactone. The increased presence of chemical compounds in wine aged with French oak chips generated prominent smoky, licorice, and toasty aromas, whereas in wines aged with American oak chips, notes of vanilla, toasty, and cacao aromas were noticed. Moreover, red wines aged with American and French oak chips were discriminated by chemometric analysis, which confirmed the evolution of aroma compounds.

gamma-Lactones are found in a wide variety of food and beverage products, in particular grapes and wine. This thesis details the work completed on some gamma-lactones in wine: their synthetic preparation, development of quantification methodologies and sensory studies. Chapter 1 outlines the history of the Australian wine industry from the arrival of the first vines on the First Fleet in 1788 with Captain Arthur Philip. This chapter provides: an overview of Australia’s position in the world of grape and wine production; an analysis of the export arm of the industry; and a look at the different wine producing regions around the country. The latter part of the chapter focuses on the different volatile compounds found in wine. Part A: Chapter 2 provides an overview on the history of barrel manufacture and the use of oak wood in cooperage, with an emphasis on oak’s well known ability to impart desirable characteristics to wine through the extraction of volatile aroma compounds. This chapter provides a summary of these odorants with a particular emphasis on the oak lactones. Previous sensory studies and synthetic work are discussed. Of great importance to this work are the recent advancements in 1,2-dioxine chemistry, highlighted in this chapter. Chapter 3 details the synthetic work completed for the preparation of all four possible oak lactone stereoisomers. A suitably substituted racemic 1,2-dioxine featured as the common intermediate and enabled preparation of the gamma-lactone moiety upon reaction with a chiral malonate diester and separation of the diastereomers by column chromatography. A key step involved the decarboxylation of the ester cleaved gamma-lactone diastereomers, which could be directed to give either the cis- or trans-products. Standard chemical transformations were then utilised to produce the desired stereoisomers of oak lactone. Chapter 4 describes the results from the sensory studies that were completed on the synthetic oak lactone samples. Odour detection thresholds were measured in both a white and a red wine. The thresholds in the former medium were calculated to be 24 ug/L, 172 ug/L, 132 ug/L and 305 ug/L, while in the latter medium the thresholds were calculated to be 57 ug/L, 380 ug/L, 175 ug/L and 285 ug/L, for (4S,5S)-cis-, (4S,5R)-trans-, (4R,5R)-cis- and (4R,5S)-trans-oak lactone, respectively. Difference testings were completed on the pairs of enantiomers and also on mixtures of the nature-identical isomers: between the cis-enantiomers a significant difference was found at the 99% confidence level, while between the trans-enantiomers and also the mixtures of cis- and trans-isomers little difference was observed. Chapter 5 contains the experimental procedures for Part A. Part B: Chapter 6 discusses the sensory properties of some gamma- and delta-lactones, with the focus on a series of five-alkyl substituted gamma-lactones: gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. Topics covered in this chapter include chirality, biosynthetic pathways and quantification results in wine from previous studies for these gamma-lactones. Chapter 7 concerns the method development for the quantification of gamma-lactones in wine using a stable isotope dilution assay (SIDA). Deuterated analogues were prepared from commercially available racemic gamma-lactones for use as internal standards. Initially a head space solid-phase microextraction (HS SPME) method was developed using d5-standards; however, analysis of bottled wine samples revealed the presence of co-eluting compounds that contained several of the selected ions. Thus an alternative method was developed using d7-standards, with a specific focus on sample clean-up, via solid-phase extraction (SPE). Using this procedure, 44 white and 120 red wines were analysed for their gamma-lactone content. The lactones were found to be significantly more common in the red wines, with gamma-nonalactone the most abundant lactone in this series. Chapter 8 deals with the extension of the SIDA method, as developed in Chapter 7, for use with a chiral gas chromatography column. Optically pure standards were prepared, from either L- or D-glutamic acid, and used to determine the order of elution of the enantiomers. A method was developed for the quantification of the individual enantiomers of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. The enantiomeric distribution of gamma-nonalactone was investigated in 34 red wines; the (R)-stereoisomer was found to be dominant with an average of 59%, although there were wines analysed that did contain the (S)-stereoisomer in greater amounts. Chapter 9 describes the results from the sensory studies that were completed on the individual enantiomers of the gamma-lactones. Odour detection thresholds were measured in a red wine. The thresholds were calculated to be 238 ug/L, 285 ug/L, 34 ug/L and 8 ug/L for the (R)-enantiomers, while the thresholds were calculated to be 135 ug/L, 91 ug/L, 47 ug/L and 39 ug/L for the (S)-enantiomers, of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone, respectively. Chapter 10 contains the experimental procedures for Part B. Chapter 11 contains the appendices, followed by the references in Chapter 12.

L'addition de l'acide acetique et du monomethylmalonate de potassium sur des olefines en presence de mn(oac)#3, 2h#2o permet d'acceder a des gamma-lactones ou de alpha-carbomethoxy-gamma-lactones en une seule etape. Des olefines cycliques a six ou a huit chainons, lineaires et fonctionnalisees, ont ete utilisees pour ces reactions. Dans la plupart des cas, nous avons observe une excellente regioselectivite et une tres bonne diastereoselectivite. Nous avons precise un certain nombre d'elements concernant l'addition de l'acide acetique. Nous avons montre que l'oxygene moleculaire avait une influence sur cette reaction et qu'il est possible d'obtenir des gamma lactones hydroxylees en alpha a partir d'alpha carbomethoxy gamma lactones. Nous avons prepare des alpha methylene gamma lactones. Les reactions de carbomethoxylation et de decarbomethoxylation ont ete mises au point sur certaines gamma lactones. Enfin, nous avons etudie l'enantioselectivite de cette reaction a partir de malonates ou d'olefines portant un auxiliaire chiral. Les premiers resultats montrent que les gamma lactones ainsi formees sont obtenues avec un exces diastereoisomerique eleve

The unprecedented enantioselective 1,8-addition of azlactone 1 to acylpyrrole 2 catalyzed by triaminophosphorane 3 was reported (J. Am. Chem. Soc. 2012, 134, 19370) by Takashi Ooi at Nagoya University. Tomislav Rovis at Colorado State University developed (Angew. Chem. Int. Ed. 2012, 51, 12330) the asymmetric oxidative hetero-Diels-Alder reaction of propionaldehyde (5) and ketone 6 to produce lactone 8, catalyzed by NHC catalyst 7 in the presence of phenazine. A related NHC catalyst 11 was utilized (Angew. Chem. Int. Ed. 2012, 51, 8276) by Xue-Wei Liu at Nanyang Technological University for the homoenolate addition of enal 9 to nitrodiene 10 to furnish 12 with high ee. The vinylogous conjugate addition of butenolide 13 to 15 to produce 16 with exquisite stereoselectivity was accomplished (Angew. Chem. Int. Ed. 2012, 51, 10069) by Kuo-Wei Huang at KAUST, Choon-Hong Tan at Henan University and Nanyang Technological University, and Zhiyong Jiang at Henan University. The enantioselective production of lactone 18 was achieved (J. Am. Chem. Soc. 2012, 134, 20197) by Jeffrey S. Johnson at the University of North Carolina at Chapel Hill by dynamic kinetic resolution (DKR) of α-keto ester 17. A related DKR strategy was employed (Org. Lett. 2012, 14, 6334) by Brinton Seashore-Ludlow at the KTH Royal Institute of Technology and Peter Somfai at Lund University in Sweden and the University of Tartu in Estonia for hydrogenation of α-amino-β-ketoester 19 to furnish aminoalcohol 21 with high Shigeki Matsunaga and Motomu Kanai at the University of Tokyo developed (Angew. Chem. Int. Ed. 2012, 51, 10275) a unique strategy for the selective production of the cross-aldol adduct 24 by in situ generation of an aldehyde enolate from allyloxyborane 23 under rhodium catalysis. The highly diastereoselective construction of adduct 26 bearing two adjacent quaternary stereocenters by ketone allylation with allyl sulfide 25 was reported (Angew. Chem. Int. Ed. 2012, 51, 7263) by Takeshi Takeda at the Tokyo University of Agriculture and Technology. Wen-Hao Hu at East China Normal University reported (Nature Chem. 2012, 4, 733) the enantioselective three-component coupling of diazoester 27, N-benzylindole (28), and imine 29 to furnish 31 under the action of Rh2(OAc)4 and phosphoric acid 30.

Weiping Tang at the University of Wisconsin, Madison reported (J. Am. Chem. Soc. 2013, 135, 12434) the total synthesis of the tropone-containing norditerpenes hain­anolidol 6 and harringtonolide 7 by making use of a strategic [5+2] oxidopyrylium cycloaddition. First, the known ketone 1 was converted through a number of steps to cycloaddition precursor 2. Treatment with DBU then effected the key cycloaddition to furnish the complex polycyclic compound 3. Additional manipulations revealed struc­ture 4 with the lactone ring in place. The tropone ring of the natural structures was con­structed by reaction of the cycloheptadiene moiety of 4 with singlet oxygen followed by Kornblum- DeLaMare rearrangement with DBU to afford ketone 5. Double elimination using TsOH then produced hainanolidol 6. The free hydroxyl of 6 was engaged in a C–H-functionalizing cyclization using Pd(OAc)₄ to yield harringtonolide 7 as well. Hanfeng Ding at Zhejiang University developed (Angew. Chem. Int. Ed. 2013, 52, 13256) a concise route to indoxamycin F 12 (as well as the related indoxamy­cins A and C). The complex intermediate 9 was accessed in only four steps from the bicyclic ketone 8, which in turn was prepared by a route involving an Ireland–Claisen rearrangement and a reductive 1,6-enyne cyclization (not shown). An impressive oxa-conjugate addition/methylenation reaction to produce 11 was accomplished by treat­ment of 9 with Grignard 10 followed by Eschenmoser’s salt. Some final decorative work then led to indoxamycin F 12. The strained polycyclophane natural product cavicularin 18 was synthesized in enantioenriched form by an innovative strategy reported (Angew. Chem. Int. Ed. 2013, 52, 10472) by Keisuke Suzuki at the Tokyo Institute of Technology.

Both 1 and 3 are inexpensive prochiral starting materials. Tae-Jong Kim of Kyungpook National University devised (Organomet. 2008, 27, 1026) a chiral Cu catalyst that efficiently converted 1 (other ring sizes worked as well) to the enantiomerically pure ester 2. Alexandre Alexakis of the University of Geneva found (Adv. Synth. Cat. 2008, 350, 1090) a chiral Cu catalyst that mediated the enantioselective coupling of 3 with Grignard reagents such as 4 . The π-allyl Pd complex derived from 6 is also prochiral. Barry M. Trost of Stanford University showed (Angew. Chem. Int. Ed. 2008, 47, 3759) that with appropriate ligand substitution, coupling with the phthalimide 7 proceeded to give 8, readily convertible to (-)-oseltamivir (Tamiflu) 9, in high ee. Jonathan W. Burton of the University of Oxford found (Chem Commun. 2008, 2559) that Mn(OAc)3 -mediated cyclization of 10 delivered the lactone 12 with high diastereocontrol. John Montgomery of the University of Michigan observed (Organic Lett. 2008, 10, 811) that the Ni-catalyzed cyclization of 12 also proceeded with high diastereocontrol. Ken Tanaka of the Tokyo University of Agriculture and Technology combined (Angew. Chem. Int. Ed. 2008, 47, 1312) Rh-catalyzed ene-yne cyclization of 14 with catalytic ortho C-H functionalization, leading to 16 in high ee. Eric N. Jacobsen of Harvard University designed (Angew. Chem. Int. Ed. 2008, 47, 1469) a chiral Cr catalyst for the intramolecular carbonyl ene reaction, that converted 17 to 18 in high ee. Using a stoichiometric prochiral Cr carbene complex 20 and the enantiomerically-pure secondary propargylic ether 19, Willam D. Wulff of Michigan State University prepared (J. Am. Chem. Soc. 2008, 130, 2898) a facially-selective Cr-complexed o -quinone methide intermediate, that cyclized to 21 with high ee. A variety of methods have been put forward for the transition metal-mediated construction of polycarbocyclic systems. One of the more powerful is the enantioselective Rh-catalyzed stitching of the simple substrate 22 into the tricycle 23 devised (J. Am. Chem. Soc. 2008, 130, 3451) by Takanori Shibata of Waseda University. Inter alia, ozonolysis of 23 delivered the cyclopentane 24 containing two all-carbon quaternary centers.

Erick M. Carreira at ETH Zürich reported (Science 2013, 340, 1065) the enantiose­lective α-allylation of aldehyde 1 with alcohol 2 to produce 3 using a dual catalytic system involving a chiral iridium complex and amine 5. This stereodivergent method allows access to all of the possible stereoisomers of 3. In a conceptually related proc­ess, John F. Hartwig at the University of California, Berkeley reported (J. Am. Chem. Soc. 2013, 135, 2068) the highly stereoselective allylic alkylation of azlactone 6 with allylic carbonate 7 catalyzed by a combination of Ir(cod)Cl₂, ligand 9, and racemic silver phosphate 10. An enantioselective three-component Mannich-type reaction of tert-butyl diazo­acetate, aniline, and imine 11 to produce α,β-bis(arylamino) acid derivative 13 under dual catalysis with Rh₂(OAc)₄ and acid 12 was developed (Synthesis 2013, 45, 452) by Wenhao Hu at the Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development. Keiji Maruoka at Kyoto University reported (Chem. Commun. 2013, 49, 1118) a one-pot cross double-Mannich reaction of acetylalde­hyde 14, and imines 16 and 17 using axially chiral amino sulfonamide 15 to obtain densely functionalized 1,3-diamine 18 as a single stereoisomer. Jeffrey S. Johnson at the University of North Carolina at Chapel Hill reported (Org. Lett. 2013, 15, 2446) the asymmetric synthesis of enantioenriched anti-α-hydroxy-β-amino acid derivative 21 from 19 by treatment with oxone followed by catalytic hydrogenation using Ru(II) complex 20. Naoya Kumagai and Masakatsu Shibasaki at the Institute of Microbial Chemistry found (Org. Lett. 2013, 15, 2632) that a sil­ver complex of bisphosphine 24 effected a syn-selective and highly enantioselective Mannich-type reaction of aldimine 22 and α-sulfanyl lactone 23 to furnish the stereo­diad 25 with very high ee. The enantioselective homocrotylation of octanal 26 with cyclopropylcarbinylbo­ronate 27 to produce alcohol 28 with high ee was disclosed (J. Am. Chem. Soc. 2013, 135, 82) by Isaac J. Krauss at Brandeis University with computational studies pro­vided by Kendall N. Houk at UCLA. Benjamin List at the Max-Planck-Institut für Kohlenforschung reported (J. Am. Chem. Soc. 2013, 135, 6677) the enantioselective epoxidation of cyclohexenone 29 utilizing cinchona alkaloid- derived catalyst 30.

Feverfew (Tanacetum parthenium) is used for prophylaxis of migraine and it had been suggested that the plant may have antithrombotic potential. We have prepared extracts from the leaves of feverfew and have demonstrated inhibition of 14C-5HT secretion in platelet-rich plasma induced by the phorbol ester PMA, l-oleoyl-2-acetyl-sn-glycerol (OAG), arachidonic acid, the thromboxane analogue U46619, adrenaline, collagen and ADP. The effects of a solution of parthenolide (an∝-methylenebutyro-lactone isolated from feverfew) were determined in parallel. Both feverfew extract (FE) and parthenolide inhibited 14C-5HT release in a concentration-dependent manner and the effectiveness depended on the nature of the aggregating agent used. Both FE and parthenolide were most effective as inhibitors of the secretion induced by PMA and OAG. When we compared the concentrations of FE and parthenolide which gave 50% inhibition of secretion for all the agents tested, a good correlation was found (r= 0.936). Further studies showed that feverfew extract and parthenolide inhiMt release of β-thromboglobulin from platelets as well as 14C-5HT. FE did not cause liberation of LDH. Inhibition of secretion by FE appears to be irreversible since washing platelets after treatment did not restore secretory activity.The structure of parthenolide suggests that it can alkylate sulphydryl (SH) groups. When agents containing SH groups (e.g. cysteine) were added to FE, anti-secretory activity was reduced. We also obtained a considerable decrease in the number of acid-soluble SH groups in platelets treated with feverfew extract or parthenolide at concentrations which inhibit secretion. However there was a less marked decrease in the number of acid-insoluble SH groups. FE itself does not induce formation of disulphide-linked proteins but such proteins were formed when platelets were activated in the presence of FE, probably as a result of decreased glutathione levels.We conclude that parthenolide or parthenolide-like compounds are responsible for the anti-secretory effects of FE, and that alkylation of sulphydryl groups in platelets may be involved.