Search

Examines the catalytic epoxidation of monoterpenes with hydrogen peroxide catalyzed by peroxotungstophosphate using chloroform as solvent. Oxidation product of terpenes in good yields and under mild conditions; Results of the epoxidation of linalool; Rationalization on the regioselectivities in the epoxidation of monoterpenes.

Focuses on cembranolide analogs containing cyclic ethers. Description of the synthesis and biological evaluation of the compound.

Outlines the concept of an intramolecular organometallic approach to the sesterterpenoid, cerorubenic acid-III. Formation of key intermediates; Non-viability of the six-membered cyclization of the intermediates; Observation of reductive deiodination; Failure of attempts to generate vinyl stannanes; Difficulties associated with the approach.

Investigates the fragmentation of a series of cyclobutylcarbinyl systems derived from [2 + 2] photoadducts which lead to bicyclo[x.y.0] carbon skeletons present in a variety of terpenoid natural products. Application of methodology to terpenoid synthesis via the preparation of an unsaturated bicyclic ketone; Synthesis of triquinane sesquiterpenoid.

Presents the conformational analysis of 10- and 13-hydroxycembrenes, a terpenoid. Nuclear magnetic resonance methods; Molecular mechanics calculations; Orientation of double bonds; Influence of substituent effects and an intramolecular hydroxide pi-hydrogen bond on conformational states of the cembranoids.

Describes a general procedure to obtain 2-R-apopinenes of high optical purity from chiral 2-organylapoisopinocampheylboranes. Use of organoborane chemistry; Details of previous studies; Description of study; Results of study; Discussion of results.

Describes the synthesis of the ABCD ring framework of cerorubenic acid-III. Anionic oxy-Cope rearrangement of the intermediate formed from an intramolecular oxidative coupling reaction; Homologation, activation and Diels-Alder reactions yielding methyl acrylate; Alternative means for elaboration of the eastern sector in the conjugate reduction.

Describes the possible enantiocontrolled route to cerorubenic acid-III. Stereochemistry of the acid established by X-ray crystallography; Assembly of two structural halves; Stereoselectivity of the coupling reaction; Competitive degradation reactions.

Investigates the possibility of achieving construction of the complete framework of cerorubenic acid-III by means of anionic oxy-Cope step followed by extrannular Robinson annulation. Preparation of dithiane and iodides; Nucleophilic addition of various classes of nucleophiles.

Presents information on an original non-terpenoid varnish which was used in the early 20th century oil painting `The White Horse,' by H. Menzel. Features of varnishes prepared during the 11th century; Methods used to identify the varnish; Results of studies conducted.

Examines the light-induced aging of natural triterpenes used in varnishes, with the use of a graphite-assisted laser desorption/ionization mass spectrometry. Popularity of triterpenoid resins in varnishes on artwork; Information on the connection between the mechanical properties and chemical changes in the natural resin; Design of the experiment; Findings of the experiment.

Presents a study which investigated the ozonolytic decomposition of terpenoids and terpenes, during sampling on Tenax, in an artificial air system at ambient concentration levels. Dependence of detrimental effect of 8-150 ppbv on chemical structure of compounds; Enhancement of analytical recoveries for many compounds when sampling duration is reduced from 10 minutes to 30 seconds.

Studies the location of the position of double bonds in unsaturated terpenes and other alkylthiolation compounds. Mass spectrometry and infrared data on dimethyl disulfides derivatives; By-products found in the reaction mixtures.

Terpinen-4-ol, the main component of tea tree oil, markedly increases the disease resistance of postharvest strawberry fruit. To understand the mechanism underlying the enhancement of disease resistance, a high-throughput RNA-seq was used to analyze gene transcription in terpinen-4-ol-treated and untreated fruit. The results show that terpinen-4-ol induces the expression of genes in the jasmonic acid (JA) biosynthesis pathway, secondary metabolic pathways such as phenylpropanoid biosynthesis, and pathways involved in plant-pathogen interactions. Terpinen-4-ol treatment reduced disease incidence and lesion diameter in strawberry fruit inoculated with Botrytis cinerea . Terpinen-4-ol treatment enhanced the expression of genes involved in JA synthesis ( FaLOX , FaAOC , and FaOPR3 ) and signaling ( FaCOI1 ), as well as genes related to disease defense ( FaPAL , FaCHI , and FaGLU ). In contrast, treatment with the JA biosynthesis inhibitor salicylhydroxamic acid (SHAM) accelerated disease development and inhibited the induction of gene expressions by terpinen-4-ol. We conclude that the JA pathway participates in the induction of disease resistance by terpinen-4-ol in strawberry fruit. More generally, the results illuminate the mechanisms by which disease resistance is enhanced by essential oils.

Indirect defense is an important strategy employed by sessile plants to defend against herbivorous insects by recruiting the natural enemies of herbivores mediated by herbivore-induced plant volatiles (HIPVs). We aimed to determine whether indirect defense occurs in Compositae with Chrysanthemum morifolium as the model and elucidate the mechanisms underlying the biosynthesis of HIPVs. Using two-choice olfactometer bioassays, we showed that C. morifolium plants following infestation by larvae of the tobacco cutworm ( Spodoptera litura , TCW) were significantly more attractive to two natural enemies of TCW larvae than control plants, indicating that indirect defense is an active defense strategy of C. morifolium . The chemical cue responsible for indirect defense in C. morifolium was identified as a complex blend of volatiles predominated by sesquiterpenes and monoterpenes. A total of 11 candidate terpene synthase (TPS) genes were identified by comparing the transcriptomes of healthy and TCW-infested plants. Gene expression analysis confirmed that up-regulated CmjTPS genes are consistent with the elevated emission of terpenes after herbivory treatment. Our study showed that the herbivore-induced emission of JA-dependent volatile terpenes attracted both predatory and parasitic enemies of herbivores. Generally, our findings indicate that indirect defense might be an important defense mechanism against insects in C. morifolium .

Sesquiterpenes are natural compounds composed of three isoprene units. They represent the largest class of terpene compounds found in plants, and many have remarkable biological activities. Furthermore, sesquiterpenes have broad applications in the flavor, pharmaceutical and biofuel industries due to their complex structures. With the development of metabolic engineering and synthetic biology, the production of different sesquiterpenes has been realized in various chassis microbes. The microbial production of sesquiterpenes provides a promising alternative to plant extraction and chemical synthesis, enabling us to meet the increasing market demand. In this review, we summarized the heterologous production of different plant sesquiterpenes using the eukaryotic yeasts Saccharomyces cerevisiae and Yarrowia lipolytica , followed by a discussion of common metabolic engineering strategies used in this field.

Nine novel polyketide-terpenoid hybrids ( 1 - 9 ), characterized by a 1-alkylated-3,5-dihydroxyphenyl derivative coupled with a modified farnesyl pyrophosphate (FPP) unit, were isolated from a soil-derived fungus Bipolaris zeicola . Their structures were determined by comprehensive spectroscopic data, single-crystal X-ray diffraction analyses, and electronic circular dichroism calculations. Structurally, compounds 1 , 2 , 5 , and 6 possess a rare thiazole moiety; compounds 3 and 4 are the first examples of meroterpenoids featuring an undescribed 6/6/6/6/5 pentacyclic system and bearing a tetrahydrofuran ring fused to a polyketide and a sesquiterpenoid subunit; compounds 7 and 8 possess a rare 2 H -1,4-thiazin-3(4 H )-one moiety; and compound 9 represents the first example of meroterpenoid having an unusual thiazol-2(3 H )-one moiety. The bioactivity assays revealed that compounds 1 , 2 , 5 , 6 , and 9 exhibited a significant immunosuppressive effect against concanavalin A (ConA)-induced T lymphocyte proliferation with IC 50 values ranging from 5.6 to 8.8 μM, and compounds 1 , 2 , and 4 exhibited moderate cytotoxic activities with IC 50 values ranging from 18.4 to 29.4 μM.

The core scaffold of paspaline-type indole-terpenes was synthesized by using the House-Meinwald rearrangement as a key step. Rearrangement of the epoxide methyl group in the precursor with methylaluminum bis(4-bromo-2,6-di- tert -butylphenoxide) as a Lewis acid proceeded smoothly to construct contiguous asymmetric quaternary carbon centers by a 1,2-chirality transfer.

Starting from commercially available ( R )- and ( S )-β-citronellol, two strategies were designed to synthesize all four stereoisomers of 2,6-dimethyloctane monoterpene chirons in four or five steps in 32-47% overall yield. The desired fragments were obtained by a key Ru-catalyzed asymmetric olefin hydrogenation step under moderate temperature (50 °C), pressure (4 bar), and low catalyst loadings (0.5 mol %) under optimized conditions. Screening of commercially available catalysts highlighted the key role of DM-SEGPHOS as an economically advantageous alternative to commonly used H8-BINAP for equal performances. These results open new possibilities for versatile and scalable syntheses of these useful building blocks.

Nitrooxy organosulfates derived from terpenes (NOS TP ) represent an important class of products formed between anthropogenic pollution (e.g., SO 2 and NO x ) and natural emissions. NOS TP compounds have been consistently detected in atmospheric environments under varying urban influences. Their chemical linkages to both anthroposphere and biosphere make them valuable markers for tracking anthroposphere-biosphere interactions. However, their quantification, formation, and transformation kinetics in atmospheric aerosols are hindered due to the lack of NOS TP standards. In this work, we developed two routes for the first concise chemical synthesis of eight NOS TP from terpenes including α-pinene, β-pinene, limonene, limonaketone, and β-caryophyllene. Subsequently, six of the synthesized NOS TP were for the first time positively identified in ambient aerosol samples, clarifying certain misidentifications in previous studies. More significantly, the availability of authentic standards allows irrefutable observation of three carbon skeleton-rearranged NOS TP , two derived from α-pinene, and one derived from β-caryophyllene, revealing the occurrence of previously unrecognized transformation pathways in the formation of NOS TP . Two synthesized NOS TP from β-pinene and limonene could not be detected, likely due to rapid hydrolysis of their immediate hydroxynitrate precursors outcompeting sulfation. Such mechanistic evidence is valuable in understanding the atmospheric chemistry of NOS TP and related compounds. This work demonstrates the usefulness of authentic standards in probing the NOS TP formation mechanisms in the atmosphere. Comparison of NOS TP ambient samples collected from four Chinese cities in two winter months indicates that anthropogenic chemical factors could outcompete terpene emissions in the formation of NOS TP .

A general and efficient method for the deconjugative α-alkylation of α,β-unsaturated aldehydes promoted by a synergistic effect between t BuOK and NaH, which considerably increases the reaction rate under mild conditions, is reported. The β,γ-unsaturated aldehyde, resulting from the α-alkylation, is transformed in high yield into the corresponding allyl acetate via a lead(IV) acetate-mediated oxidative fragmentation. This strategy could be used for the construction of the carbon skeleton of a wide variety of alkyl or arylterpenoids.

Vaporizable cannabis concentrates (VCCs) consumed as a liquid (vaping) or a waxy solid (dabbing) are becoming increasingly popular. However, their associated emissions and impacts have not been fully described. Mixtures containing different proportions of 12 VCC terpenoids and high MW compounds were heated at 100-500 °C inside a room-sized chamber to simulate emissions. Terpenoids, thermal degradation byproducts, and ultrafine particles (UFPs) were quantified in the chamber air. Air samples contained over 50% of emitted monoterpenes and less than 40% of released sesquiterpenes and terpene alcohols. Eleven degradation byproducts were quantified, including acrolein (1.3-3.9 μg m -3 ) and methacrolein (2.0 μg m -3 ). A large amount of UFPs were released upon heating and remained airborne for at least 3 h. The mode diameter increased from 80 nm at 100 °C to 140 nm at 500 °C, and particles smaller than 250 nm contributed to 90% of PM 1.0 . The presence of 0.5% of lignin, flavonoid, and triterpene additives in the heated mixtures resulted in a threefold increase in the particle formation rate and PM 1.0 concentration, suggesting that these high-molecular-weight compounds enhanced aerosol inception and growth. Predicted UFP emission rates in typical consumption scenarios (6 × 10 11 -2 × 10 13 # min -1 ) were higher than, or comparable with, other common indoor sources such as smoking and cooking.

The interaction between food crops and insect pests is mediated by semiochemicals emitted from host plants. These semiochemicals are natural behavioral modifiers and act on the insect olfactory system to locate hosts and preys. In this study, eight rice neuroactive semiochemicals were identified from rice varieties by GC-EAG and GC-MS. Their ability to modify rice pest behaviors was further studied as individual chemicals and physiologically relevant blend. The total amount of each semiochemical and the expression of their biosynthesis genes were significantly higher in pest susceptible variety than in pest-resistant variety and upregulated by the infestation of the pest Nilaparvata lugens (BPH). The semiochemicals emitted by uninfested plants (UIRVs) were more attractive to BPHs. Interestingly, the attractiveness of UIRVs was significantly reduced by the addition of the blend that mimics the natural composition of these semiochemicals emitted by infested plants (IRVs). Our study suggests a mechanism for the spread of pest infestation from infested plants to uninfested plants nearby. UIRVs initially serve as attractive signals to rice insect pests. The pest infestation changes the rice semiochemical profile to be less attractive or even repellent, which pushes further colonization to uninfested plants nearby. The identified semiochemicals can be used for crop protection based on a push-pull strategy.

Polyketide synthase-terpenoid synthase (PKS-TPS) hybrid pathways for biosynthesis of unique sesquiterpenyl epoxy-cyclohexenoids (SECs) have been found to be widely distributed in plant pathogenic fungi. However, the natural and ecological functions of these pathways and their metabolites still remain cryptic. In this study, the whole PKS-TPS hybrid pathway in the predominant nematode-trapping fungus Arthrobotrys oligospora was first proposed according to all the intermediates and their derivatives from all the A. oligospora mutants with a deficiency in each gene involved in SEC biosynthesis. Most mutants displayed significantly increased trap formation which was correlated with alteration of the ammonia level. Further analysis revealed that the main metabolites involved in ammonia metabolism were largely increased in most mutants. However, significantly retarded colonization in soil were observed in most mutants compared to the wild-type strain due to significantly decreased antibacterial activities. Our results suggested that A. oligospora used the PKS-TPS hybrid pathway for fungal soil colonization via decreasing fungal nematode-capturing ability. This also provided solid evidence that boosting fungal colonization in soil was the secondary metabolite whose biosynthesis depended on a PKS-TPS hybrid pathway.

A formal synthesis of (±)-cochlearol A was accomplished. The synthesis features Suzuki coupling and Friedel-Crafts cyclization as a convergent strategy to the functionalized tetralone ring and an intramolecular construction of the C/D ring involving sequential epoxide formation/acetal formation.

Asperterpenoid A (1), a novel sesterterpenoid with a new carbon skeleton, has been isolated from a mangrove endophytic fungus Aspergillussp. 16-5c. Its structure was characterized by extensive spectroscopic methods, and the absolute configuration was determined by single crystal X-ray diffraction analysis. Asperterpenoid A (1) exhibited strong inhibitory activity against Mycobacterium tuberculosisprotein tyrosine phosphatase B (mPTPB) with an IC50value of 2.2 μM. [ABSTRACT FROM AUTHOR]

7-Isocyano-11(20),14-epiamphilectadiene, the most potent of antimalarial amphilectenes, is synthesized in seven steps from readily available materials. The synthesis is enabled by a new dendrimeric triene (Danishefsky [3]-dendralene) and a new method for stereo- and chemoselective isocyanation. This chemistry provides a useful entry into an underexplored yet promising family of antimalarial terpenoids. [ABSTRACT FROM AUTHOR]

The article discusses a laboratory experiment on the isolation and structure elucidation of the Terpene β-thujone from cedar leaf oil by students in an advanced organic chemistry laboratory course. It notes that simple purification through filtration can be done from such technique. It also states that students use various spectroscopies including infrared (IR), mass spectrometry (MS), and nuclear magnetic resonance (NMR) to characterize and determine highly pure β-thujone.

The solubilities of ursolic acid and oleanolic acid in four solvents (methanol, ethanol, 2-propanol, and ethyl acetate) are measured over the temperature range of (283.2 to 329.7) K. The experimental solubility data are correlated by the modified Apelblat equation. The root-mean-square deviation (rmsd) between the experimental value and the calculated value is not more than 1.1267·10−4, so the calculated solubility shows good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The first total synthesis of (−)-Przewalskin B has been accomplished with an intramolecular nucleophilic acyl substitution (INAS) reaction and an intramolecular aldol condensation as key steps. [ABSTRACT FROM AUTHOR]

A concise, biomimetic total synthesis of the unprecedented terpenoid skeleton (+)-chabraol has been accomplished via 6 steps from the chiral epoxide 7. involving an intramolecular Prins double cyclization to yield the bicyclo[2.2.l] core of the natural product as the key step. The absolute configuration of natural chabranol was also designated through the first asymmetric total synthesis. [ABSTRACT FROM AUTHOR]

The sex pheromone of the longtailed mealybug, identified as 2-(1,5,5-trimethylcyclopent-2-en-1-yl)ethyl acetate, represents the first example of a new monoterpenoid skeleton. A [2,3]-sigmatropic rearrangement was used in a key step during construction of the sterically congested tetraalkylcylopentene framework. [ABSTRACT FROM AUTHOR]

The icetexane-based diterpenes (−)-barbatusol, ()-demethylsalvicanol, and (−)-brussonol were synthesized. Synthetic demethylsalvicanol was dimerized to produce ()-grandione using aqueous Diels−Alder conditions. [ABSTRACT FROM AUTHOR]

Lathyranone A (1), a novel diterpenoid with a rearrangement skeleton, along with a known diterpenoid, Euphorbia factor L11(2), was isolated from the seeds of Euphorbia lathyris. The structure and relative stereochemistry of 1were elucidated by extensive spectroscopic analysis. A possible biosynthetic pathway for lathyranone A (1) was proposed. [ABSTRACT FROM AUTHOR]

Extension of anion relay chemistry (ARC) beyond the area of dithianes has been achieved by the design of two effective ARC linchpins capable of three- and four-component couplings. To showcase the ARC tactic in natural product synthesis, a cytotoxic gorgonian linear sesquiterpene was constructed, and the absolute configuration assigned via the Kakisawa/Mosher method. The synthesis proceeded in five steps with an overall yield of 22%. [ABSTRACT FROM AUTHOR]

(±)-Paeonilide, a novel monoterpenoid metabolite from the roots of Paeonia delavayi showing anti-platelet activating factor activity, is convergently synthesized in five steps with 59% overall yield. The application of benzoyl peroxide-promoted radical addition of unsaturated ester to aldehyde and subsequent topologically favored cyclization greatly simplified the synthesis. [ABSTRACT FROM AUTHOR]

The article cites a study, conducted by the author, which identified monoterpene. Monoterpenes are compounds biosynthesized from two molecules of isopentenyl pyrophosphate. Plants emit them to attract insect pollinators, repel insects or other predators, or inhibit germination and development of seeds of competing species. For insects, monoterpenes may act as aggregation, trail, alarm, and sex pheromones or as defensive secretions. Humans use them in flavoring and fragrances and synthetic organic chemists use them as chiral starting materials or chiral auxiliaries. Monoterpenes can cause eye, skin, and respiratory tract irritation. Chloroform is a potential carcinogen and a known central nervous system depressant. In the study, a set of ten monoterpenes was chosen. All of the molecules were having ten carbons and belonged to one or more of the alcohol, alkene, or ketone functional group classes. The study is a taxing review of many concepts covered in nuclear magnetic resonance spectroscopy and provides an excellent ending to a course including these topics.

Bacillus cereus is a Gram-positive endospore-forming foodborne pathogen that causes lethal food poisoning and significant economic losses, usually through biofilm- and endospore-induced recurrent cross- and postprocessing contamination. Due to the lack of critical inhibitory targets and control strategies, B. cereus biofilm contamination is a problem that urgently needs a solution. In this study, the antibacterial and antibiofilm activities of several natural potential bacterial quorum sensing (QS) interferers, a group of spice-originated monoterpenoids, were screened, and terpinen-4-ol effectively inhibited B. cereus growth and biofilm and spore germination with minimum growth inhibition and 50% biofilm inhibitory concentrations of 8 and 2 μmol/mL, respectively. FESEM/CLSM and phenotypic research illustrated that in addition to a decrease in the number of attached B. cereus cells, (+)-terpinen-4-ol also obviously reduced extracellular matrix synthesis, especially exopolysaccharides, and inhibited the swarming motility and protease activity of B. cereus . (+)-Terpinen-4-ol did not exert a significant effect on AI-2 signals in B. cereus . Accordingly, the B. cereus -produced interspecies QS signals diffusing signal factors (DSFs, C8-C15) and diketopiperazines (DKPs) were detected and identified here, which suppressed B. cereus biofilm formation in a concentration-dependent manner. (+)-Terpinen-4-ol significantly increased the levels of specific DSF and DKP signals in B. cereus and down-regulated the gene expression of some rpfB homologues in transcription level. Moreover, both DKPs and DSFs inhibited swarming motility and protease activity in B. cereus , while just the DSF signals 2-dodecenoic acid and 11-methyl-2-dodecenoic acid inhibited exopolysaccharide synthesis like (+)-terpinen-4-ol. In summary, B. cereus strains were found to produce nine DSF- and six DKP-type QS signaling molecules, which repressed B. cereus biofilm formation. (+)-Terpinen-4-ol was confirmed to be a promising antibacterial and antibiofilm agent against B. cereus upregulating DSFs and DKPs levels, and it could target the critical genes rpfB for DSFs turnover.

Terpenoids are an important class of secondary metabolites that play an important role in food, agriculture, and other fields. Microorganisms are rapidly emerging as a promising source for the production of terpenoids. As an oleaginous yeast, Yarrowia lipolytica contains a high lipid content which indicates that it must produce high amounts of acetyl-CoA, a necessary precursor for the biosynthesis of terpenoids. Y. lipolytica has a complete eukaryotic mevalonic acid (MVA) pathway but it has not yet seen commercial use due to its low productivity. Several metabolic engineering strategies have been developed to improve the terpenoids production of Y. lipolytica , including developing the orthogonal pathway for terpenoid synthesis, increasing the catalytic efficiency of terpenoids synthases, enhancing the supply of acetyl-CoA and NADPH, expressing rate-limiting genes, and modifying the branched pathway. Moreover, most of the acetyl-CoA is used to produce lipid, so it is an effective strategy to strike a balance of precursor distribution by rewiring the lipid biosynthesis pathway. Lastly, the latest developed non-homologous end-joining strategy for improving terpenoid production is introduced. This review summarizes the status and metabolic engineering strategies of terpenoids biosynthesis in Y. lipolytica and proposes new insights to move the field forward.

Cannabis is an excellent natural source of fiber and various bioactive cannabinoids. So far, at least 120 cannabinoids have been identified, and more novel cannabinoids are gradually being unveiled by detailed cannabis studies. However, cannabinoids in both natural and isolated forms are especially vulnerable to oxygen, heat, and light. Therefore, a diversity of cannabinoids is associated with their chemical instability to a large extent. The research status of structural conversion of cannabinoids is introduced. On the other hand, the use of drug-type cannabis and the phytocannabinoids thereof has been rapidly popularized and plays an indispensable role in both medical therapy and daily recreation. The recent legalization of edible cannabis further extends its application into the food industry. The varieties of legal edible cannabis products in the current commercial market are relatively monotonous due to rigorous restrictions under the framework of Cannabis Regulations and infancy of novel developments. Meanwhile, patents/studies related to the safety and quality assurance systems of cannabis edibles are still rare and need to be developed. Furthermore, along with cannabinoids, many phytochemicals such as flavonoids, lignans, terpenoids, and polysaccharides exist in the cannabis matrix, and these may exhibit prebiotic/probiotic properties and improve the composition of the gut microbiome. During metabolism and excretion, the bioactive phytochemicals of cannabis, mostly the cannabinoids, may be structurally modified during enterohepatic detoxification and gut fermentation. However, the potential adverse effects of both acute and chronic exposure to cannabinoids and their vulnerable groups have been clearly recognized. Therefore, a comprehensive understanding of the chemistry, metabolism, toxicity, commercialization, and regulations regarding cannabinoid edibles is reviewed and updated in this contribution.

Recently, choline and geranic acid (CAGE), an ionic liquid (IL), has been recognized to be a superior biocompatible material for oral and transdermal drug delivery systems (DDS). When CAGE is administered, CAGE would be exposed to various types of physiological fluids, such as intestinal and intradermal fluids. However, the effect of physiological fluids on the structure of CAGE remains unclear. In the present study, molecular structures of CAGE with different ratios of water were investigated using small-angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR). The SAXS pattern of CAGE showed an IL-specific broad peak derived from nanoscale aggregation until 17 vol % water. Meanwhile, narrow peaks were observed in samples with 25-50 vol % water, showing a transition to the lamellar phase. With more than 67 vol % water, CAGE was found to exist as micelles in water. The 1 H NMR spectra indicated that protons of H 2 O, OH in choline (CH), and COOH in geranic acid (GA) were observed as only one peak up to 17 vol % water. This peak shifted to a high magnetic field, and the integral values increased with the water content, speculating that water is localized close to the COOH and OH groups to allow proton exchange. The 13 C NMR spectra showed that peaks related to the carboxyl group shifted with adding water. Moreover, only GA peaks were observed in the lamellar phase through 13 C cross-polarization magic-angle spinning NMR, suggesting that the main rigid component of the lamellar phase was GA. Taken together, this study suggested that CAGE still maintained its IL structure up to 17 vol % water, then transitioned to the lamellar phase with 25-50 vol % water, and finally changed to the micellar phase with more than 67 vol % water. This information would be useful in the formulation and development of DDS using CAGE.

Presents a chemistry classroom demonstration on the formation of aerosols from biogenic hydrocarbons. Identification of biogenic hydrocarbon content in volatile organic compounds; Reaction of ozone with terpenes found in oranges; Creation of ozone through the photolysis of molecular oxygen in air.

Terpenes are important contributors to wine aroma. Free and glycosidically bound terpenes are primarily formed in grapes. During fermentation, they undergo important transformation catalyzed by yeast, so that the terpene profile of grape is substantially different from that of the corresponding wine. The present paper assessed the ability of a Saccharomyces cerevisiae strain to transform 17 different terpenes. Biotransformation was performed by placing target compounds in incubation with resting cells. Volatile compounds produced were extracted by solid-phase extraction and analyzed by gas chromatography-mass spectrometry. Geranyl acetate, neryl acetate, citronellyl acetate, and menthyl acetate were formed from the corresponding terpene alcohols. β-Citronellol was the main product of geraniol transformation; geranial, an intermediate of this pathway, has also been detected. Limonene was hydroxylated by yeast to form carveol, trans -2,8-menthadien-1-ol, and cis -2,8-menthadien-1-ol. Moreover, yeast cells were found to be able to adsorb a significant portion of the terpenes present in the reaction batches, with the extent of this phenomenon being linked to terpene hydrophobicity.

There is a growing preference to move away from traditional petrochemical-based polymers toward biobased alternatives. Here, we report the microwave-assisted RAFT polymerization of several terpenoid acrylates (tetrahydrogeraniol, cyclademol, nopol, and citronellol). These biobased monomers give polymers with a broad range of glass transition temperatures and are excellent candidates to substitute oil-based (meth)acrylates in applications such as coatings and adhesives. First, the process was studied in miniemulsion, finding that all terpenoid acrylates showed a substantial increase in both polymerization rate and reaction control when microwave irradiation was applied. These observations were attributed to nonthermal microwave effects, namely, to changes in the kinetic coefficients under irradiation. The reactions were also carried out in solution, where an amplified nonthermal microwave effect was observed. The results indicate that nonthermal microwave effects allow RAFT polymerization of these terpenoid acrylates to proceed with both improved control and at higher polymerization rates compared to using conventional heating.

Microbe class I terpene cyclases (TPCs) are responsible for deriving numerous functionally and structurally diverse groups of terpenoid natural products. The conformational change of their active pockets from "open" state to "closed" state upon substrate binding has been clarified. However, the key structural basis relevant to this active pocket dynamics and its detailed molecular mechanism are still unclear. In this work, on the basis of the molecular dynamics (MD) on two microbe class I TPCs (SdS and bCinS), we propose that the active pocket dynamics is highly dependent on the residue orientation of two conserved structural bases R-D dyad and X-R-D triad, rather than the previously suggested flexibility of kink region. Actually, we considered that the flexibility of kink region is synchronous with the R residue orientation of the X-R-D triad, which could regulate the entrance size of active pocket and thus affect the substrate selectivity of active pocket by utilizing the promiscuity of the X-R-D triad. Furthermore, to better understand the function of the two structural bases, two intelligible models of "PPi catcher-locker" and "selector-PPi sensor-orienter" are proposed to, respectively, describe the R-D dyad and X-R-D triad and broadened to more microbe class I TPCs. These findings exhibit the dynamics of active pocket inaccessible in static crystal structures and provide useful structural basis knowledge for further design of microbe class I TPCs with different cyclization ability.

Investigations on the synthesis of terpenoids such as longicyclene and the pseudoguianolides, explored an associated cycloaddition mechanism between a 1,3-diene and norbornadiene (NBD), and identified an enantioselective higher order cobalt-catalyzed (4-pi + 2-pi + 2-pi) cycloaddition reaction with enantiomeric excesses over 70%. In a single operation, a seven-membered ring and a cyclopropane are produced by the diene-norbornadiene coupling reaction.