Bornyl Acetates Research Articles

Enantiospecific Synthesis of Both Enantiomers of the Longtailed Mealybug Pheromone and Their Evaluation in a New Zealand Vineyard.

The irregular monoterpenoid sex pheromone of Pseudococcus longispinus and its enantiomer were prepared from the corresponding bornyl acetates. The use of readily accessible chiral starting materials and lactone-lactone rearrangement are the highlights of the present synthesis. The biological activities of the two enantiomers and racemic mixture were tested in a New Zealand vineyard. The (S)-(+)-enantiomer was significantly more attractive to P. longispinus males than the racemic mixture or the (R)-(-)-enantiomer.

Effect of some essential oils on phagocytosis and complement system activity.

The aim of the present study was to investigate the in vitro activity of 15 essential oils, 4 essential oil fractions, and 3 pure compounds (thymol, carvacrol, and eugenol) on phagocytosis by human neutrophils and on complement system. Samples were characterized by GC and GC-MS. Most of the oils (nutmeg, clove, niaouli, tea tree, bay laurel, lemon, red thyme, ginger), nutmeg terpenes, eugenol, and carvacrol showed mild to moderate inhibition of phagocytosis (25-40% inhibition at doses ranging from 40 to 60 μg/mL); highest inhibitory activity was found for thymol (72% at 56 μg/mL), whereas the mixture of bornyl and isobornyl acetates showed a mild stimulating activity (21% at 56 μg/mL). All samples were inactive in the alternative pathway of complement system, whereas on classical pathway, clove oil, eugenol, palmarosa oil, red thyme oil, tarragon oil, and carvacrol showed the highest activity, with IC50 values ranging from 65 to 78 μg/mL.

Liquid phase acetoxylation of α-pinene over Amberlyst-70 ion-exchange resin

Heterogeneously-catalyzed and solvent-catalyzed liquid phase acetoxylation of α-pinene with acetic acid acting as both a solvent and a reagent was studied. Both solvent-catalyzed and catalytic experiments were carried out and various reaction conditions were studied. The influence of temperature, pressure, solvent and gas milieu were taken into account. Bornyl, fenchyl, verbenyl as well as α-terpinyl acetates, limonene, camphene and γ-terpinene were found among reaction products. The addition of the catalyst allowed for maximization of the yield of bornyl acetate. The predominant products obtained were α-terpinyl, verbenyl and bornyl acetates. The reaction pathways were identified and evaluated.The aim of this work was to study the feasibility of batch acetoxylation of α-pinene. The analysis of the complex product distribution is not trivial and, consequently, resolving the reaction network was important. The optimized reaction conditions were searched for aiming at an efficient conversion of α-pinene to a mixture of valuable products.

Volatile Constituents of Mandarin (Citrus reticulata Blanco) Peel Oil from Burundi

The essential oil constituents of mandarin (Citrus reticulata Blanco) grown in Burundi were extracted by cold-pressing method and analyzed by GC and GC/MS. Fifty-eight constituents, amounting to 97.2% of the total volatiles were identifed. Monoterpene hydrocarbons accounted for the most abundant chemical group (94.7%). Limonene was the most prominent constituent (84.8%), followed by γ-terpinene (5.4%), myrcene (2.2%) and α-pinene (1.1%). Sesquiterpene hydrocarbons accounted for a minor quantity (0.2%), where germacrene D and valencene were the main constituents. Oxygenated compounds of various chemical groups constituted 2.3%. Aliphatic aldehydes (0.7%) and terpene alcohols (0.7%) were the major chemical groups. The main constituents were linalool (0.7%), octanal (0.5%) and decanal (0.2%). Octyl acetate, α-sinensal, decanol and perillaldehyde occurred at 0.1% levels. Thymol, α-sinensal, methyl thymol, and the acetate esters, bornyl, α-terpinyl, geranyl, citronellyl and decyl acetates were detected, each at < 0.05%.

Study of lipase-catalyzed hydrolysis of some monoterpene esters

Studies of the hydrolysis of bornyl, citronellyl, geranyl, and terpenyl acetates by commercially available lipases of Candida rugosa, Rhizopus arrhizus, and Mucor miehei are presented. The hydrolysis of these monoterpene esters is investigated at various temperatures and pHs, and the time dependence of the percentage of esters hydrolysed is studied. The catalytic activities of the lipases in hydrolysing the esters are compared and, overall, it is observed that under the experimental conditions used the nonspecific lipase from C. rugosa produces the highest yields of the monoterpene alcohols in comparison to the primary-ester specific lipases such as R. arrhizus and M. miehei. A rate kinetic model has been used to understand the time dependence of the yield of the product acid.

Study of lipase-catalyzed hydrolysis of some monoterpene esters

Studies of the hydrolysis of bornyl, citronellyl, geranyl, and terpenyl acetates by commercially available lipases of Candida rugosa, Rhizopus arrhizus, and Mucor miehei are presented. The hydrolysis of these monoterpene esters is investigated at various temperatures and pHs, and the time dependence of the percentage of esters hydrolysed is studied. The catalytic activities of the lipases in hydrolysing the esters are compared and, overall, it is observed that under the experimental conditions used the nonspecific lipase from C. rugosa produces the highest yields of the monoterpene alcohols in comparison to the primary-ester specific lipases such as R. arrhizus and M. miehei. A rate kinetic model has been used to understand the time dependence of the yield of the product acid.Key words: enzymatic hydrolysis, kinetics, lipase, monoterpene esters.

Elimination reactions of ions in the gas phase–I: Elimination of water and acetic acid in epimeric borneols and bornylacetates

AbstractLoss of water and acetic acid in the epimeric bornyl alcohols and acetates are shown to be analogous processes by specific 2H‐labelling. Among several competing mechanisms cis‐1,2‐elimination is the most important. Mctastable ion characteristics of this specific process exhibit some unusual features and its product is shown to have a different structure from that produced by the competing reactions.

Identification des constituants de l'essence des aiguilles de Pinus pinaster

The chromatographic analysis of the volatile leaf oil of Pinus pinaster Ait. showed 42% of monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, 3-carene, limonene, cis-ocimene, terpinolene, para-cymene, 35% of sesquiterpene hydrocarbons (cubebene, copaene, caryophyllene, humulene, germacrene D, α- and γ-muurolenes, δ- and γ-cadinenes) and 23% of oxygenated compounds including esters (linalyl, bornyl, geranyl, neryl and farnesyl acetates), alcohols ( cis-hexenol, linalool, α-fenchol, trans-pinocarveol, terpinen-4-ol, α-terpineol, dihydrocarveol, guaiol, junenol and α-cadinol), one aldehyde (hexenal) and one ketone (piperitone). Three non terpenoid phenylethyl esters were also identified: phenylethyl isovalerate, methyl-2 burtyate and 3-3 dimethylacrylate. Some alcohols and mainly α-terpineol and linalool seemed to be formed during the steam distillation process, they were absent when the leaf oil was obtained by maceration of small portions of leaves in the usual solvents of terpenes.

The thermal decomposition of bornyl and isobornyl acetates

The kinetics of the thermal decomposition of bornyl and isobornyl acetates in a seasoned Pyrex vessel have been studied in a static system. The reaction is homogeneous, first-order, and predominantly molecular. The rates of reaction are expressible by the Arrhenius equations k= 1011·99 exp (–45,340/RT) and k= 1011·64 exp (–42,020/RT), respectively. The products of decomposition have been analysed by vapour-phase chromatography and confirm the results of earlier qualitative investigations.

598. Tracer studies in ester hydrolysis. Part XIV. The hydrolysis of bornyl and isobornyl acetates

598. Tracer studies in ester hydrolysis. Part XIV. The hydrolysis of bornyl and isobornyl acetates