Thienyl analogues of acyclic monoterpene alcohols and their biological activity

BACKGROUND: Thienyl analogues of linalool, geraniol, nerol and citronellol were synthesised and their sensory and anti‐ microbial activities were investigated. RESULTS: The thienyl analogues of linalool, geraniol, nerol and citronellol, in which the isobutenyl moiety was replaced by a thiophene substituent, were synthesised from commercially available 2‐ and 3‐methylthiophenes and 2‐ and 3‐thiophenecarboxaldehydes. The olfactory properties of the new compounds were generally of the corresponding parent terpene type; however, their relative volatility determined by the headspace gas chromatography method was lower by a factor of 34–42 compared with the parent alcohols. Antimicrobial activity against Aspergillus niger and Penicillium expansum of some thienyl analogues of linalool was 1.5–3 times higher than that of linalool, with a minimum inhibitory concentration of 0.2–0.1 µL mL^?1. CONCLUSION: Replacement of the isobutenyl moiety in acyclic monoterpene alcohols by a thienyl substituent results in the formation of new terpene analogues, some of which are interesting for perfumery and cosmetology because of their odour quality, tenacity and antimicrobial action. Copyright © 2009 Society of Chemical Industry     

Inhibition of oviposition by volatiles of certain plants and chemicals in the leafhopperAmrasca devastons (distant)

Oviposition by the leafhopperAmrasca devastans (Distant) on its susceptible host plant, cotton (Gossypium hirsutum var. PS-10), was inhibited by the volatiles of certain plants and by the vapors of some chemicals occurring in various plants when these were presented at a distance from the ovipositional substrate. The effectiveness of the volatiles of the plants for inhibiting the oviposition decreased in the order: eucalyptus > coriander=castor=tomato > lime,Ocimum being without effect. Among the volatile plant chemicals tested, the inhibitory effects decreased in the order: citral=carvacrol > citronellol=farnesol = geraniol=eucalyptus oil > neem oil=Cymbopogan oil. These chemicals served as volatile antiovipositants and did not reduce the arrival/stay of the insects on the host plants. Carvacrol had a slight toxic effect on the nymphs, but none of the volatiles was toxic to the adults.Homoptera: Cicadellidae.     

二氢月桂烯高效合成香茅醇

用一种硼氢化试剂———丙二酸与硼氢化钠反应生成的丙二酰氧基硼氢化钠在THF中与二氢月桂烯反应制备香茅醇。温度60℃,反应时间为6h时,反应100%发生在末端双键上,氧化生成香茅醇的质量分数大于90%,该条件下没有发现酮生成。     

Absolute configuration of sex pheromone for tea tussock moth,Euproctis pseudoconspersa (strand)via synthesis of (R)- and (S)-10, 14-dimethyl-1-pentadecyl isobutyrates

(R)- and (S)-10,14-dimethyl-1-pentadecyl isobutyrates were synthesized from (S)- and (R)-citronellols, respectively. TheR enantiomer was as active as the natural pheromone but theS enantiomer was less active in the electrophysiological analyses, which provided conclusive proof that the absolute configuration of the natural pheromone isR.     

在改性骨架镍催化剂上柠檬桉叶油选择加氢制备香茅醇

研制了适用于香茅醛在较低压力下选择加氢制备香茅醇的改性骨架镍催化剂,香茅醛的转化率达９９．５％ 以上,选择性达９９．５％ 以上,加氢的适宜温度为７５℃,压力为２ ＭＰａ。分别考察了向反应液中添加不同助催化剂及其不同用量对反应的转化率和选择性的影响,并确定了相应的工艺操作条件。     

改性BEA沸石催化香茅醛Meerwein-Ponndor-Verley(MPV)还原合成香茅醇

采用盐酸脱铝-碱金属或碱土金属离子交换制备了改性BEA沸石催化剂,并进行催化剂XRD、SEM表征.以上述改性BEA沸石为催化剂、以异丙醇为氢源,通过MPV反应考察了催化剂还原香茅醛合成香茅醇的性能.结果表明,在环化合成异胡薄荷醇和MPV还原合成香茅醇的两种竞争反应中,脱铝-离子交换改性沸石Cs-BEA对于MPV反应合成...     

The In Vitro Cytotoxicity of Eremothecium oil and Its Components—Aromatic and Acyclic Monoterpene Alcohols

The microscopic fungi Eremothecium ashbyi and E. gossypii are known for their ability to synthetize essential oil, which has a composition similar to that of rose oil. The development of Eremothecium oil technology enables the production of rose-scented products, which are demanded by pharmaceutical, food, and perfumery industries. This study focuses on assessing the in vitro cytotoxicity of Eremothecium oil, in comparison with that of rose oil, using a combination of methods and two cell types (3T3 mouse fibroblast cell line and bone-marrow-derived mesenchymal stromal cells (BM-MSCs)). The Eremothecium oil samples possessed cytotoxic effects that varied among strains and batches. The revealed cytotoxicity level may be used to tailor the qualitative and quantitative composition of Eremothecium oil to achieve a particular quality in its end products. These results require further analysis using other cell types and assays based on measuring other cell functions.     

The Contribution of Geraniol Metabolism to the Citrus Flavour of Beer: Synergy of Geraniol and β‐Citronellol Under Coexistence with Excess Linalool

The behaviour of hop‐derived monoterpene alcohols during fermentation by lager yeast was previously investigated in this laboratory. It was suggested that the concentration of geraniol and β‐citronellol in the finished beer increased depending on the initial concentration of geraniol in the wort. In addition, an additive effect among linalool, geraniol and β‐citronellol was found and 5 ug/L of geraniol and β‐citronellol was enough for this effect. In this paper, conditions regarding the enrichment of the initial concentration of geraniol in the wort were investigated. From the screening of various hop cultivars, Citra hop was selected as a geraniol‐rich cultivar. In addition, it was observed that coriander seed, which can be used in beer production as a flavourant, contained not only linalool but also geraniol at high levels. The use of Citra hop or coriander seed was effective for enriching the concentration of geraniol and β‐citronellol in the finished beers. In the Citra beer and in the coriander beer, the content of linalool was excess in comparison with the content of geraniol and β‐citronellol. Therefore, the synergy of geraniol and β‐citronellol, under coexistence of excess linalool, was examined. It was found that the flavour impression of excess linalool became more fruity and citrus by coexistence with geraniol and β‐citronellol and that the coexistence of all three monoterpene alcohols was effective for this synergy. The flavour characteristics of the Citra and coriander beer and the importance of geraniol metabolism for a citrus flavour in beer are discussed.     

酸性离子液体催化合成食用香料丙酸香茅酯

研究了以含磺酸基离子液体1-（4-磺酸基）丁基-3-甲基吡嗪四氟硼酸盐（[4-sulfbmpyrazine][BF4]）为酸性催化剂,以香茅醇、丙酸酐为原料合成丙酸香茅酯,采用正交实验方案对合成条件进行了考察。实验结果表明,以酸性离子液体为催化剂合成丙酸香茅酯的较优条件为：n（香茅醇）∶n（丙酸酐）∶n（催化剂）为50∶100∶1,反应温度70℃,反应时间2 h,按优化条件进行验证实验,产品得率为95.3%。[4-sulfbmpyrazine][BF4]催化剂循环使用5次,催化活性基本不变。