142-92-7Relevant academic research and scientific papers
Chemical defense in the stink bug Cosmopepla bimaculata
Krall, Bryan S.,Bartelt, Robert J.,Lewis, Cara J.,Whitman, Douglas W.
, p. 2477 - 2494 (1999)
Adult Cosmopepla bimaculata discharge a volatile secretion from paired ventral metathoracic glands (MTG) when disturbed. Collected volatiles were similar in both sexes and consisted of n-tridecane (67%), (E)-2-decenal (12%), (E)-2-decenyl acetate (12%), (E)-2-hexenal (3%), hexyl acetate (2%), n-dodecane (2%), a tridecene isomer (1%), and n-undecane, n-tetradecane, and n-pentadecane (all 1%). In addition, undisturbed males produced a novel insect compound, (E)-8-heneicosene, whose function is unknown. The MTG secretion emerges as an enlarging droplet, which is held in place by a cuticular projection and a pleural scent area consisting of specialized rough cuticle surrounding the gland opening. Insects can selectively discharge from either the right or left gland or both glands simultaneously, can control the amount of fluid ejected, and can resorb the ejected secretion droplet back into the gland reservoir, in feeding trials, killdeer (Charadrius vociferus), starlings (Sturnus vulgaris), robins (Turdus migratorius), and anole lizards (Anolis carolinensis) rejected or demonstrated aversion to feeding on the bugs. Furthermore, bugs that lacked the secretion were more susceptible to predation than bugs with secretion, suggesting that the secretion functions in defense against predators.
Optimized synthesis of lipase-catalyzed hexyl acetate in n-hexane by response surface methodology
Shieh, Chwen-Jen,Chang, Shu-Wei
, p. 1203 - 1207 (2001)
Hexyl acetate, a short-chain ester with fruity odor, is a significant green note flavor compound and widely used in the food industry. The ability for immobilized lipase from Mucor miehei (Lipozyme IM-77) to catalyze the transesterification of hexanol with triacetin was investigated in this study. Response surface methodology and five-level-five-factor central composite rotatable design were adopted to evaluate the effects of synthesis variables, such as reaction time (2-10 h), temperature (25-65°C), enzyme amount (10-50%; 0.024-0.118 BAUN), substrate molar ratio of triacetin to hexanol (1:1 to 3:1), and added water content (0-20%) on percentage molar conversion of hexyl acetate. The results showed that reaction temperature and substrate molar ratio were the most important parameters and that added water content had less of an effect on percent molar conversion. On the basis of canonical analysis, optimum synthesis conditions were as follows: reaction time, 7.7 h; temperature, 52.6°C; enzyme amount, 37.1% (0.089 BAUN); substrate molar ratio, 2.7:1; and added water, 12.5%. The predicted value was 88.9% molar conversion, and the actual experimental value was 86.6% molar conversion.
Characterization of Alcohol Acyltransferase from Olive Fruit
Salas, Joaquin J.
, p. 3155 - 3158 (2004)
Alcohol acyltransferase catalyzes the esterification of volatile alcohols with acyl-CoA derivatives to produce volatile esters typically present in the aroma of some fruits. This enzyme was detected in extracts from the pericarp tissues of ripe olive fruits using hexanol and acetyl-CoA as the substrates. Alcohol acyltransferase showed a very low activity level in these fruits, with an optimum pH value at 7.5 and high Km values for hexanol and acetyl-CoA. The substrate specificity of this enzyme for various alcohols was also studied. The involvement of the studied enzyme in the biogenesis of the volatile esters present in the aroma of virgin olive oil was discussed.
Bis(trimethylsilyl) Peroxide for the Baeyer-Villiger Type Oxidation
Suzuki, M.,Takada, H.,Noyori, R.
, p. 902 - 904 (1982)
A Baeyer-Villiger type oxidation of ketonic substrates is achievable under aprotic conditions by use of bis(trimethylsilyl) peroxide and a catalytic amount of trimethylsilyl trifluoromethanesulfonate.The oxidation occurs specifically at carbonyl function and carbon-carbon double bonds are not affected.
Molybdenum-modified mesoporous SiO2as an efficient Lewis acid catalyst for the acetylation of alcohols
Hlatshwayo, Xolani S.,Ndolomingo, Matumuene Joe,Bingwa, Ndzondelelo,Meijboom, Reinout
, p. 16468 - 16477 (2021/05/19)
A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO3-SiO2 as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO3-SiO2, 101 m2 g-1 compared to other catalysts, 22, 23, and 44 m2 g-1 for 5%WO3-ZrO2, 5%WO3-SiO2, and 5%MoO3-ZrO2, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO3 doping while WO3 containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.
Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio-and Stereoselective Acylation of Alcohols
Koszelewski, Dominik,Brodzka, Anna,Madej, Arleta,Trzepizur, Damian,Ostaszewski, Ryszard
, p. 6331 - 6342 (2021/05/06)
Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.
Genome Mining of Oxidation Modules in trans-Acyltransferase Polyketide Synthases Reveals a Culturable Source for Lobatamides
Ueoka, Reiko,Meoded, Roy A.,Gran-Scheuch, Alejandro,Bhushan, Agneya,Fraaije, Marco W.,Piel, J?rn
supporting information, p. 7761 - 7765 (2020/03/25)
Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) are multimodular megaenzymes that biosynthesize many bioactive natural products. They contain a remarkable range of domains and module types that introduce different substituents into growing polyketide chains. As one such modification, we recently reported Baeyer–Villiger-type oxygen insertion into nascent polyketide backbones, thereby generating malonyl thioester intermediates. In this work, genome mining focusing on architecturally diverse oxidation modules in trans-AT PKSs led us to the culturable plant symbiont Gynuella sunshinyii, which harbors two distinct modules in one orphan PKS. The PKS product was revealed to be lobatamide A, a potent cytotoxin previously only known from a marine tunicate. Biochemical studies show that one module generates glycolyl thioester intermediates, while the other is proposed to be involved in oxime formation. The data suggest varied roles of oxygenation modules in the biosynthesis of polyketide scaffolds and support the importance of trans-AT PKSs in the specialized metabolism of symbiotic bacteria.
Alkyl substituted 4-N-oxazadisilinane cations: A new family of Si protic ionic liquids and its application on esterification reactions
Alhaddad, Maha,Chakraborty, Priyanka,Hu, Jinsong,Huang, Kuo-Wei
supporting information, (2020/06/08)
A series of oxazadisilinane compounds were prepared and used as Br?nsted bases to form a series of 21 siloxane protic ionic liquids (Si-PILs) with four different acids. This new family of Si-PILs were well characterized and examined to catalyze esterification reactions.
A new Br?nsted acid MIL-101(Cr) catalyst by tandem post-functionalization; synthesis and its catalytic application
Mortazavi, Saeideh-Sadat,Abbasi, Alireza,Masteri-Farahani, Majid
, (2020/05/16)
A new heterogeneous Br?nsted solid acid catalyst was prepared by tandem post-functionalization of MIL-101(Cr) and utilized for acetic acid esterification and alcoholysis of epoxides under solvent-free conditions. First, MIL-101(Cr) was functionalized with pyrazine to achieve MIL-101(Cr)-Pyz. Afterwards, the nucleophilic reaction of MIL-101(Cr)-Pyz with 1,3-propane sultone and next acidification with diluted sulfuric acid gave MIL-101(Cr)-Pyz-RSO3H Br?nsted solid acid catalyst. Various characterization methods such as Fourier transformation infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), elemental analysis (CHNS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersiveX-ray(EDX) spectroscopy, thermal analysis (TGA/DTA), acid–base titration, and N2 adsorption/desorption analysis were employed to fully characterize the prepared catalyst. The catalyst showed high activity compared to unmodified MIL-101(Cr) in both catalytic acetic acid esterification and alcoholysis of epoxides. It can also be readily isolated from the reaction mixture and reused three times without major decrease in its activity.
Catalytic application of zinc complex of oxygen depleted 1,3-bis(pyrazole)-p-tert-butylcalix[4]arene
Sinha, Anshu Kumar,Vigalok, Arkadi,Rawat, Varun
, p. 796 - 799 (2019/02/14)
In this paper we have described the synthesis and coordination properties of monometallic Zinc complex of oxygen depleted bis(pyrazole)-p-tert-butylcalix[4]arene ligand. We also present the catalytic activity of the Zinc–bis(pyrazole) complex, in acetylation of alcohols and lactide polymerization.
