187 research outputs found
Influence of air temperature and humidity on Stratiolaelaps scimitus (Acari, Mesostigmata) locomotor activity in a laboratory experiment
Stratiolaelaps scimitus (Womersley, 1956) (Acari, Mesostigmata, Laelapidae) is a predatory soil mite massively produced in laboratories in many countries of the world. The existing spheres of S. scimitus application vary in many parameters, especially temperature and relative humidity. In this article, we analyzed temperature and humidity appropriate for fastest spread of soil predatory mite S. scimitus. Mites should be released to a new environment in such a way that they would distribute in a greenhouse, garden or field as fast as they can (i.e. providing maximum migration activity of S. scimitus), on the one hand, and provide maximum efficient control of number of target phytophage species (i.e. providing maximum trophic activity), on the other hand. In our experiment, at 14 ºC temperature, most specimens of S. scimitus did not leave the migratory circle for 10 seconds. In 15–19 ºC range, only 14.7% of mites left the migratory circle, and their examined activity in 10 s was only 5–10 mm. In 20–24 ºC range, 27.5% of mites left the migratory circle, their migratory activity increased to 15–23 mm. In 25–33 ºC range, the moving activity increased even more, the mites left the migratory circle at the first opportunity that had (some even jumped off the circle to the experimental field), 95.8% of the mites left the circle in 10 s, their examined activity reached 25–60 mm in 10 seconds. Study of thermo- and hygro-preferences for various groups of invertebrates helps to better describe their ecological niche in multidimensional space of ecologic factors
Influence of organic acids on locomotor activity of Stratiolaelaps scimitus (Mesostigmata, Laelapidae)
Increasing the activity of zoophage Acari in agrocenoses, for example luring them to concentrations of harmful insects, could be effectively performed using attractants, for example organic acids that people use in households and industry. In our experiment, we studied the influence of organic acids on the locomotor activity of Stratiolaelaps scimitus (Womersley, 1956) (Mesostigmata, Laelapidae). Different organic acids caused certain reactions in those zoophages. Acetic acid encouraged this mite to activity and attracted it, while thioacetic acid inhibited and repelled it. Fatty acids such as tridecylic and oleic acids had an activating effect on the locomotor activity of S. scimitus. Three isomers of valeric acid inhibited locomotor activity, and the mites exerted negative chemostasis to them. Maximum locomotor activity of the mites was observed when using asparagine, ornithine, propionic acid, tridecanoic acid, boric acid, and arginine. Locomotor activity of the mites was inhibited by 3,3-dimethylbutanoic acid, thioacetic acid, pivalic acid, maleic acid, formic acid, succinic acid, 2-methylbutanoic acid, isovaleric acid, 6-aminohexanoic acid, and 2-oxoglutaric acid. We propose using attractiveness coefficient and coefficient of migratory activity, which reflect the effects of aroma compounds on mites. Those coefficients are helpful in identification of a behaviour model for mites exposed to aroma compound: attack, motionless state or escape. High attractiveness and migratory-activity coefficients mean attack on victim; low coefficients indicate motionless mites; high migratory activity and low attractiveness coefficient mean escape reaction. Our results indicate complexity of behaviour reactions of mites, which were sensitive to volatile chemical compounds in the environment. We found a high potential of using those compounds in attracting zoophages during their introduction in agrocenoses of greenhouses and open plots
A simple two-step synthesis of 2-(alkylamino)-1-arylethanols, including racemic adrenaline, from aromatic aldehydes via 5-aryloxazolidines
Benzaldehydes react smoothly with nonstabilized azomethine ylides, generated in situ from sarcosine/formaldehyde or N-(methoxymethyl)-N- (trimethylsilylmethyl)benzylamine, to give 5-aryloxazolidines as intermediates. These were converted into 2-(alkylamino)-1-arylethanols in good yields by simple heating in methanol with hydrochloric acid, or by treatment with hydrazine hydrate in ethanol. © 2013 Elsevier Ltd. All rights reserved
A one-pot synthesis of tetrahydroisoquinolin-4-ols via a novel acid-catalyzed rearrangement of 5-aryloxazolidines
Benzaldehydes with electron-donating substituents react smoothly with a nonstabilized azomethine ylide derived from sarcosine and formaldehyde to form 5-aryloxazolidines as intermediates, which undergo rearrangement into 2-methyl-1,2,3,4-tetrahydroisoquinolin-4-ols in high yields by simple heating with hydrochloric acid. This one-pot synthesis of tetrahydroisoquinolines can be considered as a formal [3+3] cycloaddition of the azomethine ylide to the aromatic aldehyde. © 2013 Elsevier Ltd. All rights reserved
Reaction of 5-aryloxazolidines with arylmagnesium bromides as a new route to N-benzyl-β-hydroxyphenethylamines as starting materials for the preparation of 4-aryl-1,2,3,4-tetrahydroisoquinolines
Benzaldehydes react smoothly with the non-stabilized azomethine ylide derived from sarcosine and formaldehyde to form 5-aryloxazolidines as intermediates, which undergo ring-opening to give N-benzyl-β- hydroxyphenethylamines in good yields by the action of arylmagnesium bromides. Their subsequent acid-catalyzed cyclization into 4-aryl-1,2,3,4- tetrahydroisoquinolines was performed in moderate to good yields. © 2013 Elsevier Ltd. All rights reserved
Synthesis of benzopyranopyrrolidines via 1,3-dipolar cycloaddition of nonstabilized azomethine ylides with 3-substituted coumarins
A three-component reaction of 3-substituted coumarins with N-alkyl-α-amino acids and aldehydes gave 1-benzopyrano[3,4-c]pyrrolidines as a result of a 1,3-dipolar cycloaddition of an intermediate nonstabilized azomethine ylide at the double bond of the coumarin system in moderate to good yields. In most cases, high regio- and stereo-selectivity of the [3+2] cycloaddition was observed. © 2013 Elsevier Ltd. All rights reserved
Prospects of paramagnetic lanthanide complexes for magnetic resonance imaging, local thermosensing and diagnosing
The features of the paramagnetic properties of lanthanide (Ln) containing complexes with crown ethers, pivaloyltrifluoracetonato, and EDTA have been studied by 1H and 19F NMR techniques. These complexes are of interest due to the prospect of using some of them as sensors for biology and medicine. The temperature dependencies of the lanthanide-induced shifts revealed that Ln complexes might have practical importance for 1H and 19F NMR temperature control in solutions. It was shown in vitro (using NMR spectrometers and MRI scanners) that these complexes can serve as special NMR thermo-sensitive contrast reagents
Highly diastereoselective 1,3-dipolar cycloaddition of nonstabilized azomethine ylides to 3-nitro-2-trihalomethyl-2H-chromenes: Synthesis of 1-benzopyrano[3,4-c]pyrrolidines
Reactions of 3-nitro-2-trifluoro(trichloro)methyl-2H-chromenes, including 2-unsubstituted derivatives, with N-alkyl-α-amino acids (sarcosine, proline) and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[3,4-c]pyrrolidines in good yields as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the Δ3-bond of the chromene system. © 2013 Elsevier Ltd. All rights reserved
REACTIONS OF 5-ARYLOXAZOLIDINES AND THEIR DERIVATIVES WITH NUCLEOPHILES
Compounds 5‒7 were obtained with financial support from the Russian Science Foundation (grant no. 22-73-10008)
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