Wyniki wyszukiwania - BazTech

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Badania skuteczności działania wabików feromonowych w odławianiu inwazyjnej ćmy bukszpanowej (Cydalima perspectalis) w Polsce

Bereś Paweł, Soika Grażyna, Jabłoński Tomasz, Grodner Jacek

Przemysł Chemiczny

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2022

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T. 101, nr 9

638--645

PL

Przedstawiono wyniki badań przydatności pułapek chwytnych z nowo opracowanymi wabikami feromonowymi do odłowu motyli ćmy bukszpanowej (Cydalima perspectalis). Czynnikiem zwabiającym samce szkodnika były dyspensery z różnymi mieszankami feromonowymi, zawierającymi dwa izomeryczne aldehydy (E) i (Z) 11-heksadecenalu z dodatkiem topanolu jako antyutleniacza lub bez jego udziału. Dla celów komercyjnych zaproponowano nową, tanią i skuteczną pułapkę feromonową do monitorowania/kontroli ćmy bukszpanowej, która jest konkurencyjnym produktem dla podobnych środków obecnie dostępnych na rynku krajowym.

EN

(Z)-11-Hexadecenal and (E)-11-hexadecenal in a mass ratio of 4:1 (A) and 5:1 (B) were dissolved in hexane with or without the addn. of an antioxidant (2,6-di-tert-butyl-4-methylphenol). The org. solns. were applied to rubber carriers and put in sticky traps that were placed on the boxwood plantings in several places in Poland. In the periods from May to October 2020 and 2021, pheromone traps were controlled, counting the caught male moths of the boxwood moth. The most active lures were pheromone blends A with the addn. of the antioxidant, placed on a gray rubber cap. Their effectiveness was similar to the com. pheromone lures.

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Chiralne amidki litu : właściwości i wybrane zastosowania syntetyczne

Piwońska Magdalena

Wiadomości Chemiczne

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2021

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[Z] 75, 5-6

771--798

EN

Reactions involving carbonyl groups are one of the most important transformations in organic chemistry. The nucleophilic properties of carbonyl compounds, when they are in the form of enolate ions, offer many possibilities for creating new carbon-carbon bonds in reactions with electrophiles. In the case of cyclic ketones, enolate formation can be stereocontrolled by deprotonation with the use of chiral lithium amides. Stereoselective formation of the chiral lithium enolate determines the stereochemistry of the product of the subsequent reaction with the electrophile. The induction of chirality in the reaction of enolate ions with electrophiles can also be achieved by using metals other than lithium, i.e. magnesium. When other alkali metals are used, an organometallic catalyst containing a chiral ligand must be present in the reaction. The presence of particular structural elements allow distinguishing the chiral lithium amides between eight major classes. Due to the high reactivity of lithium enolates, they are often converted into the silyl enol ether. This is done in two ways: internal quench (in situ reaction with TMSCl) or external quench. Due to aggregation of the chiral lithium amides and, thus, a decrease in asymmetric induction, the addition of LiCl is necessary for reactions run in external quench conditions. Although there are known examples of the use of chiral lithium amides in a catalytic amount in the deprotonation of epoxides, there is only one example of using less than stoichiometric amounts of chiral lithium amides in the deprotonation of ketones. There are many reports in the literature on the use of chiral lithium amides in total syntheses. The chiral lithium amides were used to form chiral enol silyl ether intermediates, e.g. in synthesis of chlortetaine or (+)-ibogamine. They are also used to form chiral lithium enolates which reacts directly with electrophiles, e.g. in synthesis of lasonolide A.

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Ostatnie postępy w syntezie alkaloidów tropanowych i pochodnych tropanu

Sidorowicz K., Kropiwnicki K., Łaźny R.

Wiadomości Chemiczne

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2015

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[Z] 69, 11-12

1019--1045

EN

Tropane alkaloids are a long-known class of compounds possessing an 8-azabicyclo[ 3.2.1]octane skeleton. Many tropane alkaloids posses biological activity (anticholinergic, anti-Parkinsonian, hypotensive), and as such had a significant influence on medicine and played a notable role in the development of organic chemistry [1]. The most known representatives of biologically active tropane alkaloids are: cocaine, atropine, scopolamine, ecgonine, and Bao Gong Teng A. A number of natural tropane alkaloids are chiral compounds, whose preparation in optically active forms is still a big challeng [2]. The biological activity of enantiomers often differs depending on their configurations. Alkaloids are a subject of an intensive research: scopus database contains nearly 200 thousand publications with the word „alkaloid”, and almost 4,500 publications with the phrase „tropane alkaloids” (about half of them have appeared in the last ten years). About 55 papers are devoted to stereoselective synthesis of tropane derivatives in 2000-2015. About half of this concernes stereoselective methods. The organic synthesis of alkaloids has a long history and numerous synthetic approaches to the tropane skeleton have been developed, from the classical synthesis of tropinone by Willstätter at the beginning of the XX century, to more recent developments dealing with asymmetric deprotonation of tropinone with chiral lithium amide bases for the enantioselective synthesis of a range of tropanes [3, 4]. Owing to extensiveness of the field, the current review presents the most interesting, from a synthetic point of view, approaches to tropane derivatives and tropane analogues. Most of the methods of synthesis are long (often several steps), time- and recourses-intensive, and often required elaborate and hardly available starting materials. But there are also notable exceptions, based on the asymmetric deprotonation approach; e.g., from the syntheses of cocaine described in this article, the most efficient one was reported by Lee in 2000 [5]. The concise synthesis (6 steps) gave the unnatural enantiomer of cocaine starting from commercially available tropinone in 78% overall yield. This approach allows to obtain both enantiomers and racemate, by changing type of one reactant only. However, most strategies provide only one enantiomer or racemic mixture of an alkaloid. As can be seen, despite of advances in chemicall science, there is no general way to synthesize majority of the representatives of this group of structurally related compounds.

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Asymetryczna synteza α, β-diaminokwasów

Błaszczyk R., Gajda T.

Wiadomości Chemiczne

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2009

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[Z] 63, 7-8

635-684

EN

Through the years, α,β-diamino ac6ds and their derivatives have attracted a great deal of attention among organic chemists because of their biological significance [1, 2]. This review deals with the synthetic approaches of α,β-diamino acids and their derivatives (e.g., esters, amides) using asymmetric synthesis methods described in the literature up to the end of 2008. Aziridines and 3-amino-β-lactams are beyond the scope of this review and will be only considered as intermediates in the synthesis of acyclic derivatives. The methods found in the literature can be classified essentially in two main categories: methods that require a new carbon-carbon single bond construction and method based on the functional groups transformation reactions within the carboxylic acids skeleton. A great number of C-C forming methods are the addition reactions of glycine derivatives or nitro compounds to imines (Mannich-type reactions). The asymmetric induction requires chiral substrate usage (e.g., chiral sulfinimines, chiral glycinates) [30-37, 61-67] or results from the application of chiral catalysts (e.g., chiral Lewis acids, chiral PTC catalysts and other organocatalysts) [39-48, 50-60] . Strecker's reaction using chiral imines or related compounds is also often used [69-77]. Methods begining from the existing carbon skeleton and based on the modification of the functional groups are as follows: catalytic asymmetric diamination and aminohydroxylation of α,β-unsaturated carboxylic esters [92-100, 107-109]. Subsequent transformation of the hydroxy group into the amine group in the hydroxyamino acids derivatives is then necessary [100-109]. The direct introduction of the amino moiety into the β-amino esters via electrofilic amination is also described [120-131]. The title compounds can also be obtained by catalytic enantioselective reduction of dehydrodiamino acids derivatives[117-119].