Transformation of Forest Vegetation After 40 Years of Protection in the Tomczyce Nature Reserve (Central Poland)

The Tomczyce nature reserve is characterized by a degenerated forest vegetation. We assume that the regeneration process was possible to launch after the establishment of the nature reserve in 1968. The vegetation of the Tomczyce forest complex was characterized for the first time by Jakubowska-Gabara (1976) whose studies were taken as a basis of our research. The phytocenoses after 40. years of protection have a greater participation of species with higher trophic and moisture requirements. The regeneration process in communities with pine trees is caused by an expansion of broad-leaved trees and shrubs. Transformation of forest vegetation causes a decrease in cover of thermophilous and heliophilous species. On the other hand, species of oak-hornbeam forests as well as anthropophytes are in expansion. Planning of the protection activities in the nature reserve needs to include these dynamic tendencies of the vegetation

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

Selected hetaryl and aryl thioketones react with acetylenecarboxylates under thermal conditions in the presence of LiClO4 or, alternatively, under high-pressure conditions (5 kbar) at room temperature yielding thiopyran derivatives. The hetero-Diels–Alder reaction occurs in a chemo- and regioselective manner. The initially formed [4 + 2] cycloadducts rearrange via a 1,3-hydrogen shift sequence to give the final products. The latter were smoothly oxidized by treatment with mCPBA to the corresponding sulfones.The authors thank the National Science Center (Cracow, Poland) for generous financial support (Grant Maestro-3 (Dec- 2012/06/A/ST5/00219). Skilful performance of microanalyses by Ms Hanna Jatczak and Ms Agnieszka Cieślińska (University of Łódź) is gratefully acknowledge

Strong influence of the trifluoromethyl group on the chemoselectivity of [3+2]-cycloadditions of thiocarbonyl S-methanides with α,β-unsaturated ketones

The in situ-generated reactive thiocarbonyl S-methanides were reacted with fluorinated enones. The type of the obtained [3+2]-cycloadduct depends strongly on the location of the activating CF3 group. In the case of enones containing the CF3CH=CH moiety, the [3+2]- cycloaddition occurs chemo- and regioselectively onto the C=C bond to give trifluoromethylated tetrahydrothiophene derivatives. On the other hand, enones containing the CF3–C=O unit react as carbonyl dipolarophiles leading to trifluoromethylated 1,3- oxathiolanes also in a chemo- and regioselective manner. These are the first reported reactions of thiocarbonyl S-methanides with α,β-unsaturated ketones

Pro Libris: Lubuskie Pismo Literacko-Kulturalne, nr 4 (2010)

145 s. : il., portr.

Reakcje tia-Dielsa-Aldera z wykorzystaniem tioketonów oraz tiochalkonów jako aktywnych heterodienofili lub heterodienów

Considering the growing importance of thiocarbonyl compounds in modern organic synthesis and continuing interest in studies focused on the mechanisms of organic reactions, a research project based on the exploration of aryl and hetaryl thioketones, as well as structurally related thiochalcones has been implemented. Firstly, the [4+2]-cycloaddition reactions of hetaryl thioketones with non-activated dienes (thia-Diels-Alder reactions) were investigated and the obtained results confirmed extremely high reactivity of thiocarbonyl dienophiles against 1,3-dienes. Thus, hetaryl thioketones have to be considered as reagents which belong to the class of ‘superdienophiles’. Moreover, results obtained in reactions with isomeric 2,4-hexadienes have shown that they follow a non-conventional, stepwise mechanism, involving an intermediate, delocalized diradical. The presence of a hetaryl ring (preferably thiophen-2-yl or selenophen-2-yl) is essential for the appearance of these intermediates. In the next step of the study, aryl/hetaryl and dihetaryl thioketones were investigated as 1-thia-1,3-dienes in reactions with activated acetylenic dienophiles. It has been found that these cycloadditions occurred efficiently when the reaction mixtures were heated in THF solution with catalytic amounts LiClO4 as a catalyst. Derivatives of 2H-thiopyran were formed as sole product in a completely chemo- and regioselective manner. Attempts to perform the same reactions under high pressure (5 kbar) have resulted in a slight improvement of yields without the influence on the reaction times. To the best of our knowledge this was the first attempt to apply the high pressure technique in cycloaddition reactions performed with thioketones. In the extension of the study focused on thia-Diels-Alder reactions, a series of reactions of acetylenic dienophiles with thiochalcones containing aryl and hetaryl substituent have been tested. Along with dimethyl acetylenedicarboxylate also methyl propionate was used as a dienophile. Both dienophiles reacted readily with thiochalcones yielding the expected 4H-thiopyran derivatives. In the case of methyl propionate, thia-Diels-Alder reactions proceeded in a completely regioselective manner. These results point out that in the transition state, the sulfur atom of the C=S bond attacks the β carbon atom exclusively. Substantial progress was achieved by performing these reactions under microwave irradiation. Significant reduction of the reaction times and high yields have been observed. Moreover, microwave irradiation did not affect regioselectivity observed in reactions with methyl propiolate. In the next step, diaryl and aryl/hetaryl thiochalcones were reacted with in situ generated, reactive nitrile imines derived from trifluoroacetonitrile to give regioselectively 1,3,4-thiadiazole derivatives as the expected [3+2]-cycloadducts. To date these results have to be considered as first cases of an efficient applications of thiochalcones as C=S dipolarophiles in 1,3-dipolar cycloaddition reactions. Reaction of chalcones with thiocarbonyl S-methanides used as electron rich 1,3-dipoles were also studied. The obtained results showed that thiocarbonyl S-methanides react effectively only with enones activated with electron withdrawing –CF3 group. Furthermore, it has been established that [3+2]-cycloadditions occurred chemoselectively and the type of the products formed depended on the location of the activating –CF3 group. Enones with the CF3–C=O fragment were less reactive and in addition to the observed 1,3-oxathiole derivatives some amounts of corresponding thiiranes were also formed as products of competitive 1,3-dipolar electrocyclization of the intermediate thiocarbonyl S-methanide

Thia-Diels–Alder reactions of hetaryl thioketones with nonactivated 1,3-dienes leading to 3,6-dihydro-2H-pyrans: evidence for a diradical mechanism

Dihetaryl thioketones possessing thiophen-2-yl and selenophen-2-yl rings react as ''superdienophilic'' reagents with nonactivated 1,3-dienes such as 2,3-dimethylbuta-1,3-diene, cyclopentadiene, and mixtures of isomeric hexa-2,4-dienes to produce the expected 2H-thiopyrans in moderate to excellent yields. In the latter case, the corresponding cis-2,2-dihetaryl-3,6-dimethyl-3,6-dihydro-2H-thiopyrans are formed as the sole products in a stereoconvergent thia-Diels–Alder reaction. A stepwise mechanism via delocalized diradical intermediates is postulated to rationalize the observed reaction course. Treatment of 4,5-dimethyl-2,2-di(thiophen-2-yl)-3,6-dihydro-2H-thiopyran with excess of m-CPBA at room temperature leads to the oxidation of the C=C bond and the sulfur atom in the six-membered ring

Model identyfikacji produktów w magazynie przy użyciu oprogramowania Anteeo WMS

Products should always be accurately identified, regardless of the type of warehouse and the specificity of stored products. Proper acceptance of a given product into a warehouse is the basis for the implementation of subsequent warehouse processes and affects the optimization of the entire logistics chain. Appropriate marking and marking of the location of products deposited in the warehouse is currently determined by an IT system that supports companies in organizational, technological and administrative activities. The aim of the article is to present a model of the process of identification of products accepted and placed on a warehouse using the Anteeo WMS information system.Produkty powinny zawsze być dokładnie zidentyfikowane, niezależnie od rodzaju magazynu i specyfiki przechowywanych produktów. Właściwa akceptacja danego produktu w magazynie jest podstawą do realizacji kolejnych procesów magazynowych i wpływa na optymalizację całego łańcucha logistycznego. Odpowiednie oznakowanie i oznaczenie lokalizacji produktów zdeponowanych w magazynie jest obecnie określane przez system informatyczny, który wspiera firmy w działaniach organizacyjnych, technologicznych i administracyjnych. Celem artykułu jest przedstawienie modelu procesu identyfikacji produktów przyjętych i składowanych w magazynie przy użyciu systemu informatycznego Anteeo WMS

Environmental assessment of the exploitation of diesel engines powered by biofuels

Many factors, such as climate change and the associated risk of increasing the average temperature on the globe, energy security and the finishing of fossil fuel deposits have caused other renewable energy sources to be sought. Transport, as a branch of industry largely responsible for air pollution and greenhouse gas emissions in large cities, requires the necessary changes in the way vehicles are powered. Until now, the fuels available at petrol stations use admixtures of first generation biofuels, such as bioethanol, as a 5% additive to motor gasolines and biodiesel (FAME) as a 7% additive to diesel oil. The article presents the idea of biorefinery installations, specifies the spectrum of substrates of the second and advanced generations, which may be a biorefinery input, including waste oils that can be used to produce hydrogenated HVO vegetable oils and other high-value products. The paper presents he existing biorefinery plant in Venice resulting from the transformation of a conventional oil refinery in which HVO fuel is produced. The article also presents the parameters of this new biofuel and compared them with the parameters of other fuels used to power self-ignition engines, such as FAME and diesel, along with discussing the prospects for HVO fuel development in Europe