Continuous synthesis of tri- and tetrasubstituted imidazoles via a multicomponent reaction under microreactor conditions

Using a modified Radziszewski reaction, a procedure has been optimized for the generation of tri- and tetrasubstituted imidazoles via microreactor technology. Optimization included the search for a suitable solvent mixture, temperature and reaction time. Finally, the generality of the optimized reaction was tested using different starting materials. It was possible to create a variety of tri- and tetrasubstituted imidazoles in moderate to good yields via a continuous procedure. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA

Machine vision for locating objects

Bakalárska práca sa zaoberá tvorbou systému strojového videnia pre lokalizáciu objektov a možnosťami aplikácie tohto typu úlohy strojového videnia. V práci je popísaný dizajn daného systému, a tiež všetky jeho komponenty, ich vlastnosti, a výhody a nevýhody ich použitia. Takisto je zostavená vlastná scéna pre snímanie ukážkového predmetu. Pre vyhodnocovanie obrazu je použitý bežný počítač s programom Vision assistant a jeho nástroje. V tomto programe sú vytvorené a následne porovnané výkonnosti dvoch postupov vyhodnocovania obrazu.The bachelor’s thesis deals with design of machine vision system for object localization and its application possibilities. Design approach, its components and their individual advantages and disadvantages for this type of machine vision system are described. This thesis also includes simple model of machine vision system for object localization using regular PC. For image processing is used Vision Assistant and its tools. Two scripts are made in this software and their performance is compared.

One-pot synthesis, characterization, and antioxidant capacity of sulfur- and oxygen-substituted 1,4-naphthoquinones and a structural study

In the present study, we reported the one-pot synthesis of S,S- and S,O-substituted 1,4-naphthoquinones, their structural studies, and investigation of their antioxidant activity. The multicomponent reactions of 2,3-dichloro-1,4-naphthoquinone with sulfur- and oxygen-containing nucleophiles were investigated to obtain highly functionalized S,S- and S,O-substituted 1,4-naphthoquinone derivatives. All new compounds were characterized on the basis of H-1, F-19, and C-13 nuclear magnetic resonance spectroscopy, mass spectrometry, and Fourier transform infrared spectroscopy. Crystal structure of 2,3-dihydro-2-(hydroxymethyl)naphtho[2,3-b]-1,4-oxathiin-5,10-dione was determined by X-ray diffraction method. The synthesized compounds were screened for their antioxidant capacity and free radical scavenging activity using the cupric reducing antioxidant capacity method and DPPH method, respectively. 3-Chloro-2-[3-(3-chloro-1,4-dihydro-1,4-dioxonaphthalen-2-yloxy)propylsulfanyl]-1,4-naphthoquinone shows the highest antioxidant capacity with 0.63 cupric reducing antioxidant capacity-trolox equivalent antioxidant capacity coefficient