A new hyaluronan modified with β-cyclodextrin on hydroxymethyl groups forms a dynamic supramolecular network

A new hyaluronan derivative modified with β-cyclodextrin units (CD-HA) was prepared via the click reaction between propargylated hyaluronan and monoazido-cyclodextrin (CD) to achieve a degree of substitution of 4%. The modified hyaluronan was characterized by 1H-nuclear magnetic resonance spectroscopy (NMR) and size exclusion chromatography. Subsequent 1H-NMR and isothermal calorimetric titration experiments revealed that the CD units on CD-HA can form virtual 1:1, 1:2, and 1:3 complexes with one-, two-, and three-site adamantane-based guests, respectively. These results imply that the CD-HA chains used the multitopic guests to form a supramolecular cross-linked network. The free CD-HA polymer was readily restored by the addition of a competing macrocycle, which entrapped the cross-linking guests. Thus, we demonstrated that the new CD-HA polymer is a promising component for the construction of chemical stimuli-responsive supramolecular architectures. © 2019 by the authors.Internal Funding Agency of the Tomas Bata University in Zlin [IGA/FT/2019/007

Two squares in a barrel: An axially disubstituted conformationally rigid aliphatic binding motif for cucurbit[6]uril

Novel binding motifs suitable for the construction of multitopic guest-based molecular devices (e.g., switches, sensors, data storage, and catalysts) are needed in supramolecular chemistry. No rigid, aliphatic binding motif that allows for axial disubstitution has been described for cucurbit[6]uril (CB6) so far. We prepared three model guests combining spiro[3.3]heptane and bicyclo[1.1.1]pentane centerpieces with imidazolium and ammonium termini. We described their binding properties toward CB6/7 and α-/β-CD using NMR, titration calorimetry, mass spectrometry, and single-crystal X-ray diffraction. We found that a bisimidazolio spiro[3.3]heptane guest forms inclusion complexes with CB6, CB7, and β-CD with respective association constants of 4.0 × 104, 1.2 × 1012, and 1.4 × 102. Due to less hindering terminal groups, the diammonio analogue forms more stable complexes with CB6 (K = 1.4 × 106) and CB7 (K = 3.8 × 1012). The bisimidazolio bicyclo[1.1.1]pentane guest forms a highly stable complex only with CB7 with a K value of 1.1 × 1011. The high selectivity of the new binding motifs implies promising potential in the construction of multitopic supramolecular components.Internal Funding Agency of Tomas Bata University, (IGA/FT/2023/001); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LM2023042, LUAUS23144); Ústav organické chemie a biochemie Akademie věd České republiky, ÚOCHB AV ČR, (RVO: 61388963)Internal Funding Agency of Tomas Bata University in Zlin [IGA/FT/2023/001]; MEYS CR [LM2023042]; Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences [RVO: 61388963]; Ministry of Education, Youth and Sports [LUAUS23144

Modes of micromolar host-guest binding of beta-cyclodextrin complexes revealed by NMR spectroscopy in salt water

Multitopic supramolecular guests with finely tuned affinities toward widely explored cucurbit[n]urils (CBs) and cyclodextrins (CDs) have been recently designed and tested as functional components of advanced supramolecular systems. We employed various spacers between the adamantane cage and a cationic moiety as a tool for tuning the binding strength toward CB7 to prepare a set of model guests with K-CB7 and K beta-CD values of (0.6-5.0) x 10(10) M-1 and (0.6-2.6) x 10(6) M-1, respectively. These accessible adamantylphenyl-based binding motifs open a way toward supramolecular components with an outstanding affinity toward beta-cyclodextrin. H-1 NMR experiments performed in 30% CaCl2 /D2O at 273 K along with molecular dynamics simulations allowed us to identify two arrangements of the guest@beta-CD complexes. The approach, joining experimental and theoretical methods, provided a better understanding of the structure of cyclodextrin complexes and related molecular recognition, which is highly important for the rational design of drug delivery systems, molecular sensors and switches.Internal Funding Agency of the Tomas Bata University in Zlin [IGA/FT/2020/001]; Czech Science FoundationGrant Agency of the Czech Republic [18-05421S]; Ministry of Education, Youths and Sports of the Czech Republic (MEYS CR) [LQ1601]; CIISB, Instruct-CZ Center of Instruct-ERIC EU consortium - MEYS CR infrastructure project [LM2018127]; MEYS CR from the Large Infrastructures for Research, Experimental Development and Innovations [CZLM2018140]Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: CZ-LM2018140, LM2018127; Grantová Agentura České Republiky, GA ČR: 18-05421S, LQ1601; Univerzita Tomáše Bati ve Zlíně: IGA/FT/2020/001; Masarykova Univerzita, M

Návrh receptury bezlepkových müsli tyčinek s přídavkem vlákniny

The theoretical part deals with celiac disease, gluten-free diet composition and the importance of fiber consumption in gluten-free diet. The practical part deals with the production of muesli bars from gluten-free raw materials with different percentage of fiber. Two formulations have been proposed in which samples containing 0 %, 3 %, 6 % and 9 % fiber are always prepared. For these products were determined the physical properties, calculated the nutritional values. At the end was performed the sensory analysis. All results are shown by graphs. The best muesli bar was without fiber (buckwheat and rice flakes 1: 1, agave syrup, honey). The strongest was the muesli bar with 9% fiber content (buckwheat and rice flakes 1: 1, agave syrup, honey and wheat fiber). Muesli bars with 9 % fiber content showed the most favorable nutritional composition. The addition of fiber 3 % was evaluated as sensory acceptable

Studium vlivu požití kávy na antioxidační stav organismu

The theoretical part deals with the characterization of coffee, its production, chemical composition of grain and coffee swallowed impact on the health of an organism. It also deals with antioxidants, their division and their effects on the human body. There is described glutathione, one of the most important antioxidant in the blood. The practical part is engaged in an experiment consisting of the capillary blood collection and subsequent determination of thiol groups Ellman method, determine the total content of reduced glutathione by high performance liquid chromatography with electrochemical detection and determination of total protein content in blood by the Bradford method,. All results are shown in graphs. Contents of glutathion and thiol groups with regular consumption of coffee increased, protein content did not change. In the last part of the experiment, sensoric analysis of the test sample of instant coffee was carried out. Coffee was rated as average, because the overall impression was rated an average of 52.7 points

Disposal of waste liquor from 2,5 - dichlorodisulfanilic acid production

Byly vypracovány tři alternativní postupy zneškodnění odpadní lázně produkované výrobou 4-amino-2,5-dichlorbeznensulfonové kyseliny. Tato lázeň je nebezpečný kapalný odpad, který nepřijatelně inhibuje procesy biologického čištění.Three alternative procedures were worked out for disposal of waste liquor from production of 2,5-dichlorodisulfanilic acid [CAS No. 88-50-6]. This liquor is a hazardous liquid waste which inhibits processes of biological treatment

Synthesis of 2-thioxo-imidazolines via reaction of 1-unsubstituted 3-aminoquinoline-2,4-diones with isothiocyanates

3-Alkyl/Aryl-3-aminochinoline-2,4-diony reagují s isothiokyanáty za tvorby 3a-alkyl/aryl-1,2,3,3a-tetrahydro-9b-hydroxy-2-thioxo-5H-imidazo-[4,5-c]chinolin-4(9bH)-onů. Tyto sloučeniny přesmykují v kyselém prostředí na nové 4-(2-aminofenyl)-1H-imidazol-2(3H)-thiony a 1,3-bis(2-(2,3-dihydro-2-thioxo-1H-imidazol-5-yl)fenyl)močoviny.3-Alkyl/Aryl-3-aminoquinoline-2,4-diones react with isothiocyanates to give 3a-alkyl/aryl-1,2,3,3a-tetrahydro-9b-hydroxy-2-thioxo-5H-imidazo-[4,5-c]quinolin-4(9bH)-ones. These compounds rearrange in an acidit environment to give novel 4-(2-aminophenyl)-1H-imidazole-2(3H)-thiones and 1,3-bis(2-(2,3-dihydro-2-thioxo-1H-imidazol-5-yl)phenyl)ureas

Adamantylated trisimidazolium-based tritopic guests and their binding properties towards cucurbit[7]uril and beta-cyclodextrin

Two new homotritopic guests based on tris(benz) imidazolium salts with adamantane binding sites were prepared. NMR and calorimetric titration experiments revealed that each of the three sites independently binds beta-cyclodextrin (beta-CD) or cucurbit[7]uril (CB7) units to form binary host-guest complexes with 1:3 stoichiometry. The association constants for the single binding site for beta-CD and CB7 were determined using titration calorimetry and are in the order of 10(5) and 10(9-10) dm(3) mol(-1), respectively. In addition, both guests were able to form ternary systems with beta-CD and CB7 in ratios of 1:1:2 and 1:2:1, respectively.Internal Funding Agency of the Tomas Bata University in Zlin [IGA/FT/2015/005

A New Hyaluronan Modified with β-Cyclodextrin on Hydroxymethyl Groups Forms a Dynamic Supramolecular Network

A new hyaluronan derivative modified with β-cyclodextrin units (CD-HA) was prepared via the click reaction between propargylated hyaluronan and monoazido-cyclodextrin (CD) to achieve a degree of substitution of 4%. The modified hyaluronan was characterized by 1H-nuclear magnetic resonance spectroscopy (NMR) and size exclusion chromatography. Subsequent 1H-NMR and isothermal calorimetric titration experiments revealed that the CD units on CD-HA can form virtual 1:1, 1:2, and 1:3 complexes with one-, two-, and three-site adamantane-based guests, respectively. These results imply that the CD-HA chains used the multitopic guests to form a supramolecular cross-linked network. The free CD-HA polymer was readily restored by the addition of a competing macrocycle, which entrapped the cross-linking guests. Thus, we demonstrated that the new CD-HA polymer is a promising component for the construction of chemical stimuli-responsive supramolecular architectures

Supramolecular properties of amphiphilic adamantylated azo dyes

Despite environmental and health risks, azo dyes are still very popular colourising agents; therefore, methods for removing the dyes and/or related pollutants from wastewater have been developed. We have incorporated a lipophilic adamantane cage into two polar disulphonatonaphthalene-1-azobenzene dyes to prove the concept that modified dyes can be treated via host–guest supramolecular interactions using suitable cyclodextrin (CD) and cucurbit[n]uril (CBn) hosts. We conducted 1H NMR experiments to demonstrate that both dyes form specific inclusion complexes with an adamantane cage buried inside the CB7 or β-CD cavity. Using isothermal titration calorimetry, we determined association constants with β-CD and CB7 in the range of (0.7–1.3) × 106 and (1.4–3.4) × 108, respectively. As the dye@CB7 complexes were sparingly soluble in water, the dye can be efficiently removed from water by precipitation, even in the presence of β-CD. © 2021 Elsevier LtdInternal Funding Agency of Tomas Bata University in Zlin [IGA/FT/2021/001]IGA/FT/2021/001; Univerzita Tomáše Bati ve Zlín