One-pot synthesis of the new Hydroxamic acid and its complexes with metals

A one-pot conversion of 2-hydroxy-1-naphthoic aldehyde to hydroxamic acid was described. An efficient photoorganocatalytic method of synthesis was developed. The obtained hydroxamic acid was identified by various physicochemical methods such as IR, UV- and NMR-spectroscopy. Solid colored complexes of copper (II) and iron (II), respectively, green and brown colours with the obtained hydroxamic acid were synthesized in ethanol medium for the first time. The molar ratio of ligand and metal in the complex was 2:1. Their structures were established using IR, UV- spectroscopy and thermogravimetric analysis.

Synthesis and Antioxidant Properties of Novel 2-(2,4-Dioxothiazolidin-5-ylidene)-Acetamides Containing 1,3,4-Thia/Oxadiazole Moieties

A series of novel 1,3,4-thia(oxa)diazole substituted 2-(2,4-dioxothiazolidine-5-ylidene)-acetamides 3a-c, 4 and 5a-k have been synthesized following the acylation reaction of 2-amino-5-aryl-1,3,4-oxadiazoles, 5-amino-1,3,4-thiadiazole-2-thiol and it’s S-alkylated derivatives with 2-(2,4-dioxothiazolidine-5-ylidene)acetyl chloride in dioxane medium. The functionalization of compounds 3b, 3c, 5d and 5e was carried out on their N3 position under N-alkylation conditions with N-aryl-2-chloroacetamides in DMF/ethanol medium yielded the corresponding 2,4-dioxothiazolidine-3,5-diacetic acid diamides 6a-e and 7a-b. The structures of target compounds were confirmed by using 1H NMR spectroscopy and elemental analysis. The antioxidant activity evaluation in vitro of the synthesized compounds was performed by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. As a result, the highly active compound 4, namely 2-(2,4-dioxothiazolidin-5-ylidene)-N-(5-mercapto-[1,3,4]thiadiazol-2-yl)acetamide was found to be the most efficient candidate among all compounds with a radical scavenging ability of 88.9%, which was comparable that for ascorbic acid (92.7%). The experimentally calculated IC50 value of 43.1 µM for compound 4 was lower than for ascorbic acid (50.5 µM).

Developing an ethanol utilisation pathway based NADH regeneration system in Escherichia coli

Many industrially relevant biotransformation in whole-cells are dependent on cofactors such as NADH or NADPH. Cofactor regeneration is an established approach for providing a cheap source of cofactors in support of the main biotransformation reaction in biocatalysis. In essence, cofactor regeneration uses a sacrificial substrate to help regenerate a cofactor consumed by the main biotransformation reaction. Enzymatic in nature, alternative cofactor regeneration systems with high efficiency and which utilises low cost sacrificial substrate are of interest. Glucose dehydrogenase system has been dominant in NADH regeneration. But, in its current incarnation, glucose dehydrogenase system is relatively inefficient in regenerating NADH with theoretical yield of one NADH per glucose molecule. This work sought to explore the utility of a two-gene ethanol utilisation pathway in NADH regeneration. Comprising the first step that takes ethanol to acetaldehyde, and a second step that converts acetaldehyde to acetyl-CoA, NADH from both steps could be mined for supporting biotransformation reaction in cofactor regeneration mode. Theoretically, ethanol utilisation pathway (EUP) affords a higher NADH yield of two NADH per ethanol molecule, and is therefore more efficient than glucose dehydrogenase (GDH) system. In this project, the EUP pathway was coupled to a cpsADH (an alcohol dehydrogenase from Candida parapsilosis) mediated ketone to alcohol anaerobic biotransformation with concentration of alcohol product as marker for efficiency of cofactor regeneration. Experiment tests showed that EUP was more efficient than GDH. Further, EUP could support biotransformation of both butanone and acetophenone in single and two-phase biotransformation, respectively. Additional work conducted to improve biotransformation efficiency revealed that ethanol provision positively correlated with biotransformation efficiency. Growing cell biotransformation was also found to improve biotransformation efficiency compared to resting cell due largely to the driving force generated by cell growth. Tests of a growth medium effect also found that cells cultivated in M9 ethanol medium delivered higher biotransformation efficiency compared to those cultivated in LB medium. This could arise due to the lower expression of NADH dependent enzymes during growth in M9 ethanol medium compared to LB medium that allowed more NADH to be diverted to support ketone biotransformation. However, a persistent problem with the experimental system is the relatively poor consumption of ethanol that points to need for further engineering of the system. Collectively, pathway-based NADH regeneration is possible with ethanol utilisation, with biotransformation efficiency dependent on mode of biotransformation (resting cell versus growing cell) and growth medium used.

Thermal Conversion of Flax Shives in Sub- and Supercritical Ethanol in the Presence of Ru/C Catalyst

Thermal conversion of flax shives was studied in sub- and supercritical ethanol medium at 225 and 250 °C in the presence of the bifunctional catalyst 3% Ru/C. The use of 3% Ru/C catalyst in the process of thermal conversion of flax shives in supercritical ethanol was found to increase the conversion of the shives by 27% and the yield of liquid products by 10%. The use of 3% Ru/C catalyst in sub- and supercritical ethanol led to the destruction of both lignin and cellulose. The degree of delignification in the non-catalytic thermal conversion increased upon transition from subcritical (225 °C) to supercritical (250 °C) conditions. Main monomeric products of the thermal conversion process were guaiacylpropene or guaiacylpropane depending on the process temperature. In the presence of Ru/C catalyst, the molecular weight distribution was shifted towards an increase in the content of monomeric compounds in the liquid products.

Drugs in ultra-high dilution induce changes in the enthalpy associated with loss of crystallization water in lactose

Drugs in ultra-high dilution (UHD) are used in homeopathy. Lactose is used as a binding medium for UHD drugs. FTIR and Raman spectroscopy revealed that although devoid of molecules of the starting substance, different UHD drugs exhibit different amounts of free water molecules and variation in hydrogen bond strength. The aim of the present study was to establish whether specific water structures in UHD could specifically modify the water structure in lactose, particularly the water of crystallization. 3 UHD’s (potencies), 30cH, 200cH and 1000cH, of 2 drugs, Natrum muriaticum and Sulphur were mixed to lactose samples separately. Differential scanning calorimetry (DSC) of the samples was measured. The thermograms of potencies mixed to lactose differed from each other with respect to temperature and enthalpy associated with the removal of water of crystallization from lactose. We believe that the tested UHD modified the water structure in lactose thereby changing the enthalpy for the removal of water of crystallization. Different levels of thermal energy are needed to remove both free water molecules and water of crystallization from lactose. UHD’s also contributed to the change in enthalpy associated with the removal of water of crystallization from lactose. The tested UHD might have modified the number and strength of hydrogen bonds in the crystal structure of lactose. Specific water structures in liquid aqueous ethanol medium are transferable to the solid medium(lactose).

Zinc Oxide Nanoparticles Protected with Terpenoids as a Substance in Redox Imbalance Normalization in Burns

Preliminary protection of zinc oxide nanoparticles (ZnO NPs) with terpenoids such as betulin, its derivatives, and essential oils components has been proposed to produce gel-like oleophilic and hydrophilic formulations. We studied the properties of gel-like dispersions of ZnO NPs with immobilized terpenoids and their effects on the activity of LDH, GR, G6PDH, restoration of redox balance of co-enzyme pairs NAD+/NADH and NADP+/NADPH, as well as the activity of SOD, catalase, AlDH in erythrocytes in the treatment of burns in rats. Hysteresis loops on the rheograms of studied dispersions characterize their thixotropic properties. ZnO NPs with betulin diphosphate in the water–ethanol medium lead to a 20-fold increase in the hydrodynamic radius at pH 7.3 compared to the initial ZnO NPs, and facilitate the formation of Zn2+ ions and their penetration into the viable epidermis, unlike oleophilic dispersions. All dispersions reduce the healing time by one and a half times compared with the untreated control group, increase the activity of LDH, GR, G6PDH, SOD, catalase, AlDH, and contribute to the normalization of coenzyme balance. Normalization of the redox balance and wound state was more effective using hydrophilic dispersions due to Zn2 + penetration.

Acidic Pyridinium Inner Salt as a New, Effective and Reusable Catalyst for the One-Pot Three-Component Synthesis of N-substituted 5-aryl-4-benzoyl-3-hydroxy-3-pyrrolin-2-ones in Aqueous Media

Background: The present method is facile and effective for the synthesis of N-substituted 5-aryl-4-benzoyl-3-hydroxy-3-pyrrolin-2-one derivatives which are obtained by one-pot three-component condensation reactions of aromatic aldehydes, primary amines and ethyl benzoylpyruvate in the presence of a novel homogeneous catalyst including acidic pyridinium inner salt (PIS) at 50°C in ethanol and water mixture as solvent. Methods: 5-Aryl-4-benzoyl-3-hydroxy-3-pyrrolin-2-ones were synthesized through a one-pot three-component tandem formation of Schiff base cyclocondensation reaction of aromatic aldehydes, primary amines and ethyl benzoylpyruvate in the presence of 10 mol% of acidic pyridinium inner salt as a catalyst under aqueous ethanol medium at 50°C. All obtained structures were confirmed by their elemental analysis data and IR, 1H NMR and 13C NMR spectroscopy. Results: Three-component synthesis of 5-aryl-4-benzoyl-3-hydroxy-3-pyrrolin-2-ones catalyzed by acidic pyridinium inner salt with aromatic aldehydes, primary amines and ethyl benzoylpyruvate in aqueous ethanol medium at 50°C was prepared. The achieved derivatives (eight entries) were well synthesized in excellent yields. Conclusion: We found acidic pyridinium inner salt as a proper catalyst for this method. Catalyst Novelty is excellent catalytic activity, easy separation of the reaction mixture by washing with cold water and reusability of the catalyst for six consecutive periods without disrupting the activity of this catalyst system.

Synthesis and Characterization of Nickel(II) Complexes of Nitrogen based Ligands of Type N,N,N′,N′-tetrakis(2-Pyridylmethyl)alkanediamine

Hexadentate ligand of the type N,N,N′,N′-tetrakis(2-pyridylmethyl)alkanediamine (where alkane is butane (L1), hexane (L2) and octane (L3) reacted with Ni(ClO4)2·6H2O (stoichiometry 1:1) in alcoholic solutions yielding mononuclear complexes of the type [Ni(L)](ClO4)2·xH2O. The ligand L1 reacted with Ni(ClO4)2·6H2O in ethanol medium to give a violet powder of [Ni(L1)](ClO4)2·3H2O. The other mononuclear nickel(II) complexes using L2 and L3 were synthesized in methanol solution to give violet powders of [Ni(L2)](ClO4)2·2H2O and [Ni(L3)](ClO4)2·2H2O, respectively. All the three complexes were characterized by IR and elemental analysis. The X-ray crystallographic results for the purple crystals of [Ni(L1)](ClO4)2·3H2O shows the octahedral geometry on the Ni(II) ions together with the tetrahedral perchlorate anions separated from the [Ni(L1)]2+ cation. The crystal structure data show monoclinic space group P 21/c; a = 17.1748(10), b = 9.8273(6), c = 17.8146(10) Å; α = 90º, β = 95.0200(10)º, γ = 90º; V = 2995.2(3) Å3 , Z = 4.