Leishmaniasis is a neglected tropical disease, endemic in 98 countries and with more than 350 million people with risk to be sick. From 2001 to 2014, leishmanisis caused 797,849 of new cases of cutaneous and mucosal forms. Moreover, only in 2014, visceral leishmaniasis was detected in 3,624 american people, being Brazil responsible for 95% of this cases. Leishmania are protozoan parasites who lives in the midgut and foregut of the female sandfly of the genera Phlebotomus (Africa, Asia and Europe) and Lutzomyia (Central and South America), which is the sole vector responsible for transmitting this disease. Even though the knowledge in molecular biology and biochemistry about the parasite has increased, the first and second choice drugs for the treatment are still obsolete and with high toxicity in a long-term treatment. In this work, we describe the synthesis, leishmanicidal activity of furoxan derivatives against Leishmania amazonensis and Leishmania infantum and their bioavailability prediction. The compounds were synthesized from furoxan derivatives and aminoguanidine hydrochloride to give four new molecules in good global yields ranging from 30-60%. Compounds I-IV were characterized by analytical methods including NMR, infrared and mass spectrometry. The novel compounds were evaluated in two different species of Leishmania: Leishmania amazonensis and Leishmania infantum. The compounds were less cytotoxic than pentamidine. It is important to highlight the compound III, which presented a CC₅₀ in macrophages of 1095.52 µM, which is considerably higher than pentamidine (35.69 µM), what means that its cytotoxicity is remarkably lower than the second line drug used in leishmaniasis treatment.  In the evaluation against promatigotes forms, all compounds have demonstrated IC₅₀ values superior to that of pentamidin against Leishmania amazonensis and a low IC₅₀ values compared with pentamidine against Leishmania infantum. Compound II presented the most promissor IC₅₀ against Leishmania infantum strain with a value of 8.87 µM, while pentamidine presents an IC₅₀ value of 67.71 µM. For amastigote form, only two compounds with selective index superior to 15 (compounds I and III) were selected to be evaluated, and both of them presented an IC₅₀ higher than pentamidine. The bioavailability prediction has demonstrated that all compounds are in agreement with the Lipinski rule, and their intestinal absorption was around 70%.  All these data allow us to conclude that the compounds were more effective against the promastigote forms of Leishmania infantum, which is responsible for the visceral form of leishmaniasis. In addition to their important and significant low cytotoxicity, these compounds may be a future alternative to leishmaniasis treatment. 

Polyurethanes (PU) during the last 50 years have become one of the most developing polymers and it is almost impossible to find an industry field, where they are not used. This term concerns a wide range of materials, both expanded and non-expanded products. PUs are widely used in many applications as foams (flexible, semiflexible and rigid foams), elastomers, adhesives, fibers and obtained by the exothermic reaction of an oligomeric polyol (the substance which contains at least two hydroxyl groups) and polyfunctional isocyanates. PU foams are considered to be one of the most efficient materials for insulation with many desirable properties (very low conductivity, low density and water absorption, dimensional stability and high ecoeficiency index to save energy). Nowadays, rigid polyurethane foams are synthesized using vegetable-oil based polyols, which is connected to their abundance and economy. What is more, materials synthesized from renewable resources can almost fully replace their petrochemical analogs. Several types of vegetable oils have been already used, such as soy bean oil, palm oil, linseed oil and sunflower oil. Such oils are characterized by low amount of functional groups, however present in the structure unsaturated bonds can be successfully converted into hydroxyl groups. The great possibility is using waste cooking oil to synthesize polyol, but the biggest problem is low number of hydroxyl value and contaminations from food. This short communicate presents a discussion about the influence of various polyol systems on physical, mechanical and thermal insulation properties, as well as on the cellular structure of PU foams.

Abstract

In this research, Low-density polyethylene (LDPE) polymeric films containing different concentrations of silver (Ag) nanoparticles (NPs) and TiO₂ were manufactured via extrusion and subsequently characterised. Silver/TiO₂ surfaces have advantageous properties such as visible light photocatalysis, biological compatibility, and antimicrobial activity. The synthesis of polymer-Ag NPs and Ag NPS on TiO₂ are also summarized because of their industrial and environmental importance[1]. In the present study,the morphological, mechanical, and optical performance of the nanocomposite polymeric films is investigated.

An efficient general synthesis of hydrazones of 4-(3-oxobutyl)semicarbazones using novel semicarbazone-based amidoalkylation reagents has been developed. The prepared hydrazones were converted under acidic conditions into 14-membered cyclic bis-semicarbazones, 1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-diones. Plausible pathway and stereochemistry of the macrocyclization are discussed.

A plausible mechanism for the nucleophile-mediated ring expansion of 4-chloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones into 2,3,6,7-tetrahydro-1H-1,3-diazepin-2-ones based on DFT calculations at B3LYP/6-31+G(d,p) level is discussed. This mechanism involves the following subsequent steps: N₍₁₎H deprotonation under the action of nucleophile, intramolecular nucleophilic substitution of the chlorine atom to give cyclopropane bicyclic intermediate, nucleophile-promoted cyclopropane ring opening leading to 2,5-dihydro-1H-1,3-diazepin-2-one, and addition of nucleophiles to the C=N bond to afford the final diazepinones.

1,2,4-Triazole is a privileged scaffold in medicinal and agricultural chemistry. Many useful and structurally diverse compounds have been prepared using 5-amino-1,2,4-triazoles as building block. Herein, we report a new microwave-assisted synthesis of 3-(5-amino-1H-1,2,4-triazol-3-yl)propanamides via two complementary approaches. The first approach involved the initial preparation of N-guanidinosuccinimide, which then reacted with amines under microwave irradiation affording corresponding 3-(5-amino-1H-1,2,4-triazol-3-yl)propanamides. The desired products were successfully obtained in the reaction with aliphatic amines (primary and secondary) via a nucleophilic opening of the succinimide ring and the subsequent recyclization affording the 1,2,4-triazole ring. This approach failed when less nucleophilic aromatic amines were used. Therefore, we designed an alternative pathway with the initial preparation of N-arylsuccinimides and their subsequent reaction with aminoguanidine hydrochloride under microwave irradiation. In this case, the 1,2,4-triazole ring closure was most efficiently achieved in the presence of organic base. These two approaches complement each other allowing preparation of a diverse library of 3-(5-amino-1H-1,2,4-triazol-3-yl)propanamides. 

Synthesis of conjugated organic molecules having electronic and optical properties suitable for electrochromic devices (ECD), organic light emitting diode (OLED), organic field effective transistors (OFET), lasers, photodiodes and solar cell applications have gained importance in recent years.^1-3 Based on the previous studies on thienothiophenes (TT),^2,3  new donor-acceptor materials, 4-[5-[bis-(2,4,6-trimethyl-phenyl)-boranyl]-2-(4-diphenylamino-phenyl)-thieno[3,2-b]thiophen-3-yl]-benzonitrile and {4-[5-[bis-(2,4,6-trimethyl-phenyl)-boranyl]-3-(4-fluoro-phenyl)-thieno[3,2-b]thiophen-2-yl]-phenyl}-diphenyl-amine containing π-conjugated system and having electron withdrawing cyano and fluorine groups and acceptor boron⁴ were designed and synthesized. Their electronic and optical properties were investigated. They have been found to be suitable for OLED applications.

Some different catalysts, such as organic and inorganic bases and basic ionic liquids  were used for synthesis of 2-amino-4H-pyran-3-carbonitriles containing  propargyl group. Efficient catalysts of these substances were estimated. The structures of the obtained compounds were confirmed by the modern spectroscopic methods (IR, ¹H NMR, ¹³C NMR).

Some ethyl 6-amino-5-cyano-2-methyl-4-aryl-4H-pyran-3-carboxylates were synthesized by reaction of by using three-component reaction included ethyl acetoacetate, malononitrile and appropriate substituted benzaldehydes. The role of different catalysts was examined, including organic and inorganic substances and ionic liquids. Some 2-amino-4H-pyran-3-carbonitriles were converted by reacting with chloroacetyl chloride. The structures of the obtained compounds were confirmed by the modern spectroscopic methods (IR, ¹H NMR, ¹³C NMR).

Reaction of different substituted 2-chloro-4-methylquinolines with sodium azide changed the direction to substituted tetrazolo[1,5-a]quinolines instead corresponding 2-azido-4-methylquinolines. Required 2-chloro-derivatives were obtained from substituted 4-methylquinolin-2(1H)-ones, which were synthesized by ring closing corresponding (un)substituted acetoacetanildes in the presence of ionic liquid [Bmim]OH. The structures of obtained compounds have been confirmed by using spectroscopic methods (IR, NMR and MS).