Lapachol, a naphthoquinone discovered in 1858, is a natural product with a broad spectrum of therapeutic activities, along with its derivatives and analogues. Initially found in several species of the Bignoniaceae family, lapachol can also be found in other families. Lapachol arouses great interest and knowledge due to its crucial role in medicinal chemistry, playing an important role in the rational planning of research in search of bioactive substances with pharmacological action, whether as a source of raw material or helping directly or indirectly. This work aims to describe a new methodology for extracting lapachol, which differs from the conventional acid-base method, providing a highly efficient, simple and easy-to-apply process. 1858 activities analogues family families chemistry action indirectly acidbase acid base method efficient easytoapply easy apply process 185 18 1

The interactive profile between four 1,4-naphthoquinone derivatives (1-4) and human serum albumin (HSA) was studied by spectroscopic techniques and in silico calculations. The bimolecular quenching rate constant (kq ca. 1012 L mol-1 s-1) and the time-resolved fluorescence decays indicated a static fluorescence quenching mechanism. Thus, there is a spontaneous ground-state association, and based on both Stern-Volmer, modified Stern-Volmer, and van’t Hoff approaches, the association is moderate mainly driven by hydrophobic forces. The circular dichroism (CD) analysis indicated that until the proportion albumin:compound of 1:8 there is a weak perturbation on the structural content of albumin, while molecular docking results suggested subdomain IIA (site I), a positive electrostatic pocket, as the main binding site. Overall, even though the hydrogen atom replacement by methyl, fluorine, or chlorine atoms in the para position of the aromatic ring in the benzo[g]chromene-5,10-dione moiety changes the lipophilicity, it does not change the binding profile to HSA. 1,4naphthoquinone 14naphthoquinone naphthoquinone 1,4 1 4 14 (1-4 HSA (HSA calculations kq ca 101 mol1 mol mol- s1 s s-1 timeresolved time resolved mechanism Thus groundstate ground state SternVolmer, SternVolmer Stern Volmer, Volmer Stern-Volmer vant van t approaches forces CD (CD albumincompound compound 18 8 1: site I, I , I) pocket Overall methyl fluorine benzogchromene5,10dione benzogchromene510dione benzogchromenedione benzo g chromene 5,10 dione 5 10 lipophilicity 4naphthoquinone 1, (1- s- benzogchromene5 10dione benzogchromene 510 5,1 (1 51 5, (

Abstract Snake envenomation is a public health problem, and while serum therapy prevents death, the local effects of venoms can lead to amputations or morbidities. Thus, alternative treatments deserve attention. In this study, we tested eight derivatives of 1,2,3-triazole against some toxic activities of Bothrops jararaca venom. The derivatives were synthesized, and their structures analyzed by infrared and nuclear magnetic resonance. After that, the ability of compounds to inhibit hemolysis, coagulation, proteolysis, hemorrhaging, edema, and lethal activities of B. jararaca venom was investigated. The derivatives were incubated with B. jararaca venom (incubation protocol), administered before (prevention protocol) or after (treatment protocol) injecting venom into the mice. Then, hemorrhaging assay occurred. As a result, most of the derivatives inhibited the activities, even if they were incubated, injected before or after B. jararaca venom. However, the derivatives TRI 07 and TRI 18 seemed to be the most efficient in impairing hemorrhaging. The derivatives showed a low drug score of toxicity based on an in silico technique. Therefore, the derivatives fulfilled physicochemical and biological requirements to become drugs, and they may be a brand new initiative for designing antivenom molecules to complement antivenom therapy to efficiently block tissue necrosis or any other local effects. problem death morbidities Thus attention study 1,2,3triazole 123triazole triazole 1,2,3 1 2 3 synthesized resonance that hemolysis coagulation proteolysis edema B investigated incubation protocol, protocol , prevention treatment mice Then occurred result However 0 technique Therefore drugs 3triazole 123 1,2, 12 1,2 1,

ABSTRACT Naphthoquinones are the most commonly occurring type of quinones in nature. They are a diverse family of secondary metabolites that occur naturally in plants, lichens and various microorganisms. This subgroup is constantly being expanded through the discovery of new natural products and by the synthesis of new compounds via innovative techniques. Interest in quinones and the search for new biological activities within the members of this class have intensified in recent years, as evidenced by the evaluation of the potential antimicrobial activities of quinones. Among fungi of medical interest, yeasts of the genus Candida are of extreme importance due to their high frequency of colonization and infection in humans. The objective of this review is to describe the development of naphthoquinones as antifungals for the treatment of Candida species and to note the most promising compounds. By using certain criteria for selection of publications, 68 reports involving both synthetic and natural naphthoquinones are discussed. The activities of a large number of substances were evaluated against Candida albicans as well as against 7 other species of the genus Candida. The results discussed in this review allowed the identification of 30 naphthoquinones with higher antifungal activities than those of the currently used drugs.

BACKGROUND Malaria persists as a major public health problem. Atovaquone is a drug that inhibits the respiratory chain of Plasmodium falciparum, but with serious limitations like known resistance, low bioavailability and high plasma protein binding. OBJECTIVES The aim of this work was to perform molecular modelling studies of 2-hydroxy-1,4-naphthoquinones analogues of atovaquone on the Qo site of P. falciparum cytochrome bc1 complex (Pfbc1) to suggest structural modifications that could improve their antimalarial activity. METHODS We have built the homology model of the cytochrome b (CYB) and Rieske iron-sulfur protein (ISP) subunits from Pfbc1 and performed the molecular docking of 41 2-hydroxy-1,4-naphthoquinones with known in vitro antimalarial activity and predicted to act on this target. FINDINGS Results suggest that large hydrophobic R2 substituents may be important for filling the deep hydrophobic Qo site pocket. Moreover, our analysis indicates that the H-donor 2-hydroxyl group may not be crucial for efficient binding and inhibition of Pfbc1 by these atovaquone analogues. The C1 carbonyl group (H-acceptor) is more frequently involved in the important hydrogen bonding interaction with His152 of the Rieske ISP subunit. MAIN CONCLUSIONS Additional interactions involving residues such as Ile258 and residues required for efficient catalysis (e.g., Glu261) could be explored in drug design to avoid development of drug resistance by the parasite.

The aim of this paper was to revive the accurate determination of the boiling point of organic compounds using the percolator technique developed in the 1960s. Although this method is simple, fast and efficient it is omitted from current textbooks. This method has several advantages over Siwoloboff such as high reproducibility and direct measurement of the boiling point of the sample obtained by observing the temperature of the vapor-liquid equilibrium. The experiments were performed in the organic chemistry laboratory but allow interdisciplinary integration with other disciplines of several academic areas.

Coal, oil, natural gas, and shale gas are biomass that is formed millions of years ago. These are non-renewable and depleting, even considering the recent discovery of new sources of oil in the presalt and new technologies for the exploitation of shale deposits. Currently, these raw materials are used as a source of energy production and are also important for the production of fine chemicals. Since these materials are finite and their (oil) price is increasing, it is clear that there will be a progressive increase in the chemical industry to use renewable raw materials as a source of energy, an inevitable necessity for humanity. The major challenge for the society in the twenty first century is to unite governments, universities, research centers, and corporations to jointly act in all areas of science with one goal of finding a solution to global problems, such as conversion of biomass into compounds for the fine chemical industry.Non-renewable raw materials are used in the preparation of fuels, chemical intermediates, and derivatives for the fine chemical industry. However, their stock in nature has a finite duration, and their price is high and will likely increase with their depletion. In this scenario, the alternative is to use renewable biomass as a replacement for petrochemicals in the production of fine chemicals. As the production of biomass-based carbohydrates is the most abundant in nature, it is judicious to develop technologies for the generation of chain products (fuels, chemical intermediates, and derivatives for the fine chemicals industry) using this raw material. This paper presents some aspects and opportunities in the area of carbohydrate chemistry toward the generation of compounds for the fine chemical industry.

Non-renewable biomass, such as coal, oil and natural gas are not only energy sources but also important starting materials for the production of a variety of chemicals ranging from gasoline, diesel oil and fine chemicals. In this regard, carbohydrates, the most abundant class of enantiopure organic compounds, are very suitable for generation of chemicals of great practical value. Their bulk-scale availability associated with low cost make them unique starting materials for organic preparative purpose. They are a most attractive alternative for construction of enantiopure target molecules by asymmetric synthesis. This review addresses, in addition to the use of low molecular weight carbohydrates, issues related to renewable biomass from photosynthesis and alternatives for the production of bulk and fine chemicals.

The aromatic six-membered heterocycles having three nitrogen atoms are denominated triazines. Among these heterocycles, isocyanuric chloride and cyanuric chloride are inexpensive and readily available 1,3,5-triazine derivatives, which have been attracting significant attention of organic chemists due to their different kinds of applications, which vary from pharmaceuticals to explosives. This short overview explores their uses in synthetic methods, as chlorinating and oxidating agents and some procedures for their preparation.