Elier Galarraga

Bio: Elier Galarraga is an academic researcher from Simón Bolívar University. The author has contributed to research in topics: Chemistry & Pyrazole. The author has an hindex of 3, co-authored 6 publications receiving 24 citations. Previous affiliations of Elier Galarraga include University of the Andes.

Binary and ternary nickel (II) complexes with 2-methylquinoline-8-carboxylic acid and some amino acids

Abstract: In this work, the ligand 2-methylquinoline-8-carboxylic acid (HL) was prepared using a modification of a previous protocol, and its protonation constants were studied. The stability constants of th...

In vitro cytotoxicity of hydrazones, pyrazoles, pyrazolo-pyrimidines, and pyrazolo-pyridine synthesized from 6-substituted 3-formylchromones

Abstract: : Pyrazoles 4a–f , hydrazones 5a–c and 6a–c , pyrazolo[1,5- a ]pyrimidines 7a , b , and pyrazolo[3,4- b ]pyri-dine 8 were prepared in good yields (80–95 %) from the reaction of 6-substituted (H, Me, F) 3-formylchromones 1a–c with N -substituted hydrazines 2a–c and aminopyra-zole 3 . The cytotoxicity of the synthesized compounds was assessed through the brine shrimp lethality assay. IC 50 val-ues were between 80 and 300 μm. Fluorine substitution decreased IC 50 values. Keywords: brine shrimp lethality assay; hydrazones; pyrazolo[1,5- a ]pyrimidines; pyrazolo[3,4- b ]pyridines. DOI 10.1515/znb-2014-0236Received October 1, 2014; accepted February 5, 2015 1 Introduction Benzopyrone group-based compounds, such as chr-omones, are widely recognized as an important class of biological active substances from both natural and syn-thetic origins [1–3]. Numerous studies show their wide range of activities, such as antioxidant [4], antimicrobial [5, 6], antiviral [7, 8] and antitumor [9, 10]. The chromone nucleus is also found within the chemical structure of flavonoids, an important group of naturally occurring substances that are of current interest because of their cytotoxic activity [11, 12].Among the functionalized chromones, 3-formylchr-omone is a highly reactive compound, and is used as a starting material in many reactions due to the presence of three electron-deficient centers at C-2, C-4, and the C-3 formyl group. Reaction of the -CHO group with nitro-gen nucleophiles, such as hydrazine and aminopyrazole derivatives, has led to the formation of a variety of mol-ecules that have been studied in detail for being of interest to drug discovery [13–21].π-Electron-rich compounds like chromone-3-car-boxyaldehydes react with aromatic primary hydrazines (1:1 molar ratio) mainly at the formyl group by a straight forward 1,2-addition to form the corresponding hydrazone [22–26]. On prolonged heating, a pyrazole-type structure is produced by a 1,4-addition reaction accompanied by pyrone ring-opening followed by recyclization and proton transfer. Meanwhile, the reaction of 3-formylchromone with equimolar quantities of aminopyrazole derivatives affords only pyrazolo[1,5-

Triterpenos y saponinas triterpénicas de Phytolacca icosandra y Phytolacca rugosa

Abstract: El estudio fitoquimico de los extractos metanolicos de las hojas y ramas de Phytolacca ico­sandra y P rugosa, especies utilizadas tradicionalmente en Venezuela como repelentes contra las garrapatas del ganado vacuno ( Boophilus ssp ), permitio el aislamiento de dos triterpenos penta­ciclicos y cinco saponinas triterpenicas Estos compuestos fueron identificados mediante tecni­cas espectrales (FAB- o ESI-EM, RMN-1H, RMN-13C y 2D-RMN) como acido espergulagenico [1] , acido epi -acetilaleuritolico [2] , acido 3- O -[-α-l-rhamnopiranosil(1→2)-β-d-glucopiranosil(1→2)-β-d-glucopiranosil]-28- O -β-d-gluco piranosil-serjanico [3] , acido 3- O -(β-d-glucopiranosil)-28- O -β-d-glucopiranosil-serjanico [4] , acido 3- O -[β-d-glucopiranosil (1→2)-β-d-glucopiranosil]-28- O -β-d-glucopiranosil-serjanico [5] , acido 3- O -[β-d-galactopiranosil(1→3)-β-d-gluco piranosil]-28- O -β-d-glucopiranosil-serjanico [6] y acido 3- O -[β-d-glucopiranosil (1→3)-β-d-galactopiranosil (1→3)-β-d-glucopiranosil]-28- O -β-d-glucopiranosil-serjanico [7]

Artificial Triterpenoid Fatty Acid Ester Isolated From the Leaves of Phytolacca icosandra L.

Abstract: The methanol extract form the leaves of Phytolacca icosandra L., afforded the unprecedented artificial triterpenoid fatty acid ester 1 derived from the new natural triterpenoid phytolaccagenic acid 3-O-myristate (1a), along with the three known triterpenoids serjanic, acinosolic and phytolaccagenic acid (2 – 4). Their structures were stablished by HR-EI-MS, 1D and 2D NMR techniques. The possible mechanistic formation of 1 is proposed, and the in vitro toxicity of all compounds was assessed using the brine shrimp lethality assay (BSLA).

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Abstract: Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Synthesis of Chromone-Related Pyrazole Compounds.

Abstract: Chromones, six-membered oxygen heterocycles, and pyrazoles, five-membered two-adjacent-nitrogen-containing heterocycles, represent two important classes of biologically active compounds. Certain derivatives of these scaffolds play an important role in medicinal chemistry and have been extensively used as versatile building blocks in organic synthesis. In this context, we will discuss the most relevant advances on the chemistry that involves both chromone and pyrazole rings. The methods reviewed include the synthesis of chromone-pyrazole dyads, synthesis of chromone-pyrazole-fused compounds, and chromones as starting materials in the synthesis of 3(5)-(2-hydroxyaryl)pyrazoles, among others. This review will cover the literature on the chromone and pyrazole dual chemistry and their outcomes in the 21st century.