Therapeutic Potential of Isoxazole-(Iso)oxazole Hybrids: Three Decades of Research.

Heterocyclic compounds are a common subject in the field of medicinal chemistry due to their numerous pharmaceutical applications. Among these, nitrogen- and oxygen-containing five-membered heterocyclic rings, namely oxazole and isoxazole, are particularly significant, exhibiting a broad spectrum of biological activities. Molecular hybridization, the process that enables the fusion of bioactive scaffolds, is a powerful strategy for the development of novel compounds characterized by enhanced or multitarget activities.

7-(4-Chlorophenyl)-1-hydroxy-5-methylpyrido[3,4-d]pyridazin-4(3H)-one: synthesis, solvatomorphism, in vitro anti-inflammatory and cytotoxic activity studies and in silico analysis.

The newly obtained compound 7-(4-chlorophenyl)-1-hydroxy-5-methylpyrido[3,4-d]pyridazin-4(3H)-one (CPM) was crystallized as two new variable solvates, namely, the dimethyl sulfoxide monosolvate, CHClNO·CHSO (I), and the sesquisolvate, CHClNO·1.5CHSO (II), and their structures were confirmed by single-crystal X-ray diffraction analysis. In previous work, 1-hydroxy-5-methyl-7-phenylpyrido[3,4-d]pyridazin-4(3H)-one (PM) was found to display anticancer activity.

Oxazolo[5,4-]pyrimidines as Anticancer Agents: A Comprehensive Review of the Literature Focusing on SAR Analysis.

Oxazolo[5,4-]pyrimidines have been found to exhibit a wide range of biological activities, including the inhibition of various enzymes and signaling pathways associated with carcinogenesis. The objective of this review is to demonstrate that the oxazolo[5,4-]pyrimidine scaffold represents a valuable structure for the design of novel anticancer therapies. The article provides a comprehensive overview of the chemical structure and pharmacological properties of oxazolo[5,4-]pyrimidine derivatives, drawing upon the literature and international patents from 1974 until the present.

Antimicrobial Activity of Naphthyridine Derivatives.

To combat the problem of the increasing drug resistance of microorganisms, it is necessary to constantly search for new medicinal substances that will demonstrate more effective mechanisms of action with a limited number of side effects. Naphthyridines are N-heterocyclic compounds containing a fused system of two pyridine rings, occurring in the form of six structural isomers with different positions of nitrogen atoms, which exhibit a wide spectrum of pharmacological activity, in particular antimicrobial properties. This review presents most of the literature data about the synthetic and natural naphthyridine derivatives that have been reported to possess antimicrobial activity.

Novel Isoxazole-Based Antifungal Drug Candidates.

Microbiological communities have a significant impact on health and disease. are ubiquitous fungal pathogens that colonize the mucosal surfaces of the genital, urinary, respiratory, and gastrointestinal tracts, as well as the oral cavity. If the immune system is inadequate, then infections may pose a significant threat.

Pyrimidine Schiff Bases: Synthesis, Structural Characterization and Recent Studies on Biological Activities.

Recently, 5-[(4-ethoxyphenyl)imino]methyl-N-(4-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine has been synthesized, characterized, and evaluated for its antibacterial activity against in combination with antineoplastic activity against gastric adenocarcinoma. In this study, new 5-iminomethylpyrimidine compounds were synthesized which differ in the substituent(s) of the aromatic ring attached to the imine group. The structures of newly obtained pyrimidine Schiff bases were established by spectroscopy techniques (ESI-MS, FTIR and H NMR).

Antimicrobial and Cytotoxic Activities of Water-Soluble Isoxazole-Linked 1,3,4-Oxadiazole with Delocalized Charge: In Vitro and In Vivo Results.

The distinct structure of cationic organic compounds plays a pivotal role in enhancing their water solubility, which in turn influences their bioavailability. A representative of these compounds, which contains a delocalized charge, is 5-amino-2-(5-amino-3-methyl-1,2-oxazol-4-yl)-3-methyl-2,3-dihydro-1,3,4-oxadiazol-2-ylium bromide (ED). The high-water solubility of ED obviates the need for potentially harmful solvents during in vitro testing.

Search for immunomodulatory compounds with antiproliferative activity against melanoma.

Background: Melanoma is a highly aggressive neoplasm with a high degree of malignancy and rapid acquisition of resistance by cancer cells.

Methods: Biological studies of a series of isoxazole compounds with immunomodulatory properties were preceded by in silico analysis. The assay evaluated the viability of NHDF and A375 cell cultures after the administration of isoxazole compounds after a 24-hour incubation period in the MTT test.

The In Vitro Impact of Isoxazole Derivatives on Pathogenic Biofilm and Cytotoxicity of Fibroblast Cell Line.

The microbial, biofilm-based infections of chronic wounds are one of the major challenges of contemporary medicine. The use of topically administered antiseptic agents is essential to treat wound-infecting microorganisms. Due to observed microbial tolerance/resistance against specific clinically-used antiseptics, the search for new, efficient agents is of pivotal meaning.

New Oxazolo[5,4-]pyrimidines as Potential Anticancer Agents: Their Design, Synthesis, and In Vitro Biological Activity Research.

Cancer is a large group of diseases in which the rapid proliferation of abnormal cells generally leads to metastasis to surrounding tissues or more distant ones through the lymphatic and blood vessels, making it the second leading cause of death worldwide. The main challenge in designing a modern anticancer therapy is to develop selective compounds that exploit specific molecular targets. In this work, novel oxazolo[5,4-]pyrimidine derivatives were designed, synthesized, and evaluated in vitro for their cytotoxic activity against a panel of four human cancer cell lines (lung carcinoma: A549, breast adenocarcinoma: MCF7, metastatic colon adenocarcinoma: LoVo, primary colon adenocarcinoma: HT29), along with their P-glycoprotein-inhibitory ability and pro-apoptotic activity.

5-Amino-3-methyl-Isoxazole-4-carboxylic Acid as a Novel Unnatural Amino Acid in the Solid Phase Synthesis of α/β-Mixed Peptides.

The hybrid peptides consisting of α and β-amino acids show great promise as peptidomimetics that can be used as therapeutic agents. Therefore, the development of new unnatural amino acids and the methods of their incorporation into the peptide chain is an important task. Here, we described our investigation of the possibility of 5-amino-3-methyl-isoxazole-4-carboxylic acid (AMIA) application in the solid phase peptide synthesis.

New water-soluble isoxazole-linked 1,3,4-oxadiazole derivative with delocalized positive charge.

Herein we present a synthesis and characterization of a new and unique low-weight heterocyclic compound 5-amino-2-(5-amino-3-methyl-1,2-oxazol-4-yl)-3-methyl-2,3-dihydro-1,3,4-oxadiazol-2-ylium bromide with the unusual electron charge delocalization owing the local positive charge at the carbon atom of oxadiazole moiety. X-ray single crystal of CHNO·Br showed the molecule crystalized in monoclinic, space group 2/. Both five membered rings are planar and twisted forming the ring motif with the counter ion where H⋯Br interactions are one of the dominant.

FDA-Approved Small Molecule Compounds as Drugs for Solid Cancers from Early 2011 to the End of 2021.

Solid cancers are the most common types of cancers diagnosed globally and comprise a large number of deaths each year. The main challenge currently in drug development for tumors raised from solid organs is to find more selective compounds, which exploit specific molecular targets. In this work, the small molecule drugs registered by the Food and Drug Administration (FDA) for solid cancers treatment between 2011 and 2022 were identified and analyzed by investigating a type of therapy they are used for, as well as their structures and mechanisms of action.

FDA-Approved Drugs for Hematological Malignancies-The Last Decade Review.

Hematological malignancies, also referred to as blood cancers, are a group of diseases involving abnormal cell growth and persisting in the blood, lymph nodes, or bone marrow. The development of new targeted therapies including small molecule inhibitors, monoclonal antibodies, bispecific T cell engagers, antibody-drug conjugates, recombinant immunotoxins, and, finally, Chimeric Antigen Receptor T (CAR-T) cells has improved the clinical outcomes for blood cancers. In this review, we summarized 52 drugs that were divided into small molecule and macromolecule agents, approved by the Food and Drug Administration (FDA) in the period between 2011 and 2021 for the treatment of hematological malignancies.

Preclinical Study of Immunological Isoxazole Derivatives as a Potential Support for Melanoma Chemotherapy.

(1) Background: Melanoma is an aggressive neoplasm derived from melanocyte precursors with a high metastatic potential. Responses to chemotherapy and immunotherapy for melanoma remain weak, underlining the urgent need to develop new therapeutic strategies for the treatment of melanoma. (2) Methods: The viability of NHDF and A375 cell cultures after the administration of the tested isoxazole derivatives was assessed after 24-h and 48-h incubation periods with the test compounds in the MTT test.

Synthesis, Physicochemical Characteristics and Plausible Mechanism of Action of an Immunosuppressive Isoxazolo[5,4-e]-1,2,4-Triazepine Derivative (RM33).

Previous studies demonstrated strong anti-inflammatory properties of isoxazolo[5,4-e]-1,2,4-triazepine (RM33) in vivo. The aim of this investigation was to describe synthesis, determine physicochemical characteristics, evaluate biological activities in murine and human in vitro models, as well as to propose mechanism of action of the compound. The compound was devoid of cell toxicity up to 100 μg/mL against a reference A549 cell line.

Selected β-, β- and β-Amino Acid Heterocyclic Derivatives and Their Biological Perspective.

Heterocyclic moieties, especially five and six-membered rings containing nitrogen, oxygen or sulfur atoms, are broadly distributed in nature. Among them, synthetic and natural alike are pharmacologically active compounds and have always been at the forefront of attention due to their pharmacological properties. Heterocycles can be divided into different groups based on the presence of characteristic structural motifs.

Synthesis and Biological Activity of New 7-Amino-oxazolo[5,4-]Pyrimidine Derivatives.

The synthesis of a series of novel 7-aminooxazolo[5,4-]pyrimidines , transformations during their synthesis and their physicochemical characteristics have been described. Complete detailed spectral analysis of the intermediates -, the -cyanooxazolylacetamidine by-products and final compounds has been carried out using MS, IR, 1D and 2D NMR spectroscopy. Theoretical research was carried out to explain the privileged formation of 7-aminooxazolo[5,4-]pyrimidines in relation to the possibility of their isomer formation and the related thermodynamic aspects.

The '-Substituted Derivatives of 5-Chloro-3-Methylisothiazole-4-Carboxylic Acid Hydrazide with Antiproliferative Activity.

Thanks to the progress in oncology, pharmacological treatment of cancer is gaining in importance and in the near future anti-cancer chemotherapeutics are expected to be the main method of treatment for cancer diseases. What is more, the search for new anti-cancer compounds with the desired application properties is constantly underway. As a result of designed syntheses, we obtained some new '-substituted 5-chloro-3-methylisothiazole-4-carboxylic acid hydrazide derivatives with anticancer activity.

The 5-hydrazino-3-methylisothiazole-4-carboxylic acid, its new 5-substituted derivatives and their antiproliferative activity.

Currently, the basic method of treatment of colon cancer is surgery. The range of anticancer drugs used in the treatment of colorectal cancer is small and is based mainly on systemic combination chemotherapy. As a result of the designed syntheses, we received new isothiazole derivatives with anticancer activity.

Isoxazole Derivatives as Regulators of Immune Functions.

In this review, we present reports on the immunoregulatory properties of isoxazole derivatives classified into several categories, such as immunosuppressive, anti-inflammatory, immunoregulatory, and immunostimulatory compounds. The compounds were tested in various models using resident cells from rodents and humans, cell lines, and experimental animal disease models corresponding to human clinical situations. Beneficial features of the described isoxazole derivatives include low toxicity and good bioactivity at low doses.

Synthesis, Immunosuppressive Properties, and Mechanism of Action of a New Isoxazole Derivative.

This work describes the synthesis of a new series of isoxazole derivatives, their immunosuppressive properties, and the mechanism of action of a representative compound. A new series of ′-substituted derivatives of 5-amino-,3-dimethyl-1,2-oxazole-4-carbohydrazide (⁻) was synthesized in reaction of 5-amino-,3-dimethyl-1,2-oxazole-4-carbohydrazide with relevant carbonyl compounds. The isoxazole derivatives were tested in several in vitro models using human cells.

Immunoregulatory effects of 4-(4-chlorophenyl)-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide (06K) in non-immunized and SRBC-immunized mice.

Objectives: Immunoregulatory properties of 06K derivative (4-(4-chlorophenyl)-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide) in mouse in vivo models were investigated.

Methods: Several in vivo models were used: humoral and cellular immune response, carrageenan inflammatory reaction and determination of lymphocyte subsets in non-immunized mice.

Key Findings: The compound administered before or after immunization with sheep erythrocytes (sheep red blood cell (SRBC)) elevated the number of plaque-forming cells (PFC), and this effect was stronger at lower doses.

5-Amino-3-methyl-4-isoxazolecarboxylic acid hydrazide derivatives with in vitro immunomodulatory activities.

Isoxazoles are an important class of compounds of potential therapeutic value. The aim of this study was to determine immunotropic effects of 5-amino-3-methyl-4-isoxazolecarboxylic acid hydrazide derivatives on spontaneous and mitogen-induced lymphocyte proliferation in young and old mice, cytokine production by peritoneal cells as well as possible mechanism of action in a model of Jurkat cells. Three-month-old and 13-month-old BALB/c mice were used as donors of the cells from a thymus, a spleen, mesenteric lymph nodes, and a peritoneal cavity.