Adamantane Derivatives Research Articles

In Situ Self-Assembly of Antibody-Rhamnose Complex as a Pre-Targeting Strategy for Enhanced Cancer Immunotherapy.

Enhancing the Fc effector functions of monoclonal antibodies (mAbs) is a proven strategy for improving cancer immunotherapy. In this study, we present a novel pre-targeting approach that integrates host-guest chemistry with an antibody-recruiting concept to create mAbs with superior effector functions. Using rituximab (RTX), a clinically approved anti-CD20 mAb, as our model, we modified RTX by conjugating it with adamantane (Ada) derivatives and various polyethylene glycol (PEG) linkers to produce RTX-Ada conjugates. These conjugates effectively formed RTX-rhamnose (Rha) complexes in situ through self-assembly, driven by host-guest interactions with Rha-modified β-cyclodextrin. This mechanism successfully redirected endogenous anti-Rha antibodies to target cells, enhancing the availability of Fc domains for improved effector functions, including complement-dependent cytotoxicity (CDC). A structure-activity relationship study indicated that the potency of these in situ complexes was significantly influenced by the length of the PEG linker used; shorter PEG linkers correlated with higher CDC activity. Given the variability in endogenous antibody levels among individuals, this strategy presents a flexible and promising platform for enhancing the efficacy of mAb-based cancer immunotherapy.

Selection of Conditions for the Synthesis of Methacrylate Monomers Based on Adamantane

AbstractAdamantane-based methacrylates are important monomers for the design of polymers used for the development of chemically amplified photoresists. Herein, we present the selection of reaction conditions for obtaining of 2-ethyladamantan-2-yl methacrylate, 2-methyladamantan-2-yl methacrylate, adamantan-1-yl methacrylate, and 3-hydroxyadamantan-1-yl methacrylate from adamantane derivatives and methacryloyl chloride. It is shown that the combination of pyridine as a solvent and base with 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base allows reproducible preparation of the desired products with good yields. The results obtained provide valuable information for upscaling the synthesis of important products for the microelectronics industry.

Effect of Cyclodextrins Formulated in Liposomes and Gold and Selenium Nanoparticles on siRNA Stability in Cell Culture Medium

Background: Encapsulation of siRNA fragments inside liposome vesicles has emerged as an effective method for delivering siRNAs in vitro and in vivo. However, the liposome’s fluid-phospholipid bilayer of liposomes allows siRNA fragments to diffuse out of the liposome, decreasing the dose concentration and therefore the effectiveness of the carrier. We have previously reported that β-cyclodextrins formulated in liposomes help increase the stability of siRNAs in cell culture medium. Here, we continued that study to include α, γ, methyl-β-cyclodextrins and β-cyclodextrin-modified gold and selenium nanoparticles. Methods: We used Isothermal Titration Calorimetry to study the binding thermodynamics of siRNAs to the cyclodextrin-modified nanoparticles and to screen for the best adamantane derivative to modify the siRNA fragments, and we used gel electrophoresis to study the stabilization effect of siRNA by cyclodextrins and the nanoparticles. Results: We found that only β- and methyl-β-cyclodextrins increased siRNA serum stability. Cyclodextrin-modified selenium nanoparticles also stabilize siRNA fragments in serum, and siRNAs chemically modified with an adamantane moiety (which forms inclusion complexes with the cyclodextrin-modified-nanoparticles) show a strong stabilization effect. Conclusions: β-cyclodextrins are good additives to stabilize siRNA in cell culture medium, and the thermodynamic data we generated of the interaction between cyclodextrins and adamantane analogs (widely used in drug delivery studies), should serve as a guide for future studies where cyclodextrins are sought for the delivery and solvation of small organic molecules.

Comparative studies on the nature and kinetics of phase transitions in plastic crystals: Hydrogen-bonded adamantane derivatives

In this paper, the results of thermal, structural, and spectroscopic studies on 3-amino-1-adamantanol (3-NH2-1-OH-ADM) were discussed with those recently published for 1-hydroxyl and 1-amine derivatives of adamantane (1-OH-ADM, 1-NH2-ADM). Calorimetric measurements showed that the examined compound, like 1-NH2-ADM, is characterized by multiple thermal events in the thermogram measured on heating and cooling. Further X-ray diffraction, Fourier-transform infrared, and Raman spectroscopy investigations suggested that two of them correspond to the transition from the ordinary crystal (OC) to the plastic crystal (PC) phase I and the transition between two PC phases (PC(I) and PC(II)), while the third subtle one is rather not related to a phase transition. Interestingly, ambient pressure dielectric studies performed during heating and cooling cycles revealed changes in the imaginary and real parts of the complex dielectric permittivity at temperatures close to the temperatures of phase transitions detected by the calorimetry. Such behavior resembled that reported for 1-NH2-ADM. Finally, isothermal time-dependent dielectric and infrared studies, supported by the analysis of asynchronous 2D-IR correlation spectra, indicated that the first endothermic peak, visible in the thermogram of 3-NH2-1-OH-ADM over an enormously large temperature interval and related to the OC-PC(I) phase transition, similarly to the one, assigned to the PC(I)-PC(II) transition in 1-NH2-ADM, has a character of the kinetic process. Importantly, during the annealing of 3-NH2-1-OH-ADM at T = 328–343 K, we observed a clear change in the dc-conductivity as well as intramolecular dynamics related to the vibrations of CH, NH2, and OH moieties that occur at different rates.

Memantine and the Kynurenine Pathway in the Brain: Selective Targeting of Kynurenic Acid in the Rat Cerebral Cortex.

Cytoprotective and neurotoxic kynurenines formed along the kynurenine pathway (KP) were identified as possible therapeutic targets in various neuropsychiatric conditions. Memantine, an adamantane derivative modulating dopamine-, noradrenaline-, serotonin-, and glutamate-mediated neurotransmission is currently considered for therapy in dementia, psychiatric disorders, migraines, or ischemia. Previous studies have revealed that memantine potently stimulates the synthesis of neuroprotective kynurenic acid (KYNA) in vitro via a protein kinase A-dependent mechanism. Here, the effects of acute and prolonged administration of memantine on brain kynurenines and the functional changes in the cerebral KP were assessed in rats using chromatographic and enzymatic methods. Five-day but not single treatment with memantine selectively activated the cortical KP towards neuroprotective KYNA. KYNA increases were accompanied by a moderate decrease in cortical tryptophan (TRP) and L-kynurenine (L-KYN) concentrations without changes in 3-hydroxykynurenine (3-HK) levels. Enzymatic studies revealed that the activity of cortical KYNA biosynthetic enzymes ex vivo was stimulated after prolonged administration of memantine. As memantine does not directly stimulate the activity of KATs' proteins, the higher activity of KATs most probably results from the increased expression of the respective genes. Noteworthy, the concentrations of KYNA, 3-HK, TRP, and L-KYN in the striatum, hippocampus, and cerebellum were not affected. Selective cortical increase in KYNA seems to represent one of the mechanisms underlying the clinical efficacy of memantine. It is tempting to hypothesize that a combination of memantine and drugs could strongly boost cortical KYNA and provide a more effective option for treating cortical pathologies at early stages. Further studies should evaluate this issue in experimental animal models and under clinical scenarios.

Synthesis, infra red and nmr intensities of amphiphilic adamantane derivatives: Impact of hydroxylation, acetylation and chlorination

Novel chloro substituted adamantanamide was designed to have better supramolecular sites and accordingly synthesized via hydroxylation, acetylation and chlorination. Due to the specific electronic properties of chlorine atom it imparts better applications. Functionalization of highly unreactive adamantane was achieved with an overall yield of 80% under milder reaction conditions. Hydroxylation of adamantamine was carried out using urea as catalyst (10mol%) with an yield of 97%. Acetylation was optimized using acylating reagent (acetyl chloride, 1.1 equivalents) and DIPEA (1.5 equivalents) which resulted 97% yield. Finally, chlorination was carried out with thionyl chloride (2.0 equivalents) at 65 °C (84% yield). IR and NMR (including D2O exchanded) spectra were analyzed along with ESI-MS data of all the products. DFT studies were carried using B3LYP level {6–311++G (d, p) basis set}out for all the products to predict the stability, reactivity and other global descriptors.

A Comprehensive Review on Selective Catalytic Methods for Functionalization of Adamantane Scaffolds

AbstractOver the decades, conventional techniques have been reported for the direct conversion of a substantial framework of adamantyl C(sp3)‐H/Br/COOH bonds to various C−C, C−N, and other C−X bonds enabled by various catalytic conditions and reagents. There are various simple and direct methods for converting adamantane tertiary and secondary C‐(Sp3)‐H/X/M bonds to quaternary/ tertiary carbon‐carbon bonds that have been reported in previous years, which include methods such as catalytic approaches, cross‐coupling reactions, C−H bond functionalization, radical reactions, organometallics, and dual catalysis, etc. The selective catalytic techniques published between 2010 and 2023 are covered in this article. These adamantane derivatives are broadly studied in various fields such as medicinal chemistry applications, drug development, supramolecular chemistry, material science, catalysts/ligands, and nanotechnologies.

The conceptual design of pH responsive ZnO-adamantane nanosystems for insulin amyloidosis

Adamantane derivatives are already being explored in amyloidogenic diseases, while ZnO nanoparticles (NPs) have the potential for affecting amyloidosis. Herein, the transformation of ZnO NPs and adamantane-1-carboxylic acid (ADA) to advanced pH responsive nanosystems is reported. Primary ZnO NPs were isolated under a simple solvothermal self-assembly synthetic procedure in the sole presence of octadecylamine (ODA). By adjusting the reaction time (8–24 h), wurtzites of crystallite sizes 19, 21 and 23 nm, respectively, were synthesized with co-crystallized ODA in monoloayer or bilayer conformation. The NPs with the bilayer of ODA have been functionalized with ADA through an amide bond, while those with the ODA monolayer were further PEGylated and ADA was loaded. Loaded ADA-ZnO nanosystems affected insulin amyloidosis in acidic pH (4.8), both in terms of final aggregation status (40 %) and by retarding the lag phase of amyloids formation. The sustained release profile of ADA was confirmed, while interaction with calf thymus DNA (CT-DNA) was evidenced by hyperchromicity. The pH of 4.8 was not enough to cleave the peptide bond, and thus the direct conjugation of ADA was effective only in prolonging the lag phase, without affecting the final amyloid formation, giving rise to the inherent properties of ZnO, foregrounding a prodrug character.

New derivatives of dehydroabiethylamine and adamantane: synthesis and activity as inhibitors of the repair enzyme TDP1

New derivatives of dehydroabiethylamine and adamantane: synthesis and activity as inhibitors of the repair enzyme TDP1

Structure-Activity Relationships, Deuteration, and Fluorination of Synthetic Cannabinoid Receptor Agonists Related to AKB48, 5F-AKB-48, and AFUBIATA.

Synthetic cannabinoid receptor agonists (SCRAs) are a growing class of new psychoactive substances (NPS) commonly derived from an N-alkylated indole, indazole, or 7-azaindole scaffold. Diversification of this core (at the 3-position) with amide-linked pendant amino acid groups and modular N-alkylation (of the indole/indazole/7-azaindole core) ensures that novel SCRAs continue to enter the illicit drug market rapidly. In response to the large number of SCRAs that have been detected, pharmacological evaluation of this NPS class has become increasingly common. Adamantane-derived SCRAs have consistently appeared throughout the market since 2011, and as such, a systematic set of these derivatives was synthesized and pharmacologically evaluated. Deuterated and fluorinated adamantane derivatives were prepared to evaluate typical hydrogen bioisosteres, as well as evaluation of the newly detected AFUBIATA.

Determination of Acetylamantadine by γ-Cyclodextrin-Assisted α-HL Nanopore for Potential Cancer Prediagnosis.

The high expression of Spermidine/spermine N1-acetyltransferase (SSAT-1) is an important indicator in early cancer diagnosis. Here, we developed a nanopore-based methodology with γ-cyclodextrin as an adaptor to detect and quantify acetylamantadine, the specific SSAT-1-catalyzed product from amantadine, to accordingly reflect the activity of SSAT-1. We employ γ-cyclodextrin and report that amantadine cannot cause any secondary signals in γ-cyclodextrin-assisted α-HL nanopore, while its acetylation product, acetylamantadine, does. This allows γ-cyclodextrin to practically detect acetylamantadine in the interference of excessive amantadine, superior to the previously reported β-cyclodextrin. The quantification of acetylamantadine was not interfered with even a 50-fold amantadine and displayed no interference in artificial urine sample analysis, which indicates the good feasibility of this nanopore-based methodology in painless cancer prediagnosis. In addition, the discrimination mechanism is also explored by 2-D nuclear magnetic resonance (NMR) and nanopore experiments with a series of adamantane derivatives with different hydrophilic and hydrophobic groups. We found that both the hydrophobic region matching effect and hydrophilic interactions play a synergistic effect in forming a host-guest complex to further generate the characteristic signals, which may provide insights for the subsequent design and study of drug-cyclodextrin complexes.

Novel Adamantane Derivatives: Synthesis, Cytotoxicity and Antimicrobial Properties

Seventeen adamantane derivatives were synthesized according to facile condensation reaction protocols. Spectral analysis (1H NMR and 13C NMR) was applied to confirm the chemical structure of the obtained substances. The synthesized compounds were tested for in vitro antimicrobial activity against a panel of Gram-positive and Gram-negative bacterial strains and towards fungi from Candida spp. Among them, four derivatives numbered 9, 14, 15 and 19 showed the highest antibacterial potential with MIC = 62.5–1000 µg/mL with respect to all Gram-positive bacteria. S. epidermidis ATCC 12228 was the most susceptible among the tested bacterial strains and C. albicans ATCC 10231 among fungi. Additionally, the cytotoxicity for three derivatives was measured with the use of the MTT test on A549, T47D, L929 and HeLa cell lines. Our cytotoxicity studies confirmed that the tested substances did not cause statistically significant changes in cell proliferation within the range of the tested doses.

Assessment of the Impact of Polycyclic Derivatives of the Frame Series on the Replicative Properties of the SARS-CoV-2 Virus in an <I>in vitro</I> Experiment

The aim of the work was to determine the cytotoxicity and the influence of polycyclic derivatives of the framework series on the replicative properties of the SARS-CoV-2 virus in Vero-E6 cell culture in vitro. Materials and methods. The virus inhibiting effect of 50 adamantane and bicyclo[3.3.1]nonane derivatives with carbocyclic and heterocyclic substituents was investigated. The studies were carried out on Vero-E6 cell culture by assessing the cytopathic effect of the virus. The impact of the compounds on the replicative properties of the SARS-CoV-2 virus was estimated by the decrease in virus titer in the presence of the compounds compared to the control. Based on the virus titer values in the presence of a series of successively decreasing concentrations of the compound, the 50 % effective concentration was calculated.Results and discussion. A study of polycyclic derivatives of the framework series has identified two compounds with antiviral properties against the SARS-CoV-2 virus. Among bicyclo[3.3.1]nonane derivatives containing heterocyclic fragments, compound No. 15144 has showed an inhibitory effect against the SARS-CoV-2 virus. The protective effect of the compound was manifested in maximum tolerable concentration (MTC) (70.0 μg/ml) and ½ MTC (35.0 µg/ml). A decrease in virus titers under the influence of MTC by 0.95 lg TCD50/ml, in ½ MTC (35.0 μg/ml) – by 0.35 lg TCID50/ml has been detected. The effective concentration (EC50) value of the compound No. 15144 was 64.0 μg/ml, the MTC/EC50 ratio was 1.09. Compound No. 14838 (adamantane derivative containing carbocyclic fragments) had less pronounced antiviral activity. As a result of research, it has been established that sample No. 14838 at a dose of MTC (45.0 μg/ml) reduces the infectious titer by 0.78 lg TCD50/ml, in ½ MTC (22.5 μg/ml) by 0.15 lg TCD50/ml compared to the control. The EC50 value of compound No. 14838 was 37.0 μg/ml, the MTC/EC50 ratio was 1.22.

The synthesis for adamantane derivatives of high energy density fuel catalyzed by HY zeolite based on the DFT

The adamantane derivatives are promising high-energy-density fuel due to preferable fuel properties, the activity of HY zeolite is key for synthesis adamantane derivatives on account of easy separation from liquid fuels. The effect of acid strength and type of zeolite on activity from DMTCD to 2c,2t-dimethyladamantane is investigated by the DFT method. The activity on HAlY zeolite with stronger Brønsted acid strength is superior compared to HGaY, HFeY, HInY and HBY. Thus, AlO+/HAlY zeolite is investigated obtaining that smaller gap between LUMO and HOMO leads to the better activity than HAlY. And oxoaluminum cations as Lewis acid improves Brønsted acid strength, in which the activity of AlO+/HAlY with stronger Brønsted/weaker Lewis acid strength is preferable than other HAlY with Lewis acid. Therefore, this work provides guidance for screening of HY zeolite with preferable activity of hydro-isomerization.

Quantum Chemical Study of the Production of 1-Vinyladamantane As a Result of Ionic Alkylation of Adamantane with Ethylene

A multi-stage process is considered for the formation of vinyl adamantane via the ionic alkylation of adamantane with ethylene using aluminum chloride as a catalyst. A feature of the ionic alkylation of adamantane with olefins is the formation of saturated and unsaturated derivatives. Quantum chemical methods means are used to study the kinetic and thermodynamic parameters of the corresponding elementary acts of chemical reactions. A comparative analysis of the characteristics of the reaction for the production of unsaturated adamantane derivatives via ionic alkylation with ethylene is performed using alkylation with propylene.

Nascent pharmacological advancement in adamantane derivatives.

The adamantane moiety has attracted significant attention since its discovery in 1933 due to its remarkable structural, chemical, and medicinal properties. This molecule has a notable impact in the therapeutic field because of its "add-on" lipophilicity to any pharmacophoric moieties. As in the case of molecular hybridization, in which one pharmacophore is attached to another one(s) with a probability of increasing the biological activity, adding an adamantane unit improves the absorption distribution, metabolism and excretion properties of the resultant hybrid molecule. This review summarizes various reports highlighting the biological activities of adamantane-based synthetic compounds and their structure-activity relationship study. The information presented in this review may open up possible dimensions for adamantane-based drug development and discovery in the pharmaceutical industry after proper structural modifications.

Effect of methyl substituent on adamantane pyrolysis at atmospheric and high pressure: A combined experimental and theoretical study

Adamantane derivatives, as promising high-density fuels, have been widely concerned in fields of volume-limited aerospace vehicles due to high density, heat of combustion and thermal oxidation stability. To reveal insights into their high-temperature decomposition behaviors, an experimental and theoretical investigation of adamantane (A) and 1-methyl adamantane (1-MA) pyrolysis was performed in a flow tube reactor at atmospheric to high pressure. Over twenty species were detected and identified, including C1-C5 light hydrocarbons, C5-C7 cyclic olefins as well as C6-C12 aromatics. The favorable decomposition channels of A and 1-MA are proposed and the effects of fuel structure characteristics and pressures on product formation behaviors are revealed. For the primary decomposition of A and 1-MA, the contributions of reaction types exhibit the obvious dependence on the pressures and temperatures, involving the unimolecular C-C dissociations by ring-opening, CH3-elimination as well as H-abstractions by H and CH3 attacking. Considering methyl-substitution weakens dissociation energies of C-C and C-H bonds and leads more H-abstraction sites, 1-MA shows a higher pyrolysis reactivity than A. The effects of structure characteristics are also embodied in the formation of newly chain-branched unsaturated species and the concentrations of common small hydrocarbons and aromatics. Compared to A decomposition, the methyl substituent in 1-MA promotes the emergence of 1-butene, 2-methyl-1-butene, mesitylene, methylindane and methylnaphthalene, and increases the concentrations of methane, 2-methylpropene and xylene isomers, formed via β-scission, hydrogen transfer, isomerization and dehydrogenation routes of fuel radicals. Meanwhile, more methyl-substitutions accelerate the decomposition of alkyl-adamantanes and pyrolysis activity follows by a sequence of dimethyl-adamantane > methyl-adamantane > adamantane, boosting the production of methyl-specific species.

Synthesis of 1,2-Disubstituted Adamantane Derivatives by Construction of the Adamantane Framework.

This review summarizes achievements in the synthesis of 1,2-disubstituted adamantane derivatives by the construction of the tricyclic framework either by total synthesis or by ring expansion/contraction reactions of corresponding adamantane homologues. It is intended to complement reviews focusing on the preparation of 1,2-disubstituted derivatives by C-H functionalization methods.

Adamantane-containing drug delivery systems

Adamantane is a weakly functional hydrocarbon widely used to develop new drug molecules to improve their pharmacokinetic and pharmacodynamic parameters. The compound has an affinity for the lipid bilayer of liposomes, enabling its application in targeted drug delivery and surface recognition of target structures. This review presents the available data on developed liposomes, cyclodextrin complexes, and adamantane-based dendrimers. Adamantane has been used in two ways – as a building block to which various functional groups are covalently attached (adamantane-based dendrimers) or as a part of self-aggregating supramolecular systems, where it is incorporated based on its lipophilicity (liposomes) and strong interaction with the host molecule (cyclodextrins). Adamantane represents a suitable structural basis for the development of drug delivery systems. The study of adamantane derivatives is a current topic in designing safe and selective drug delivery systems and molecular carriers.

Metabolic profiling to evaluate the impact of amantadine and rimantadine on the secondary metabolism of a model organism

Metabolic profiling offers huge potential to highlight markers and mechanisms in support of toxicology and pathology investigations during drug development. The main objective was to modify therapy with adamantane derivatives: amantadine and rimantadine, to increase their bioavailability and evaluate the influence of such therapy on drug metabolism using Saccharomyces cerevisiae as the model organism. In this study, the profile of endogenous metabolites of a model organism was measured and interpreted to provide an opportunity to investigate changes induced by treatment with amantadine and rimantadine. It was found that resveratrol supplementation synergistically enhanced the effects of amantadine treatment and increased rimantadine metabolism, potentially reducing side effects. The fingerprinting strategy was used as an efficient technique for qualitatively evaluating and monitoring changes in the profiles of endogenous components and their contents in a model organism. Chemometric tools were employed to find marker compounds that can be defined as characteristic indicators of a pharmacological response to a therapeutic intervention. An improved understanding of the mechanisms involved in drug effect and an increased ability to predict individual variations in the drug response of organisms will improve the treatment process and the development of new therapies.