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The Chan–Lam reaction conditions were optimized for the synthesis of N-aryl derivatives of adamantane-containing amines. A number of adamantane-containing amines and diamines with different steric hindrances at the primary amino groups were reacted with p-tolylboronic acid under the optimized conditions [0.1 M solution of amine in MeCN, p-tolylboronic acid (2 equiv), DBU (2 equiv), copper(II) acetate (20 mol %), 25°C, 24 h]. The reactivity of the amines was found to strongly depend on their structure, and the maximum yield of the target products reached 74% from the monoamines and 66% from the diamines. [ABSTRACT FROM AUTHOR]

N-(Het)arylation of adamantane-containing amines with halonaphthalenes and haloquinolines catalyzed by either CuI or copper nanoparticles with an average size of 25 nm in the presence of 2-isobutyrylcyclohexanone, rac-BINOL, and l-proline as a ligand and Cs2CO3 as a base in DMSO at 110 °C was studied. The reactions proceed smoothly with 2-iodonaphthalene and 6-iodoquinoline, the possibility of successful reactions with 6- and 3-bromoquinolines was also shown. In the case of 1-bromonaphthalene, 5- and 8-bromoquinolines, only Pd-catalyzed amination can provide the high yields of the products. An alternative possibility of C(sp2)—N bond formation was studied employing the Chan—Lam reaction with of 2-naphthaleneboronic acid and pinacolates of 6- and 3-quinolineboronic acids. [ABSTRACT FROM AUTHOR]

The electrochemical ion‐sensor performance of the self‐assembled monolayer (SAM) of 3H‐imidazo[4,5‐b]pyridine, which is known as a metal ionophore, was examined using a triad composed of ferrocene, an ionophore, and a tripodal trithiol with adamantane core. The voltammetry of the SAM‐modified Au electrode showed a large positive change (280 mV) in the ferrocene oxidation potential via the addition of Pb2+, with a detection limit of 10–6 M. A Langmuir adsorption‐type analysis of the ion binding equilibrium suggested that as much as 70% of the imidazopyridine ligand was actually functioning as a Pb2+ ionophore on the SAM, whereas the rest of the ligand was uncomplexed because of the crowding of the molecules in the SAM. Control experiments using an analogous triad of monothiol revealed a strong advantage in using trithiol; thus, tripod‐shaped anchor is requisite for the ionophore to function well as a sensor. [ABSTRACT FROM AUTHOR]

Rapid development of the copper-catalyzed amination of aryl halides in the beginning of the 21st century, known as the Renaissance of the Ullmann chemistry, laid foundations for the use of this method as a powerful tool for the construction of the C(sp2)-N bond and became a rival of the Buchwald–Hartwig amination reaction. Various applications of this approach are well-documented in a number of comprehensive and more specialized reviews, and this overview in the form of a personal account of the Cu-catalyzed arylation and heteroarylation of the adamantane-containing amines, and di- and polyamines, covers a more specific area, showing the possibilities of the method and outlining general regularities, considering reagents structure, copper source and ligands, scope, and limitations. The material of the last decade is mainly considered, and recent data on the application of the unsupported copper nanoparticles and possibilities of the Chan-Lam reaction as an alternative to the use of aryl halides are also discussed. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: 2,4,6,8‐Tetraazanoradamantane skeleton is a unique rigid cage‐like organic structure that has not been established. In this article, a facile protocol to build all‐bridge‐position‐functionalized 2,4,6,8‐tetraazanoradamantane skeleton by condensation of glyoxal, primary amines and disubstituted malondialdehydes, which were in situ generated from 2,2‐dipropenyl‐1,3‐dioxolane or 4,4‐dimethoxyhepta‐2,5‐diene via ozonation, is reported for the first time. A variety of primary amines are compatible with this process, and the corresponding 2,4,6,8‐tetraalkyl‐2,4,6,8‐tetraazanoradamantane‐9‐one ethylene or methyl ketals were achieved in 16%—58% yields. N‐Benzyl group could be converted to other functionalities such as acetyl and nitro, which indicates the structural diversity of this scaffold. [ABSTRACT FROM AUTHOR]

The regularities of the reduction of unsaturated nitriles containing the 2-adamantyl fragment with lithium aluminum hydride and nickel—aluminum alloy were studied. In both cases, the double bond and nitrile group were simultaneously reduced. The presence of bulky substituents in the substrate in the α-position to the adamantyl fragment and hydroxy groups significantly retards the process, and the 80–90% yield of the corresponding products is achieved only when the temperature is raised to 65 °C. In the case of using a nickel—aluminum alloy, its 4—6-fold excess is required. The calculation of the potential pharmacological activity of the synthesized compounds shows that they can have antiviral, analgesic, and antidiabetic activity. [ABSTRACT FROM AUTHOR]

Introduction of adamantane moieties on diamondoids such as adamantane, 2‐azaadamantane or diamantane by amide formation and reduction to the corresponding amine was performed in a straightforward and easy way by amidation under Schotten–Baumann conditions and reduction with BH3 ⋅ THF. The obtained amides and amines were studied in terms of structural properties towards the perspective of transformation into nanodiamonds. Crystal structure and dynamic NMR experiments of the most crowded amide obtained gave structural insights into the effect of bulkiness and steric strain on out‐of‐planarity of amide bonds (16.0°) and the kinetics and thermodynamics of amide bond rotation (ΔG≠298K=11.5–13.3 kcal ⋅ mol−1). [ABSTRACT FROM AUTHOR]

The N-heteroarylation of n-octylamine and adamantane-containing amines with 2-iodopyridine and 2-bromopyridine and its fluorinated derivatives under the catalysis of CuI and copper nanoparticles in DMSO in the presence of various ligands was studied. 2-Isobutyrylcyclohexanone was found to be the most efficient ligand in the reactions catalyzed by CuI. In the reactions catalyzed by copper nanoparticles, 2-isobutyrylcyclohexanone or l-proline turned to be most active. The yields of the reactions catalyzed by copper nanoparticles were better than or equal to those in the CuI-catalyzed processes. The possibility of nanocatalyst recycling was studied, and its reuse in 6 cycles without loss of activity was demonstrated. [ABSTRACT FROM AUTHOR]

N-Arylation of n-octylamine and adamantane-containing amines with iodobenzene and its deriva-tives has been performed in DMSO using copper(I) iodide and copper nanoparticles in the presence of various ligands as catalysts. In all cases, 2-isobutyrylcyclohexanone turned out to be the most efficient ligand, and higher yields of the arylation products were obtained in the presence of copper nanoparticles. The nanocatalyst can be recycled 9 times without significant loss of yield. [ABSTRACT FROM AUTHOR]

A comparative study of the catalytic efficiency of Pd(0) and Cu(I) complexes in the reactions of adamantanamines with fluoro- and trifluoromethyl-substituted 2-bromopyridines was carried out using previously optimized catalytic systems. It was shown that in the absence of steric hindrances in the starting compounds, the copper and palladium catalysts were comparable in efficiency. In some cases, the yields of the target N-heteroarylated compounds in the copper-catalyzed reactions were even higher, which can be explained by the formation of N,N-diheteroarylated by-products under palladium-catalyzed conditions. At the same time, ortho-fluorine- and ortho-trifluoromethyl-substituted 2-bromopyridines successfully react exclusively under palladium catalysis. [ABSTRACT FROM AUTHOR]

Ethyl [(adamantan-1-yl)alkylene(phenylene)amino]oxoacetates and N1,N2-bis[(adamantan-1-yl)-alkylene(phenylene)oxamides were prepared in yields of 72–87 and 18–60%, respectively, by the reaction of amines of the adamantane series with ethyl chlorooxoacetate and oxalyl chloride in methylene chloride in mild conditions. [ABSTRACT FROM AUTHOR]

The catalytic efficiencies of palladium(0) and copper(I) complexes in the amination of 2-bromopyridine and its fluorine-containing derivatives with (1-adamantyl)methanamine and 2-(1-adamantyloxy)ethanamine were compared. Both types of catalytic systems were shown to be applicable for the preparation of the corresponding N-pyridyl derivatives from 3- and 5-fluoro- and 4-, 5-, and 6-trifluoromethyl-2-bromopyridines. DavePhos was found to be the most efficient ligand in the Pd(0)-catalyzed reactions; however, the reactions with 2-bromo-4-(trifluoromethyl)pyridine and 2-bromo-5-(trifluoromethyl)pyridine were accompanied by formation of a considerable amount of the diarylation product. The diarylation process was significantly suppressed in the presence of copper(I) complexes. [ABSTRACT FROM AUTHOR]

1,5-Dimethylbispidinone (1,5-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-one) reacts with natural ketones, including optically active ones, to give new aminal-type compounds combining diazaadamantane and aliphatic fragments. [ABSTRACT FROM AUTHOR]

Abstract Hydrophobic monoamines containing only a hydrophobic/aromatic moiety and protonated amino group are a recently described class of acid-sensing ion channel (ASIC) modulators. Intensive studies have revealed a number of active compounds including endogenous amines and pharmacological agents and shown that these compounds potentiate and inhibit ASICs depending on their specific structure and on subunit composition of the target channel. The action of monoamines also depends on the application protocol, membrane voltage, conditioning and activating pH, suggesting complex mechanism(s) of the ligand-receptor interaction. Without understanding of these mechanisms analysis of structure-function relationships and predictive search for new potent and selective drugs are hardly possible. To this end, we investigated the modes of action for a representative series of amine and guanidine derivatives of adamantane and phenylcyclohexyl. The study was performed on transfected Chinese hamster ovary (CHO) cells and rat hippocampal interneurons using whole-cell patch clamp recording. We found that complex picture of monoamine action can be rationalized assuming four modes of action: (1) voltage-dependent pore block, (2) acidic shift of activation, (3) alkaline shift of activation and (4) acidic shift of steady-state desensitization. Structure-activity relationships are discussed in the light of this framework. The experiments on native heteromeric ASICs have shown that some of these mechanisms are shared between them and recombinant ASIC1a, implying that our results could also be relevant for amine action in physiological and pathological conditions. [ABSTRACT FROM AUTHOR]

2-Fluorophenyl isocyanate reacted with adamantan-1(2)-amines and their homologs in DMF to give 31-92% of the corresponding N,N′-disubstituted ureas that are target-oriented human soluble epoxide hydrolase (sEH) inhibitors. Introduction of a fluorine atom increases the sEH inhibitory activity by a factor of 4.5. [ABSTRACT FROM AUTHOR]

N-Aryl(benzyl)adamantane-1-carboxamides were synthesized in 54–87% yields by reaction of adamantane-1-carboxylic acid with aromatic amines in the presence of phosphorus trichloride, 4-dimethylaminopyridine, and triethylamine on heating at 80°C for 8 h. [ABSTRACT FROM AUTHOR]

Abstract: Passivation of electronic defects is an effective strategy to boost the performance and operational stability of perovskite solar cells (PSCs). Identifying molecular materials that achieve this purpose is a key target of current research efforts. Here, adamantane (AD) and 1‐adamantylamine (ADA) are introduced as molecular modulators to abate electronic defects present within the bulk and at the perovskite–hole conductor interface. To this effect, the modulator is added either into the antisolvent (AS) to precipitate it together with the perovskite (AS method) or they are spin coated (SC) onto its surface (SC method). Time‐resolved photoluminescence measurements show substantially longer lifetimes for perovskite films treated with AD and ADA compared to the reference sample. In line with this observation, it is found that the presence of AD and ADA molecules at the interface between the perovskite film and the hole conductor increases all photovoltaic metrics, in particular the open circuit photovoltage (V oc) as well as the operational stability of the PSC. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed heteroarylation of adamantylalkyl amines characterized by different steric hindrances at the amino group was carried out using 2,3-, 2,5-, 2,6-, and 3,5-dihalogenopyridines. The dependence of the results of the coupling on the nature of the halogen atoms (bromine, chlorine), their position in the pyridine ring, and on the structure of adamantylalkyl amines was investigated. The application of dichloropyridines or bromochloropyridines was shown to be advantageous over the use dibromopyridines in many cases. Selective substitution of bromine atom in positions 3 and 5 in the presence of chlorine atom in position 2 of the pyridine ring was observed. The possibility of N,N-diheteroarylation of adamantane-containing amines with 2,5-dihalogenopyridines was shown, and diamination of 2,6- and 3,5- dihalogenopyridines was demonstrated. [ABSTRACT FROM AUTHOR]

We report the inclusion of carboxy- and amine-substituted molecular nanodiamonds (NDs) adamantane, diamantane, and triamantane by β-cyclodextrin and γ-cyclodextrin (β-CD and γ-CD), which have particularly well-suited hydrophobicity and symmetry for an optimal fit of the host and guest molecules. We studied the host-guest interactions in detail and generally observed 1:1 association of the NDs with the larger γ-CD cavity, but observed 1:2 association for the largest ND in the series (triamantane) with β-CD. We found higher binding affinities for carboxy-substituted NDs than for amine-substituted NDs. Additionally, cyclodextrin vesicles (CDVs) were decorated with d-mannose by using adamantane, diamantane, and triamantane as non-covalent anchors, and the resulting vesicles were compared with the lectin concanavalin A in agglutination experiments. Agglutination was directly correlated to the host-guest association: adamantane showed lower agglutination than di- or triamantane with β-CDV and almost no agglutination with γ-CDV, whereas high agglutination was observed for di- and triamantane with γ-CDV. [ABSTRACT FROM AUTHOR]

A facile synthesis for 1-fluoro-3-(trifluoromethyl)adamantane, based on fluorination of 3-hydroxyadamantane-1-carboxylic acid, was developed. Its synthetic potentialities for preparation of (trifluoromethyl)adamantane derivatives containing diverse functional groups (acids, amines, etc.) in a bridgehead position, were disclosed. [ABSTRACT FROM AUTHOR]

A reaction of methyl 2-(4-allyl-2-methoxyphenoxy)acetate with adamantan-2-amine and (adamantan-1-yl)methylamine in butanol leads, together with the target amides, to the formation of butyl ester of the corresponding acid, which is resistant to aminolysis. [ABSTRACT FROM AUTHOR]

Two new silver(I) complexes, namely [Ag(qyAm) 2 ](CF 3 SO 3 ) ( 1 ) and [Ag(qyTAm) 2 ](CF 3 SO 3 ) ( 2 ), (qyAm = 2-(quinonyl)iminoadamantane, qyTAm = 2-(quinonyl)iminotriazaadamantane) have been synthesized and characterized by elemental analyses, 1 H NMR, IR, electronic absorption spectroscopy, and X-ray diffraction. The coordination geometry of the silver center in both complexes is distorted tetrahedral where their respective qyAm and qyTAm ligand bind in a bidentate fashion using the imine and quinoline nitrogen atoms. Complex 2 is soluble in water and exhibits strong antimicrobial actions on both Gram-negative ( E . coli , and P . aeruginosa ) and Gram-positive ( S . aureus ) bacteria. The minimal inhibitory concentration (MIC) values for complex 2 (4, 4, and 8 μg for E . coli , P . aeruginosa , and S . aureus , respectively) are comparable to MIC values of silver nitrate and silver sulfadiazine. [ABSTRACT FROM AUTHOR]

Non-seeded ultrafast microwave synthesis of all-silica DDR zeolite was realized using 1-adamantane amine and tetraethylammonium hydroxide. XRD, SEM, NMR, FT-IR, TGA and nitrogen adsorption were used to characterize the obtained samples. The presence of TEAOH suppressed the formation of other phases which allowed the synthesis to be carried out at high temperature. High quality DDR crystals were obtained in only 30 min without seeding, which is the fastest synthesis up to now. 1-Adam serves as template for zeolite DDR and TEAOH is not occluded in zeolite channels. The ultra fast synthesis is the synergy of fast heating from microwave energy, fast kinetics (nucleation and crystallization) at high temperature and phase selectivity from the TEAOH. The obtained DDR crystals have similar properties as those prepared with traditional method. [ABSTRACT FROM AUTHOR]

Amination of 3,6-dichloropyridazine, chloropyrazine, 2,3and 2,6-dichloropyrazines, 2-chloroquinoxaline, 1-chloroand 1,3-dichloroisoquinolines with various adamantane-containing amines characterized by different steric hindrances at the amino group was studied. The yields of the amination products depended on the structure of starting compounds. In the reactions of all the dichloroheteroarenes, selective substitution of only one chlorine atom took place, with the best yields being observed for 2,6-dichloropyrazine. In the reaction of 1,3-dichloroisoquinoline, the chlorine atom at position 1 was selectively substituted in up to 90% yield. [ABSTRACT FROM AUTHOR]

A copper(I) complex-catalyzed N, N'-diarylation of diamines based on 1,3-disubstituted adamantane, using aryl iodides bearing electron-donating and electron-withdrawing substituents, was studied. In the case of 2,2'-(adamantane-1,3-diyl)ethanediamine, the optimal catalyst system is CuI-2-(isobutyryl)cyclohexanone-CsCO-DMF. The highest yield of diarylation product was reached in the case of 4-methoxyiodobenzene (79%). In the case of more spatially hindered adamantane-1,3-diyldimethanamine, 1,1'-binaphthalene-2,2'-diol (BINOL) should be used, with the highest yield of the target product (84%) being reached in the reaction with iodobenzene. [ABSTRACT FROM AUTHOR]

A simple and efficient catalytic system including 3-methyl-4-oxa-5-azahomoadamantane and FeCl for aerobic oxidative synthesis of benzimidazoles from primary amines and o-phenylenediamine is presented. This process uses O as economic and green oxidant and water as green solvent, tolerates a wide range of substrates, and can afford the target products in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

Addition of polyfunctionalized aryl, heteroaryl, and tertiary alkylmagnesium reagents to tertiary nitroalkanes at 25 °C in tetrahydrofuran produces, after reductive workup with FeCl2 and NaBH4 in ethanol, the corresponding polyfunctional secondary amines in high yields. [ABSTRACT FROM AUTHOR]

A simple and efficient catalytic system for the aerobic oxidation of primary amines into corresponding oximes has been developed, with 3-methyl-4-oxa-5-azahomoadamantane as catalyst, acetaldoxime as co-catalyst and water as solvent. This process, which uses oxygen (O2) as an economic and green oxidant and water as a green solvent, tolerates a wide range of substrates, affording the target oximes in moderate to excellent yields. It was found that high selectivity was achieved when 3-methyl-4-oxa-5-azahomoadamantane was used, and E-type oximes were the only detected products. A possible mechanism for this catalytic process is proposed. [ABSTRACT FROM AUTHOR]

Catalyst-free reactions of 2-fluoropyridine with amines and diamines bearing the adamantyl moiety at either the N atom or in the side chain were studied. Amines, which do not contain secondary alkyl substituents at the amino group, react with an excess of 2-fluoropyridine to give N-(pyridin-2-yl) derivatives in the yields from moderate to good. 2-Fluoro-5-halopyridines were found to be more reactive than 2-fluoropyridine. [ABSTRACT FROM AUTHOR]

Hexamethylenetetramine is a versatile reagent in organic synthesis. It plays a major role in modern organic synthesis. This review focuses on hexamine reagent for its significant role in organic synthesis during the past decades and is able to provide a valuable perspective from synthetic point of view. [ABSTRACT FROM AUTHOR]

The set of 42 diastereomeric structures resulting from various degrees of substitution of secondary -CH2- groups by amines -NH- within the adamantane skeleton are investigated. They are placed into a substitution-reaction network viewed as a partial ordering, and the resultant reaction network (or Hasse diagram) displayed to illustrate different features. Ground-state ab-initio total energies of the 42 species are computed. A systematic cluster expansion of these total energies and associated internal energies is described in the context of this partial ordering. The results given support the idea, that recognition of the partial ordering is worthwhile. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Novel dendrimers having an adamantane structure as a core were synthesized such that even low generation dendrimers had a globular structure. Moreover we tried to give them biodegradable function by using ester bonds. Synthesis of the dendrimers, particularly at higher generations, proved difficult via a stepwise procedure, and thus a convergent route was used in which the adamantane core is coupled to the dendritic segments in the final step. We achieved the synthesis of two separate dendrimers with convergent methods till the third generations. The convergent dendrimers were synthesized in good yields compared with divergent one and both dendrimers were found to have narrow polydispersities by GPC analysis. [Copyright &y& Elsevier]

Reactions of 2-adamantan-2-one, acetone cyanohydrin, and amine lead to the formation of substituted 2-amino-2-cyanoadamantanes. The reaction is of a general character as has been proved by examples on a series of ketones and amines and it proceeds through the formation from the acetone cyanohydrin and amines of 2-amino-2-cyanopropane derivatives reacting further with the carbonyl compounds. [ABSTRACT FROM AUTHOR]

Novel building blocks for the synthesis of supramolecular components based on adamantane-bearing benzylamines were prepared. The binding properties of these amines and the corresponding acetamides towards β-cyclodextrin (β-CD) were studied using mass spectrometry, NMR spectrometry, isothermal titration calorimetry and semi-empirical calculations. It was found that all of the examined guests predominantly formed 1:1 inclusion complexes in an enthalpy-driven manner with association constants of the order of 102–103 M− 1. Stronger binding to the β-CD cavity was observed for guests with a longer spacer between the adamantane and benzene moieties and/or a 1,4-disubstituted benzene ring. [ABSTRACT FROM AUTHOR]

Pd-catalyzed amination of isomeric 2,6-, 2,8-, 4,8- and 4,7-dichloroquinolines was studied using adamantane-containing amines in which substituents at the nitrogen atom differ in bulkiness. The selectivity of the amination of 2,6-dichloroquinoline was very low, substantially better results were obtained with 2,8-dichloroquinoline, and 4,8- and 4,7-dichloroquinolines provided the best yields of the amination products. Diamination of 4,8- and 4,7-dichloroquinolines was carried out with two amines which differ strongly in the bulkiness of the alkyl group. In the majority of cases BINAP ligand was successfully applied, however, it had to be replaced with DavePhos in certain reactions when using the most sterically hindered amine as well as for the diamination reactions. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed amination of 3-bromopyridine with amines of the adamantane series in the presence of Pd(dba)/L [L = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl or 2-dimethylamino-2′-dicyclohexylphosphinobiphenyl] gave the desired N-(pyridin-3-yl)-substituted amines in 74-97% yields. Diamines of the adamantane series reacted with 2 equiv of 3-bromopyridine in a complicated fashion to produce mono- and triaryl-substituted derivatives as by-products, while the yields of N, N′-diarylation products were 18-56%. [ABSTRACT FROM AUTHOR]

Abstract: Various 1-acyl-2,4,10-trioxaadamantanes were prepared from the corresponding 1-methoxycarbonyl derivatives, via conversion to the N-acylpiperidine derivatives followed by reaction with a Grignard reagent in refluxing THF. These α-keto orthoformates were converted to the corresponding imines with 1-(S)-phenethyl amine (TiCl4/Et3N/toluene/reflux), with the Schiff bases being reduced further with NaBH4 (MeOH/0°C) into the corresponding 1-(S)-phenethyl amines (diastereomeric excess 91:9 by NMR). Hydrogenolysis of the phenethyl group (Pd-C/MeOH) finally led to the 1-(aminoalkyl)trioxaadamantanes, which are chiral C-protected α-amino acids, in excellent overall yields. [Copyright &y& Elsevier]

New pyrazoles; 1,2,4-triazoles; β- and γ-glycols; amidrazones; and amines of the adamantane series have been synthesized. Their activity with respect to smallpox vaccine virus has been studied. High anti-smallpox activity was observed for ethyl-3-(1-adamantyl)-5-(4-methylphenyl)-1 H-pyrazole-4-carboxylate (VI) and 1,4- bis(1-adamantyl)-1,4-butanediol (XII). [ABSTRACT FROM AUTHOR]

Several novel anilines bearing 1-adamantyl substituents that are useful for drug modification were synthesised from the corresponding 1-adamantyl (nitrophenyl) ketones. The host–guest systems of these prepared ligands with β-cyclodextrin (β-CD) were studied using electrospray ionisation mass spectrometry, NMR spectroscopy, titration calorimetry and semi-empirical calculations. The complexes with 1:1 stoichiometry were found to predominantly exist as pseudorotaxane-like threaded structures with the adamantane cage sitting deep in the cavity of β-CD close to the wider rim. Such geometry was observed for all examined amines and is independent of their structure and/or presence of protic substituents. [ABSTRACT FROM PUBLISHER]

The transmembrane domain of the influenza M2 protein (M2TM) forms a tetrameric proton channel important for the virus lifecycle. The proton-channel activity is inhibited by amine-containing adamantyl drugs amantadine and rimantadine, which have been shown to bind specifically to the pore of M2TM near Ser31. However, whether the polar amine points to the N- or C-terminus of the channel has not yet been determined. Elucidating the polar group direction will shed light on the mechanism by which drug binding inhibits this proton channel and will facilitate rational design of new inhibitors. In this study, we determine the polar amine direction using M2TM reconstituted in lipid bilayers as well as dodecylphosphocholine (DPC) micelles. 13C-2H rotational-echo double-resonance NMR experiments of 13C-labeled M2TM and methyl-deuterated rimantadine in lipid bilayers showed that the polar amine pointed to the C-terminus of the channel, with the methyl group close to Gly34. Solution NMR experiments of M2TM in DPC micelles indicate that drug binding causes significant chemical shift perturbations of the protein that are very similar to those seen for M2TM and M2(18-60) bound to lipid bilayers. Specific 2H-labeling of the drugs permitted the assignment of drug-protein cross peaks, which indicate that amantadine and rimantadine bind to the pore in the same fashion as for bilayer-bound M2TM. These results strongly suggest that adamantyl inhibition of M2TM is achieved not only by direct physical occlusion of the channel, but also by perturbing the equilibrium constant of the proton-sensing residue His37. The reproduction of the pharmacologically relevant specific pore-binding site in DPC micelles, which was not observed with a different detergent, DHPC, underscores the significant influence of the detergent environment on the functional structure of this membrane protein. [ABSTRACT FROM AUTHOR]

We performed a first principles total energy investigation on the structural, electronic, and vibrational properties of adamantane molecules, functionalized with amine and ethanamine groups. We computed the vibrational signatures of amantadine and rimantadine isomers with the functional groups bonded to different carbon sites. By comparing our results with recent infrared and Raman spectroscopic data, we discuss the possible presence of different isomers in experimental samples. [ABSTRACT FROM AUTHOR]

The formation of a three-dimensional assembly of gold nanoparticles driven by host−guest interactions is described. Assembly is achieved via host−guest interactions between cyclodextrin-modified gold nanoparticles which associate with the adamantane unit of a redox active metal complex [Os(CAIPA)3](ClO4)2, where CAIPA is 2-(4-carboxyphenyl)imidazo[4,5-f][1,10]-phenanthroline-1-adamantylamine. The electrochemical properties of thin films formed on glassy carbon electrodes have been probed using cyclic voltammetry. In aqueous LiClO4, the homogeneous charge transport diffusion coefficient, DCT, is (8.4 ± 0.4) × 10−9cm2s−1for both oxidation and reduction of the osmium complexes. Significantly, this charge transport rate is significantly larger than that obtained for a solid deposit of [Os(CAIPA)3](ClO4)2alone where DCTis 2.3 × 10−10cm2s−1. The higher DCTvalue observed for the nanoparticle arrays suggests that the incorporated nanoparticles facilitate electron transfer between the bound osmium centers. [ABSTRACT FROM AUTHOR]

An unusual intramolecular cyclization of tris(β-oximinoalkyl)amines 1into 4,6,10-trihydroxy-1,4,6,10-tetraazaadamantanes 2was discovered. Compounds 2are related to a previously unknown type of heteroadamantanes that contain the cage isomeric to urotropin. A simple three-step synthesis of tetraazaadamantanes 2and their N-substituted derivatives 3and 4from ammonia and aliphatic nitro compounds via the intermediacy of available tris-oximes 1was developed. [ABSTRACT FROM AUTHOR]

Abstract: The first aliphatic bis(chlorovinylidene cyanide) monomer, 1,3-bis(1-chloro-2,2-dicyanovinyl)adamantane, has been synthesized and polymerized with appropriate diamines to give adamantane-containing aromatic-aliphatic and all aliphatic poly(enaminonitriles) (PEANs) via vinylic nucleophilic substitution polymerization. The PEANs showed excellent solubility in polar aprotic solvents and good thermal stability (10% weight loss in air>320°C), despite the aliphatic contents of the polymers. Solution inherent viscosities of 0.23–0.90dL/g were obtained. Three other new PEANs containing the adamantane-based cardo group were also synthesized via vinylic nucleophilic substitution polymerization from the adamanaine-containing cardo diamine 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane. The cardo PEANs showed better solubility in common organic solvents than the corresponding cardo polyamides. They also showed good thermal stabilities (10% weight loss in air>339°C) comparable to those of the corresponding cardo polyamides. [Copyright &y& Elsevier]

Abstract: The synthesis of several (2-oxaadamant-1-yl)amines is reported. They were evaluated as NMDA receptor antagonists and several of them were more active than amantadine, but none was more potent than memantine. None of the tested compounds displayed antiviral activity. Two of the derivatives showed a significant level of trypanocidal activity. [Copyright &y& Elsevier]

Abstract: 1–2 Annulated adamantane piperidines 4, 6, 16, 17, 19, 23 and 25 were synthesized and evaluated for anti-influenza A virus activity. The stereoelectronic requirements for optimal antiviral potency were investigated. Piperidine 23 proved to be the most active of the compounds tested against influenza A virus, being 3.5-fold more active than amantadine, equipotent to rimantadine and 15-fold more potent than ribavirin. It is noteworthy that piperidine 23 displayed one of the highest selectivity indexes (SI>732) among aminoadamantanes or other cage structure amines tested till now. [Copyright &y& Elsevier]

New carboxamides having two and three adamantane fragments were synthesized from adamantanecarboxylic acid chlorides and adamantane-containing amines. The amides were reduced to the corresponding amines, and the latter were converted into N-p-nitrophenylsulfonyl and N-p-tolylsulfonylcarbamoyl derivatives by treatment with p-nitrobenzenesulfonyl chloride and p-toluenesulfonyl isocyanate, respectively. The structure of the newly synthesized compounds was confirmed by IR and 1H NMR spectroscopy. Some carboxamides turned out to be inactive in the reduction with lithium tetrahydridoaluminate, which was discussed in terms of the results of semiempirical quantum-chemical calculations. [ABSTRACT FROM AUTHOR]

Abstract: Spiro[aziridine-2,2′-adamantanes] 1 and 2, spiro[azetidine-2,2′-adamantanes] 3 and 5, spiro[azetidine-3,2′-adamantane] 13, spiro[piperidine-4,2′-adamantanes] 25 and 27, and spiro barbituric analog 18 were synthesized and tested for their anti-influenza A virus properties and for trypanocidal activity. The effect of ring size on potency was investigated. Piperidine 25 showed significant anti-influenza A virus activity, being 12-fold more active than amantadine, about 2-fold more active than rimantadine, and 54-fold more potent than ribavirin. It also proved to be the most active of the compounds tested against bloodstream forms of the African trypanosome, Trypanosoma brucei, being 1.5 times more potent than rimantadine and at least 25 times more active than amantadine. [Copyright &y& Elsevier]