Amido Group Research Articles

Stereoselective Total Synthesis of 1,4-Dideoxy-1,4-imino-L-ribitol by an Intramolecular Ring Opening of Epoxide with a Tethered Amide

Stereoselective total synthesis of 1,4-dideoxy-1,4-imino-L-ribitol has been accomplished from D-glucose. The key step involved in this synthesis is the regioselective ring-opening of the epoxide with a tethered amido group to give the N-tosyl-3,6-dideoxy-3,6-imino-1,2- O-isopropylidene-α-D-glucofuranose.

Development of a Novel Ferrocenyl Histone Deacetylase Inhibitor for Triple-Negative Breast Cancer Therapy

Owing to the lack of target-directed therapies, triple-negative breast cancer (TNBC) is difficult to effectively treat. In this article, a novel organometallic histone deacetylase (HDAC) inhibitor, Fc-SelSA, based on the selenocyanide (SelSA) zinc-binding motif, was synthesized using a ferrocenyl group as the cap to confer activity against TNBC. The synthesized Fc-SelSA was evaluated for bioactivity in vitro and in vivo. An enzymatic assay showed that Fc-SelSA was a potent HDAC inhibitor with a half-maximum inhibitory concentration (IC50) of 14.8 nM. Molecular docking studies of Fc-SelSA with HDAC suggested that the ferrocenyl unit overlaps with the phenyl group of suberoylanilide hydroxamic acid (SAHA) and the amido group of Fc-SelSA can form hydrogen bonds with the D98 and G151 residues of HDAC, but SAHA and SelSA do not show similar interactions. Moreover, Fc-SelSA reactivated the estrogen receptor alpha (ERα) expression, sensitized TNBC cells to the antagonist tamoxifen, and exerted more potent antitu...

Metal-free Deamidative Ugi Access to Isoindolinones

A two-step isoindolone synthesis has been achieved by using an Ugi/oxidative vicarious nucleophilic substitution sequence starting from 3-nitrobenzoic acid and aromatic aldehydes. Loss of the amido group was observed as well as a further oxidative process towards hydroxyisoindolone derivatives after prolonged stirring open to the atmosphere.

Nicotinamide complex of silver(III) with expanded coordination number

In strongly alkaline media ([OH−] ≥ 0.12 M), nicotinamide (nica) forms a complex with square-planar Ag(OH)4− [nica] ≥ 0.05 M. The complex decomposes in seconds to nicotinamide N-oxide. The correlation of maximum absorbance of the complex with concentrations of nicotinamide and hydroxide requires that the complex is either the five-coordinate Ag(OH)4(H-1nica)2− or the six-coordinate Ag(OH)5(nica)2−. Comparison with the reactions of Ag(OH)4− with nicotinate ion (nic−) and acetamide under similar conditions indicates that nicotinamide coordinates with Ag(OH)4− by the amido group rather than the nitrogen on the pyridine ring or the amido oxygen. Kinetics of the Ag(III)-nica redox reaction are consistent with direct reaction between nicotinamide and uncoordinated Ag(OH4)−. Oxidation takes place at the pyridine ring, yielding nicotinamide N-oxide. Silver(III) is reduced to monovalent silver.

Antineoplastic activity of linear leucine homodipeptides and their potential mechanisms of action.

Galaxamide is a rare cyclic homopentapeptide composed of three leucines and two N-methyl leucines isolated from marine algae Galaxaura filamentosa. The strong antitumor activity of this compound makes it a promising candidate for tumor therapy. The synthesis of galaxamide, however, is a complex process, and it has poor water solubility. On the basis of its special chemical composition, we designed a series of linear leucine homopeptides. Among seven dipeptide derivatives, five compounds with terminal protection groups and methyl substitution of the hydrogen in the amido group showed remarkable inhibitory effects against various cancer cells. N-tertbutyl-D-leucine-N-methyl-D-leucinebenzyl (A7), the only stereomer condensed by two D-leucines, showed the highest antineoplastic activity. A7-treated cells showed cell cycle arrest and morphological changes typical of cells undergoing apoptosis. The population of Annexin-V positive/propidium iodide-negative cells also increased, indicating the induction of early apoptosis. A7 promoted the cleavage of caspase-9 and caspase-3, as well as increased intracellular Ca levels and decreased the mitochondrial membrane potential. Collectively, certain linear leucine dipeptides derived from cyclic pentapeptide are able to inhibit tumor cell proliferation through cell cycle arrest and apoptosis induction. The N-methyl group in the side chain and the D/L conformation of the amino-acid residue are critical for their activity.

Computational Insights into the Gold‐Catalyzed Ring‐Opening of Methylenecyclopropanes and Vinylcyclopropanes with Sulfonamides

AbstractComputational studies were carried out to investigate the mechanisms of gold‐catalyzed ring‐opening of methylenecyclopropanes (MCPs) and vinylcyclopropanes (VCPs), respectively, with sulfonamides to afford homoallylic amine intermediates, which would subsequently produce pyrrolidine derivatives. The detailed activation modes of MCPs mediated by the AuI catalyst were comprehensively explored. Computational results suggested that the activation of MCP by the AuI catalyst was less feasible. Instead, the AuI catalyst mediated activation of sulfonamides could result in the increased acidity of the N−H bond, which is ready to undergo intermolecular proton transfer to the C=C moiety of MCP to form a cyclopropylcarbinyl cation intermediate. Subsequently, the nucleophilic attack of the formed amido group to the three‐membered ring moiety of the yielded cyclopropylcarbinyl cation intermediate in an SN2 manner could follow to afford the ring‐opening homoallylic sulfonamide. In addition, computational studies indicated that such mechanistic pathway could also apply to the VCPs involved hydroamination with sulfonamides. The mechanism of triflic acid catalyzed hydroamination of MCPs and VCPs with sulfonamides also proceeds via the cyclopropylcarbinyl cation intermediates formed by the protonation of the alkene moiety of MCPs and VCPs, respectively. The ineffectiveness of amines as aminating reagents in the AuI‐catalyzed hydroamination of MCPs and VCPs was discussed.

Carboxylate Analogues of Aryl-Urea-Substituted Fatty Acids That Target the Mitochondria in MDA-MB-231 Breast Cancer Cells to Promote Cell Death.

Selective targeting of the tumor cell mitochondrion is a viable approach for the development of anticancer agents because the organelle is functionally different from the mitochondria of normal cells. We recently developed a novel aryl-urea fatty acid, 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid (1) that was found to disrupt mitochondria and to activate apoptosis in MDA-MB-231 breast cancer cells. However, there is currently little information on the structural requirements for the activity of compound 1 analogues. The present study evaluated the role of the carboxylic acid group on the anticancer activity of 1. Bioisosteric replacement of the carboxylate in 1 maintained activity. Thus, like 1, the sulfonic acid analogue 1-SA and the oxo-thiadiazole analogue 1-OT were also found to target the mitochondrion and to activate cell killing capacity. The hydroxamic acid analogue 1-HA also killed MDA-MB-231 cells, but its onset of action was slower than that of 1-SA and 1-OT. In contrast, replacement of the carboxylate with non-bioisosteric amido and methylamido groups produced analogues that minimally altered mitochondrial function and showed little capacity to decrease tumor cell viability. These findings suggest that the carboxylate moiety in the novel mitochondrially targeted agent 1 is an important determinant of the kinetics and efficacy of anticancer cell activities of compound 1 analogues. Further development of carboxylate-modified analogues of aryl-urea fatty acids as potential anticancer agents could now be warranted.

Well-Defined β-Diketiminatocobalt(II) Complexes for Alkene Cyclohydroamination of Primary Amines

A well-defined low-coordinate β-diketiminatocobalt(II) alkyl complex is reported as an active precatalyst for the selective alkene cyclohydroamination of unprotected primary amines under mild conditions (rt–90 °C). The reaction mechanism has been investigated by deuterium-labeling, kinetics, and stoichiometric experiments and in-depth computational DFT studies. On the basis of these studies, we propose a stepwise noninsertive mechanism that features a rate-determining nucleophilic attack of the amido group of a monomeric cobalt(II) amidoalkene-aminoalkene adduct intermediate to the noncoordinated pendant alkene followed by a rapid proton transfer from the coordinated aminoalkene to the cyclized adduct.

Stereoselective Allylation of Linear and Chiral β-Amino-α-Hydroxy Aldehydes: Total Syntheses of Tetraacetyl d-lyxo-, d-ribo-, and d-arabino-Phytosphingosines

The stereoselective allylations of β-amino-α-hydroxy aldehydes­ are described. Several Lewis acids (BF3·OEt2, SnCl4, TiCl4, ZnCl2­, and MgBr2·OEt2) were utilized in the allylations. The allylation of anti-β-NHCbz-α-OTBS substrate mediated by SnCl4 afforded the syn-selective­ product, while its allylation mediated by BF3·OEt2 afforded the anti-selective product. The allylation of syn-β-NHCbz-α-OTBS mediated by SnCl4 afforded the anti-selective product. The mechanism involves the chelation between the amido group and aldehyde oxygen by SnCl4, and the Felkin–Anh model by BF3·OEt2. The resulting allylation products were used for the total syntheses of tetraacetyl d-lyxo-, d-ribo-, and d-arabino-phytosphingosines.

B3LYP Study of 3-hydroxynaphthalene-2-carboxanilide para-derivatives

A systematic DFT investigation of 3-hydroxy-N-phenylnaphthalene-2-carboxamide and its sixteen para-derivatives is presented. The structural analysis showed that the energetically preferred conformation of all derivatives is practically planar and it is stabilised via intramolecular hydrogen bonds occurring between (C)O...H(3)O atomic pairs. The quantum chemically evaluated partition coefficients logarithms correlate well with Quantitative Structure-Activity Relationship models as well as with experimentally determined isocratic retention factors logarithm. Theoretical gas-phase proton affinities of amido and hydroxyl group together with selected partial atomic charges reflect the terminal phenyl substitution effect. These quantities are linearly dependent on the in vitro activity against the Mycobacterium Kansasii. Obtained linear correlation functions based on quantum chemically evaluated microscopic properties and selected experimental data may serve as the effective tool in modern drug design for the description of substitution effect.

Complexes of Fe(II) and Mn(II) with N-(2-Hydroxybenzamido)phthalimide

Complexes of Fe(II) and Mn(II) with N-(2-hydroxybenzamido)phthalimide of the general formula [M(LH)2] were synthesized and studied by IR, electronic absorption, and ESR spectroscopy and thermogravimetry. The ligand coordinates to Fe(II) and Mn(II) through the oxygen atom of the amido group which is present in the enolic form.

Tunable Robust pacs-MOFs: a Platform for Systematic Enhancement of the C2H2 Uptake and C2H2/C2H4 Separation Performance.

As a modulatable class of porous crystalline materials, metal-organic frameworks (MOFs) have gained intensive research attention in the domain of gas storage and separation. In this study, we report on the synthesis and gas adsorption properties of two robust MOFs with the general formula [Co3(μ3-OH)(cpt)3Co3(μ3-OH)(L)3(H2O)9](NO3)4(guests) n [L = 3-amino-1,2,4-triazole (1) and 3,5-diamino-1,2,4-triazole (2); Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], which show the same pacs topology. Both MOFs are isostructural to each other and show MIL-88-type frameworks whose pore spaces are partitioned by different functionlized trinuclear 1,2,4-triazolate-based clusters. The similar framework components with different amounts of functional groups make them an ideal platform to permit a systematic gas sorption/separation study to evaluate the effects of distinctive parameters on the C2H2 uptake and separation performance. Because of the presence of additional amido groups, the MOF 2 equipped with a datz-based cluster (Hdatz = 3,5-diamino-1,2,4-triazole) shows a much improved C2H2 uptake capacity and separation performance over that of the MOF 1 equipped with atz-based clusters (Hatz = 3-amino-1,2,4-triazole), although the surface area of the MOF 1 is almost twice than that of the MOF 2. Moreover, the high density of open metal sites, abundant free amido groups, and charged framework give the MOF 2 an excellent C2H2 separation performance, with ideal adsorbed solution theory selectivity values reaching up to 11.5 and 13 for C2H2/C2H4 (1:99) and C2H2/CO2 (50:50) at 298 K and 1 bar, showing potential for use in natural gas purification.

Photoinduced Multicomponent Synthesis of α-Silyloxy Acrylamides, an Unexplored Class of Silyl Enol Ethers.

The photoinduced, multicomponent reaction of α-diazoketones, silanols, and isocyanides affords α-silyloxy acrylamides, formally derived from α-keto amides. The presence of a secondary amido group makes classic preparative methods for silyl enol ethers unfeasible in this case, while the mild conditions required by this photochemical approach allow their synthesis in good yields; moreover, the general structure can be easily modified by varying each component of the multicomponent reaction. Fine-tuning of the reaction conditions (i.e., solvents, radiation, additives) can be exploited to obtain complete Z selectivity. The reactivity of this overlooked class of silyl enol ethers has been investigated, and features that could pave the way to new applications have been found.

A Stable Heroin Analogue That Can Serve as a Vaccine Hapten to Induce Antibodies That Block the Effects of Heroin and Its Metabolites in Rodents and That Cross-React Immunologically with Related Drugs of Abuse.

An improved synthesis of a haptenic heroin surrogate 1 (6-AmHap) is reported. The intermediate needed for the preparation of 1 was described in the route in the synthesis of 2 (DiAmHap). A scalable procedure was developed to install the C-3 amido group. Using the Boc protectng group in 18 allowed preparation of 1 in an overall yield of 53% from 4 and eliminated the necessity of preparing the diamide 13. Hapten 1 was conjugated to tetanus toxoid and mixed with liposomes containing monophosphoryl lipid A as an adjuvant. The 1 vaccine induced high anti-1 IgG levels that reduced heroin-induced antinociception and locomotive behavioral changes following repeated subcutaneous and intravenous heroin challenges in mice and rats. Vaccinated mice had reduced heroin-induced hyperlocomotion following a 50 mg/kg heroin challenge. The 1 vaccine-induced antibodies bound to heroin and other abused opioids, including hydrocodone, oxycodone, hydromorphone, oxymorphone, and codeine.

The Reaction between Furfuryl Alcohol and Model Compound of Protein.

To guide the preparation of protein-based adhesive, especially the soy-based adhesive, the reaction between a simple dipeptide N-(2)-l-alanyl-l-glutamine (AG), being used as a model compound of protein, and its cross-linker furfuryl alcohol were studied in this paper. The products that were prepared with furfuryl alcohol and AG under different pHs were analyzed by ESI-MS, 13C NMR, and FT-IR. It was found that the medium environment had great effects on the competition of the co-condensation reaction between furfuryl alcohol and AG and self-condensation reaction of furfuryl alcohol molecules in the mixing system with furfuryl alcohol and AG. Under alkaline conditions, both co- and self-condensation were not obviously detected. Only when the value of pH was higher than 11, were a few co-condensation reaction products gotten. The reaction occurred mainly between furfuryl alcohol and the primary amido groups of AG. Under acid conditions, both co- and self-condensation were observed. The more acid the preparation conditions were, the easier to be observed the self-condensation of furfuryl alcohol molecules would be than the co-condensation between furfuryl alcohol and AG. When the value of pH was higher than 5, both co- and self-condensation were not outstanding. In this study, under pH 3, the co- and self-condensation found equilibrium. There was a great possibility for the primary amido and aliphatic amino groups of AG molecules to react with furfuryl alcohol molecules. No reaction was detected between the secondary amido groups of AG and furfuryl alcohol.

3D-QSAR (CoMFA, CoMSIA) and Molecular Docking Studies on Histone Deacetylase 1 Selective Inhibitors.

Histone deacetylases (HDACs) are attractive therapeutic targets for the treatment of cancer and other diseases. There are numerous published patent applications till 2017. It was claimed that novel HDACIs were optimized as potential drug candidates, designed for regional or systemic release, and created as significant inhibitors. In the present study, 3D-QSAR and molecular docking were used to provide a theoretical basis for finding highly potent anti-tumor drugs. QSAR was used to generate models and predict the HDAC1 inhibitory activity using the Sybyl program (x1.2 version). Biaryl benzamides (n=73) as selective HDAC1 inhibitors were selected as our data set, which was split randomly into training (n=63) and test sets (n=10). Docking was carried out using the MOE software. Partial least square was used as QSAR model-generation method. External validation and cross-validation (leave-one-out and leave-10-out) were used as validation methods. Both CoMFA (q2, 0.663; rncv 2 , 0.909) and CoMSIA models (q2, 0.628; rncv 2 , 0.877) for training set yielded significant statistical results. The predictive ability of the derived models was examined by a test set of 10 compounds and external validation results displayed rpred 2 and rm 2 values of 0.767 and 0.664 for CoMFA and 0.722 and 0.750 for CoMSIA, respectively. The obtained models showed a good predictive ability in both internal and external validation and could be used for designing new biaryl benzamides as potent HDAC1 inhibitors in cancer treatment. The amido and amine groups of benzamide part as scaffold and the bulk groups as a hydrophobic part were key factors to improve inhibitory activity of HDACIs.

Synthesis and Characterization of an Eclipsed Digermylene as a Building Block to Construct a Cyclic Octagermylene.

The preparation of an unprecedented GeI -GeI bonded digermylene [K2 {Ge2 (μ-κ2 :η2 :η4 -2,6-(2,6-i Pr2 C6 H3 -N)2 -4-CH3 C5 H2 N)2 }] in an eclipsed conformation stabilized by two bridging diamidopyridyl ligands is presented. Although it exhibits an eclipsed conformation, the Ge-Ge bond length is 2.5168(6) Å, which is shorter than those in the trans-bent and gauche digermylenes. In combination with two pendant amido groups, the GeI2 motif is employed as a building block to assemble the first example of octagermylene [Ge4 (μ-κ2 :κ1 -2,6-(2,6-i Pr2 C6 H3 -N)2 -4-CH3 C5 H2 N)2 ]2 showing a cyclic configuration and containing three distinct types of GeI -GeI bonds.

Design and Synthesis of Chiral Diene Ligands for RhI -Catalyzed Enantioselective Arylation of N-DPP-protected Aldimines: Synthesis of the Antifungal Agent Bifonazole.

Herein we describe the design and synthesis of a novel family of bifunctional, chiral bicyclo[2.2.1]heptadiene ligands bearing aryl and secondary amido groups, and demonstrate their usefulness in the RhI -catalyzed enantioselective addition reaction of arylboronic acids to N-diphenylphosphinyl (N-DPP)-protected aldimines. Unlike the analogous RhI -catalysts comprising diene ligands substituted with aryl and carboxylic ester groups, or only with aryl groups, the addition reaction proceeded with high stereoselectivity. The protocol tolerated a range of N-DPP-aldimines and arylboronic acids, producing the desired optically active N-DPP-protected amines with yields between 31-99 % and with ee values up to 91-99 %. The synthetic utility of the method was demonstrated by the conversion of N-DPP-protected amine 3 ae into the antifungal agent, bifonazole (13).

Synthesis of new drug model has an effective antimicrobial and antitumors by combination of cephalosporin antibiotic drug with silver(I) ion in nano scale range: Chemical, physical and biological studies

The present study describes the synthesis, structural characterization and antimicrobial assays of four silver(I) complexes with four generations of the cephalosporin drugs cefradine (Cef-1; 1st), cefoxitin sodium (Cef-2; 2nd), cefotaxime sodium (Cef-3; 3rd) and cefepime hydrochloride (Cef-4; 4th). The microanalytical analyses led to 1:1 (Ag+/ligand) compositions, suggesting the speculated general formulas [Ag2(Cefn)2] where n=1st, 2nd, 3rd, or 4th. Infrared and proton NMR spectroscopic measurements indicated all Cefn ligands coordination to Ag+ through the oxygen atoms of the carbonyl β-lactam and carboxylate groups, whereas oxygen atom of amido (NH-CO) group and nitrogen atom of amino group of does not participate in the chelation with the silver metal ions. The proposed coordination modes shows the bridging case of coordination, that the two Ag+ ions linked bridge between the oxygen atom of the carbonyl β-lactam and carboxylate groups of two Cefn ligands. Antimicrobial assessments indicated that silver(I) complexes are more active against some kind of bacteria (Gram-positive bacteria, Staphylococcus aureus (MSSA 22) and Bacillus subtilis (ATCC 6051), and two Gram-negative bacteria, Escherichia coli (K 12) and Pseudomonas aeruginosa (MTCC 2488) than the parents Cefn drugs. The nature of the synthesized silver(I) nanoparticles AgNPs compounds were analyzed using UV–Vis spectrophotometer, solid X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The particle size of AgNPs compounds were within 113–173nm nano scale range.

Enantioselective Conjugate Addition Catalyzed by a Copper Phosphoramidite Complex: Computational and Experimental Exploration of Asymmetric Induction

The stereochemical role of the phosphoramidite ligand in the asymmetric conjugate addition of alkylzirconium species to cyclic enones has been established through experimental and computational studies. Systematic, synthetic variation of the modular ligand established that the configuration of the binaphthol backbone is responsible for absolute stereocontrol, whereas modulation of the amido substituents leads to dramatic variations in the level of asymmetric induction. Chiral amido substituents are not required for enantioselectivity, leading to the discovery of a new family of easily synthesized phosphoramidites based on achiral amines that deliver equal levels of selectivity to Feringa’s ligand. A linear correlation between the length of the aromatic amido groups and experimentally determined enantioselectivity was uncovered for this class of ligand, which, following an optimization, led to highly selective ligands (up to 94% ee) with naphthyl rather than phenyl groups. An electronic effect of stericall...