Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

The efficient synthesis of two new stereoisomeric 3-aminocyclooctanetriols and their new halocyclitol derivatives starting from cis,cis-1,3-cyclooctadiene are reported. Reduction of cyclooctene endoperoxide, obtained by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc yielded a cyclooctene diol followed by acetylation of the hydroxy group, which gave dioldiacetate by OsO4/NMO oxidation. The cyclooctane dioldiacetate prepared was converted to the corresponding cyclic sulfate via the formation of a cyclic sulfite in the presence of catalytic RuO4. The reaction of this cyclic sulfate with a nucleophilic azide followed by the reduction of the azide group provided the target, 3-aminocyclooctanetriol. The second key compound, bromotriol, was prepared by epoxidation of the cyclooctenediol with m-chloroperbenzoic acid followed by hydrolysis with HBr(g) in methanol. Treatment of bromotriol with NaN3 and the reduction of the azide group yielded the other desired 3-aminocyclooctanetriol. Hydrolysis of the epoxides with HCl(g) in methanol gave stereospecifically new chlorocyclooctanetriols.

N-Glycosylation with Sulfoxide Donors for the Synthesis of Peptidonucleosides

<p>We report here the synthesis of peptidonucleosides obtained after glycosylation of different pyrimidine bases with glucopyranosyl donors carrying an azide group at the C4 position. A methodological study involving different anomeric leaving groups (acetate, phenylsulfoxide and <i>ortho</i>-hexynylbenzoate) showed that a sulfoxide donor in combination with trimethylsilyl triflate as the promoter led to the best yields.</p>

N-Glycosylation with Sulfoxide Donors for the Synthesis of Peptidonucleosides

<p>We report here the synthesis of peptidonucleosides obtained after glycosylation of different pyrimidine bases with glucopyranosyl donors carrying an azide group at the C4 position. A methodological study involving different anomeric leaving groups (acetate, phenylsulfoxide and <i>ortho</i>-hexynylbenzoate) showed that a sulfoxide donor in combination with trimethylsilyl triflate as the promoter led to the best yields.</p>

3-R-4-(5-methyleneazide-1,2,4-oxadiazol-3-yl)furazan and its ionic salts as low-sensitivity and high-detonation energetic materials

As an environmentally friendly energetic group, the azide group can not only control the melting point but also increase the energy of the compound. Therefore, the design and synthesis of...

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

The efficient synthesis of two new stereoisomeric 3-aminocyclooctanetriols and new halocyclitol derivatives of them starting from cis,cis-1,3-cyclooctadiene are reported. Reduction of cyclooctene endoperoxide, obtained by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc yielded a cyclooctene diol followed by acetylation of the hydroxyl group, which gave dioldiacetate by OsO4/NMO oxidation. The cyclooctane dioldiacetate prepared was converted to the corresponding cyclic sulphate via the formation of a cyclic sulphite in the presence of catalytic RuO4. Reaction of this cyclic sulphate with a nucleophilic azide followed by the reduction of the azide group provided the target, 3-aminocyclooctanetriol. The second key compound, bromotriol, was prepared by epoxidation of the cyclooctene diol with m-chloroperbenzoic acid followed by hydrolysis with HBr(g) in methanol. Treatment of bromotriol with NaN3 and the reduction of the azide group yielded the other 3-aminocyclooctanetriol desired. Hydrolysis of the epoxides with HCl(g) in methanol gave stereospecifically new chlorocyclooctanetriols.

Recent developments in the synthesis of tetrazoles and their pharmacological relevance

Abstract:: The heterocycle ring tetrazole is an important moiety relevant to medicinal chemistry since it is present in some drugs with clinical importance. Its primary biological activity is being a bioisosteric analogue of the carboxylic acid and cisamide groups. Its metabolic stability and other physicochemical properties make it an attractive structure for designing and synthesizing new pharmaceuticals. The biological activity of tetrazoles is quite extensive and includes antiviral, antibacterial, anticancer, antifungal, and antioxidant properties; all of them are discussed in this review. The most effective way to obtain tetrazoles is by azide derivatives, either in the starting materials like the cycloaddition [3 + 2] of organic azides and nitriles or by preparing a reactive imidoyl azide intermediate. The nucleophilic behavior of the azide group is discussed when the raw materials include isocyanides. Some other methods include alternative synthetic routes like thermoslysis. This review also highlights some of the developments regarding the use of different heterogeneous catalysts to synthesize different tetrazole derivatives.

Crystal structure of (N^C) cyclometalated AuIII diazide at 100 K

The title compound, an (N^C)-cyclometalated gold(III) diazide, namely, diazido[5-ethoxycarbonyl-2-(5-ethoxycarbonylpyridin-2-yl)phenyl-κ2 C 1,N]gold(III), [Au(C17H16NO4)(N3)2] or Au(ppyEt)(N3)2, was synthesized by reacting Au(ppyEt)Cl2 with NaN3 in water for 24 h. The complex has been structurally characterized and features a gold center with a square-planar environment. The Au—N(azide) bond lengths are significantly different depending on the influence of the atom trans to the azide group [Au—N(trans to C) of 2.067 (2) Å versus Au—N(trans to N) of 2.042 (2) Å]. The azide groups are twisted in-and-out of plane by 56.2 (2)°.

Efficient β-Carboline Alkaloid-Based Probe for Highly Sensitive Imaging of Endogenous Glutathione in Wheat Germ Tissues

Discriminative detection of GSH is achieved by employing a highly sensitive and selective fluorescent probe (KL-DN) that bears β-carboline alkaloid as a potential fluorophore and an azide group as the recognition unit. A rapid fluorescence off-on change is caused by special redox reaction; KL-DN has the capability of monitoring endogenous GSH in wheat germ tissues, indicating that this probe holds great potential for biological applications in plant tissues.

Synthesis of Organic–Inorganic Hybrid Nanocomposites via a Simple Two-Phase Ligands Exchange

The surface of nanocrystals (NCs) was precisely engineered with bifunctional ligands via a simple yet effective two-phase ligand exchange strategy where the introduction of bifunctional ligands and displacement of insulating aliphatic ligands are simultaneously occurred. This is advantageous compared to conventional ligands exchange procedure where the desired ligands are often introduced through two-step processes after treating NC surface with short mobile ligands such as pyridine or short amines. In this study, 4-azidobenzoic acid possessing carboxylic acid for binding with NCs and azide group for chemical coupling was utilized as bifunctional ligands. A correlation between the concentration and the efficiency of ligands replacement was corroborated by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (1H NMR) spectroscopy measurement. Lastly, organic–inorganic nanocomposites were crafted via click coupling between 1-octyne and azidobenzoic acid capped CdSe NCs. The success of coupling was substantiated by FTIR and 1H NMR.

Synthesis of One New Sugar Imine Molecule

In this research, the molecule Nand#39;-((E)-5-methoxy-2-((1-((2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-4,5-dihydro-1H-1,2,3-triazol-4-yl)methoxy) benzylidene)-4-methyl-1,2,3-thiadiazole-5-carbohydrazide were synthesized and characterized by several conventional analysis methods. Its physical properties and thermal stability was studied. The synthesis was conducted based on D-glucose using concept of click chemistry reaction mechanism. Some of the reaction was conducted using microwave irradiation. The synthesis steps initiated by adding propargyl bromide to 2- hydroxy-5-methoxy benzaldehyde under vigorous measure of moister isolated environment to produce propargyl ether(5-methoxy-2-(prop-2-yn-1-yloxy)benzaldehyde) 3 in which has terminal triple bond. In parallel a glycocyl azide was prepared by applying glycocyl acetate (acetate for protection) via bromination and then substituted by treatment with sodium azide to produce glycocyl azide in which actively reacted with terminated triple bond by click reaction in the present of Cu(II) catalyst. The coupling reaction of terminal alkyle group in compound 3 with azide group of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-azidotetrahydro-2H-pyran-3,4,5-triyl triacetate) has given high yield of triazole. The produced triazole molecule is triazole(2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(4-((2-formyl-4-methoxy)methyl)-1H-1,2,3-triazole-1-yl)tetrahydro-2H-pyran-3,4,5,-triyacetate) 7 undergoes further reaction to substitute carbonyl of the aromatic with hydrazide by applying 4-methyl-1,2,3-thiadiazole-5-carbohydrazide reagent. The glycocyl acetate was de-esterifide by sodium methoxide to remove the acetate protection. The structure of all these synthesized molecules was confirmed by FTIR, H1NMR, C13 NMR.