Cu(OTf)2-Catalyzed 1,2,3-triazole-ring-controlled selective phenolic O–H bond methylthiomethylation

Copper-catalyzed selective methylthiomethylation of 1,4-disubstituted 1,2,3-triazole phenols using DMSO as a methylthiomethylation reagent was achieved. Controlled by the triazole ring, the ortho-phenolic hydroxyl in N(1) aryl can be selectively methylthiomethylated, generating functionalized 1,4-disubstituted 1,2,3-triazoles bearing aryl methylthiomethyl ether fragment.     

L ‐Proline‐Promoted CuI‐Catalyzed C‐S Bond Formation between Aryl Iodides and Thiols

An improved, mild procedure for the CuI‐catalyzed coupling reactions of aryl iodides with aliphatic and aromatic thiols, using L ‐proline as the ligand, is reported. This procedure is noteworthy given its high generality and exceptional level of functional group toleration.     

Direct Pyridazine Ring Synthesis from β-Cyano Esters. A Facile Synthesis of the Derivatives of Tetrahydro-3,6-pyridazinedione 3-Hydrazone

4-Substituted tetrahydro-3,6-pyridazinedione 3-hydrazones (2) (or their 3-hydrazino tautomers 3), useful intermediates in the synthesis of bicyclic pyridazine derivatives, were prepared in satisfactory yields in the reaction of the corresponding alkyl 3-substituted 3-cyanopropionates with hydrazine hydrate.     

An Improving Method For the Preparation of Ethynylferrocene

Ethynylferrocene was prepared in satisfactory yield by reaction of formylferrocene with triphenylphosphine and carbon tetrachloride followed by dehydrohalogenation in presence of n-butyllithum. The reaction condition is mild and the reaction time is much shorter. The method is convenient and economical.     

Synthesis of [1,2,3]Triazolo[5,1-a]isoquinoline Derivatives via a Selective Cascade Cyclization Sequence of 1,2-bis(Phenylethynyl)benzene Derivatives

A direct, concise, synthetic method for the generation of [1,2,3]triazolo[5,1-a]isoquinoline derivatives, using a selective cascade cyclization of unsymmetrical substituted 1,2-bis(phenylethynyl)benzene derivatives with NaN₃, has been developed. The reaction gave different substituted [1,2,3]triazolo[5,1-a]isoquinolines in moderate to good yields. It was found that the substituents on the alkynes were important for the selectivities of the cascade cyclization sequences.     

Practical Approach for Synthesis of 2-Amino-benzoxazole in Water

A practical copper-catalyzed amination of benzoxazole with secondary amine in water has been developed. This reaction has proved to be effective to some cyclic amines, and the substituted group of nitrogen has a great impact on the amination reaction. A copper-catalyzed/ amine-induced ring opening of the benzoxazole and recyclization/oxidation mechanism was also proposed.     

Three New C19‐Diterpenoid Alkaloids from Aconitum forrestii

A further study of the alkaloid constituents of Aconitum forrestii led to the isolation of three new C₁₉‐diterpenoid alkaloids, named 14‐acetoxy‐8‐O‐methylsachaconitine ( 1 ), 14‐acetoxyscaconine ( 2 ), and 8‐O‐ethylcammaconine ( 3 ). Their structures were determined by UV, IR, and MS, 1D‐ and 2D‐NMR analyses.     

DNAzyme based electrochemical sensors for trace uranium

We have developed a uranyl-specific DNAzyme that was immobilized on the surface of a gold electrode to give a highly sensitive and selective biosensor for uranyl ion. The typical DNAzyme system consisted of the RNA (rA) as the substrate (ADNA), and the other strand is the enzyme (TDNA) with a ferrocene (Fc). The presence of uranyl ion induces the cleavage of the DNA substrate strand at the rA position to form two fragments. The Fc unit thereby is released from the surface of the electrode, and this results in a decreased peak current. This electrochemical biosensor has a dynamic range from 2 nM to 14 nM of uranyl ion, with a detection limit at 1 nM. It exhibits high sensitivity and excellent selectivity over other metal ions, and thus represents a promising technique for simple, fast, on-site, and real-time electrochemical sensing of UO₂(II) ion. It also serves as a guide in choosing different methods for designing electrochemical sensors for other metal ions.

Computational design and structure-property relationship studies on (I2GaN3) n (n = 1–4) clusters

To look for the single-source precursors, density functional theory calculations were performed to study structures, IR spectra, and stabilities of the possible isomers for the clusters (I₂GaN₃) _n (n = 1–4). It is found that the optimized (I₂GaN₃) _n (n = 2–4) clusters all possess cyclic structure containing Ga-N_α-Ga linkages, and azido group in azides has linear structure. Trends in geometrical parameters with the oligomerization degree n are discussed. The IR spectra are obtained and assigned by vibrational analysis. Thermodynamic properties are linearly correlated with the oligomerization degree n as well as the temperature. Mean-while, the oligomerizations can occur spontaneously at 298.2 K.     

Ferric(III) Nitrate Supported on Kieselguhr: A New Reagent for Selective Oxidation of Alcohols

A selective and effective oxidation of alcohols into the corresponding aldehydes and ketones, respectively, with a new reagent, ferric(III) nitrate supported on kieselguhr, under heterogeneous conditions is reported.