Simple preparations of 4 and 5-iodinated pyrazoles as useful building blocks

The pyrazole nucleus has recently become a recurrent scaffold in the research fields of CropScience and oncology. We report here the preparation of an array of 4- and 5-iodinated pyrazole derivatives, such as 4-iodo-3-trifluoromethylpyrazole or ethyl 5-iodo-4-carboxy-3-trifluoromethylpyrazoles. This work provide access to many new pyrazole derivative, including 11 original out of 16 iodinated building blocks, thus opening accesses to new chemical entities featuring a pyrazole nucleus.     

Process Development for Separation of Conformers from Derivatives of Resorcin[4]arenes and Pyrogallol[4]arenes

Macrocyclic compounds, such as resorcin[4]arenes and pyrogallol[4]arenes, have proven to be useful building blocks in the construction of supramolecular organic frameworks (SOFs) because of their unique bowl‐like shape and ability to interact through variety of intermolecular interactions. Herein, we report the synthesis and crystal structures of two functionalized resorcin[4]arenes and pyroagllol[4]arenes, 4‐hydroxyphenylresorcin[4]arenes, and 4‐hydroxyphenylpyrogallol[4]arenes. These phenyl‐functionalized macrocycles usually have different conformers, such as cone, boat, chair, saddle, and diamond. The successful separation of predominant conformers from the crude product was carried out with solvent‐extraction technique. The shape and molecular arrangement of these conformers in the individual crystal structure was verified with single‐crystal X‐ray diffraction studies.     

On the Loewy length of the center of a block with elementary abelian defect groups

Let G be a finite group and k an algebraically closed field of characteristic p. In this paper we investigate the Loewy structure of centers of indecomposable group algebras kG, for groups G with a normal elementary abelian Sylow p-subgroup. Furthermore, we show a reduction result for the case that a normal abelian Sylow p-subgroup is acted upon by a subgroup of its automorphism group; this is fundamental in providing generic formulae for the Loewy lengths considered.     

DAIB/TEMPO mediated synthesis of anomeric lactones from anomeric hydroxides

Anomeric sugar lactones are important intermediates for the synthesis of C-glycosides, carbasugars and iminosugars. Herein we present a facile synthesis of anomeric sugar lactones via the DAIB/TEMPO oxidation of anomeric hydroxides. The reactions are very efficient providing the lactones in 2–4 h in almost quantitative yields. The reaction conditions tolerate several common protecting groups used in carbohydrate synthesis. The advantages of the present methodology over previously reported non-metal based methods have also been demonstrated through head to head comparisons. Finally, we have applied the reaction for the sequential conversion of anomeric thioglycosides to the lactones through sequential reactions with NBS followed by the oxidation with DAIB/TEMPO.     

Sm2Co17 magnet blocks for the in-vacuum undulators (IVU20) at the SSRF

The design and development status of Sm<,2>Co<,17> magnet blocks for two in-vacuum undulators (IVU20) at the SSRF with the same hybrid design has been described. By the technological improvement of some processes and comparison with the experimental Sm<,2>Co<,17> magnet blocks for the IVU25A, magnetic properties such as the intrinsic coercive force H<,ci> and the average magnetic moment M are increased, the bend point magnetic field H<,k> value and pass rate are significantly increased, and the magnetic field uniformity of the magnet blocks are significantly improved. The basic developmental method of high uniformity Sm<,2>Co<,17> magnet blocks for IVU20 is presented. The magnetic field qualities of the magnet blocks, including the magnetic property, the magnetic moment distribution, the magnetization deviation angle and the magnetic field uniformity, basically satisfy the specifications of the two IVU20 in-vacuum undulators.     

Studies on the Conformation of Polyhydroxyalkylpyrazolo (3,4-b) Quinoxalines

¹H NMR spectral studies on polyhydroxyalkylpyrazolo-(3,4-b)-quinoxaline derivatives of sugars having five to seven carbon atoms have shown that the polyhydroxyalkyl chain exists in a conformation in which a hydrogen bond is formed between the l'-hydroxyl group and N-2 of the pyrazolo(3,4-b)-quinoxaline base moiety. The polyhydroxyalkyl chain exists in the planar zigzag conformation, where no 1,3 syn axial interaction is present. Substitution in the base moiety did not change the extent of the population of the planar zigzag conformation.     

Synthesis and Practical Use of 1H‐1,2,3‐Benzotriazole‐5‐carboxaldehyde for Reductive Amination

A reliable synthetic procedure to obtain multigram quantities of 1H‐1,2,3‐benzotriazole‐5‐carboxaldehyde has been developed. This material can be used in reductive amination reactions with primary and secondary amines to provide good to excellent yields of the desired products without protection of the starting material.