Enhanced clickability of doubly sterically-hindered aryl azides

Steric character is one of the most fundamental factors to determine the reactivity of the substrate in organic synthesis. In bimolecular reaction, the sterically-bulky group situated close to the reactive center generally prevents the approach of the reaction partner retarding the bond formation. This report describes, to the contrary, significantly enhanced reactivity of 2,6-disubstituted phenyl azides observed in catalyst-free 1,3-dipolar cycloaddition with alkynes, unexpectedly reacting faster than unsubstituted phenyl azide and even more faster than unhindered alkyl azide, despite the steric hindrance adjacent to the reactive azido group. Experimental and computational studies have indicated that the steric hindrance eliciting the inhibition of resonance between azido group and the aromatic ring is the primary cause of this apparently-paradoxical phenomenon. This is the first type of steric acceleration, indicating a possibility of designing a highly reactive functional group by strategically locating it in the sterically-congested environment

Transformation of Cocrystalline Phase in Binary Mixture of Trimethoprim and Sulfamethoxazole by Slurry Technique

The purpose of this work was to characterize and investigate the transformation of cocrystalline phase in binary mixture of trimethoprim and sulfamethoxazole induced by slurry technique and to establish the rate of transformation at various temperatures. Cocrystallization was performed simply by adding distilled water as solvent to equimolar binary mixture of powder trimethoprim and sulfamethoxazole. A new solid phase was characterized by thermomicroscopy, scanning electron microscope, powder X-ray diffraction, differential scanning calorimetry. The rate of transformation in slurry was studied as function of storage temperature, measured by powder X-ray diffractometry. Physical characterization showed that the trimethoprim and sulfamethoxazole cocrystalline phase had a unique thermal, powder X-ray diffraction property. Cocrystals prepared by slurry technique were similar in PXRD pattern to those prepared by solvent methods. The transformation to cocrystalline phase was accelerated by increasing the temperature of storage. It could be concluded that slurry could be carried out to induce a new equimolar cocrystalline phase between sulfamethoxazole and trimethoprim. The rate of transformation to cocrystalline phase was affected by the temperature of storage. Keywords: Trimethoprim; sulfamethoxazole; cocrystalline phase; slurry technique and rate of transformation

Evaluasi Peran Sistem Pengendalian Manajemen untuk Meminimalkan Konflik pada Badan USAha Keluarga “K” di Tulungagung

Penelitian ini bertujuan untuk mengevaluasi peran sistem pengendalian manajemen untuk meminimalkan konflik. Penelitian ini merupakan applied research yang dilakukan menggunakan pendekatan kualitatif. Objek penelitian dalam penelitian ini yaitu badan USAha keluarga “K” di Tulungagung. Sumber data untuk penelitian ini adalah narasumber yang terdiri dari direktur, supervisor dan karyawan. Metode pengumpulan data yang digunakan adalah wawancara semi structured, observasi, dan analisis dokumen. Hasil evaluasi yang dilakukan dalam penelitian ini menunjukkan bahwa sistem pengendalian manajemen yang diterapkan oleh badan USAha “K” sudah berhasil meminimalkan konflik seperti substantive conflict. Namun ada beberapa bentuk pengendalian manajemen yang masih memiliki kelemahan yang berpotensi dan telah menimbulkan process conflict dan affective conflict khususnya di badan USAha “K” saat ini

Hasil cek similarity " X-Ray Diffraction And Vibrational Spectroscopic Studies Of The Intermolecular Interactions On The Grinding And Compaction Behaviours Of Lopinavir And Ritonavir Crystals"

Lopinavir (LPV) and ritonavir (RTV) are anti-viral drugs used in combination and commonly prepared through hot-melt extrusion techniques. Mechanical processes are greatly involved, including blending and milling. Therefore, the crystal behaviour of LPV and RTV under the mechanical process is an interesting study. Here, the LPV, RTV, and their mixtures were processed by two different treatments: grinding and compression processes. The solid-state properties of the drugs were evaluated by powder x-ray diffraction (PXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). Single-crystal XRD analysis was also carried out to confirm the packing structure in the crystal lattice. It was observed that LPV was very sensitive to the grinding process, where it tends to form an amorphous solid in both the pure and mixture forms. On the other hand, RTV has a very stable crystalline structure and was able to retain its crystallinity even under grinding. Both LPV and RTV were observed to be quite stable under compression, where both retained their crystalline form with only slight changes in their d-spacing values. This study highlighted the molecular origin of LPV and RTV crystal behaviour after grinding and compression processes

Potassium clavulanate

The title salt, K+·C8H8NO5 − [systematic name: potassium (2R,5R,Z)-3-(2-hy­droxy­ethyl­idene)-7-oxo-4-oxa-1-aza­bicyclo­[3.2.0]heptane-2-carb­oxyl­ate], a widely used β-lactam anti­biotic, is usually chemically unstable even in the solid state owing to its tendency to be hydrolysed. In the crystal structure, the potassium cations are arranged along the a axis, forming inter­actions to the carboxyl­ate and hy­droxy groups, resulting in one-dimensional ionic columns. These columns are arranged along the b axis, connected by O—H⋯O hydrogen bonds, forming a layer in the ab plane