Versatile C(sp2)−C(sp3) ligand couplings of sulfoxides for the enantioselective synthesis of diarylalkanes

The reaction of chiral (hetero)aryl benzyl sulfoxides with Grignard reagents affords enantiomerically pure diarylalkanes in up to 98% yield and greater than 99.5% enantiomeric excess. This ligand coupling reaction is tolerant to multiple substitution patterns and provides access to diverse areas of chemical space in three operationally simple steps from commercially available reagents. This strategy provides orthogonal access to electron-deficient heteroaromatic compounds, traditionally synthesised via transition metal-catalysed cross-couplings, which circumvents common issues associated with proto-demetalation and β-hydride elimination

Ligand Coupling Reactions Through Hypervalent and Similar Valence-Shell Expanded Intermediates

A new concept of Iigand coupling reactions through hypervalent and similar valence-shell expanded interrnediates is presented with numerous experimental data to support the argument, especially reactions involving the attack of nucleophiles on the tricoordinate sulfur atom

Isolation, Modification and Characterization of Tiger-Nut, Maize, Cassava and Potato Starch

Four different sources of starchy foods were used for the isolation of starch using commercially cheap and readily available chemical-hypo (3.5 % active Chlorine). The isolated starch was modified through NaIO4 oxidation under mild reaction conditions. Carbonyl functional group test was employed for confirmation of the success of oxidation. FT-IR and Scanning Electron Microscopy (SEM) were used for functional group identification and morphological examination of both modified and native samples to further confirm the success of modification. The appearance of the carbonyl band at 1747-1746 cm-1 and 1647 – 1637 cm-1 indicated the successful synthesis of oxidized starch. Proximate results showed that the isolated starches were rich in mineral content: 0.25-2.13; crude fibre: 0.85-3.31; fat: 0.23-0.28 and energy: 1331-1410. The study showed that commercial hypo could be a useful replacement for metabisulphite for starch isolation without side effects on starch properties. SEM images showed that morphological architecture of granules was not destroyed during surface functionalization. Characteristic and nutritional features of the oxidized starch showed that it could find useful applications in food and pharmaceutical industries

Glutathione Peroxidase-Based Amperometric Biosensor for the Detection of S -Nitrosothiols

A new biosensor is described for the detection of S -nitrosothiols (RSNOs) based on their decomposition by immobilized glutathione peroxidase (GPx), an enzyme containing selenocysteine residue that catalytically produces nitric oxide (NO) from RSNOs. The enzyme is entrapped at the distal tip of a planar amperometric NO sensor. The new biosensor shows good sensitivity, linearity, reversibility, and response times towards various RSNO species in PBS buffer, pH 147.4 . In most cases, the response time is less than 5 14min, and the response is linear up to 6 ΜM of the tested RSNO species. The lowest detection limit is obtained for S -nitrosocysteine (CysNO), at approx. 0.2 14ΜM. The biosensor's sensitivity is not affected by the addition of EDTA as a chelating agent; an advantage over other potential catalytic enzymes that contain copper ion centers, such as CuZn-superoxide dismutase and xanthine oxidase. However, lifetime of the new sensor is limited, with sensitivity decrease of 50% after two days of use. Nonetheless, the new amperometric GPx based RSNO sensor could prove useful for detecting relative RSNO levels in biological samples, including whole blood.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55900/1/2043_ftp.pd

Isolation of stable non cyclic 1,2-disulfoxides: revisiting the thermolysis of S-aryl sulfinimines

The thermolysis of S-aryl sulfinimines is shown to generate 1,2-disulfoxides and disulfides via initial Cope elimination, dimerisation of the produced sulfenic acid to a thiosulfinate, and subsequent disproportionation of the thiosulfinate

Chronic instability of the anterior tibiofibular syndesmosis of the ankle. Arthroscopic findings and results of anatomical reconstruction

<p>Abstract</p> <p>Background</p> <p>The arthroscopic findings in patients with chronic anterior syndesmotic instability that need reconstructive surgery have never been described extensively.</p> <p>Methods</p> <p>In 12 patients the clinical suspicion of chronic instability of the syndesmosis was confirmed during arthroscopy of the ankle. All findings during the arthroscopy were scored. Anatomical reconstruction of the anterior tibiofibular syndesmosis was performed in all patients. The AOFAS score was assessed to evaluate the result of the reconstruction. At an average of 43 months after the reconstruction all patients were seen for follow-up.</p> <p>Results</p> <p>The syndesmosis being easily accessible for the 3 mm transverse end of probe which could be rotated around its longitudinal axis in all cases during arthroscopy of the ankle joint, confirmed the diagnosis. Cartilage damage was seen in 8 ankles, of which in 7 patients the damage was situated at the medial side of the ankle joint. The intraarticular part of anterior tibiofibular ligament was visibly damaged in 5 patients. Synovitis was seen in all but one ankle joint. After surgical reconstruction the AOFAS score improved from an average of 72 pre-operatively to 92 post-operatively.</p> <p>Conclusions</p> <p>To confirm the clinical suspicion, the final diagnosis of chronic instability of the anterior syndesmosis can be made during arthroscopy of the ankle. Cartilage damage to the medial side of the tibiotalar joint is often seen and might be the result of syndesmotic instability. Good results are achieved by anatomic reconstruction of the anterior syndesmosis, and all patients in this study would undergo the surgery again if necessary.</p