A microwave-assisted and heteropolyacids-catalysed cyclocondensation reaction for the synthesis of 4(3H)-quinazolinones

We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction.     

Change in Collagen Fibril Diameter Distribution of Bovine Anterior Cruciate Ligament upon Injury Can Be Mimicked in a Nanostructured Scaffold

More than 200,000 people are suffering from Anterior Cruciate Ligament (ACL) related injuries each year in the US. There is an unmet clinical demand for improving biological attachment between grafts and the host tissue in addition to providing mechanical support. For biological graft integration, it is important to provide a physiologically feasible environment for the host cells to enable them to perform their duties. However, behavior of cells during ACL healing and the mechanism of ACL healing is not fully understood partly due to the absence of appropriate environment to test cell behavior both in vitro and in vivo. This study aims at (i) investigating the change in fibril diameter of bovine ACL tissue upon injury and (ii) fabricating nanofiber-based scaffolds to represent the morphology and structure of healthy and injured ACL tissues. We hypothesized that distribution and mean diameter of ACL fibrils will be altered upon injury. Findings revealed that the collagen fibril diameter distribution of bovine ACL changed from bimodal to unimodal upon injury with subsequent decrease in mean diameter. Polycaprolactone (PCL) scaffold fiber diameter distribution exhibited similar bimodal and unimodal distribution behavior to qualitatively represent the cases of healthy and injured ACL, respectively. The native ACL tissue demonstrated comparable modulus values only with the aligned bimodal PCL scaffolds. There was significant difference between mechanical properties of aligned bimodal and unaligned unimodal PCL scaffolds. We believe that the results obtained from measurements of diameter of collagen fibrils of native bovine ACL tissue can serve as a benchmark for scaffold design.     

A mild and efficient route to 2-benzyl tryptamine derivatives via ring-opening of β-carbolines

We described a mild and easy method, in two steps, by which various benzyl groups were introduced in the C-2 position of tryptamine. The first step consisted on the synthesis of β-carbolines, starting from tryptamine derivatives, by a Pictet-Spengler reaction. Ring-opening of the β-carbolines, by hydrogenation, led to the desired 2-substituted benzyl tryptamine indole products. A supplementary step of alkylation could be realized to give N-alkyl-2-substituted benzyl tryptamine. During these reactions, nitrogen atoms require no step of protection.     

Synthesis,characterization, and evaluation of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine as biological agents

Five new silver(I) complexes were synthesized with mixed ligands of thiosemicarbazone derivatives and diphenyl(p-tolyl)phosphine in search of new biologically active compounds. A CHN elemental analysis, powder X-ray diffraction (PXRD) data and several spectroscopic techniques such as Fourier-transform infrared spectroscopy, energy-dispersive X-ray, ¹H, ¹³C, and ³¹P{¹H} NMR were performed to elucidate the structure of these complexes. Elemental analysis suggested that the stoichiometry of the complexes formed by the reaction of silver nitrate with thiosemicarbazone in the presence of (p-tolyl)PPh₂ was indeed 1:2:1 molar ratio. The silver ions were discovered to be coordinated to the sulfur of thiosemicarbazone and phosphorus of (p-tolyl)PPh₂, having a tetrahedral geometry based on the spectroscopic data obtained. The PXRD patterns were studied to see the degree of crystallinity of the complexes. The in vitro antiproliferative activity of these complexes was investigated toward the MDA-MB-231 and MCF-7 breast cancer cell lines, as well as the HT-29 colon cancer cell line, which yielded IC₅₀ values in low micromolar range. The antiplasmodial activity of these complexes was also examined against chloroquine-resistant Plasmodium falciparum parasite which demonstrated good activity and further tested for their selectivity index.     

Anticorrosive and Microbial Inhibition Performance of a Coating Loaded with Andrographis paniculata on Stainless Steel in Seawater

With the trend for green technology, the study focused on utilizing a forgotten herb to produce an eco-friendly coating. Andrographis paniculata or the kalmegh leaves extract (KLE) has been investigated for its abilities in retarding the corrosion process due to its excellent anti-oxidative and antimicrobial properties. Here, KLE was employed as a novel additive in coatings and formulations were made by varying its wt%: 0, 3, 6, 9, and 12. These were applied to stainless steel 316L immersed in seawater for up to 50 days. The samples were characterized and analyzed to measure effectiveness of inhibition of corrosion and microbial growth. The best concentration was revealed to be 6 wt% KLE; it exhibited the highest performance in improving the ionic resistance of the coating and reducing the growth of bacteria.