Convenient and Scalable Synthesis of 2,3-Dihydroquinazolin-4(1H)-one Derivatives and Their Anticancer Activities

An efficient and mild InBr₃-catalyzed approach to synthesize 2,3-dihydroquinazolin-4(1H)-one derivatives (3a–3aa) has been developed. Notably, all the products were isolated by recrystallization and the reaction is accessible on a gram scale. Moreover, the reactions only require 10–60 min. All the synthesized compounds were evaluated for their in vitro anticancer activity against four human cancer cell lines.     

Tailoring approach for exploring electron densities and electrostatic potentials of molecular crystals

Experimental and theoretical studies of electron densities and the corresponding derived entities such as electrostatic potentials have been the primary means of understanding the chemical nature and electronic properties of crystalline substances. Conventional crystal calculation methods such as the embedded cluster models are capable of performing calculations on small and medium-sized molecules, while periodic ab initio methods can treat crystals with up to 200 atoms per unit cell. A linear scaling method, viz. the molecular tailoring approach, has recently been developed for obtaining ab initio quality one-electron properties. In the present study, the molecular tailoring approach is employed to generate electron density, electrostatic potential and interaction density maps with the ibuprofen crystal as a test case. The interaction density and electrostatic potential maps produced in the present work succinctly bring out the actual crystalline environment around a given reference molecule by including the interactions with atoms in its neighborhood. The results obtained from the molecular tailoring approach may thus be expected to enhance our understanding of the environment in the crystalline material with reasonably small computational effort.Contribution to the Jacopo Tomasi Honorary Issue     

One‐Pot Synthesis of Hydrophobically Modified Iminosugar C‐Alkynylglycosides: Facile Synthesis of Polyhydroxy Tetrahydroindolizines

A mild and efficient one‐pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugar C‐alkynylglycosides. The generality of this methodology has been demonstrated with a wide variety of amines and copper acetylides. This one‐pot method has been exploited in the synthesis of new class of DNA cross‐linking agents, polyhydroxy 1‐vinyl‐tetrahydroindolizine derivatives.     

Total Synthesis of (+)‐Cryptocaryalactone and of a Diastereoisomer of (+)‐Strictifolione via Ring‐Closing Metathesis (RCM) and Olefin Cross‐Metathesis (CM)

Ring‐closing metathesis (RCM) and olefin cross‐metathesis (CM) reactions were used as the key steps for the synthesis of (+)‐cryptocaryalactone ( 1 ) and the first synthesis of the diastereoisomer 3 of (+)‐strictifolione, starting from the commercially available L ‐malic acid (=(2S)‐2‐hydroxybutanedioic acid).     

Vibrational spectroscopy differentiates between multipotent and pluripotent stem cells

Over the last few years, there has been an increased interest in the study of stem cells in biomedicine for therapeutic use and as a source for healing diseased or injured organs/tissues. More recently, vibrational spectroscopy has been applied to study stem cell differentiation. In this study, we have used both synchrotron based FTIR and Raman microspectroscopies to assess possible differences between human pluripotent (embryonic) and multipotent (adult mesenchymal) stem cells, and how O(2) concentration in cell culture could affect the spectral signatures of these cells. Our work shows that infrared spectroscopy of embryonic (pluripotent) and adult mesenchymal (multipotent) stem cells have different spectral signatures based on the amount of lipids in their cytoplasm (confirmed with cytological staining). Furthermore, O(2) concentration in cell culture causes changes in both the FTIR and Raman spectra of embryonic stem cells. These results show that embryonic stem cells might be more sensitive to O(2) concentration when compared to mesenchymal stem cells. While vibrational spectroscopy could therefore be of potential use in identifying different populations of stem cells further work is required to better understand these differences.     

1-Heptanesulfonic acid sodium salt： One pot efficient synthesis of 2-aryl- 1-arylmethyl- 1 H- 1,3-benzo[d]imidazoles

Synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzo[d]imidazoles by the reaction of o-phenylenediamine with substituted aromatic aldehydes in the presence of l-heptanesulfonic acid sodium salt (10 mol%) at room temperature.The reactions were performed in acetonitrile:water (8:2).The method was proved to be eco-friendly,convenient and the products were isolated with good yields (82-90%).     

Synthesis of oxalate doped polyaniline and its corrosion protection performance

It is known that dopants present in polyaniline (PANI) play an important role in corrosion protection of mild steel since the dopant ions form a secondary layer with iron. Since oxalate ions form a stable iron oxalate layer on mild steel, a study has been made on the corrosion protection performance of steel by vinyl coating containing oxalate doped PANI in acid and neutral media. Electrochemical impedance spectroscopy (EIS) studies have shown that the oxalate doped PANI is able to protect mild steel in sodium chloride solution since the impedance values are maintained at 10¹⁰ Ω cm² even after 100 days of exposure.     

Stereospecific approach to α,β-disubstituted nitroalkenes via coupling of α-bromonitroalkenes with boronic acids and terminal acetylenes

(Z)-α-Bromo-β-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh₃)₄ as catalyst to afford (E)-α,β-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of α-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful α,β-disubstituted nitroethylenes.     

HPLC-assisted automated oligosaccharide synthesis

A standard HPLC was adapted to polymer supported oligosaccharide synthesis. Solution-based reagents are delivered using a software-controlled solvent delivery system. The reaction progress and completion can be monitored in real time using a standard UV detector. All steps of oligosaccharide assembly including loading, glycosylation, deprotection, and cleavage can be performed using this setup.     

Effect of Glass Substrates on the Formation of Gold-Silver Colloids in Nanocomposite Thin Films

A sol-gel route to synthesize nanocomposite thin films containing phase separated metal colloids of gold (Au) and silver (Ag) was developed. Ag—Au colloids were prepared in silica films using dip coating technique. The annealing of the samples in air results in the formation of phase separated Ag and Au colloids in SiO₂ thin films, showing the surface plasmon peaks at 410 nm and 528 nm. For the synthesis of phase separated Ag and Au colloids on float glass substrates, formation of the silver colloids was found strongly dependent on the surface of the float glass. On the tin rich surface formation of both gold and silver colloids took place, whereas, on the tin poor surface the formation of only gold colloids was observed. The surface dependence of the formation of silver colloids was attributed to the presence of tin as Sn²⁺ state on the glass surface, which oxidizes into Sn⁴⁺ during heat treatment, reducing Ag⁺ into silver colloids.