Silica-bonded n-propyltriethylene-tetramine (SBNPTT) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes. Chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oC under solvent-free conditions. The heterogeneous solid base showed much the same efficiency when u...

In this research, SO3H-functionalizedphthalimide (SFP) has been prepared through simple reaction of phthalimide with chlorosulfonic acid, and characterized using FT-IR, 1H NMR, 13C NMR, SEM (scanning electron microscopy), mass and TG (thermal gravimetric) spectra. Afterward, the solid acid has been utilized as an efficient, green, heterogeneous and recyclable ca...

Enantioselective organocatalysis has become a field of central importance within asymmetric chemical synthesis and appears to be efficient approach toward the construction of complex chiral molecules from simple achiral materials in one-pot transformations under mild conditions with high stereocontrol. This review addresses the most significant synthetic methods reported on chiral-amine-catalyz...

We present a Hilbert-style axiomatization of a paraconsistent logic, called G3, recently introduced. G ′ 3 is based on a 3-valued semantics. We prove a soundness and completeness theorem. The replacement theorem holds in G3. As it has already been shown in previous work, G ′ 3 can express some nonmonotonic semantics.

Most current anticancer drugs have shown excellent therapeutic effects on human oral squamous cell carcinoma (OSCC), but they also produce potent cytotoxicity in normal oral keratinocytes. This review article summarizes our extensive research of tumor specificity and keratinocyte toxicity of nine groups of compounds synthesized in our laboratory. Among a total of 133 compounds, (E)-3-[2-(4-hydr...

tention in the search for bioactive compounds to develop new drugs. We have taken note of brown algae of the genus Sargassum (Sargassacea, Fucales), which contain structurally unique secondary metabolites such as palstoquinones, chromanol, and chromenes. In the course of studies on search for bioactive molecules of algae, we isolated plastoquinones [hydroquinone (1) and quinone (2)] together wi...