Refernces
10.1016/S0040-4039(00)86037-2
The study focuses on the total synthesis of the methyl ester of L-660631, a novel natural product obtained from actinomyces fermentation, which is a potent inhibitor of cytosolic P-ketothiolase. The researchers aimed to develop a synthetic route that allows for the systematic replacement of the 1,3,5-hexatriyne subunit with more stable fragments to enhance the compound's stability while retaining its inhibitory activity. Key chemicals involved include cyclooctene, which serves as the starting material, and various reagents such as vinyl magnesium bromide, phenyl isocyanate, and lithium trifluoroborate organoalkyls. The study details the synthesis process, highlighting challenges such as the instability of concentrated L-660,631 and the difficulty in achieving selective addition reactions. The researchers employed techniques like asymmetric Sharpless kinetic resolution to set the stereochemistry at C.6 and C.9, and explored different methods for the oxidation and reduction steps to overcome the instability issues. The final product, L-660,631 methyl ester, was synthesized and found to be stable at room temperature, with future plans to evaluate its inhibitory activity against mammalian P-ketothiolase.
10.1039/b202699f
The study investigates the discontinuous pressure effects on the enantiodifferentiating photosensitized isomerization of cyclooctene and cycloocta-1,5-diene, sensitized by chiral benzene-1,2,4,5-tetracarboxylates. The purpose of the study was to understand how hydrostatic pressure up to 750 MPa influences the enantiomeric excess (ee) of the (E)-isomer produced, indicating a switch in the enantiodifferentiation mechanism due to conformational changes in the chiral auxiliaries. The chemicals used included (Z)-cyclooctene, (Z,Z)-cycloocta-1,5-diene, and chiral benzene-1,2,4,5-tetracarboxylates (3a–c) as chiral sensitizers. These sensitizers served to induce the isomerization process and were crucial in examining the pressure's effect on asymmetric photosensitization, which could be useful for controlling product chirality and ee.
10.1016/j.catcom.2010.11.025
The research focuses on the synthesis, characterization, and catalytic activity of tin incorporated periodic mesoporous organosilicas (Sn–PMOs) in the epoxidation reaction of olefins. The Sn–PMOs were prepared using alkyl trimethylammonium bromide surfactants with different alkyl chain lengths under basic conditions. Key chemicals involved in the synthesis include 1,2-bis(triethoxysilylethane) (BTEE), octadecyltrimethylammonium bromide (C18-TMABr), tin tetrachloride (SnCl4), sodium hydroxide (NaOH), and hydrochloric acid (HCl) for surfactant removal. The synthesized materials were characterized using various techniques such as powder X-ray diffraction (XRD), nitrogen adsorption–desorption, solid-state NMR, UV–Vis spectroscopy, and thermal analysis (TG-DTA). The Sn–PMOs exhibited excellent catalytic activity and reusability in the epoxidation of norbornene and cis-cyclooctene, outperforming a Sn–MCM-41 sample. The superior performance was attributed to the higher tin incorporation, better accessibility of reactants to active sites, and enhanced hydrophobicity due to the organic groups in the framework walls.
