摘要:
Chelating ligand precursors for the preparation of olefin methathesis catalysts are disclosed. The resulting catalysts are air stable monomeric species capable of promoting various methathesis reactions efficiently, which can be recovered from the reaction mixture and reused. Internal olefin compounds, specifically beta-substituted styrenes, are used as ligand precursors. Compared to terminal olefin compounds such as unsubstituted styrenes, the beta-substituted styrenes are easier and less costly to prepare, and more stable since they are less prone to spontaneous polymerization. Methods of preparing chelating-carbene methathesis catalysts without the use of CuCl are disclosed. This eliminates the need for CuCl by replacing it with organic acids, mineral acids, mild oxidants or even water, resulting in high yields of Hoveyda-type methathesis catalysts. The invention provides an efficient method for preparing chelating-carbene metathesis catalysts by reacting a suitable ruthenium complex in high concentrations of the ligand precursors followed by crystallization from an organic solvent.
摘要:
Chelating ligand precursors for the preparation of olefin methathesis catalysts are disclosed. The resulting catalysts are air stable monomeric species capable of promoting various methathesis reactions efficiently, which can be recovered from the reaction mixture and reused. Internal olefin compounds, specifically beta-substituted styrenes, are used as ligand precursors. Compared to terminal olefin compounds such as unsubstituted styrenes, the beta-substituted styrenes are easier and less costly to prepare, and more stable since they are less prone to spontaneous polymerization. Methods of preparing chelating-carbene methathesis catalysts without the use of CuCl are disclosed. This eliminates the need for CuCl by replacing it with organic acids, mineral acids, mild oxidants or even water, resulting in high yields of Hoveyda-type methathesis catalysts. The invention provides an efficient method for preparing chelating-carbene metathesis catalysts by reacting a suitable ruthenium complex in high concentrations of the ligand precursors followed by crystallization from an organic solvent.
摘要:
This disclosure relates generally to olefin metathesis, and more particularly relates to the synthesis of terminal alkenes from internal alkenes using a cross-metathesis reaction catalyzed by an olefin metathesis catalyst. According to one aspect, for example, a method is provided for synthesizing a terminal olefin, the method comprising contacting, in the presence of a ruthenium alkylidene metathesis catalyst, an olefinic substrate comprised of at least one internal olefin with a cross metathesis partner comprised of an alpha olefinic reactant, under reaction conditions effective to allow cross-metathesis to occur, wherein the reaction conditions include a reaction temperature of at least 35° C. The methods, compositions, reactions and reaction systems herein disclosed have utility in the fields of catalysis, organic synthesis, and industrial chemistry.
摘要:
Chelating ligand precursors for the preparation of olefin metathesis catalysts are disclosed. The resulting catalysts are air stable monomeric species capable of promoting various metathesis reactions efficiently, which can be recovered from the reaction mixture and reused. Internal olefin compounds, specifically beta-substituted styrenes, are used as ligand precursors. Compared to terminal olefin compounds such as unsubstituted styrenes, the beta-substituted styrenes are easier and less costly to prepare, and more stable since they are less prone to spontaneous polymerization. Methods of preparing chelating-carbene metathesis catalysts without the use of CuCl are disclosed. This eliminates the need for CuCl by replacing it with organic acids, mineral acids, mild oxidants or even water, resulting in high yields of Hoveyda-type metathesis catalysts. The invention provides an efficient method for preparing chelating-carbene metathesis catalysts by reacting a suitable ruthenium complex in high concentrations of the ligand precursors followed by crystallization from an organic solvent.
摘要:
This invention provides reagents and methods for specifically delivering antibiotic, antimicrobial and antiviral compounds, drugs and agents to phagocytic mammalian cells. The invention also relates to specific delivery to and uptake of such compounds by phagocytic cells. The invention specifically relates to reagents and methods for facilitating the entry of antibiotic, antimicrobial and antiviral compounds, drugs and agents into phagocytic cells. The invention specifically provides compositions of matter and pharmaceutical embodiments of such compositions comprising such antibiotic, antimicrobial or antiviral compounds, drugs and agents conjugated to, impregnated with or coated onto particulate carriers generally termed microparticles. In particular embodiments, the antibiotic, antimicrobial and antiviral compounds, drugs and agents are covalently linked to a microparticle via a specifically-degradable linker molecule which is the target of a microorganism-specific protein having enzymatic activity. Also provided are porous microparticles impregnated with antibiotic, antimicrobial or antiviral compounds, drugs and agents wherein the surface or outside extent of the microparticle is covered with a degradable coating that is specifically degraded within an infected phagocytic mammalian cell. Also provided are nonporous microparticles coated with antibiotic, antimicrobial or antiviral compounds, drugs and agents and further coated wherein the surface or outside extent of the microparticle is covered with a degradable coating that is specifically degraded within an infected phagocytic mammalian cell. Thus, the invention provides cell targeting of drugs wherein the targeted drug is only released in cells infected with a particular microorganism. Methods of inhibiting, attenuating, arresting, combating and overcoming microbial infection of phagocytic mammalian cells in vivo and in vitro, especially cells infected with tuberculosis-causing and other Mycobacterium species microorganisms, are also provided.
摘要:
The present invention relates to aldolase catalyzed stereo-selective synthesis of sugars and compositions of matter comprising arabinohexulose, xyloheptulose, threohexulose, and xylohexulose.
摘要:
A new and practical method for synthesizing heterocyclic polyhydroxylated alkaloids using enzymatic aldol condensation and catalytic intramolecular reductive amination is disclosed.
摘要:
Described are methods of making organic compounds by metathesis chemistry. The methods of the invention are particularly useful for making industrially-important organic compounds beginning with starting compositions derived from renewable feedstocks, such as natural oils. The methods make use of a cross-metathesis step with an olefin compound to produce functionalized alkene intermediates having a pre-determined double bond position. Once isolated, the functionalized alkene intermediate can be self-metathesized or cross-metathesized (e.g., with a second functionalized alkene) to produce the desired organic compound or a precursor thereto. The method may be used to make bifunctional organic compounds, such as diacids, diesters, dicarboxylate salts, acid/esters, acid/amines, acid/alcohols, acid/aldehydes, acid/ketones, acid/halides, acid/nitriles, ester/amines, ester/alcohols, ester/aldehydes, ester/ketones, ester/halides, ester/nitriles, and the like.
摘要:
The invention is directed to methods of making organic compounds by metathesis and hydrocyanation. The method of the invention may be used, for example, to make industrial important organic compounds such as diacids, diesters, acid-amines, acid-alcohols, acid-nitriles, ester-amines, ester-alcohols, and ester-nitriles.
摘要:
The invention is directed to methods of making organic compounds by metathesis and hydrocyanation. The method of the invention may be used, for example, to make industrial important organic compounds such as diacids, diesters, acid-amines, acid-alcohols, acid-nitriles, ester-amines, ester-alcohols, and ester-nitriles.