The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The present invention discloses a nitrogen-containing fused heterocyclic compound, as well as a preparation method, intermediate, composition and application thereof. The nitrogen-containing fused heterocyclic compound of the present invention as represented by formula (I), as well as the pharmaceutically acceptable salt, enantiomer, diastereomer, tautomer, solvate, metabolite or drug precursor thereof, exhibit a high selectivity and a high inhibitory activity with respect to CDK4 and CDK6 at a molecular level, an excellent inhibitory activity with respect to breast cancer cells at a cellular level, and significant inhibition of tumor cell proliferation associated with cyclin-dependent kinase activity at an animal level. The invention also exhibits a good stability with respect to human or mouse liver microsomes without significant inhibition of metabolic enzymes, good in vivo absorption in mice and rats, a high bioavailability and good druggability.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

Provided herein are prodrug compounds, their preparation and their uses, such as treating liver diseases or nonliver diseases via intervening in molecular pathways in the liver. Novel prodrug compounds of acid/alcohol derivatives such as phosphates, phosphonates, phosphonamidates, phosphoramidates, carboxylates, phenolates, and alkoxylates, their preparation and their uses are described. Some of the novel prodrug compounds described herein do not generate a vinyl keto reactive intermediate in the activation process. Another aspect includes the use of prodrugs to treat diseases that benefit from enhanced drug distribution to the liver and like tissues and cells.

A method for preparing a phosphorus-containing ligand is provided, which includes: mixing a phosphorus chloride compound, polypyridine ionic liquid-loaded porous microspheres with a first organic solvent to obtain a first mixture, and mixing a compound in Formula (2) with a second organic solvent to obtain a second mixture,

##STR00001## wherein Z is a multivalent aliphatic hydrocarbon group or a multivalent aromatic hydrocarbon group comprising at least one substituent group, wherein the substituent group is selected from hydrogen atom, halogen atom, C.sub.1-C.sub.10 alkyl group, C.sub.1-C.sub.10 alkoxy group, C.sub.1-C.sub.10 alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, and n is an integer from 1 to 8; and mixing the first mixture with the second mixture to make the first mixture react with the second mixture to obtain a reaction mixture, removing generated HCl, filtrating to obtain a filter liquor, and treating the filter liquor to obtain the phosphorus-containing ligand.