CAS: 10294-40-3; Barium Chromate

专利信息

专利号:US-6479685-B2
优先权日:1998-01-09
标题 :Metallocene catalysts for synthesis of high-melting polyolefin copolymer elastomers
发明人：WAYMOUTH ROBERT M; KRAVCHENKO RAISA L; MACIEJEWSKI PETOFF JENNIFER; HUNG JOYCE
权利人:TRUSTEES OF THE LELAND STANDAR
摘要:Metallocene catalysts having plural coordination geometries for synthesis of high melting polyolefin copolymers suitable as thermoplastic elastomers. The inventive catalysts comprise unbridged, substituted or unsubstituted cyclopentadienyl metallocene catalysts that are capable of inter-converting between states with different polymerization or copolymerization characteristics, which interconversion is controlled by selecting the substituents of the cyclopentadienyl ligands so that the rate of interconversion of the two states is within several orders of magnitude of the rate of formation of a single polymer chain. Where r i >r f the polymer can be characterized as multiblock; where r i
专利号:US-4219489-A
优先权日:1978-09-05
标题:Synthesis of steroids
发明人：BUNES LEONARD A; JOHNSON WILLIAM S
权利人:STANFORD LELAND JUNIOR UNIV TR
摘要:Method and compounds are provided for use in the synthesis of steroids wherein a polyolefin is provided having an initiating group having a chalcogen atom in juxtaposition to a double bond, so as to be capable of bond formation to close to form a ring and having a terminating group involving pi unsaturation (a double or triple bond) conjugated to an aromatic ring. Upon acid catalysis, sigma bonds are formed through the interaction of a carbocation formed at the carbon atom bonded to the chalcogen atom and the double bond intermediate the initiating group and the terminating group, which close to form rings of a steroid nucleus, the carbocation interacting with the pi unsaturation conjugated with the aromatic group and being captured by a nucleophile present in the acidic reaction medium. The resulting steroid product may then be modified in known ways to produce known steroids.

专利号:US-3904698-A
优先权日:1972-08-17
标 题:Steroid synthesis
发明人：JOHNSON WILLIAM S; MARKEZICH RONALD L; MCCARRY BRIAN E
权利人:UNIV LELAND STANFORD JUNIOR
摘要:Synthesis of steroids by cyclization of a dienyne terminating at one end of the molecule in an acetylenic group and at the other end in a cyclohexene ring wherein the olefinic group forms an allylic group with a substituent such as a thioketal or hydroxy group. Invention includes novel synthesis of the cyclization substrate, novel substrate and novel intermediates, whereby resolution of racemic mixtures and the production of d, l and dl enantiomers are made possible.

专利号:US-8552175-B2
优先权日:2009-04-23
标题:Sulfur transfer reagents for oligonucleotide synthesis
发明人：GUZAEV ANDREI P
权利人:GUZAEV ANDREI P; A M CHEMICALS INC
摘要:The use of N-formamidino-5-amino-3H-1,2,4-dithiazole-3-thiones, 5-phenyl-3H-1,2,4-dithiazole-3-thiones, and derivatives thereof as novel, efficient sulfur-transfer reagents is disclosed. Sulfur transfer from these reagents to compounds containing a P(III) atom (e.g., triphenylphosphine, 5′-O-DMT-thymidine 2-cyanoethyl-(N,N-diisopropyl)phosphoramidite, and 5′-O-DMT-3′-O-levulinyl dithymidilyl 2-cyanoethyl phosphite), was studied in solution by 31 P NMR and HPLC. The sulfur transfer from title compounds was also studied in the solid-phase synthesis of oligonucleotide phosphorothioates by phosphoramidite methods. In this application, the efficiency of the sulfur transfer reaction for 2′-deoxyoligonucleotides was better than 99.5%. The novel sulfurizing agents are synthesized, at low cost, using simple chemical methods. As opposed to many sulfur transfer reagents known in the prior art such as 1,2-benzodithiol-3-one-1,1-dioxide (Beaucage reagent) and 5-ethoxy-3H-1,2,4-dithiazole-2-one (EDIT), the sulfurizing agents disclosed herein are highly stable in solution, which increases their practical and commercial value.

专利号:US-2010055750-A1
优先权日:2008-09-03
标 题:Polyester synthesis
发明人：WOSNICK JORDAN H
权利人:XEROX CORP
摘要:The present disclosure provides for enzymatic polymerization to produce polyester resins suitable for use in manufacturing toners. In embodiments, crystalline copolymers, which are polyesters, may be synthesized from lactones, cyclic anhydrides, cyclic carbonates, and combinations thereof. These crystalline copolymers, in turn, may be utilized in the synthesis of toner particles.

专利号:US-4267234-A
优先权日:1978-03-17
标题:Polyglutaraldehyde synthesis and protein bonding substrates
发明人：REMBAUM ALAN
权利人:CALIFORNIA INST OF TECHN
摘要:Polyglutaraldehyde (PGL) is polymerized in aqueous base or in aqueous highly polar solvent basic media to prepare powders, castable films or coatings for substrates such as amine substituted microbeads. PGL microspheres can be prepared by suspension polymerization in presence of a surfactant or by precipitating PGL from solution containing surfactant. Magnetic PGL microspheres are formed by suspension polymerization in the presence of magnetic particles such as iron oxide. Polyglutaraldehyde can be converted to a fluorescent polymer by reaction with m-aminophenol or other reagent. Proteins can be readily covalently bound to the polyglutaraldehyde.