Probing the electronic demands of transmetalation in the palladium-catalyzed cross-coupling of arylsilanolates
摘要:
The electronic characteristics of coupling partners in the transmetalation step for the cross-coupling reaction of arylsilanolates have been investigated. The ability to interrogate the transmetalation event by in situ preparation of the arylpalladium(II) silanolate intermediate has enabled a Hammett analysis for both the aryl electrophile and arylsilanolate to be conducted. These studies reveal that electron-donating groups on the silicon nucleophile and electron-withdrawing groups on the electrophile accelerate the transmetalation process. (C) 2011 Elsevier Ltd. All rights reserved.
SYNTHETIC METHOD FOR MONTELUKAST SODIUM INTERMEDIATE
申请人:Zhao Zhiquan
公开号:US20120165535A1
公开(公告)日:2012-06-28
A synthesis method for preparing Montelukast sodium intermediate 2-(2-(3-(2-(7-chloro-2-quinolyl)vinyl)phenyl-3-oxopropyl)phenyl) propanol is provided. In this method, the target compound is prepared by condensing the starting materials 7-chloroquinaldine and 3-cyanobenzaldehyde, and then reacting the resultant product with 2-(2-ortho-(2-haloethyl)-phenylpropyl)tetrahydropyrane ether. The present invention can easily obtain start materials and is applicable for mass production.
CATALYSTS, PROCESSES FOR MAKING CATALYSTS, PROCESSES FOR MAKING POLYOLEFIN COMPOSITIONS, AND POLYOLEFIN COMPOSITIONS
申请人:Kuhlman Roger L.
公开号:US20100227990A1
公开(公告)日:2010-09-09
The present invention relates to compositions and processes of making catalysts and polyolefins. More particularly, the invention relates to snap shut catalysts, processes for making the catalysts, processes for making polyolefins using the catalysts and the polyolefins resulting therefrom.
Method for the Preparation of Palladium(I) Tri-Tert-Butylphosphine Bromide Dimer and Process for its Use in Isomerization Reactions
申请人:Goossen Lukas
公开号:US20140187803A1
公开(公告)日:2014-07-03
The invention provides a new method for the preparation of the dimeric Pd(l) tri-tert.-butylphosphine bromide complex, characterized by the chemical formula [Pd(μ-Br)(P
t
Bu
3
)]
2
. The method is based on a comproportionation reaction in which a Pd(ll) compound (=PdBr
2
) is reacted with a Pd(0) compound (=Pd(P
t
Bu
3
)
2
) in organic solvents to yield the [Pd(μ-Br)(P
t
Bu
3
)]
2
compound having the Pd atoms in the formal oxidation state +1. Unreacted PdBr
2
may be reused in the process. The method is straightforward and applicable for industrial scale production and provides high product yields. Further, a new process for the isomerization of allyl ethers of the general type R
1
—C(O)—O—CH(R
2
)—C(R
3
)═CH
2
employing the compound Pdμ-Br)(P
t
Bu
3
)]
2
as a catalyst is disclosed.
Process for advancing epoxy resins comprising up to 1.0%wt of water
申请人:SHELL INTERNATIONALE RESEARCH
MAATSCHAPPIJ B.V.
公开号:EP0302560A2
公开(公告)日:1989-02-08
A process is disclosed for preparing an advanced epoxy resin by reacting a relatively low molecular weight polyepoxide with a phenolic compound; in the presence of a catalytic amount of an alkyl substituted phosphonium salt such as tri-t-butyl phosphonium bromide. The process can be carried out under reaction conditions, such as the presence of water, which are deleterious to certain epoxy advancement catalysts.
SYNTHETIC METHOD OF MONTELUKAST SODIUM INTERMEDIATE
申请人:Shandong New Time Pharmaceutical Co., Ltd.
公开号:EP2474535A1
公开(公告)日:2012-07-11
A synthesis method for preparing Montelukast sodium intermediate 2-(2-(3-(2-(7-chloro-2-quinolyl)vinyl)phenyl-3-oxopropyl)phenyl) propanol is provided. In this method, the target compound is prepared by condensing the starting materials 7-chloroquinaldine and 3-cyanobenzaldehyde, and then reacting the resultant product with 2-(2-ortho-(2-haloethyl)-phenylpropyl)tetrahydropyrane ether. The present invention can easily obtain start materials and is applicable for mass production.