Functionalization of Fe3O4 magnetic nanoparticles for organocatalytic Michael reactions
作者:Paola Riente、Carolina Mendoza、Miquel A. Pericás
DOI:10.1039/c1jm10535c
日期:——
(S)-α,α-Diphenylprolinol trimethylsilyl ether supported onto well-defined (5.7 ± 1.1 nm) superparamagnetic Fe3O4 nanoparticles was used as a highly active, magnetically recoverable and reusable catalyst for the asymmetric, organocatalytic Michael addition of propanal to nitroolefins leading to high enantioselectivities. The assembly of the catalytic functional nanoparticles involves two successive steps: (i) introduction of a 3-azidopropyl unit through the formation of Si–O bonds, and (ii) integration of the organocatalytic unit by means of a copper-catalysed alkyne–azide cycloaddition reaction leading to a 1,2,3-triazole linker. Neither the process of nanoparticle assembly nor its catalytic use in dichloromethane solution provokes particle growth or agglomeration, this behaviour being key for the observation of high catalytic activity and for recyclability.
Tetrahydroisoquinolines as alpha-2 antagonists and biogenic amine uptake
申请人:Abbott Laboratories
公开号:US05389638A1
公开(公告)日:1995-02-14
The present invention provides a tetrahydroisoquinoline compound of the formula ##STR1## or a pharmaceutically acceptable salt thereof which is an antagonist for alpha-2 adrenoreceptors and/or which inhibits biogenic amine uptake.
Organocatalytic Asymmetric Michael Addition of 2,2-Dimethyl-1,3-dioxan-5-one to Nitro Alkenes Employing Proline-Based Catalysts
作者:Dieter Enders、Sharon Chow
DOI:10.1002/ejoc.200600464
日期:2006.10
The organocatalytic asymmetric Michael addition of 2,2-dimethyl-1,3-dioxan-5-one (1) was performed with various nitroalkenes 2 using a number of proline-based catalysts (A–M) affording polyfunctional nitro ketones 3. Reverse diastereoselectivity was observed with the diphenylprolinol catalyst J, and the best diastereo- and enantiomeric excesses were achieved with the sulfonamide catalyst M (de = 84–98 %
Organocatalysts and methods of use in chemical synthesis
申请人:Wang Wei
公开号:US20090088588A1
公开(公告)日:2009-04-02
The present invention is directed to compositions comprising organocatalysts that facilitate stereo-selective reactions and the method of their synthesis and use. Particularly, the invention relates to metal-free organocatalysts for facilitation of stereo-selective reactions, and the method of their synthesis and use.
Substituted pyrazolopyrimidines, a process for their preparation and their use as medicine
申请人:Danysz Wojciech
公开号:US20080039458A1
公开(公告)日:2008-02-14
Substituted pyrazolopyrimidine derivatives of formula (I)
wherein
Y
1
, Y
2
, Y
3
, Y
4
represent N or C—, whereby at least two of the groups Y
1
to Y
4
represent a carbon atom, R
1
represents chloro or bromo,
R
2
to R
7
represent e.g. hydrogen, methyl or ethyl; and
R
10
and R
11
independently represent e.g. hydrogen or C
1
-C
6
alkyl, are potent mGluR5 modulators and are useful for the prevention of acute and chronic neurological disorders.