摘要:
One aspect of the present invention relates to quinine-based and quinidine-based catalysts. In certain embodiments, the quinine-based and quinidine-based catalysts contain a hydroxy group at the 6′ position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an O-aryl group or an O-aroyl group at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an optionally substituted O-diazene group or an optionally substituted O-benzoyl group at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain a thiourea at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an NH(═S)NH-aryl group at the C9 position. Another aspect of the present invention relates to a method of preparing a chiral, non-racemic compound from a prochiral electron-deficient alkene or prochiral imine, comprising the step of: reacting a prochiral alkene or imine with a nucleophile in the presence of a catalyst; thereby producing a chiral, non-racemic compound; wherein said catalyst is a derivatized quinine or quinidine. In certain embodiments, the nucleophile is a malonate or β-ketoester. In certain embodiments the nucleophile is an alkyl or aryl or aralkyl 2-cyano-2-alkylacetate. In certain embodiments the nucleophile is an alkyl or aryl or aralkyl 2-cyano-2-alkylacetate.Another aspect of the present invention relates to a method of kinetic resolution, comprising the step of: reacting a racemic aldehyde or racemic ketone with a nucleophile in the presence of a derivatized quinine or quinidine, thereby producing a non-racemic, chiral compound. In certain embodiments, the kinetic resolution is dynamic.
摘要:
One aspect of the present invention relates to quinine-based and quinidine-based catalysts. In certain embodiments, the quinine-based and quinidine-based catalysts contain a hydroxy group at the 6′ position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an O-aryl group or an O-aroyl group at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an optionally substituted O-diazene group or an optionally substituted O-benzoyl group at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain a thiourea at the C9 position. In certain embodiments, the quinine-based and quinidine-based catalysts contain an NH(═S)NH-aryl group at the C9 position. Another aspect of the present invention relates to a method of preparing a chiral, non-racemic compound from a prochiral electron-deficient alkene or prochiral imine, comprising the step of: reacting a prochiral alkene or imine with a nucleophile in the presence of a catalyst; thereby producing a chiral, non-racemic compound; wherein said catalyst is a derivatized quinine or quinidine. In certain embodiments, the nucleophile is a malonate or β-ketoester. In certain embodiments the nucleophile is an alkyl or aryl or aralkyl 2-cyano-2-alkylacetate. In certain embodiments the nucleophile is an alkyl or aryl or aralkyl 2-cyano-2-alkylacetate. Another aspect of the present invention relates to a method of kinetic resolution, comprising the step of: reacting a racemic aldehyde or racemic ketone with a nucleophile in the presence of a derivatized quinine or quinidine, thereby producing a non-racemic, chiral compound. In certain embodiments, the kinetic resolution is dynamic.
摘要:
One aspect of the present invention relates to quinine-based and quinidine-based catalysts. Another aspect of the invention relates to a method of preparing a derivatized quinine-based or quinidine-based catalyst comprising 1) reacting quinine or quinidine with base and a compound that has a suitable leaving group, and 2) converting the ring methoxy group to a hydroxy group. Another aspect of the present invention relates to a method of preparing a chiral, non-racemic compound from a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral ketone, comprising the step of: reacting a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral ketone with a nucleophile in the presence of a catalyst; thereby producing a chiral, non-racemic compound; wherein said catalyst is a derivatized quinine or quinidine. Another aspect of the present invention relates to a method of kinetic resolution, comprising the step of: reacting racemic chiral alkene with a nucleophile in the presence of a derivatized quinine or quinidine.
摘要:
In certain embodiments, the present invention relates to methods for asymmetric Friedel-Crafts alkylation catalyzed by bifunctional cinchona alkaloids. In certain embodiments, the catalyst is a 6′-OH cinchona alkaloid. In certain embodiments, the electrophile is an α-ketoester or aldehyde. In certain embodiments, the nucleophile is an aromatic heterocycle. In certain embodiments, the nucleophile is an aromatic N-containing heterocycle. In certain embodiments, the nucleophile is an indole. In certain embodiments, the methods of the invention are relatively insensitive to concentration, temperature, air and moisture.
摘要:
One aspect of the present invention relates to asymmetric catalytic nitroaldol (Henry) reactions with ketones as the electrophilic component. In one embodiment, the present invention relates to asymmetric nitroaldol reactions with α-keto esters catalyzed by a new C6′-OH cinchona alkaloid catalyst. In certain embodiments, this reaction is operationally simple and affords high enantioselectivity as well as good to excellent yield for an exceptionally broad range of α-keto esters.
摘要:
One aspect of the present invention relates to quinine-based and quinidine-based catalysts. Another aspect of the invention relates to a method of preparing a derivatized quinine-based or quinidine-based catalyst comprising 1) reacting quinine or quinidine with base and a compound that has a suitable leaving group, and 2) converting the ring methoxy group to a hydroxy group. Another aspect of the present invention relates to a method of preparing a chiral, non-racemic compound from a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral ketone, comprising the step of: reacting a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral ketone with a nucleophile in the presence of a catalyst; thereby producing a chiral, non-racemic compound; wherein said catalyst is a derivatized quinine or quinidine. Another aspect of the present invention relates to a method of kinetic resolution, comprising the step of: reacting racemic chiral alkene with a nucleophile in the presence of a derivatized quinine or quinidine.
摘要:
One aspect of the present invention relates to asymmetric catalytic nitroaldol (Henry) reactions with ketones as the electrophilic component. In one embodiment, the present invention relates to asymmetric nitroaldol reactions with α-keto esters catalyzed by a new C6′-OH cinchona alkaloid catalyst. In certain embodiments, this reaction is operationally simple and affords high enantioselectivity as well as good to excellent yield for an exceptionally broad range of α-keto esters.
摘要:
In certain embodiments, the present invention relates to methods for asymmetric Friedel-Crafts alkylation catalyzed by bifunctional cinchona alkaloids. In certain embodiments, the catalyst is a 6′-OH cinchona alkaloid. In certain embodiments, the electrophile is an α-ketoester or aldehyde. In certain embodiments, the nucleophile is an aromatic heterocycle. In certain embodiments, the nucleophile is an aromatic N-containing heterocycle. In certain embodiments, the nucleophile is an indole. In certain embodiments, the methods of the invention are relatively insensitive to concentration, temperature, air and moisture.
摘要:
A semiconductor switch insulation protection device and a power supply assembly. Said semiconductor switch protection device comprises a semiconductor switch having a metal component, an insulation component, and a pin installed at a bottom plane of said insulation component, and an insulation protection cover having a body with a second hole and a side belt. A front surface of said metal component is installed on a back surface of said insulation component. A metal portion, with a first hole and having a first height, is extended above an upper plane of said insulation component. Said second hole and said side belt are extended toward a back surface of said body, respectively, to form a hole column having a second height and a sidewall having a third height. Said metal portion is disposed in a groove formed by said back surface of said body, hole column and sidewall.
摘要:
A method for brain tumor segmentation in multi-parametric 3D magnetic resonance (MR) images, comprising: determining, for each voxel in the multi-parametric 3D MR image sequence, a probability that the voxel is part of brain tumor; extracting multi-scale structure information of the image; generating multi-scale tumor probability map based on initial tumor probability at voxel level and multi-scale structure information; determining salient tumor region based on multi-scale tumor probability map; obtaining robust initial tumor and non-tumor label based on tumor probability map at voxel level and salient tumor region; and generating a segmented brain tumor image using graph based label information propagation. The present invention is capable of achieving statistical reliable, spatially compact, and robust tumor label initialization, which is helpful to the accurate and reliable tumor segmentation. And the label information propagation framework could partially alleviate the performance degradation caused by image inconsistency between images to be segmented and training images.