- New method for synthesizing (S)-metolachlor and its analogue
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The invention relates to a new method for preparing (S)-metolachlor and its analogue. The (S)-metolachlor is taken as an example: the (S)-metolachlor is prepared from 2-methyl-6-ethylaniline and R-propylene glycol monomethyl ether through a four-step reaction. The method has the advantages of cheap and easily available raw materials, mild reaction conditions, high efficiency and very simple separation process.
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Paragraph 0087-0090; 0091; 0092
(2020/03/12)
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- Chiral organic catalysts for the stereoselective reduction of carbon-nitrogen double bonds for the preparation of enantiomerically enriched amines
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The invention relates to compounds of general formula (I): wherein R1-R7 are as defined in the description for use as catalysts in the stereoselective reduction of imines in the presence of trichlorosilane as reducing agent.
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Page/Page column 11-12
(2009/06/27)
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- Chiral Lewis base promoted trichlorosilane reduction of ketimines. An enantioselective organocatalytic synthesis of chiral amines
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The reduction of the carbon-nitrogen double bond is an important transformation. Here we report our studies on a family of chiral organic catalysts able to promote the stereoselective reduction of ketimines with trichlorosilane. The very cheap, metal-free catalysts were easily prepared in one step from commercially available products, namely a chiral aminoalcohol and picolinic acid derivatives. The catalyst structure was extensively modified in a study that allowed to identify an extremely active species, able to promote the reduction on a large variety of substrates with high efficiency (up to 95% ee). A three component methodology has been also developed, where the enantiomerically enriched amine was isolated after performing the reaction by mixing a ketone and an amine in the presence of trichlorosilane and the catalyst. Its synthetic potentiality was demonstrated by employing the present metal-free catalytic procedure in the preparation of (S)-metolachlor, a potent and widely used herbicide.
- Guizzetti, Stefania,Benaglia, Maurizio,Cozzi, Franco,Annunziata, Rita
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experimental part
p. 6354 - 6363
(2010/01/06)
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- Process for the preparation of secondary amines
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N,N-disubstituted amines in which the amino nitrogen atom is bound to the carbon atom of an aromatic ring disubstituted in the positions ortho to the carbon atom, are prepared by allowing a primary amine and a compound in which an ortho, ortho-disubstituted aromatic compound carrying a nucleofuge substituent, to react in a basic environment in the presence of a catalytic palladium(0) complex and a ligand, the ratio of palladium complex to ligand being greater than at least 1:1. A typical embodiment involves the reaction of 2-methyl-6-ethylphenyl-trifluoromethylsulfonate and (S)-1-methoxy-2-aminopropane in the presence of bis(dibenzylideneacetone)palladium, tri-tert.-butylphosphine, and sodium tert.-butoxide to yield (S)-N-(1-methoxyprop-2-yl)-2-methyl-6-ethylphenylamine.
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- Chiral poisoning of rac-diop iridium complexes in the catalytic enantioselective hydrogenation of imines
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Dimeric Ir(III) complexes [Ir(P-P)HI2]2 (P-P = enantiopure bisphosphine) have previously been shown to be efficient catalysts for the enantioselective hydrogenation of imines. In the present study we have prepared the analogues using
- Sablong, Rafael,Osborn, John A.,Faller
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- Asymmetric hydrogenation of imines catalysed by carboxylato(diphosphine)iridium(III) complexes
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The synthesis of three new families of monomeric carboxylato(diphosphine)iridium(III) complexes is described (e.g. diphosphine = diop, binap, bdpp). Some of these complexes catalyse the asymmetric hydrogenation of prochiral imines to amines in good activi
- Sablong, Rafael,Osborn, John A.
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p. 3059 - 3062
(2007/10/03)
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