C - Chemistry – Metallurgy – 07 – B
Patent
C - Chemistry, Metallurgy
07
B
C07B 53/00 (2006.01) C07B 57/00 (2006.01) C07C 51/02 (2006.01) C07C 57/52 (2006.01) C07C 69/65 (2006.01)
Patent
CA 2599409
A process for preparing enantiopure E-(2S)-alkyl-5-halopent-4-enoic acids and their esters of the formula (I), in which R is a C1-C6-alkyl radical, R1 is H or C1-C4-alkyl and X is chlorine, bromine or iodine, in which the corresponding racemic 2-alkyl-5-halopent-4-enoic acid a) is reacted in a suitable solvent first with (S)-3-Methyl-2-phenylbutylamine, quinine or with N- methyl-D-glucamine, after which b) the corresponding (S)-3-Methyl-2- phenylbutylamine salt, quinine or glucamine salt of the (R)-pentenoic acid is precipitated and removed, and c) the remaining filtrate is mixed with a second chiral base or an inorganic salt, after which the corresponding salt of the (S)-pentenoic acid is precipitated and d) is then converted into the corresponding E-(2S)-alkyl-5-halo-4-pentenoic acid and subsequently where appropriate into the corresponding ester of the formula (I) in which R1 is C1- C4-alkyl.
Procédé servant à préparer des acides E-(2S)-alkyl-5-halopent-4-énoïques énantiomériquement purs et leurs esters de formule (I), dans laquelle R est un radical alkyle C1-C6, R1 est H ou un alkyle en C1-C4 et X est un atome de chlore, de brome ou d'iode, lequel procédé comprend a) de faire réagir l'acide 2-alkyl-5-halopent-4-énoïque racémique correspondant dans un solvant approprié d'abord avec de la (S)-3-méthyl-2-phénylbutylamine, de la quinine ou de la N-méthyl-D-glucamine, puis b) de faire précipiter et d'enlever le sel de (S)-3-méthyl-2-phénylbutylamine, de quinine ou de glucamine de l'acide (R)-penténoïque correspondant, c) de mélanger le filtrat restant avec une seconde base chirale ou un sel inorganique, et de faire ensuite précipiter le sel de l'acide (S)-penténoïque correspondant et d) de convertir ensuite celui-ci en acide E-(2S)-alkyl-5-halogéno-4-penténoïque correspondant et à la suite de cela, dans les cas appropriés, en ester de formule (I) correspondant où R1 est un alkyle en C1-C4.
Pojarliev Peter
Roessler Markus
Steinbauer Gerhard
Dsm Fine Chemicals Austria Nfg Gmbh & Co Kg
Smart & Biggar
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