- Preparation methods of aprepitant impurity
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The invention discloses preparation methods of an aprepitant impurity, which comprise isomer impurity synthesis method of six aprepitant key intermediates (2R, 3S)-2-[(1R)-1-[3, 5-bis (trifluoromethyl)-phenyl] ethoxy]-3-(4-fluorophenyl) morpholine, respectively, synthesis of four diastereomer impurities, synthesis of one enantiomer impurity and synthesis of one by-product impurity. The methods have the beneficial effects that the five synthesis methods are simple and feasible, the raw materials are easy to obtain, the conditions are mild, the cost is low, the production is facilitated, and meanwhile, the isomer impurities of the synthesized aprepitant key intermediate provide a new intermediate raw material for the preparation of aprepitant.
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- Efficient synthesis of NK1 receptor antagonist aprepitant using a crystallization-induced diastereoselective transformation
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An efficient stereoselective synthesis of the orally active NK1 receptor antagonist Aprepitant is described. A direct condensation of N-benzyl ethanolamine with glyoxylic acid yielded a 2-hydroxy-1,4-oxazin-3-one which was activated as the corresponding trifluoroacetate. A Lewis acid mediated coupling with enantiopure (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethan-1-ol afforded a 1:1 mixture of acetal diastereomers which was converted into a single isomer via a novel crystallization-induced asymmetric transformation. The resulting 1,4-oxazin-3-one was converted via a unique and highly stereoselective one-pot process to the desired α-(fluorophenyl)morpholine derivative. Interesting and unexpected [1,2]-Wittig and [1,3]-sigmatropic rearrangements were identified during the optimization of these key steps. In the final step, a triazolinone side chain was appended to the morpholine core. The targeted clinical candidate was thus obtained in 55% overall yield over the longest linear sequence.
- Brands, Karel M. J.,Payack, Joseph F.,Rosen, Jonathan D.,Nelson, Todd D.,Candelario, Alexander,Huffman, Mark A.,Zhao, Matthew M.,Li, Jing,Craig, Bridgette,Song, Zhiguo J.,Tschaen, David M.,Hansen, Karl,Devine, Paul N.,Pye, Philip J.,Rossen, Kai,Dormer, Peter G.,Reamer, Robert A.,Welch, Christopher J.,Mathre, David J.,Tsou, Nancy N.,McNamara, James M.,Reider, Paul J.
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p. 2129 - 2135
(2007/10/03)
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