The preparation method of (2r,4r)-4-methylpiperidine-2-ethyl carboxylate compound
A technology of ethyl piperidine carboxylate and ethyl formate, which is applied in the field of medicine and chemical industry, can solve the problems of low yield, long synthetic route, poor reaction selectivity, etc., and achieve the effects of easy availability of raw materials, high yield and high purity of products
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Embodiment 1
[0045] 1. Preparation of (2R,4R)-4-methyl-1-((S)-1-phenethyl)tetrahydropyridine-2-carboxylic acid ethyl ester
[0046] Combine (2R)-4-methyl-1-((S)-1-phenethyl)-1,2,3,6-tetrahydropyridine-2-carboxylic acid ethyl ester (328 g, 1.2 mol) and ethanol ( 2500mL) into the 5L autoclave, add rhodium-alumina catalyst (10% rhodium loading, 60g), feed H 2 , reacted at 35°C and 1MPa for 12h, filtered and recovered the catalyst. The reaction solution was concentrated under reduced pressure, ethyl acetate (1000 mL) was added, washed with saturated brine (250 mL x 2), dried over anhydrous sodium sulfate and filtered, and the filtrate was concentrated under reduced pressure to obtain a colorless transparent liquid product (310 g).
[0047] Determination by liquid chromatography: the content of (2R,4R)-4-methyl-1-((S)-1-phenethyl)-2-piperidinecarboxylic acid ethyl ester was 73.2%.
[0048] 2. Preparation of (2R,4R)-4-methylpiperidine-2-carboxylic acid ethyl ester
[0049] The crude product (...
Embodiment 2
[0055] 1. Preparation of (2R,4R)-4-methyl-1-((S)-1-phenethyl)tetrahydropyridine-2-carboxylic acid ethyl ester
[0056] Combine (2R)-4-methyl-1-((S)-1-phenethyl)-1,2,3,6-tetrahydropyridine-2-carboxylic acid ethyl ester (328.1 g, 1.2 mol) and ethanol (2500mL) was added to the 5L autoclave, rhodium-carbon catalyst (5% rhodium loading, 50g) was added, and H 2 , at 40 ℃, 1Mpa reaction 12h. Filtration, recovery catalyst. The reaction solution was concentrated under reduced pressure, ethyl acetate (1000 mL) was added, washed with saturated brine (250 mL x 2), dried over anhydrous sodium sulfate and filtered, silica gel was added to the filtrate to decolorize, filtered, and the filtrate was concentrated under reduced pressure to obtain a colorless transparent Liquid product (315g).
[0057] Determination by liquid chromatography: (2R,4R)-4-methyl-1-((S)-1-phenethyl)-2-piperidinecarboxylic acid ethyl ester content was 68.5%.
[0058] 2. Preparation of (2R,4R)-4-methylpiperidine-2-ca...
Embodiment 3
[0065] 1. Preparation of (2R,4R)-4-methyl-1-((S)-1-phenethyl)tetrahydropyridine-2-carboxylic acid ethyl ester
[0066] Combine (2R)-4-methyl-1-((S)-1-phenethyl)-1,2,3,6-tetrahydropyridine-2-carboxylic acid ethyl ester (273 g, 1.0 mol) and ethanol ( 2000mL) in the 5L autoclave, add rhodium-alumina catalyst (5% rhodium loading, 75g), feed H 2 , at 25 ℃, 0.5Mpa reaction for 12h. Filtration, recovery of the catalyst. The reaction solution was concentrated under reduced pressure, ethyl acetate (1000 mL) was added, washed with saturated brine (250 mL x 2), dried over anhydrous sodium sulfate and filtered, silica gel was added to the filtrate to decolorize, filtered, and the filtrate was concentrated under reduced pressure to obtain a colorless transparent Liquid product (250 g).
[0067] Determination by liquid chromatography: (2R,4R)-4-methyl-1-((S)-1-phenethyl)-2-piperidinecarboxylic acid ethyl ester content was 62.3%.
[0068] 2. Preparation of (2R,4R)-4-methylpiperidine-2-car...
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