Preparation method of (S)-4-hydroxy-2-oxo-1-pyrrolidineacetamide
A technology for pyrrolidine acetamide and hydroxyl, applied in the field of preparation of -4-hydroxy-2-oxo-1-pyrrolidine acetamide and -4-hydroxy-2-oxo pyrrolidine derivatives, capable of Solve the problems of adding reaction steps, low synthesis yield, and total yield reduction, and achieve the effects of short cycle, low pollution, and low toxicity
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Embodiment 1
[0023] The preparation method of (S)-4-hydroxyl-2-oxo-1-pyrrolidineacetamide is carried out as follows:
[0024] 1. Preparation of crude product:
[0025] (a) Add 139.6 g of ethyl glycine hydrochloride to 1,300 ml of anhydrous ether, cool to -2°C and blow in 22.1 g of ammonia gas to dissociate ethyl glycine hydrochloride into ethyl glycine, wherein ethyl glycine hydrochloride Salt: anhydrous ether: ammonia gas is 1mol: 1300ml: 1.3mol;
[0026] (b) Add absolute ethanol 672ml, sodium bicarbonate 84.0g, dropwise (S)-4-chloro-3-hydroxyl-butyric acid ethyl ester 250.0g in the above-mentioned product, and described dropping time is 2.5 hours, in React at pH 8.2 and temperature 66°C for 28 hours;
[0027] (c) Filtrate, fully wash the filtrate with ethanol, concentrate, dissolve the concentrate in water, add ethyl acetate 7 times the weight of the filtrate to extract, concentrate the water phase, and separate by column chromatography; the final mass percentage concentration is 26% ...
Embodiment 2
[0034] The preparation method of (S)-4-hydroxyl-2-oxo-1-pyrrolidineacetamide is carried out as follows:
[0035] 1. Preparation of crude product:
[0036] (a) Add glycine ethyl ester hydrochloride to anhydrous ether, cool it to 1°C and pass through ammonia gas to dissociate glycine ethyl ester hydrochloride into glycine ethyl ester, wherein glycine ethyl ester hydrochloride: anhydrous ether: Ammonia is 1mol: 1395ml: 1.5mol;
[0037] (b) Add anhydrous methanol, sodium carbonate, (S)-4-iodo-3-hydroxy-butyric acid ethyl ester to the above product, and react for 30 hours at a pH of 8 and a temperature of 70°C;
[0038] (c) Filtrate, fully wash the filtrate with ethanol, concentrate, dissolve the concentrate in water, then add 6 times the weight of the filtrate in dichloromethane for extraction, concentrate the water phase, and separate by column chromatography; finally add a mass percentage concentration of 25% Aqueous ammonia was reacted at 20° C. for 5 hours to obtain the crud...
Embodiment 3
[0044] The preparation method of (S)-4-hydroxyl-2-oxo-1-pyrrolidineacetamide is carried out as follows:
[0045] 1. Preparation of crude product:
[0046] (a) ethyl glycine hydrochloride is suspended in chemically pure ether, then feed ammonia to make ethyl glycine hydrochloride free into ethyl glycine;
[0047] (b) Add absolute ethanol, sodium bicarbonate, dropwise (S)-4-bromo-3-hydroxy-butyric acid ethyl ester to the above product;
[0048] (c) Then filter, fully wash the filtrate with ethanol, concentrate, dissolve the concentrate in water, then add 4 times the weight of the filtrate in chloroform for extraction, concentrate and separate the water phase; finally add concentrated ammonia water and react at 25°C for 6 hours to prepare Obtain the crude product of (S)-4-hydroxy-2-oxo-1-pyrrolidineacetamide;
[0049] 2. Purification of crude product:
[0050] (a) dissolve the above-mentioned crude product with water, pass through 732# strongly acidic cation exchange resin, th...
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