- A convenient approach for vinylation reaction in the synthesis of 5-vinyl-2-pyrrolidinone, a key intermediate of vigabatrin
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A convenient, safe and cost-effective method for carrying out the key vinylation of 5-ethoxy-2-pyrrolidinone (8) in the preparation of 5-vinyl-2-pyrrolidinone (2) in the presence of potassium carbonate is described. This present procedure is developed by replacing inherently hazardous ethyl magnesium bromide with inexpensive and eco-friendly potassium carbonate. The reaction was performed on a multi-gram scale, with vinyl magnesium bromide as the vinylation reagent, in an 81% yield to give the 5-vinyl-2-pyrrolidinone with excellent purity and without the need for chromatography.
- Karumanchi, Kishore,Natarajan, Senthil Kumar,Gadde, Sunil,Vanchanagiri, Krishna
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p. 2035 - 2039
(2020/01/02)
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- Preparation method of aminohexenoic acid
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The invention discloses a preparation method of aminohexenoic acid, which is characterized by comprising the following steps: with diethyl malonate and 1,4-dichloro-2-butene as raw materials, preparing 2-vinylcyclopropane-1,1-dicarboxylic acid diethyl ester; then carrying out a reaction on 2-vinylcyclopropane-1,1-dicarboxylic acid diethyl ester in the presence of ammonia and formamide to prepare 2-carbonyl-5-vinyl-pyrrolidine-3-amide; preparing a 4-amino-5-hexenoic acid crude product from the 2-carbonyl-5-vinyl-pyrrolidine-3-amide under an acidic condition; then preparing triisopropylsilyl-4-aminohexyl-5-alkenyl ester from 4-amino-5-hexenoic acid and triisopropylchlorosilane in the presence of triethylamine and ammonia; recrystallizing the triisopropylsilyl-4-aminohexyl-5-alkenyl ester inchloroform/methanol to obtain a purified product of the triisopropylsilyl-4-aminohexyl-5-alkenyl ester; wherein the volume ratio of chloroform to methanol is 1:7; and hydrolyzing the purified productof the triisopropylsilyl-4-aminohexyl-5-alkenyl ester under an alkaline condition to obtain the aminohexylenic acid.
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Paragraph 0016; 0043; 0044; 0051; 0053; 0062; 0063
(2020/02/14)
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- Process for making 4-aminohex-5-enoic acid
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Novel compounds of the following general formula are useful in the preparation of 4-aminohex-5-enoic acid and 4-aminohex-5-ynoic acid which are useful pharmacological agents: STR1 wherein R1 is hydroxy, amino, or tert-butoxy.
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