55666-11-0Relevant academic research and scientific papers
Enantioselective Synthesis of Chiral Substituted 2,4-Diketoimidazolidines and 2,5-Diketopiperazines via Asymmetric Hydrogenation
Xiao, Guiying,Xu, Shuang,Xie, Chaochao,Zi, Guofu,Ye, Weiping,Zhou, Zhangtao,Hou, Guohua,Zhang, Zhanbin
supporting information, p. 5734 - 5738 (2021/08/01)
An enantioselective hydrogenation of 5-alkylidene-2,4-diketoimidazolidines (hydantoins) and 3-alkylidene-2,5-ketopiperazines catalyzed by the Rh/f-spiroPhos complex under mild conditions has been developed, which provides an efficient approach to the highly enantioselective synthesis of chiral hydantoins and 2,5-ketopiperazine derivatives with high enantioselectivities up to 99.9% ee.
A preparation in the aqueous phase the alkone is bright ammonia acid calcium green process
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Paragraph 0029; 0030; 0035; 0036, (2016/10/24)
The invention relates to an environment-friendly technology for preparing ketoleucine calcium in an aqueous phase. Isobutylidene hydantoin and a calcium chloride aqueous solution serve as raw materials, and water serves as a solvent. The environment-friendly technology comprises the steps that heating reflux hydrolysis is carried out on the isobutylidene hydantoin in water and industrial liquid alkali, the calcium chloride aqueous solution is dropwise added, the mixed solution is filtered, filtered liquid is collected and cooled, hydrochloric acid acidification is carried out, vacuum nitrogen displacement is carried out, caustic soda liquid is added for alkalization, cooling is carried out, the calcium chloride aqueous solution is dropwise added, calcium salt is obtained, cooling is carried out, a crude product is obtained through filtering, the crude product is refined in purification water, and a ketoleucine calcium refined product is obtained. The environment-friendly technology for preparing the ketoleucine calcium in the aqueous phase has the advantages of being easy to operate, simple in steps, high in yield coefficient, good in product quality, environmentally friendly and the like. According to the environment-friendly technology for preparing the ketoleucine calcium in the aqueous phase, the environment-friendly water is adopted as the solvent completely, the requirement of green chemistry development is met, the pollution problem is solved from the source, and the environment-friendly technology is suitable for industrialized mass production.
Independent valine and leucine isotope labeling in Escherichia coli protein overexpression systems
Lichtenecker, Roman J.,Weinhaeupl, Katharina,Reuther, Lukas,Schoerghuber, Julia,Schmid, Walther,Konrat, Robert
, p. 205 - 209 (2014/01/06)
The addition of labeled α-ketoisovalerate to the growth medium of a protein-expressing host organism has evolved into a versatile tool to achieve concomitant incorporation of specific isotopes into valine- and leucine-residues. The resulting target proteins represent excellent probes for protein NMR analysis. However, as the side-chain resonances of these residues emerge in a narrow spectral range, signal overlap represents a severe limitation in the case of high-molecular-weight NMR probes. We present a protocol to eliminate leucine labeling by supplying the medium with unlabeled α-ketoisocaproate. The resulting spectra of a model protein exclusively feature valine signals of increased intensity, confirming the method to be a first example of independent valine and leucine labeling employing α-ketoacid precursor compounds.
Synthesis and reactivity of 5-methylenehydantoins
Fraile, José M.,Lafuente, Gustavo,Mayoral, José A.,Pallarés, Antonio
experimental part, p. 8639 - 8647 (2011/11/30)
5-Methylenehydantoin, as well as the N-mono- and N,N-di-protected derivatives, can be obtained by different synthetic routes. These compounds can undergo a large variety of reactions, such as Diels-Alder, epoxidation, methanol addition and conjugate addition reactions of different types of nucleophiles, including carbon (cyanide), nitrogen (piperidine) and sulfur (thiols, thioacetate) nucleophiles. The reactivity with electrophilic reagents, such as m-CPBA or methanol in acidic medium, and the need for Lewis acids to promote the conjugate addition reactions indicate that hydantoin is a poor electron-withdrawing group.
Process for production of hydantoin derivatives
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, (2008/06/13)
Hydantoin derivatives are industrially advantageously produced at a high yield by reacting hydantoin with carbonyl compounds in the presence of (i) amino acids or the salts thereof and (ii) inorganic alkali compounds for a relatively short reaction time in an aqueous medium.
