- Synthesis process of N-paraphthalyl(diethanol)amino-L-phenylalanine ethyl ester
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The invention provides a synthesis process of N-paraphthalyl(diethanol)amino-L-phenylalanine ethyl ester. The process includes the first step of amino protection reaction, the second step of esterification reaction, the third step of reduction reaction and the fourth step of substitution reaction. According to the synthesis process, amino is protected by phthalic anhydride, and then esterification, reduction and substitution are conducted obtain the product. The process has the advantages of being low in cost, mild in reaction condition, low in toxicity, convenient to operate, high in yield and suitable for industrial production.
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Paragraph 0028; 0029; 0043; 0058; 0072
(2017/10/28)
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- Substituent effect on the stereoselectivity of acylation of racemic heterocyclic amines with N-phthaloyl-3-aryl-(S)-alanyl chlorides
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The acylative kinetic resolution of racemic 2-methyl-1,2,3,4- tetrahydroquinoline and 2,3-dihydro-3-methyl-4H-1,4-benzoxazine using acyl chlorides of N-phthaloyl-(S)-phenylalanine, N-phthaloyl-3-(4-nitrophenyl)-(S)- alanine and N-phthaloyl-O-methyl-(S)-tyrosine as chiral resolving agents has been carried out. It is shown that the effectiveness of an acylative kinetic resolution depends on the electronic effects of substituents in the phenyl fragment of the acylating agent and increases as the electron-donating properties of the para-substituent (OMe > H > NO2) in phenyl fragment of N-phthaloyl-3-aryl-(S)-alanyl chlorides increase; conducting the process at a reduced temperature also contributes to an enhancement of the kinetic resolution.
- Levit, Galina L.,Gruzdev, Dmitry A.,Krasnov, Victor P.,Chulakov, Evgeny N.,Sadretdinova, Liliya Sh.,Ezhikova, Marina A.,Kodess, Mikhail I.,Charushin, Valery N.
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experimental part
p. 185 - 189
(2011/04/26)
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- Neighbouring group effects promote substitution reactions over elimination and provide a stereocontrolled route to chloramphenicol
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In reactions of β-brominated valine and p-nitrophenylalanine derivatives to give β-hydroxy amino acid derivatives the carboxyl group, when protected as an amide, exerts a neighbouring group effect to facilitate the substitution process, and reduce competing elimination reactions. As a consequence of the effect, the (2R,3R)- and (2R,3S)-stereoisomers of 3-bromo-N-tert-butyl-N(α)-phthaloyl-p-nitrophenylalaninamide both react to give (2S,3R)-3-hydroxy-N-tert-butyl-N(α)-phthaloyl-p-nitrophenylalaninamid e, providing a stereoconvergent route to chloramphenicol.
- Easton, Christopher J.,Hutton, Craig A.,Merrett, Martin C.,Tiekink, Edward R. T.
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p. 7025 - 7036
(2007/10/03)
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