- Method for preparing 3-(3-chloropropyl)-4-oxopyrrolidin-1-carboxylate
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The invention provides a method for preparing 3-(3-chloropropyl)-4-oxopyrrolidin-1-carboxylate (I). The method comprises the steps: subjecting glycinate or an acceptable salt thereof (VIII), which serves as a raw material, to a reaction with chloroformate (VII), so as to produce an intermediate ethoxycarbonyl glycinate (VI); subjecting the intermediate (VI) to cyclization with acrylate (V) under alkaline conditions, so as to obtain a pyrrolidone intermediate (IV); and subjecting the intermediate (IV) to a reaction with 1,3-halochloropropane (III) so as to obtain an intermediate (II), and then,carrying out decarboxylation under acidic conditions, thereby obtaining the 3-(3-chloropropyl)-4-oxopyrrolidin-1-carboxylate (I). Compared with old processes, the method has the advantages that processing steps are shortened, processing operations are simplified, and the emission of waste gases, waste water and waste residues and the cost are greatly reduced, thereby being beneficial to industrialized enlarged production.
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Paragraph 0035
(2020/02/19)
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- Catalysts and temperature driven melt polycondensation reaction for helical poly(ester-urethane)s based on natural L-amino acids
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Catalyst and temperature driven melt polycondensation reaction was developed for natural L-amino acid monomers to produce new classes of poly(ester-urethane)s. Wide ranges of catalysts from alkali, alkali earth metal, transition metal and lanthanides were developed for the condensation of amino acid monomers with diols to yield poly(ester-urethane)s. A-B Diblock and A-B-A triblock species were obtained by carefully choosing mono- or diols in model reactions. More than two dozens of transition metal and lanthanide catalysts were identified for the polycondensation to yield high molecular weight poly(ester-urethane)s. Theoretical studies revealed that the carbonyl carbon in ester possessed low electron density compared to the carbonyl carbon in urethane which driven the thermo-selective polymerization process. Optical purity of the L-amino acid residues in the melt polycondensation process was investigated using D- and L-isomers and the resultant products were analyzed by chiral-HPLC and CD spectroscopy. CD analysis revealed that the amino acid based polymers were self-assembled as β-sheet and polyproline type II secondary structures. Electron and atomic force microscopic analysis confirmed the formation of helical nano-fibrous morphology in poly(ester-urethane)s. The newly developed melt polycondensation process is very efficient and optimized for wide range of catalysts to produce diverse polymer structures from natural L-amino acids.
- Anantharaj, Santhanaraj,Jayakannan, Manickam
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p. 1065 - 1077
(2016/03/12)
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- Polymers from amino acids: Development of dual ester-urethane melt condensation approach and mechanistic aspects
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A new dual ester-urethane melt condensation methodology for biological monomers-amino acids was developed to synthesize new classes of thermoplastic polymers under eco-friendly and solvent-free polymerization approach. Naturally abundant l-amino acids were converted into dual functional ester-urethane monomers by tailor-made synthetic approach. Direct polycondensation of these amino acid monomers with commercial diols under melt condition produced high molecular weight poly(ester-urethane)s. The occurrence of the dual ester-urethane process and the structure of the new poly(ester-urethane)s were confirmed by 1H and 13C NMR. The new dual ester-urethane condensation approach was demonstrated for variety of amino acids: glycine, β-alanine, l-alanine, l-leucine, l-valine, and l-phenylalanine. MALDI-TOF-MS end group analysis confirmed that the amino acid monomers were thermally stable under the melt polymerization condition. The mechanism of melt process and the kinetics of the polycondensation were studied by model reactions and it was found that the amino acid monomer was very special in the sense that their ester and urethane functionality could be selectively reacted by polymerization temperature or catalyst. The new polymers were self-organized as β-sheet in aqueous or organic solvents and their thermal properties such as glass transition temperature and crystallinity could be readily varied using different l-amino acid monomers or diols in the feed. Thus, the current investigation opens up new platform of research activates for making thermally stable and renewable engineering thermoplastics from natural resource amino acids.
- Anantharaj,Jayakannan
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experimental part
p. 2446 - 2455
(2012/10/08)
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- Site selectivity in the Rhodium(II)-catalyzed reaction of α-diazoimides. Ligand and substituent effects
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The product distribution obtained from Rh(II)-catalyzed decomposition of α-diazoimides derived from glycine methyl ester has been found to be selectively controlled by the proper choice of catalyst. When the reaction was carried out using perfluorinated l
- Prein, Michael,Manley, Peter J.,Padwa, Albert
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p. 7777 - 7794
(2007/10/03)
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- Aminosaeuren, I. Darstellung von Aminosaeuren aus Halogencarbonsaeure-alkylestern mit Alkalimetallcyanaten
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α- and ω-halo- as well as α,ω-dihalocarboxylic alkyl esters react with potassium cyanate in the presence of alcohol at 80 - 120 deg C in dipolar aprotic solvents to yield α- and ω-(alkoxycarbonylamino)- and α,ω-bis(alkoxycarbonylamino)carboxylic alkyl esters, respectively, in good yields.Hydrolytic cleavage of these mono- or diurethanes with an aqueous solution of hydrochloric acid/formic acid leads to the corresponding amino acid hydrochlorides in nearly quantitative yields.
- Effenberger, Franz,Drauz, Karlheinz,Foerster, Siegfried,Mueller, Wolfgang
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p. 173 - 189
(2007/10/02)
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- Process for the production of aminoacid hydrochlorides/or diaminoacid dihydrochlorides
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Aminoacid hydrochlorides or diaminoacid dihydrochlorides are produced by first reacting a halocarboxylic acid ester with an alkali metal cyanate in the presence of an alcohol to form the corresponding mono- or diurethane and then saponifying this to the corresponding mono- or dihydrochloride. The new process is relatively versatile in its use and above all opens up an elegant synthesis route for lysine.
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