- Optical methyl 2-chloropropionate synthesis by decomposition of methyl 2-(chlorocarbonyloxy)propionate with hexaalkylguanidinium chloride hydrochloride
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The decomposition of methyl S-(-)-2-(chlorocarbonyloxy)propionate in the presence of hexaalkylguanidinium chloride hydrochloride was confirmed to correspond to a nucleophilic substitution of the second order. However, racemization occured by the contact between the catalyst and methyl R-(+)-2-chloropropionate (I). This phenomenon is caused by the exchange between the chloride ion from catalyst and the chlorine atom of (I) according to a SN2 mechanism as well.
- Violleau, Frédéric,Thiébaud-Roux, Sophie,Borredon, Elisabeth,Le Gars, Pierre
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- Novel method for preparing hexamethyl propyleneamine oxime and intermediate thereof
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The present invention relates to a novel synthesis method of hexamethyl propyleneamine oxime (HMPAO) and an intermediate thereof, wherein the method comprises a step of conducting a reaction of a compound of chemical formula 4a with methyl magnesium halide (CH_3MgX) or methyl lithium (CH_3Li) to synthesize a compound represented by chemical formula 3a. Unlike conventional methods having unsatisfactory separation efficiency, or complicated synthesis processes and low yield, the synthesis method of the present invention can produce l-HMPAO, d-HMPAO and d,l-HMPAO in a high yield without producing meso-HMPAO.COPYRIGHT KIPO 2018
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Paragraph 0089; 0091
(2018/05/03)
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- A synthetic S-2-chloropropionic acid methyl ester method
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The invention discloses a method for synthesizing S-2-methyl chloropropionate. The method comprises the following steps of: (1) preparing a Vilmerier reagent: adding a chlorinating agent into a reaction kettle, adding short chain aliphatic series dropwise to replace amide to serve as a solvent, and reacting under the stirring condition to obtain a Vilmerier reagent solution; (2) synthesizing S-2-methyl chloropropionate: adding a small amount of solvent into the Vilmerier reagent solution obtained in the step 1 to obtain a mixed solution, adding R-methyl lactate into the mixed solution dropwise, and stirring to perform chlorination to obtain a product solution, namely the S-2-methyl chloropropionate solution; and (3) washing the S-2-methyl chloropropionate solution obtained in the step 2, desolventizing and distilling to obtain the product S-2-methyl chloropropionate. The synthesis method is mild in reaction condition, easy to operate, low in environmental pollution and suitable for large-scale industrialized production.
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Paragraph 0036-0039
(2017/03/17)
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- A substrate-driven approach to determine reactivities of α,β-unsaturated carboxylic esters towards asymmetric bioreduction
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The degree of C=C bond activation in the asymmetric bioreduction of α,β-unsaturated carboxylic esters by ene-reductases was studied, and general recommendations to render these "borderline-substrates" more reactive towards enzymatic reduction are proposed. The concept of "supported substrate activation" was developed. In general, an additional α-halogenated substituent proved to be beneficial for enzymatic activity, whereas β-alkyl or β-aryl substituents were detrimental for the reactivity of nonhalogenated substrates, and α-cyano groups showed little effect. The alcohol moiety of the ester functionality was found to have a strong influence on the reaction rate. Overall, activities were determined by both steric and electronic effects. Biotransformation: The asymmetric bioreduction of α,β-unsaturated carboxylic esters by ene-reductases could be tuned by varying the degree of C=C bond activation (see scheme). An additional α-halogenated substituent proved to be beneficial for enzymatic activity, whereas β-alkyl or β-aryl substituents were detrimental for the reactivity of nonhalogenated substrates. Copyright
- Tasnádi, Gábor,Winkler, Christoph K.,Clay, Dorina,Sultana, Nargis,Fabian, Walter M. F.,Hall, Mélanie,Ditrich, Klaus,Faber, Kurt
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experimental part
p. 10362 - 10367
(2012/10/08)
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- Optically active maleimide derivatives and polymaleimides for use as chiral adsorbent in chromatography
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An optically active maleimide dericative represented by the following formula (1): as well as the polymer synthesized therefrom. The polymers are useful as chival adsorbents in chomatography.
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- Asymmetric reduction of 2-chloroacrylic acid to (S)-2-chloropropionic acid by a novel reductase from Burkholderia sp. WS
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Burkholderia sp. WS has a novel enzyme that catalyzes the asymmetric reduction of 2-chloroacrylic acid to yield (S)-2-chloropropionic acid, which is used as a building block for the synthesis of aryloxyphenoxypropionic acid herbicides. NADPH is required as a co-substrate for this reaction.
- Kurata, Atsushi,Kurihara, Tatsuo,Kamachi, Harumi,Esaki, Nobuyoshi
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p. 2837 - 2839
(2007/10/03)
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- Direct Organocatalytic Asymmetric α-Chlorination of Aldehydes
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The direct organocatalytic enantioselective α-chlorination of aldehydes has been developed. The reaction proceeds for a series of different aldehydes with NCS as the chlorine source using easily available catalysts such as L-proline amide and (2R,5R)-diphenylpyrrolidine. The α-chloro aldehydes are obtained in up to 99% yield and up to 95% ee. The synthetic utility of the enantioselective α-chlorination of aldehydes is demonstrated by transformation of the α-chloro aldehydes to the corresponding α-chloro alcohols (>90% yield) by standard reduction and further transformation to both a terminal epoxide and amino alcohol, both obtained without loss of optical purity. Oxidation of the α-chloro aldehydes followed by esterification gave optically active α-chloro esters without loss of optical purity. It is demonstrated that these optically active α-chloro esters can be converted into nonproteinogenic amino acids in overall high yields, maintaining the enantiomeric excess obtained in the catalytic enantioselective α-chlorination step. Copyright
- Halland, Nis,Braunton, Alan,Bachmann, Stephan,Marigo, Mauro,Jorgensen, Karl Anker
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p. 4790 - 4791
(2007/10/03)
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- 2-heterosubstituted-3-(4-methylsulfonyl)phenyl-5-trifluoromethyl pyridines as selective and orally active cyclooxygenase-2 inhibitors
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A series of novel 2-alkoxy, 2-thioalkoxy and 2-amino-3-(4- methylsulfonyl)phenylpyridines has been synthesized and shown to be highly potent and selective cyclooxygenase-2 (COX-2) inhibitors. Structure-activity relationship studies have demonstrated that central pyridine ring substituents play an important role in the COX-2 potency, selectivity vs the COX-1 enzyme, and oral activity.
- Dube, Daniel,Brideau, Christine,Deschenes, Denis,Fortin, Rejean,Friesen, Richard W.,Gordon, Robert,Girard, Yves,Riendeau, Denis,Savoie, Chantal,Chan, Chi-Chung
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p. 1715 - 1720
(2007/10/03)
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- Asymmetric nitrogen: 81. * diastereomeric derivatives of 1-alkoxy-2,2-bis(trifluoromethyl)aziridines. Structure and absolute configuration
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The 1H NMR spectra of O-derivatives of 1-hydroxy-2,2-bis(trifluoromethyl)aziridine containing such substituents as EtO2CCH2, (R/S)-RO2CCH(Me) (R = Me, Pri, or But), (R/S)-H2NC(O)CH(Me), and (R)-H2NC(O)CH(Me) were analyzed. Both of the diastereomerically pure amides of the latter type were isolated. The validity of the 1H NMR criteria, which were suggested for the determination of absolute configurations of diastereomers of N-alkoxyaziridines, was confirmed by X-ray diffraction study of the (R,R)-amide.
- Prosyanik,Mishchenko,Zelenskaya,Forni,Moretti,Torre,Bruekner,Malpezzi,Kostyanovsky,Kostyanovsky
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p. 1359 - 1364
(2007/10/03)
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- A new simple and industrial process for bromination of alcohols
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Alcohols treated with thionylchloride, followed by chlorine/bromine exchange using gaseous hydrobromic acid and thermal decomposition in the presence of a tertiary amine give the corresponding brominated compounds. The process is regio/stereo selective.
- Mas,Metivier
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p. 2187 - 2191
(2007/10/02)
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- A NEW CHIRAL HOST COMPOUND 10,10'-DIHYDROXY-9,9'-BIPHENANTHRYL. OPTICAL RESOLUTION OF PROPIONIC ACID DERIVATIVES, BUTYRIC ACID DERIVATIVES, AND 4-HYDROXYCYCLOPENT-2-EN-1-ONE DERIVATIVES BY COMPLEXATION
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Optically active 10,10'-dihydroxy-9,9'-biphenanthryl was designed as a new chiral host compound for optical resolution of guest compounds, and was found to be wery effective for resolution of the title guest compounds.
- Toda, Fumio,Tanaka, Koichi
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p. 1807 - 1810
(2007/10/02)
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