29617-66-1Relevant articles and documents
Optimization of the use of a chiral bio-based building block for the manufacture of DHPPA, a key intermediate for propionate herbicides
Fleer, Michel P. M.,Verkuijl, Bastiaan J. V.
, p. 3993 - 3998 (2014)
An alternative route for the production of (R)-2-(4-hydroxyphenoxy) propionic acid (DHPPA), a key intermediate in herbicide chemistry, is proposed. This route makes use of a chiral building block, initially produced by fermentation. The route has been optimized based on two steps: chlorination and etherification. The chlorination step has a maximum ee of 99% and a yield of 85% after distillation. The etherification step has a yield of 66%. Comparison of the route with the industrial standard shows a significant improvement in terms of green chemistry: waste streams are lowered up to 7-fold and the toxicity of the waste streams is reduced. This journal is the Partner Organisations 2014.
Roof shape chiral alcohol: auxiliary for asymmetric synthesis of α-halo acid derivatives
Jain, Nilesh,Bedekar, Ashutosh V.
, p. 692 - 695 (2016)
Roof shape chiral enantiopure alcohol, obtained by bio-catalytic separation of isomers, was used as a new auxiliary for asymmetric synthesis of α-halo acid derivatives. Esterification reaction of roof shape chiral enantiopure alcohol and racemic α-halo acids in the presence of DCC, DMAP furnished diastereomers of ester in non-racemic manner. Diastereoselectivity up to 90% was observed, the absolute configuration of newly generated chiral center was established by the single crystal X-ray diffraction analysis.
Asymmetric reduction of 2-chloroacrylic acid to (S)-2-chloropropionic acid by a novel reductase from Burkholderia sp. WS
Kurata, Atsushi,Kurihara, Tatsuo,Kamachi, Harumi,Esaki, Nobuyoshi
, p. 2837 - 2839 (2004)
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.
Energetics of the C-Cl bond in CH3CH(Cl)COOH. Enthalpy of formation of (S)-(-)-2-chloropropionic acid and of the 1-carboxyethyl radical
Lagoa, Ana L.C.,Diogo, Herminio P.,Minas da Piedade, Manuel E.,Amaral, Luisa M.P.F.,Guedes, Rita C.,Costa Cabral, Benedito J.,Kulikov, Dmitry V.,Verevkin, Sergey P.,Siedler, Michael,Epple, Matthias
, p. 9855 - 9861 (2002)
The energetics of the C-Cl bond in 2-chloropropionic acid was investigated by using a combination of experimental and theoretical methods. The standard molar enthalpy of formation of liquid (S)-(-)-2-chloropropionic acid, at 298.15 K, was determined as ΔfH°m(C3H5O2Cl, l) = - 534.6 ± 1.1) kJ?mol-1, by rotating-bomb combustion calorimetry. The corresponding enthalpy of vaporization, ΔvapH°m (C3H5O2Cl) = (64.9 ± 0.5) kJ?mol-1, was also obtained from vapor pressure versus temperature measurements by the transpiration method, leading to ΔfH°m(C3H5O2Cl, g) = -(469.7 ± 1.2) kJ?mol-1. This value, together with the enthalpy of the isodesmic and isogyric gas-phase reaction CH3CH(X)COOH(g) + C2H5(g) → CH3CHCOOH(g) + C2H5X(g) (X = H, Cl) predicted by density functional theory calculations and other auxiliary data, was used to derive the enthalpy of formation of the gaseous 1-carboxyethyl radical as ΔfH°[CH(CH3)COOH, g] = -(293 ± 3) kJ?mol-1, from which DH°[H-CH(CH3COOH] = 380.7 ± 3.9 kJ?mol-1 and DH°[Cl-CH(CH3)COOH] = 298.0 ± 3.2 kJ?mol-1 were obtained. These values are compared with the corresponding C-H and C-Cl bond dissociation enthalpies in XCH2COOH, XCH3, XC2H5, XCH2-Cl, XCH(CH3)Cl, XCH-CH2, and XC6H5 (X = H, Cl). The order DH°(C-H) 3)COOH] and DH°[X-CH2COOH] (X = H, Cl) indicates that the replacement of a hydrogen of the CH2 group of XCH2COOH by a methyl group leads to a decrease of both the C-H and C-Cl bond dissociation enthalpy. It is finally concluded that the major qualitative trends exhibited by the C-Cl bond dissociation enthalpies for the series of compounds addressed in this work can be predicted based on Pauling's electrostatic-covalent model.
A facile microwave assisted synthesis and structure elucidation of (3R)-3-alkyl-4,1-benzoxazepine-2,5-diones by crystallographic, spectroscopic and DFT studies
Raza, Abdul Rauf,Nisar, Bushra,Khalid, Muhammad,Gondal, Humaira Yasmeen,Khan, Muhammad Usman,de Alcantara Morais, Sara Figueirêdo,Tahir, Muhammad Nawaz,Braga, Ataualpa Albert Carmo
, (2020/01/21)
The use of microwave (MW) irradiation in organic synthesis has become increasingly popular within the pharmaceutical and academic arenas because it is a new enabling technology for drug discovery and development. It is a rapid way of synthesis, which involves faster reaction rates and high selectivity to conventional heating method of syntheses. The MW-assisted 7-exo-tet cyclization of N-acylanthranilic acids afforded (3R)-3-alkyl-4,1-benzoxazepines-2,5-diones in very short duration (20 min) with extraordinary high yields in comparison to conventional heating mode of synthesis. The method development, comparative yields of MW-assisted and thermal method of syntheses, crystallographic, spectroscopic and density functional theory (DFT) studies are reported herein. Four novel compounds with chemical formulas C10H9BrClNO3 5m, C19H19NO3 6e, C13H14ClNO3 6h and C12H11Br2NO3 6h were synthesized, validated by 1HNMR, 13CNMR, FT-IR, UVVis, EIMS spectroscopic techniques and confirmed by using single crystal X-ray diffraction (SC-XRD) study. The DFT and TDDFT calculations at B3LYP/6-311 + G(d,p) level of theory were performed for comparative analysis of spectroscopic data, optimized geometries, frontier molecular orbitals (FMOs), natural bond orbital (NBO) analysis and nonlinear optical (NLO) properties of 5m, 6e, 6h and 6o. Overall, experimental findings were supported nicely by corresponding DFT computed results. The NBO analysis confirmed that the presence of non-covalent interactions, hydrogen bonding and hyper- conjugative interactions are pivotal cause for the existence of 5m, 6e, 6h and 6o in the solid-state. NLO analysis showed that 5m, 6e, 6h and 6o have significant NLO properties as compared to prototype standard compound which disclosed their potential for technology related applications.
Applications of chiral naphthyloxycyclohexanols in deracemization of α-substituted carboxylic acids by dynamic thermodynamic resolution
Khanvilkar, Aditya N.,Samanta, Sudeep G.,Bedekar, Ashutosh V.
, p. 2670 - 2683 (2019/03/12)
Two derivatives of trans-2-naphthyloxycyclohexanol were synthesized, their enantiomers were separated by enzyme mediated kinetic resolution and their absolute configuration was established by synthesizing their diastereomers with esters of known chiral description. Chiral alcohols were then used as chiral auxiliaries for the preparation of esters by coupling with racemic α-halo acids. During the coupling reactions with DCC and a suitable base, an efficient dynamic thermodynamic resolution was observed and the products were isolated in high diastereomeric purity. The effect of several parameters on the reaction was studied and the absolute configuration of a newly created chiral centre was established by single crystal X-ray analysis; the correlation of the structure of chiral auxiliary and diastereoselectivity was investigated. The observed diastereoselectivity was in accordance with the relative energy profile of the products. The chirally pure α-halo acid could be separated from the auxiliary, without any loss of optical purity of both components.
Synthetic method of high-purity and high-yield L-2-chloropropionic acid
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Paragraph 0021; 0023; 0025; 0027; 0029, (2018/04/26)
The invention discloses a synthetic method of L-2-chloropropionic acid. The synthetic method comprises the steps of firstly dissolving L-alanine into hydrochloric acid, introducing nitrosyl chloride and hydrogen chloride gas for reaction, after the raw materials are converted, filtering, continuing to stir for 1-2 hours, and an alkaline reagent for neutralization, extracting by virtue of an organic solvent, combining organic phases, drying by virtue of anhydrous calcium chloride, filtering, and carrying out rectification, so as to obtain a product, namely L-2-chloropropionic acid. The method has the advantages that the operation is simple, and the emission of wastewater is reduced; and by taking nitrosyl chloride with relatively high activity as a diazotization regent, aliphatic amino canbe rapidly converted into chlorine, so that the raw material conversation rate and the yield are greatly increased, the yield can reach 90% or above, an original configuration is not reversed in the reaction process, and the optical purity ee value can reach 99.1%.
Synthesis method of pesticide intermediate (S)-(-)-2-chloropropionic acid
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Paragraph 0033-0050, (2020/05/19)
The invention relates to a synthesis method of pesticide intermediate (S)-(-)-2-chloropropionic acid. The method comprises the step of enabling (S)-2-chloropropionic acid, used as a starting raw material, and sodium nitrite to be subjected to a diazo-reaction in presence of a catalyst and lewis acid so as to obtain the (S)-(-)-2-chloropropionic acid product. The synthesis method improves the yield, content and optical purity of the product, reduces the production cost, and improves the product quality; the optical purity of the obtained (S)-(-)-2-chloropropionic acid is e.e. 99% or above, andthe reaction yield is 85% or above; the synthesis method is short in reaction route and simple in aftertreatment, and has a great guiding significance for process amplification and production.
Di(1-naphthyl) methanol ester of carboxylic acids for absolute stereochemical determination
Zhang, Jun,Sheng, Wei,Gholami, Hadi,Nehira, Tatsuo,Borhan, Babak
supporting information, p. 141 - 146 (2017/11/13)
The absolute stereochemistry of chiral carboxylic acids is determined as a di(1-naphthyl)methanol ester derivative. Computational scoring of conformations favoring either P or M helicity of the naphthyl groups, capable of exciton-coupled circular dichroic coupling, leads to a predicted stereochemistry for the derivatized carboxylic acids.
Novel method for preparing hexamethyl propyleneamine oxime and intermediate thereof
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Paragraph 0090, (2018/05/03)
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
