42558-54-3Relevant articles and documents
Synthetic method of methyl isobutyrylacetate
-
Paragraph 0016-0027, (2021/05/29)
The invention belongs to the technical field of medicine preparation, and particularly relates to a synthetic method of methyl isobutyrylacetate. The method comprises the following steps: reacting acetonitrile and isobutyryl chloride in a reaction solvent in the presence of a base catalyst to prepare methyl isobutyrylacetate, regulating the pH value to 1 by using hydrochloric acid, adding methanol, carrying out hydrolytic esterification reaction, and separating a product from an organic phase through atmospheric distillation and reduced pressure distillation. The raw material acetonitrile used in the synthetic method of methyl isobutyrylacetate is cheaper, has a low boiling point and is easy to separate from the product, the product can be purified only through reduced pressure distillation after the reaction is finished, and the energy consumption is low.
Cu-Mediated Expeditious Annulation of Alkyl 3-Aminoacrylates with Aryldiazonium Salts: Access to Alkyl N2-Aryl 1,2,3-Triazole-carboxylates for Druglike Molecular Synthesis
Liu, Hao-Nan,Cao, Hao-Qiang,Cheung, Chi Wai,Ma, Jun-An
supporting information, p. 1396 - 1401 (2020/02/22)
Alkyl N-aryl 1,2,3-triazole-carboxylates are important molecules or intermediates in medicinal chemistry, but the synthesis of N2-aryl counterparts remains elusive. Herein, we describe a Cu-mediated annulation reaction of alkyl 3-aminoacrylates with aryldiazonium salts, both of which are readily available substrates. Furthermore, alkyl 2-aminoacrylates are also viable substrates. Diverse alkyl N2-aryl 1,2,3-triazole-carboxylates and their analogues can be rapidly prepared under mild conditions. Especially, this protocol allows one to access several druglike variants of carbonic anhydrase inhibitors and celecoxib.
Chiral Vanadyl(V) Complexes Enable Efficient Asymmetric Reduction of β-Ketoamides: Application toward (S)-Duloxetine
Chen, Chien-Tien,Maity, Nabin Ch.,Agarwal, Rachit,Lai, Chien-Fu,Liao, Yiya,Yu, Wei-Ru
supporting information, p. 6408 - 6419 (2020/07/14)
High-valent chiral oxidovanadium(V) complexes derived from 3,5-substituted-N-salicylidene-l-tert-leucine were used as catalysts in asymmetric reduction of N-benzyl-β-ketoamides. Among six different solvents, three different alcohol additives, and two different boranes examined, the use of pinacolborane in tetrahydrofuran (THF) with a t-BuOH additive led to the best results at -20 °C. The corresponding β-hydroxyamides can be furnished with yields up to 92percent and an enantiomeric excess (ee) up to 99percent. We have successfully extended this catalytic protocol for the synthesis of an (S)-duloxetine precursor.
Preparation method of atorvastatin calcium
-
Paragraph 0012; 0013, (2018/07/30)
The invention belongs to the technical field of medicine preparation and particularly relates to a patent application about a novel preparation method of atorvastatin calcium. The method includes steps of preparing intermediates including: 2-methyl-3-carbonyl-methyl pentanoate, 2-methyl-3,5-dicarbonyl-5-anilino-butane, 4-methyl-3-oxo-N-phenyl-2-benzylidene pentanamide, 4-(4-fluorophenyl)-2-(2-methylpropionyl)-4-oxo-N-beta-diphenyl butyrylamide. The preparation method employs cheap and easy-to-obtained raw materials, has simple reactions and operations, and has great industrial application prospect. In conclusion, the preparation method has high reaction efficiency and product yield, is good in repeatability, is suitable for industrial production and has great application value and promotion and application significance.
α-Alkylidene-γ-butyrolactone Formation via Bi(OTf)3-Catalyzed, Dehydrative, Ring-Opening Cyclizations of Cyclopropyl Carbinols: Understanding Substituent Effects and Predicting E/Z Selectivity
Sandridge, Matthew J.,McLarney, Brett D.,Williams, Corey W.,France, Stefan
, p. 10883 - 10897 (2017/10/27)
A Bi(OTf)3-catalyzed ring-opening cyclization of (hetero)aryl cyclopropyl carbinols to form α-alkylidene-γ-butyrolactones (ABLs) is reported. This transformation represents different chemoselectivity from previous reports that demonstrated formation of (hetero)aryl-fused cyclohexa-1,3-dienes upon acid-promoted cyclopropyl carbinol ring opening. ABLs are obtained in up to 89% yield with a general preference for the E-isomers. Mechanistically, Bi(OTf)3 serves as a stable and easy to handle precursor to TfOH. TfOH then catalyzes the formation of cyclopropyl carbinyl cations, which undergo ring opening, intramolecular trapping by the neighboring ester group, subsequent hydrolysis, and loss of methanol resulting in the formation of the ABLs. The nature and relative positioning of the substituents on both the carbinol and the cyclopropane determine both chemo- and stereoselective outcomes. Carbinol substituents determine the extent of cyclopropyl carbinyl cation formation. The cyclopropane donor substituents determine the overall reaction chemoselectivity. Weakly stabilizing or electron-poor donor groups provide better yields of the ABL products. In contrast, copious amounts of competing products are observed with highly stabilizing cyclopropane donor substituents. Finally, a predictive model for E/Z selectivity was developed using DFT calculations.
Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3-Dicarbonyls and Styrenes: Construction of Five-Membered Heterocycles
Ko, Tae Yun,Youn, So Won
supporting information, p. 1934 - 1941 (2016/07/06)
A cooperative indium(III)/silver(I) system for the synthesis of various five-membered heterocycles, including dihydrofurans, pyrroles, spirolactones, and spiroiminolactones, through the sequential oxidative coupling/annulation reaction of 1,3-dicarbonyl compounds with styrenes has been developed. Four different heterocyclic systems were successfully synthesized depending on the substitution pattern of the substrates using readily available starting materials. This system has the advantages of a broad substrate scope, moderate to good chemical yields, an operationally easy and simple procedure, and short reaction times. (Figure presented.) .
Efficient Synthesis of the Nucleus of Atorvastatin Calcium
Xing, Yuzhi,Chen, Shipeng,Zhou, Yingtao,Liu, Na,Chen, Ligong,Li, Yang
, p. 2832 - 2840 (2015/12/23)
An efficient synthetic route for the parent nucleus of atorvastatin calcium was successfully established through the modification of the related reactions. Under the optimized conditions, compound 1 was obtained in 61.2% yield (lit. 51.4%) from methyl isopropyl ketone via five steps. Two impurities generated by the aldol condensation of methyl isopropyl ketone were identified by gas chromatography-mass spectrometry and their generation can be inhibited by reducing the mixing time of methyl isopropyl ketone and NaH. One oxybromination protocol with hydrogen peroxide was employed to make the best of bromine. A debromination by-product was isolated and confirmed by 1H NMR, 13C NMR, and high-resolution mass spectrometry and its generation mechanism was discussed. The impurity can be inhibited by protecting the reaction from light and easily removed by recrystallization.
Highly atom-efficient oxidation of electron-deficient internal olefins to ketones using a palladium catalyst
Mitsudome, Takato,Yoshida, Syuhei,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
, p. 5961 - 5964 (2013/06/27)
A 100 % atom-efficient synthesis of ketones from electron-deficient internal olefins was achieved using O2 as a "green" oxidant (see scheme, DMA=N,N-dimethylacetamide, EWG=electron-withdrawing group). Various electron-deficient olefins were oxidized to the corresponding ketones with over 99 % selectivity and without the formation of olefin isomers or their oxidized products. Copyright
Triclorosilane-mediated stereoselective synthesis of β-amino esters and their conversion to highly enantiomerically enriched β-lactams
Guizzetti, Stefania,Benaglia, Maurizio,Bonsignore, Martina,Raimondi, Laura
supporting information; experimental part, p. 739 - 743 (2011/04/22)
A highly stereoselective trichlorosilane-mediated reduction of N-benzyl enamines was developed; the combination of a low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to perform the reaction on substrates with different structural features often with total control of the stereoselectivity. By easy deprotection through hydrogenolysis followed by conversion of β-aminoester to 2-azetidinones, the synthesis of enantiomerically pure β-lactams (>98% e.e.) was successfully accomplished.
Highly enantioselective synthesis of β-amino acid derivatives by the lewis base catalyzed hydrosilylation of β-enamino esters
Zheng, Hong-Jie,Chen, Wen-Bing,Wu, Zhi-Jun,Deng, Jin-Gen,Lin, Wen-Qing,Yuan, Wei-Cheng,Zhang, Xiao-Mei
supporting information; experimental part, p. 9864 - 9867 (2009/10/02)
A study was conducted to demonstrate highly enantioselective synthesis of β-amino acid derivatives by the Lewis base catalyzed hydrosilylation of βenamino esters. It was found that these catalyst and its analogue displayed excellent activities and enantioselectivities in promoting hydrosilylation of N-aryl β-enamino esters. N-picolinoylpyrrolidine derivatives and N-picolioylephedrine were also evaluated in hydrosilylation of (Z)-methyl 3-phenyl-3-(phenylamino)acrylate. The generality of the Lewis base organocatalyzed hydrosilylation of various β-enamino esters were examined under the optimized conditions. It was observed that the catalytic system exhibited a high sensitivity to the N-substituents, while all the N-aryl β-enamino esters underwent the hydrosilylation smoothly to give corresponding β-amino esters.
