- Synthetic method of methyl isobutyrylacetate
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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.
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Paragraph 0016-0027
(2021/05/29)
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- 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
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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.
- Liu, Hao-Nan,Cao, Hao-Qiang,Cheung, Chi Wai,Ma, Jun-An
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supporting information
p. 1396 - 1401
(2020/02/22)
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- Chiral Vanadyl(V) Complexes Enable Efficient Asymmetric Reduction of β-Ketoamides: Application toward (S)-Duloxetine
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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.
- Chen, Chien-Tien,Maity, Nabin Ch.,Agarwal, Rachit,Lai, Chien-Fu,Liao, Yiya,Yu, Wei-Ru
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supporting information
p. 6408 - 6419
(2020/07/14)
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- Preparation method of atorvastatin calcium
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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.
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Paragraph 0012; 0013
(2018/07/30)
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- 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
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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.
- Sandridge, Matthew J.,McLarney, Brett D.,Williams, Corey W.,France, Stefan
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p. 10883 - 10897
(2017/10/27)
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- Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3-Dicarbonyls and Styrenes: Construction of Five-Membered Heterocycles
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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.) .
- Ko, Tae Yun,Youn, So Won
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supporting information
p. 1934 - 1941
(2016/07/06)
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- Efficient Synthesis of the Nucleus of Atorvastatin Calcium
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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.
- Xing, Yuzhi,Chen, Shipeng,Zhou, Yingtao,Liu, Na,Chen, Ligong,Li, Yang
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p. 2832 - 2840
(2015/12/23)
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- Highly atom-efficient oxidation of electron-deficient internal olefins to ketones using a palladium catalyst
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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
- Mitsudome, Takato,Yoshida, Syuhei,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 5961 - 5964
(2013/06/27)
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- Triclorosilane-mediated stereoselective synthesis of β-amino esters and their conversion to highly enantiomerically enriched β-lactams
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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.
- Guizzetti, Stefania,Benaglia, Maurizio,Bonsignore, Martina,Raimondi, Laura
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supporting information; experimental part
p. 739 - 743
(2011/04/22)
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- Highly enantioselective synthesis of β-amino acid derivatives by the lewis base catalyzed hydrosilylation of β-enamino esters
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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.
- Zheng, Hong-Jie,Chen, Wen-Bing,Wu, Zhi-Jun,Deng, Jin-Gen,Lin, Wen-Qing,Yuan, Wei-Cheng,Zhang, Xiao-Mei
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supporting information; experimental part
p. 9864 - 9867
(2009/10/02)
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- An efficient synthesis of highly substituted pyrrole and bis pyrrole derivatives
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(Chemical Equation Presented) An efficient synthesis of highly substituted pyrrole and bis pyrrole derivatives is reported.
- Sagyam, Rajeshwar Reddy,Vurimidi, Himabindu,Padi, Pratap Reddy,Ghanta, Mahesh Reddy
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p. 923 - 926
(2008/03/29)
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- Structure-activity relationship study of [1,2,3]thiadiazole necroptosis inhibitors
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Necroptosis is a regulated caspase-independent cell death mechanism that results in morphological features resembling non-regulated necrosis. This form of cell death can be induced in an array of cell types in apoptotic deficient conditions with death receptor family ligands. A series of [1,2,3]thiadiazole benzylamides was found to be potent necroptosis inhibitors (called necrostatins). A structure-activity relationship study revealed that small cyclic alkyl groups (i.e. cyclopropyl) and 2,6-dihalobenzylamides at the 4- and 5-positions of the [1,2,3]thiadiazole, respectively, were optimal. In addition, when a small alkyl group (i.e. methyl) was present on the benzylic position all the necroptosis inhibitory activity resided with the (S)-enantiomer. Finally, replacement of the [1,2,3]thiadiazole with a variety of thiophene derivatives was tolerated, although some erosion of potency was observed.
- Teng, Xin,Keys, Heather,Jeevanandam, Arumugasamy,Porco Jr., John A.,Degterev, Alexei,Yuan, Junying,Cuny, Gregory D.
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p. 6836 - 6840
(2008/03/14)
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- PYRROLE COMPOUNDS AND USES THEREOF
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Pyrrole compounds, compositions and methods are provided for the treatment, prevention, or amelioration of neurodegenerative diseases, cardiovascular diseases, proliferative diseases and visual disorders. In particular, pyrrole compounds, compositions and methods for the treatment of stroke are disclosed herein.
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Page/Page column 51
(2010/11/24)
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- Synthesis of β-Keto Esters Promoted by Yttria-Zirconia Based Lewis Acid Catalyst
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A variety of aldehydes react with methyl/ethyl diazoacetate in the presence of yttria-zirconia based catalyst to afford the corresponding β-keto esters in excellent yields.
- Pandey, Rajesh K.,Deshmukh, Anis N.,Kumar, Pradeep
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p. 1117 - 1123
(2007/10/03)
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- Synthesis and NMR analysis in solution of oligo(3-hydroxyalkanoic acid) derivatives with the side chains of alanine, valine, and leucine (β-depsides): Coming full circle from PHB to β-peptides to PHB
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Oligomers of 3-hydroxyalkanoic acids that contain two, three, and six residues with and without O-terminal (tBu)Ph2Si and C-terminal PhCH2 protection have been synthesized in such a way that the side chains on the oligoester backbone were those of the proteinogenic amino acids Ala (Me), Val (CHMe2), and Leu (CH2CHMe2). The enantiomerically pure 3-hydroxyalkanoates were obtained by Noyori hydrogenation of the corresponding 3-oxo-alkanoates with [Ru((R)-binap)Cl2](binap=2,2′bis(diphenylphosphanyl)-1, 1′-binaphthalene)/H2 (Scheme 1), and the coupling was achieved under the conditions (pyridine/(COCl)2, CH2Cl2, -78°) previously employed for the synthesis of various oligo(3-hydroxybutanoic acids) (Schemes 2 and 3). The Cotton effects in the CD spectra of the new oligoesters provided no hints about chiral conformation (cf. a helix) in MeOH, MeCN, octan-1-ol, or CF3CH2OH solutions (Figs. 1 and 2). Detailed NMR investigations in CDCl3 solution (Figs. 3-6, and Tables 1-5) of the hexa(3-hydroxyalkanoic acid) with the side chains of Val (HC), Ala (HB), Leu (HH), Val, Ala, Leu (from O- to C-terminus; 3) gave, on the NMR time-scale, no evidence for the presence of any significant amount of a 21- or a 31-helical conformation, comparable to those identified in stretched fibers of poly[(R)-3-hydroxybutanoic acid], or in lamellar crystallites and in single crystals of linear and cyclic oligo[(R)-3-hydroxybutanoic acids], or in the corresponding β-peptide(s) (the oligo(3-aminoalkanoic acid) analogs; 1-3). Thus, the extremely high flexibility (averaged or 'random-coil' conformation) of the polyester chain (CO - O rotational barrier ca. 13 kcal/mol; no hydrogen bonding), as compared to polyamide chains (CO - NH barrier ca. 18 kcal/mol; hydrogen bonding) has been demonstrated once again. The possible importance of this structural flexibility, which goes along with amphiphilic properties, for the role of PHB in biology, in evolution, and in prebiotic chemistry is discussed. Structural similarities of natural potassium-channeling proteins and complexes of oligo(3-hydroxybutanoates) with Na+, K+, or Ba2+ are alluded to (Figs. 7-9).
- Albert, Matthias,Seebach, Dieter,Duchardt, Elke,Schwalbe, Harald
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p. 633 - 658
(2007/10/03)
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- Ketone derivatives and medical application thereof
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The present invention relates to ketone derivatives represented by the following formula and medical agents containing the ketone derivatives or pharmacologically acceptable salts thereof as an active ingredient, and in particular, relates to a hematopoietic agent; it is shown that the present invention increases blood cells, such as platelets, white blood cells, and red blood cells, and is effective in preventing and treating cytopenia caused by cancer chemotherapy, radiation therapy, and the like.
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- Reaction of methyl diazoacetate with aldehydes, amines, thiols, alcohols and acids over transition metal-exchanged clays
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Metal-exchanged clays (M = Rh and Cu) catalyze effectively the reaction of methyl diazoacetate with various aldehydes, affording the corresponding β-keto esters in high yields. They have also been effective in the decomposition of methyl diazoacetate to form metallocarbenes which, in turn, successfully insert into X-H (X = N, O, S, CO2) bonds of a variety of amines, aldehydes, thiols and acids, thereby producing the corresponding esters. The Royal Society of Chemistry 1999.
- Phukan, Prodeep,Mohan, Jakkam Madan,Sudalai, Arumugam
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p. 3685 - 3689
(2007/10/03)
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- Benzopyranones, a method for producing them and uses therefor
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Novel 2H-1-benzopyran-2-ones (coumarin derivatives) of the general formula (I) are provided: STR1 wherein R1, R2, R3, R4, X and Y are defined as in the specification, and the addition compounds thereof with physiologically compatible acids, intermediates and methods for the preparation thereof. The coumarin compounds possess a neuroprotective and anti-allergic action.
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- Process for the preparation of β-ketocarboxylic acid esters
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The invention relates to a process for the preparation of β-ketocarboxylic acid esters of the general formula STR1 in which R1 is an alkyl radical having 1 to 4 C atoms, R2 is an alkyl radical or alkenyl radical having 2 to 15 C atoms or a phenyl radical and R3 is hydrogen or an alkyl or alkenyl radical having 1 to 6 C atoms, characterized in that acetocarboxylic acid esters of the general formula STR2 in which R1 and R3 are as defined, are reacted with calcium hydroxide or calcium oxide in the presence of an organic solvent and in the absence of water, the calcium chelate complexes formed are acylated with carboxylic acid chloride and the products are then cleaved with aqueous ammonium salt solution to form the β-ketocarboxylic acid esters of formula (I). The β-ketocarboxylic acid esters readily accessible by the process according to the invention can be used as important intermediates in the synthesis of pharmaceutically active ingredients or plant protection agents.
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- Knoevenagel Reactions with β-Oxo Acids. Regiospecific Enol Equivalents for Syntheses of α,β-Unsaturated Ketones and of Some β-Ketols
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3-Oxobutanoic acid reacts with aliphatic aldehydes in the presence of pyridine to give α,β-unsaturated methyl ketones in good yields.Analogous results were obtained with a series of other β-oxo acids.Synthesis of (E)-7-methyloct-4-en-3-one, a major constituent of the marine sponge Plakortis zygompha, has been carried out using this methodology.Aromatic aldehydes are generally less reactive under these conditions but give β-ketols when the phenyl ring bears an electron-withdrawing substituent.Some observations on the mechanism of the reaction between 3-oxobutanoic acid and benzaldehyde are presented.
- Grayson, David H.,Tuite, Mathew R. J.
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p. 2137 - 2142
(2007/10/02)
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- A NEW PREPARATIVE METHOD FOR 1,3-DICARBONYL COMPOUNDS BY THE REGIOSELECTIVE OXIDATION OF α,β-UNSATURATED CARBONYL COMPOUNDS, CATALYZED BY PdCl2 USING HYDROGENPEROXIDES AS THE REOXIDANT OF Pd0
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α,β-Unsaturated esters and ketones are oxidized regioselectively to give β-keto esters and 1,3-diketones in good yields in aqueous acetic acid using Na2PdCl4 as the catalyst and t-butyl hydroperoxide or hydrogen peroxide as the reoxidant of Pd0.
- Tsuji, Jiro,Nagashima, Hideo,Hori, Kimihiko
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p. 257 - 260
(2007/10/02)
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- α-Carboxylation reaction of carbonyl compounds with bromomagnesium ureide-carbon dioxide adducts
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Bromomagnesium ureide-carbon dioxide adducts, models of the carboxylated biotin complex, undergo caboxylation of a variety of carbonyl compounds in good yield.
- Sakurai, Hideki,Shirahata, Akihiko,Hosomi, Akira
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p. 1967 - 1970
(2007/10/02)
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