59729-33-8Relevant articles and documents
Palladium-catalyzed heteroallylation of unactivated alkenes-synthesis of citalopram
Hewitt, Joanne F. M.,Williams, Lewis,Aggarwal, Pooja,Smith, Craig D.,France, David J.
, p. 3538 - 3543 (2013)
A palladium-catalyzed difunctionalization of unactivated alkenes with tethered nucleophiles is reported. The versatile reaction occurs with simple allylic halides and can be carried out under air. The methodology provides rapid access to a wide array of desirable heterocyclic targets, as illustrated by a concise synthesis of the widely prescribed antidepressant citalopram.
Method for preparing citalopram and S - citalopram
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Paragraph 0011; 0024-0025, (2021/07/01)
The invention relates to a method of preparing citalopram and S-citalopram by carrying out cyclization reaction on a diol compound (II) or S-diol compound (II') in a nixed solvent of a C4-C7 ketone solvent and water and aryl sulfonyl chloride or alkyl sulfonyl chloride under an alkaline condition. The solvent used by the invention is great in solubility to reactants and products, so that the use level of the solvent is reduced, the yield is improved and meanwhile the method is good in post-treatment extraction effect and simple and convenient to operate. The compounds (II and II') are as shown in the specification.
MANGANESE (III) CATALYZED C--H AMINATIONS
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Paragraph 0710-0712, (2019/04/25)
Reactions that directly install nitrogen into C—H bonds of complex molecules are significant because of their potential to change the chemical and biological properties of a given compound. Selective intramolecular C—H amination reactions that achieve high levels of reactivity, while maintaining excellent site-selectivity and functional-group tolerance is a challenging problem. Herein is reported a manganese perchlorophthalocyanine catalyst [MnIII(ClPc)] for intermolecular benzylic C—H amination of bioactive molecules and natural products that proceeds with unprecedented levels of reactivity and site-selectivity. In the presence of Br?nsted or Lewis acid, the [MnIII(ClPc)]-catalyzed C—H amination demonstrates unique tolerance for tertiary amine, pyridine and benzimidazole functionalities. Mechanistic studies indicate that C—H amination proceeds through an electrophilic metallonitrene intermediate via a stepwise pathway where C—H cleavage is the rate-determining step of the reaction. Collectively these mechanistic features contrast previous base-metal catalyzed C—H aminations.
Ex situ generation of stoichiometric HCN and its application in the Pd-catalysed cyanation of aryl bromides: Evidence for a transmetallation step between two oxidative addition Pd-complexes
Kristensen, Steffan K.,Eikeland, Espen Z.,Taarning, Esben,Lindhardt, Anders T.,Skrydstrup, Troels
, p. 8094 - 8105 (2017/11/27)
A protocol for the Pd-catalysed cyanation of aryl bromides using near stoichiometric and gaseous hydrogen cyanide is reported for the first time. A two-chamber reactor was adopted for the safe liberation of ex situ generated HCN in a closed environment, which proved highly efficient in the Ni-catalysed hydrocyanation as the test reaction. Subsequently, this setup was exploited for converting a range of aryl and heteroaryl bromides (28 examples) directly into the corresponding benzonitriles in high yields, without the need for cyanide salts. Cyanation was achieved employing the Pd(0) precatalyst, P(tBu)3-Pd-G3 and a weak base, potassium acetate, in a dioxane-water solvent mixture. The methodology was also suitable for the synthesis of 13C-labelled benzonitriles with ex situ generated 13C-hydrogen cyanide. Stoichiometric studies with the metal complexes were undertaken to delineate the mechanism for this catalytic transformation. Treatment of Pd(P(tBu)3)2 with H13CN in THF provided two Pd-hydride complexes, (P(tBu)3)2Pd(H)(13CN), and [(P(tBu)3)Pd(H)]2Pd(13CN)4, both of which were isolated and characterised by NMR spectroscopy and X-ray crystal structure analysis. When the same reaction was performed in a THF : water mixture in the presence of KOAc, only (P(tBu)3)2Pd(H)(13CN) was formed. Subjection of this cyano hydride metal complex with the oxidative addition complex (P(tBu)3)Pd(Ph)(Br) in a 1 : 1 ratio in THF led to a transmetallation step with the formation of (P(tBu)3)2Pd(H)(Br) and 13C-benzonitrile from a reductive elimination step. These experiments suggest the possibility of a catalytic cycle involving initially the formation of two Pd(ii)-species from the oxidative addition of LnPd(0) into HCN and an aryl bromide followed by a transmetallation step to LnPd(Ar)(CN) and LnPd(H)(Br), which both reductively eliminate, the latter in the presence of KOAc, to generate the benzonitrile and LnPd(0).
Copper-catalysed cyanoalkylative cycloetherification of alkenes to 1,3-dihydroisobenzofurans: development and application to the synthesis of citalopram
Ha, Tu M.,Wang, Qian,Zhu, Jieping
supporting information, p. 11100 - 11103 (2016/09/19)
A copper-catalysed cyanoalkylative cycloetherification of alkenes was developed. Heating a solution of substituted (2-vinylphenyl)methanol in MeCN/MeOH (v/v 7/3) in the presence of a catalytic amount of copper(ii) tetrafluoroborate hydrate [Cu(BF4)2·6H2O], bathophenanthroline, K3PO4, BnOH and (tBuO)2 afforded 1,3-dihydroisobenzofurans (phthalanes) via formation of one C(sp3)-C(sp3) and one C(sp3)-O bonds. A concise synthesis of citalopram, a marketed anti-depressant drug, was accomplished by applying this novel synthetic transformation.
Alkene Dioxygenation with Malonoyl Peroxides: Synthesis of γ-Lactones, Isobenzofuranones, and Tetrahydrofurans
Alamillo-Ferrer, Carla,Karabourniotis-Sotti, Marianna,Kennedy, Alan R.,Campbell, Matthew,Tomkinson, Nicholas C. O.
, p. 3102 - 3105 (2016/07/13)
Treatment of homoallylic alcohols or carboxylic acids with malonoyl peroxide 1 provides a stereoselective method for the preparation of tetrahydrofurans, γ-lactones, and isobenzofuranones in 44-82% yield and up to 27:1 trans selectivity. Application of this simple and effective heterocyclization in the synthesis of the antidepressant citalopram is also described.
Novel and improved process for the preparation of citalopram
Reddy, M. Pulla,Bhujanga Rao,Usharani,Dubey
experimental part, p. 1829 - 1832 (2012/01/13)
A novel process for the preparation of citalopram (1) has been described. The key intermediate 1-(4-fluorophenyl)-1,3-dihydroisobenzofuran- 5-carbonitrile (2) of citalopram is prepared using novel intermediates. The process involves simple acylation, hydrolysis and reduction, which can be easily adapted to commercial scale.
Preparation of Escitalopram, Its Salts and Intermediates
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, (2011/05/03)
The present patent application relates to an improved process for the preparation of escitalopram, its salts and intermediates. It also relates to a novel crystalline form S of citalopram diol intermediate, process for preparation and its use in the preparation of citalopram, escitalopram and their salts.
Process for the Preparation of Escitalopram
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Page/Page column 7-8, (2010/08/18)
The present invention provides a novel process for the preparation of a compound of Formula III, and novel processes for preparing escitalopram using the compound of Formula III.
PREPARATION OF ESCITALOPRAM, ITS SALTS AND INTERMEDIATES
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Page/Page column 20, (2010/04/03)
The present patent application relates to an improved process for the preparation of escitalopram, its salts and intermediates. It also relates to a novel crystalline form S of citalopram diol intermediate, process for preparation and its use in the preparation of citalopram, escitalopram and their salts.
