scholarly journals Synthesis of Functionalized Diethyl (pyrrolidin-2-yl)Phosphonate and Diethyl (5-oxopyrrolidin-2-yl)Phosphonate

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3160
Author(s):  
Iwona E. Głowacka ◽  
Anna Hartwich ◽  
Iwona Rozpara ◽  
Dorota G. Piotrowska
Keyword(s):  
Intramolecular Cyclization ◽  
Subsequent Treatment ◽  
Dipolar Cycloaddition ◽  
Amino Group ◽  
Synthetic Strategy ◽  
Dimethyl Maleate

Short and efficient syntheses of functionalized (pyrrolidin-2-yl)phosphonate and (5-oxopyrrolidin-2-yl)phosphonate have been developed. The synthetic strategy involved the diastereospecific 1,3-dipolar cycloaddition of N-benzyl-C-(diethoxyphosphoryl)nitrone to cis-1,4-dihydroxybut-2-ene and dimethyl maleate, respectively. O,O-Diethyl 3-carbamoyl-4-hydroxy(5-oxopyrrolidin-2-yl)phosphonate was obtained from O,O-diethyl 2-benzyl-4,5-dimethoxycarbonyl(isoxazolidin-3-yl)phosphonate by hydrogenation and subsequent treatment with ammonia, whereas transformation of O,O-diethyl 2-benzyl-4,5-dihydroxymethyl(isoxazolidin-3-yl)phosphonate into O,O-diethyl 3-aminomethyl-4-hydroxy(pyrrolidin-2-yl)phosphonate was accomplished by mesylation followed by hydrogenolysis to undergo intramolecular cyclization and the introduction of amino group via ammonolysis. Stereochemistry of the isoxazolidine cycloadducts, as well as the final functionalized (pyrrolidin-2-yl)- and (5-oxopyrrolidin-2-yl)phosphonates were established based on conformational analyses using vicinal H–H, H–P, and C–P couplings and supported by the observed diagnostic NOESY correlation signals.

Synthesis and crystal structures of three novel benzimidazole/benzoindolizine hybrids

2016 ◽  
Vol 71 (3) ◽  
pp. 231-239 ◽  
Author(s):  
Roumaissa Belguedj ◽  
Sofiane Bouacida ◽  
Hocine Merazig ◽  
Ali Belfaitah ◽  
Aissa Chibani ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Crystal Structures ◽  
Dipolar Cycloaddition ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimethyl Maleate

AbstractThree benzoindolizine derivatives, 1, 2, and 3, were obtained via 1,3-dipolar cycloaddition. The reaction of 1-(2′-benzimidazolylmethyl)isoquinolinium ylides with dimethyl acetylenedicarboxylate gave a mixture of pyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (1) and 1,10b-dihydropyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (2) derivatives containing a benzimidazole moiety. The reaction of this isoquinolinium N-ylide with dimethyl maleate gave an unexpected 2,3-dihydropyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (3). The structures of all reported compounds have been examined by X-ray crystallography, mass spectrometry, and NMR spectroscopy.

Highly Diastereoselective 1,3-Dipolar Cycloaddition of a d-Galactose-Derived Nitrone with Dimethyl Maleate: Synthesis of Polyhydroxylated Perhydroaza­azulenes

Synlett ◽  
2009 ◽  
Vol 2009 (12) ◽  
pp. 1959-1963
Author(s):  
Dilip Dhavale ◽  
Omprakash Bande ◽  
Vrushali Jadhav ◽  
Vedavati Puranik
Keyword(s):  
Dipolar Cycloaddition ◽  
Dimethyl Maleate

scholarly journals Base-Catalyzed Synthesis of Flavones via Thiol-Assisted Sequential Demethylation/Cyclization of 1-(2-methoxyphenyl)prop-2-yn-1-ones

2021 ◽  
Author(s):  
Ritiele Heck ◽  
Thiago Anjos ◽  
Maira R Giehl ◽  
Ricardo F Schumacher ◽  
Benhur Godoi
Keyword(s):  
Reaction Time ◽  
Secondary Metabolites ◽  
Transition Metal ◽  
Intramolecular Cyclization ◽  
Important Class ◽  
Short Reaction Time ◽  
Metal Free ◽  
Synthetic Strategy ◽  
Pharmacologically Active ◽  
Active Substances

Flavone and analogues represent an important class of biologically and pharmacologically active substances commonly found in the composition of diverse plants as part of the class of secondary metabolites. Herein, we have demonstrated an efficient and regioselective synthetic strategy for the preparation of functionalized flavones through sequential demethylation/6-endo-dig intramolecular cyclization of propyn-1-ones, using catalytic amounts of base in the presence of a thiol, by employing NMP as the solvent. The reactions proceeded smoothly under transition-metal-free and open to air conditions, furnishing the desired six-membered heterocycles in moderate to excellent yields, in short reaction time.

Intramolecular Cyclization of Aryl Propargyl Ethers: A Straightforward and Convenient Approach to Benzofuran Derivatives

2018 ◽  
Vol 15 (7) ◽  
pp. 972-981 ◽  
Author(s):  
Akram Hosseinian ◽  
Mirzaagha Babazadeh ◽  
Ladan Edjlali ◽  
Zahra Rahmani ◽  
Esmail Vessally
Keyword(s):  
Intramolecular Cyclization ◽  
Low Cost ◽  
Biologically Active ◽  
Specific Class ◽  
Unsaturated Ketones ◽  
Synthetic Strategy ◽  
Comprehensive Development ◽  
One Step ◽  
Large Application ◽  
The Subject

Background: Benzofurans are very important structural motifs found in a great number of natural products and biologically active compounds. Many commercially available drugs, including citalopram, dronedarone, saprisartan, darifenacin, and galantamine are derived from benzofuran core entities. Due to the diversity of benzofuran derivatives in the therapeutic response profile, developing novel and truly efficient methods for their synthesis from low-cost and easily accessible starting materials in one-step has been the subject of number of papers in recent years. Objective: Propargylic ethers are one of the most specific class of heteroatom-containing alkynes showing a large application as intermediates in organic synthesis. These compounds were successfully transformed into various organic compounds, including chromenes, carbazoles, cyclopentanones, 1, 2-dihydropyridines, α, β- unsaturated ketones, alcohols, allenes and many more. Synthesis of benzofurans via intramolecular cyclization of aryl propargyl ethers has become one of the most popular applications of theses versatile compounds. In this review we will highlight the recent discoveries and advances in this interesting research arena. Method: The review is divided into two major sections. The first will discuss cyclization of ortho-halo aryl propargylic ethers, while the second focuses exclusively on cyclization of ortho-unsubstituted aryl propargyl ethers. It is should be mentioned that special emphasis is placed on the mechanistic aspects of these reactions. Conclusion: Synthesis of benzofuran derivatives via intramolecular cyclization of corresponding aryl propargyl ethers have witnessed rapid and comprehensive development in recent years. The main advantages of this synthetic strategy include the use of simple, inexpensive, non-toxic, and readily accessible starting materials, and its pot, atom, and step economy.

scholarly journals Continuous multistep synthesis of 2-(azidomethyl)oxazoles

2018 ◽  
Vol 14 ◽  
pp. 506-514 ◽  
Author(s):  
Thaís A Rossa ◽  
Nícolas S Suveges ◽  
Marcus M Sá ◽  
David Cantillo ◽  
C Oliver Kappe
Keyword(s):  
Process Integration ◽  
Building Blocks ◽  
Subsequent Treatment ◽  
Flow Process ◽  
Synthetic Strategy ◽  
Multistep Synthesis ◽  
Nucleophilic Displacement ◽  
Displacement Reactions ◽  
Continuous Flow Process ◽  
Vinyl Azides

An efficient three-step protocol was developed to produce 2-(azidomethyl)oxazoles from vinyl azides in a continuous-flow process. The general synthetic strategy involves a thermolysis of vinyl azides to generate azirines, which react with bromoacetyl bromide to provide 2-(bromomethyl)oxazoles. The latter compounds are versatile building blocks for nucleophilic displacement reactions as demonstrated by their subsequent treatment with NaN3 in aqueous medium to give azido oxazoles in good selectivity. Process integration enabled the synthesis of this useful moiety in short overall residence times (7 to 9 min) and in good overall yields.

CuI-Catalyzed [3+2] Cycloaddition of Hindered Vinylidenebisphosphonates (VBP) with Azomethine Imines for Highly Regioselective Access to Dinitrogen-Heterobicycle-Containing Bisphosphonates

Synthesis ◽  
2018 ◽  
Vol 50 (13) ◽  
pp. 2601-2607
Author(s):  
Zhongxiang Zhu ◽  
Qinghe Wang ◽  
Dulin Kong ◽  
Tiao Huang ◽  
Mingshu Wu
Keyword(s):  
Biological Activity ◽  
Low Cost ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Atom Economy ◽  
Mild Conditions ◽  
Synthetic Strategy ◽  
Fused Heterocycles ◽  
Azomethine Imines ◽  
High Stereoselectivity

A concise, atom-economic, and highly regioselective synthetic strategy for the construction of several dinitrogen-fused heterocycles bearing bisphosphonates by 1,3-dipolar cycloaddition reaction of azomethine imines with tetraethyl vinylidene-1,1-bisphosphonate in the presence of CuI in toluene media has been developed. The targeted compounds were obtained in good yields and with excellent regioselectivity. This method for the synthesis of gem-bisphosphonates (BPs) is particularly attractive due to features such as low cost, mild conditions, atom economy, high stereoselectivity, and potential biological activity of the product.

scholarly journals Synthesis and Structure of the Bis- and Tris-Polyhedral Hybrid Carboranoclathrochelates with Functionalizing Biorelevant Substituents—The Derivatives of Propargylamine Iron(II) Clathrochelates with Terminal Triple C≡C Bond(s)

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3635
Author(s):  
Genrikh E. Zelinskii ◽  
Ilya P. Limarev ◽  
Anna V. Vologzhanina ◽  
Valentina A. Olshevskaya ◽  
Anton V. Makarenkov ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Cycloaddition Reaction ◽  
Intramolecular Interactions ◽  
Dipolar Cycloaddition ◽  
X Ray Diffraction ◽  
Hybrid Molecule ◽  
Chlorine Atoms ◽  
Synthetic Strategy ◽  
Dihydrogen Bonding ◽  
Derivatives Of

A synthetic strategy for obtaining structurally flexible hybrid iron(II) carboranoclatrochelates functionalized with biorelevant groups, based on a combination of a 1,3-dipolar cycloaddition reaction with nucleophilic substitution of an appropriate chloroclathrochelate precursor, was developed. In its first stage, a stepwise substitution of the dichloroclathrochelate precursor with amine N-nucleophiles of different natures in various solvents was performed. One of its two chlorine atoms with morpholine or diethylamine in dichloromethane gave reactive monohalogenoclathrochelate complexes functionalized with abiorelevant substituents. Further nucleophilic substitution of their remaining chlorine atoms with propargylamine in DMF led to morpholine- and diethylamine-functionalized monopropargylamine cage complexes, the molecules of which contain the single terminal C≡C bond. Their “click” 1,3-cycloaddition reactions in toluene with ortho-carborane-(1)-methylazide catalyzed by copper(II) acetate gave spacer-containing di- and tritopic iron(II) carboranoclatrochelates formed by a covalent linking between their different polyhedral(cage) fragments. The obtained complexes were characterized using elemental analysis, MALDI-TOF mass, UV-Vis, 1H, 1H{11B}, 11B, 11B{1H}, 19F{1H} and 13C{1H}-NMR spectra, and by a single crystal synchrotron X-ray diffraction experiment for the diethylamine-functionalized iron(II) carboranoclathrochelate. Its encapsulated iron(II) ion is situated almost in the center of the FeN6-coordination polyhedron possessing a geometry intermediate between a trigonal prism and a trigonal antiprism with a distortion angle φ of approximately 28º. Conformation of this hybrid molecule is strongly affected by its intramolecular dihydrogen bonding: a flexibility of the carborane-terminated ribbed substituent allowed the formation of numerous C–H…H–B intramolecular interactions. The H(C) atom of this carborane core also forms the intermolecular C–H…F–B interaction with an adjacent carboranoclathrochelate molecule. The N–H…N intermolecular interaction between the diethylamine group of one hybrid molecule and the heterocyclic five-membered 1Н-[1,2,3]-triazolyl fragment of the second molecule of this type caused formation of H-bonded carboranoclathrochelate dimers in the X-rayed crystal.

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