Recent Developments in the Synthesis of Five- and Six-Membered Heterocycles Using Molecular Iodine (original) (raw)
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6-Iodo-2-isopropyl-4H-3,1-benzoxazin-4-one as building block in heterocyclic synthesis
Synthetic Communications, 2016
As a part of ongoing studies in the synthesis of a variety of heterocycles of biological importance, we report here an efficient and convenient method for the synthesis of novel compounds from 6iodo-2-isopropyl-4H-3,1-benzoxazin-4-one 1 as building block. The reaction of benzoxazinone 1 with various reagents such as diethylmalonate, sodium azide, and phosphorus pentasulfide yielded the compounds 2-5. The behavior of benzothiazin-4-thione 5 toward formamide and hydrazine hydrate was investigated, forming the compounds 6 and 7. The reaction of quinazolinone derivative 8 with β-D-glucose pentaacetate, ethyl 2-methyl-5-((1S,2R,3R)-1,2,3,4-tetrahydroxybutyl)furan-3-carboxylate, epichlorohydrin and benzenesulphonyl chloride afforded quinazolinone derivatives 9, 10, 12, and 13 respectively. The reaction of quinazolinone derivative 10 with acetic anhydride resulted in formation of the acylated compound 11. The behavior of quinazolinylacetohydrazide derivative 14 toward carbon electrophiles [16] has been investigated by its reaction with ethyl benzoylacetate, potassium thiocyanate, and phenyl isothiocyanate, affording the quinazolinone derivatives 15, 16, and 18, respectively. Treatment of compound 16 with sodium hydroxide followed by hydrochloric acid yielded the mercapto-triazole derivative 17. The structures of the newly synthesized compounds were confirmed by elemental analysis, infrared (IR), 1 H NMR, 13 C NMR, and mass spectra. The antimicrobial activities of some of the synthesized compounds were preliminarily evaluated.
The Journal of Organic Chemistry, 2005
A variety of furan-2-ylacetates have been prepared by dehydrogenation of monocyclic 2-alkylidenetetrahydrofurans, which are readily available by cyclizations of open-chained 1,3-dicarbonyl dianions with 1-bromo-2-chloroethane. 5′H-[2,3′]Bifuranyl-2′-ones are available based on sequential "cyclization/dehydrogenation" reactions of R-acetyl-γ-butyrolactones. A variety of 7-(alkoxycarbonyl)benzofurans and 7-(alkoxycarbonyl)-2,3-dihydrobenzofurans were prepared by a cyclization/ dehydrogenation strategy. These reactions rely on cyclizations of 2-oxocycloalkane-1-carboxylatederived 1,3-dicarbonyl dianions ("free dianions") or 1,3-bis-silyl enol ethers ("masked dianions") with various 1,2-dielectrophiles. * Corresponding author. Fax: +381 4986412. † Universitä t Rostock. ‡ Universitä t Greifswald. § Leibniz-Institut fü r Organische Katalyse an der Universitä t Rostock e. V. (IfOK).
Heterocycles, their Synthesis and Industrial Applications: A Review
International Journal for Research in Applied Science and Engineering Technology, 2020
Aromatic heterocycles are planar rings of atoms containing at least one non-carbon atom (N, S, O) and contains (4n+2)π electrons. A vast number of different classes exists for example pyrrole, thiophene, furan, pyridine, azoles, indoles, Isoindoles, quinolines, isoquinolines, Benzofurans, Isobenzofurans, benzothiophenes, Isobenzothiophenes, pteridines, purines. These ring compounds possess interesting pharmacological and biological activities which include: anti-malarial, analgesic, anti-inflammatory, anticancer, antifungal, antibacterial and are also used as pesticides: herbicides, fungicides, insecticides, rodenticides, and as stimulators and regulators of plant growth as well as fluorescence materials, ionic liquids, dyes and pigments. There are several established methods for their synthesis. This research paper aims at highlighting these very diversities of these ring compounds and the different methods by which they could be synthesized.
Tetrahedron Letters, 2005
N-Trimethylsilyloxy-N-benzyl-1-alkyl-2-acetoxy-3-buten-1-amines 13, obtained in good yields and moderate diastereoselectivities by TMSOTf promoted a-acetoxyallylation of nitrones using metallic zinc and 3-bromo-propenyl acetate 11, are exploited in a stereospecific 5-exo-trig iodocyclization reaction to afford 4,5-cis-3-alkyl-4-acetoxy-5-iodomethyl isoxazolidines 14, promising starting materials for the synthesis of pyrrolidine azasugars.