The Diels-Alder reactions of 2-alkyl-5-methoxy-4-(p-nitrophenyl)oxazoles with ethylenic, acetylenic, and azo-type dienophiles.

スポンサーリンク

概要

• 論文の詳細を見る

• The Diels–Alder reactions of 2-methyl- and 2-ethyl-5-methoxy-4-(<I>p</I>-nitrophenyl)oxazoles with <I>N</I>-methyl-, <I>N</I>-ethyl-, and <I>N</I>-phenylmaleimides gave endo- and exo-adducts. When the reactions were carried out in an acetonitrile solution containing a small amount of water as an impurity, <I>N</I>-substituted 3-hydroxy-2-(<I>p</I>-nitrophenyl)-4,5-pyridinecarboximides were obtained via the decomposition of the Diels–Alder adducts, while the methanol was eliminated. The decomposition might be catalyzed by contaminated water at the initial stage of the reaction. The adducts of <I>N</I>-phenylmaleimide and <I>N</I>-ethylmaleimide were shown to undergo the retro-Diels–Alder reaction on heating at 80°C to give the starting maleimides and oxazole. Diethyl azodicarboxylate and 4-phenyl-3<I>H</I>-1,2,4-triazole-3,5(4<I>H</I>)-dione gave the corresponding single adducts. A reaction with dimethyl acetylenedicarboxylate gave <I>p</I>-nitrobenzonitrile (<B>10</B>), dimethyl 2-methyl-5-methoxy-3,4-furandicarboxylate (<B>11</B>), and tetramethyl 3,5-epoxy-3-methoxy-5-methyl-1,4-cyclohexadiene-1,2,4,5-tetracarboxylate (<B>12</B>), although the expected adduct was not isolated. These products were explained on the basis of the Diels–Alder reaction, followed by the retro-Diels–Alder reaction, thus affording <B>10</B> and <B>11</B>, which gave <B>12</B> upon cycloaddition with the second molecule of DMAD.

• 公益社団法人 日本化学会の論文

著者

• TOYODA Jiro

  Institute for Molecular Science

• Ibata Toshikazu

  Institute Of Chemistry College Of General Education Osaka University

• Nakano Shuji

  Institute of Chemistry, College of General Education, Osaka University

• Isogami Yasushi

  Institute of Chemistry, College of General Education, Osaka University

• Nakawa Hiroyuki

  Institute of Chemistry, College of General Education, Osaka University

関連論文

• Dimeric Hydrogen - Bonded Transition Metal Complex Containing Bidentate Mono - deprotonated 2,2'-Biimidazolate Ligand
• Synthesis and Properties of 1,6-Diselenapyrene (DSPY) and Its Methyl Chalcogeno Derivatives
• Hydrogen-bonded Charge-Transfer Complex of Ethylenediaminoglyoxime Transition Metal Complex with Tetracyanoquinodimethane
• Nucleophilic Substitution Reaction of Aromatic Chlorides with Cyclic Tertiary Amines under High Pressure
• Formation and Reaction of Azomethine Ylide by the Reaction of Cu(acac)2-ketocarbenoids with 1,1-Diphenylmethanimine
• Formation and Reaction of Acyl Substituted Nitrile Ylide through the Rh_2(OAc)_4-Catalyzed Reaction of α-Diazocarbonyl Compounds with Benzonitrile
• Molecular structure of the exo-Diels-Alder-adduct of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with N-methylmaleimide.
• Synthesis and molecular structure of the 2:1-cycloadduct of 1-methoxy-2-benzopyrylium-4-olate with acenaphthylene.
• The BF3 catalyzed decomposition of diazo compounds in the presence of carbonyl compounds.
• The reaction of diazo ketones in the presence of metal chelates. VIII. The stereochemistry of the 1,3-dipolar cycloaddition of 1-methoxy-2-benzopyrylium-4-olates to ethylenic dipolarophiles.
• Formation and reaction of oxazoles. Synthesis of N-substituted 2-(aminomethyl)oxazoles.
• Aromatic nucleophilic substitution of halobenzenes with amines under high pressure.
• Reaction of diazo ketones in the presence of metal chelates. VII. 1,3-Dipolar cycloaddition of 1-methoxybenzo[c]pyrylium-4-olate with acetylenic dipolarophiles.
• The acid catalyzed decomposition of diazo compounds. I. Synthesis of oxazoles in the BF3 catalyzed reaction of diazo carbonyl compounds with nitriles.
• Formation of 1,3-oxathiole-2-thione and 1,2,4-trithiolane derivatives by the catalytic reaction of .ALPHA.-diazocarbonyl compounds with carbon disulfide.
• Formation and molecular structure of the 2:1-adducts of 1-alkoxy-2-benzopyrylium-4-olates with carbon disulfide.
• The Diels-Alder reactions of 2-alkyl-5-methoxy-4-(p-nitrophenyl)oxazoles with ethylenic, acetylenic, and azo-type dienophiles.
• The Acid-catalyzed Decomposition of α-Diazo β-Hydroxy Ketones
• Formation and reaction of carbonyl ylides. 1,3-Dipolar cycloaddition of 2-benzopyrylium-4-olates with carbonyl compounds.
• The high pressure Diels-Alder reactions of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with ethylenic dienophiles.
• The acid-catalyzed decomposition of diazo carbonyl compounds. II. Synthesis of 2- or 5-heteroatom-substituted oxazoles.

もっと見る 閉じる

スポンサーリンク