Isoxazoles. XXI. Ring Conversion Reactions of 2,3,4-Trisubstituted Isoxazolium Salts with Some Nucleophiles

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概要

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• Ring conversion reactions of the quaternary salts : 2,4-dimethyl-3-phenyl-, 3,4-diphenyl-2-methyl- and 2-methyl-3-phenylisoxazolium perchlorate (Ia, b and c) with some nucleophiles were investigated. Reactions of I with alkyl malonates in the presence of sodium alcoholates gave the corresponding 4-unsubstituted-2-pyridone-3-carboxylates (II) and their 4-hydroxy derivatives (III), along with 2,5-diphenyl-1,3,4-trimethylpyrrole (IV) and alkyl cinnamates (V). Similar reactions of Ia with some active methylene compounds were also examined. Reactions of I with cyclic enamines gave 4-unsubstituted 1-methyl-2,3-trimethylene or tetramethylenepyridinium perchlorates (XIII) besides β-kteo acid amides (XIV). Reactions of Ia with potassium cyanate and with phenylhydrazine in the presence of sodium hydroxide gave 3,5-dimethyl-4-phenyluracil (XV) and 1,5-diphenyl-3-hydroxy-4-methylpyrazole (XVI), respectively. On the contrary, the reaction of Ia with phenylhydrazine in the absence of sodium hydroxide resulted in the formation of 1,5-diphenyl-4-methyl- and 1,3-diphenyl-4-methylpyrazole (XVII and XVIII). A tentative mechanism of these ring conversion reactions of I are presented.

• 公益社団法人日本薬学会の論文
• 1969-11-25

著者

• 足達 郁夫

  Shionogi Research Laboratories Shionogi & Co. Ltd.

関連論文

• Studies on Dihydropyridines. III. : Synthesis of 4,7-Dihydrothieno[2,3,-b]-pyridines with Vasodilator and Antihypertensive Activities
• Isoxazoles. XVI. The Reaction of Nitrous Acid on 5-Amino-3,4-dialkylisoxazoles
• Isoxazoles. XXIII. Synthesis of N-Substituted 4-Isoxazolines and Their Conversion into 2-Acylaziridines
• Isoxazoles. XXII. A New Synthesis of 4-Isoxazolines and Their Thermal Conversion into Pyrroles
• Isoxazoles. XXI. Ring Conversion Reactions of 2,3,4-Trisubstituted Isoxazolium Salts with Some Nucleophiles
• Isoxazoles. XX. Base-induced Ring Cleavage Reactions of 2,3,4-Trisubstituted Isoxazolium Salts
• Isoxazoles. XIX. Synthesis and Cleavage Reaction of Some 3,4-Disubstituted Isoxazoles

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