Electrooxidative cyclization of N-acylhydrazones of aldehydes and ketones to .DELTA.3-1,3,4-oxadiazolines and 1,3,4-oxadiazoles
摘要:
The electrolytic oxidation of ketone N-acylhydrazones (1) in methanolic sodium acetate induced their intramolecular cyclization to the corresponding 2-methoxy-DELTA(3)-1,3,4-oxadiazolines 3. The thermal stability of a given oxadiazoline and what products were formed by its thermal decomposition was found to depend on the natures of the substituents at C-2. Thus, 2-methoxy-2-phenyloxadiazolines preferentially yielded oxiranes 5, whereas 2-alkyl-2-methoxyoxadiazolines preferentially gave enol ethers 6. 2,2-Dimethoxyoxadiazolines decomposed to the parent ketones and many unidentified products. The electrolytic oxidation of aldehyde N-acylhydrazones 2 gave 2,5-disubstituted 1,3,4-oxadiazoles 4. The oxidative cyclization of the N-benzoylhydrazones of aliphatic aldehydes gave especially high yields of the corresponding heterocycles.
Electrooxidative cyclization of N-acylhydrazones of aldehydes and ketones to .DELTA.3-1,3,4-oxadiazolines and 1,3,4-oxadiazoles
摘要:
The electrolytic oxidation of ketone N-acylhydrazones (1) in methanolic sodium acetate induced their intramolecular cyclization to the corresponding 2-methoxy-DELTA(3)-1,3,4-oxadiazolines 3. The thermal stability of a given oxadiazoline and what products were formed by its thermal decomposition was found to depend on the natures of the substituents at C-2. Thus, 2-methoxy-2-phenyloxadiazolines preferentially yielded oxiranes 5, whereas 2-alkyl-2-methoxyoxadiazolines preferentially gave enol ethers 6. 2,2-Dimethoxyoxadiazolines decomposed to the parent ketones and many unidentified products. The electrolytic oxidation of aldehyde N-acylhydrazones 2 gave 2,5-disubstituted 1,3,4-oxadiazoles 4. The oxidative cyclization of the N-benzoylhydrazones of aliphatic aldehydes gave especially high yields of the corresponding heterocycles.
Yang Rui-Yang, Dai Li-Xin, J. Org. Chem., 58 (1993) N 12, S 3381-3383
作者:Yang Rui-Yang, Dai Li-Xin
DOI:——
日期:——
Electrooxidative cyclization of N-acylhydrazones of aldehydes and ketones to .DELTA.3-1,3,4-oxadiazolines and 1,3,4-oxadiazoles
作者:Toshiro Chiba、Mitsuhiro Okimoto
DOI:10.1021/jo00031a014
日期:1992.2
The electrolytic oxidation of ketone N-acylhydrazones (1) in methanolic sodium acetate induced their intramolecular cyclization to the corresponding 2-methoxy-DELTA(3)-1,3,4-oxadiazolines 3. The thermal stability of a given oxadiazoline and what products were formed by its thermal decomposition was found to depend on the natures of the substituents at C-2. Thus, 2-methoxy-2-phenyloxadiazolines preferentially yielded oxiranes 5, whereas 2-alkyl-2-methoxyoxadiazolines preferentially gave enol ethers 6. 2,2-Dimethoxyoxadiazolines decomposed to the parent ketones and many unidentified products. The electrolytic oxidation of aldehyde N-acylhydrazones 2 gave 2,5-disubstituted 1,3,4-oxadiazoles 4. The oxidative cyclization of the N-benzoylhydrazones of aliphatic aldehydes gave especially high yields of the corresponding heterocycles.
Hypervalent iodine oxidation of N-acylhydrazones and N-phenylsemicarbazone: an efficient method for the synthesis of derivatives of 1,3,4-oxadiazoles and .DELTA.3-1,3,4-oxadiazolines
作者:Ruiyang Yang、Lixin Dai
DOI:10.1021/jo00064a027
日期:1993.6
The oxidation of ketone N-acylhydrazones 1 by phenyliodine(III) diacetate (PIDA) in alcohol gave 2-alkoxy-DELTA3-1,3,4-oxadiazolines 4 in excellent yields, while the oxidative cyclization of aldehyde N-acylhydrazone 2 by PIDA in methanolic sodium acetate gave 2,5-disubstituted 1,3,4-oxadiazoles in good yields. The oxidation of acetone 4-phenylsemicarbazone afforded 2-(N-phenylimino)-DELTA3-1,3,4-oxadiazoline in excellent yield.