Y Zinc Chloride Mediated Synthesis of 1,4-Oxazepines from N-Propargylic -Enaminones

Kelgokmen, Yılmaz
Çayan, Yasemin
Zora, Metin
An efficient and general method for the synthesis of 1,4-oxazepines is described. When reacted with ZnCl2 in DCM at 40 degrees C or CHCl3 at 61 degrees C, N-propargylic -enaminones undergo 7-exo-dig cyclization to afford 2-methylene-2,3-dihydro-1,4-oxazepines in good to high yields. This cyclization has been found to be general for a diverse range of N-propargylic -enaminones, and proceeds with high efficiency and with broad functional group tolerance. The reactions in refluxing CHCl3 produced 1,4-oxazepines in comparatively short reaction times and with better yields that those obtained in refluxing DCM. This operationally easy method may provide rapid access to a library of functionalized 1,4-oxazepine derivatives of pharmacological interest.


Efficient synthesis of ferrocenylenones by Friedel-Crafts acylation with EtAlCl2-Me3Al
Efficient synthesis of ferrocenyl en ones using a Friedel-Crafts acylation reaction is described. Acryloyl, methacryloyl, crotonoyl, cinnamoyl, and beta-methylcrotonoyl chlorides react with ferrocene in the presence of a Lewis acid (EtAlC2 or EtAlCl2-Me3Al) to give the corresponding ferrocenyl en ones (acryloyl, methacryloyl, crotonoyl, cinnamoyl, and methylcrotonoylferrocenes) in good isolated yields. Besides ferrocenylenones, chloroactylferrocene is also synthesised by this method.
A New Strategy for the Synthesis of 4-Propargyl-Substituted 1H-Pyrroles from N-(5-phenyl-2,4-pentadiynyl) beta-Enaminones
Yılmaz, Elif Serel; Zora, Metin (2019-10-09)
A new method for the synthesis of 4-propargyl-substituted 1H-pyrroles is described. When treated with sodium hydride in refluxing dichloromethane, N-(5-phenyl-2,4-pentadiynyl) beta-enaminones, synthesized by the coupling of N-propargylic beta-enaminones with phenylacetylene, afforded 4-propargyl-substituted pyrrole derivatives. This conversion was general for a variety of N-(5-phenyl-2,4-pentadiynyl) beta-enaminones and displayed broad functional group tolerance. During the reaction, not only cyclization of...
Manganese(III) acetate-mediated oxidative coupling of phenylhydrazines with benzene: a novel method for biaryl coupling
Demir, Ayhan Sıtkı; Reis, O; Ozgul-Karaaslan, E (2001-01-01)
The reaction of phenylhydrazines with benzene in the presence of manganese(III) acetate affords biaryls in good yields. The same reaction was carried out with similar oxidants, such as Co-III, Ce-IV and Pb-IV; among these oxidants Mn-III acetate shows higher efficiency and selectivity.
A new approach for the synthesis of spiro and gem-dimethyl-substituted 1,4-oxazepines from N-propargylic beta-enaminones
Karadeniz, Eda; Kelgökmen, Yılmaz; Zora, Metin (Wiley, 2020-11-01)
An efficient and general method for the synthesis of spiro-1,4-oxazepines and 3,3-dimethyl-1,4-oxazepines is reported. When treated with ZnI2 and AgSbF6 in refluxing DCE, cyclohexane-embedded N-propargylic beta-enaminones underwent 7-exo-dig cyclization to afford spiro-1,4-oxazepines, specifically 12-methylene-11-oxa-7-azaspiro[5.6]dodeca-7,9-dienes, in good to high yields. Accordingly, N-(1,1-dimethyl)propargylic beta-enaminones produced 3,3-dimethyl-1,4-oxazepines. Cyclization was found to be general for ...
Selective synthesis of N-substituted pyrrolo[1,2-a]pyrazin-1(2H)-one derivatives via alkyne cyclization
Cetinkaya, Yasin; Balcı, Metin (2014-12-03)
A novel and efficient synthesis of N-substituted pyrrolo-pyrazinone derivatives has been developed. A trichloroacetyl group connected to the pyrrole ring was converted into the desired carboxamide derivatives. Promoted by NaH, the pyrrole carboxamide derivatives underwent a tandem reaction with propargyl bromide to afford pyrrolo-pyrazinones with high efficiency under very mild conditions. The mechanism for the formation of the products is discussed and supported by DFT calculations. (C) 2014 Elsevier Ltd. ...
Citation Formats
Y. Kelgokmen, Y. Çayan, and M. Zora, “Y Zinc Chloride Mediated Synthesis of 1,4-Oxazepines from N-Propargylic -Enaminones,” EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, pp. 7167–7178, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37981.