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

2017-12-22
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.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY

Suggestions

Efficient synthesis of ferrocenylenones by Friedel-Crafts acylation with EtAlCl2-Me3Al
Doğan, Özdemir; ZEYTİNCİ, SERHAT; KOYUNCU, HASAN; BULUT, ADNAN (2005-01-17)
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.
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. ...
TFA catalyzed sequential amination/annulation/aromatization reaction of 2-propynyl-1.3-dicarbonyl compounds with amines: A new one-pot approach to functionalized pyrroles
Demir, Ayhan Sıtkı; Aybey, Asuman; Kayalar, Metin (ARKAT USA, Inc., 2005-10-9)
Highly flexible and efficient syntheses of 1,2,3,5-substituted pyrroles starting from 2-propynyl1,3-dicarbonyl compounds and amines are presented. TFA catalyzed formation of the pyrroles is suggested to proceed through sequential amination of the carbonyl compounds followed by regioselective 5-exo-dig cyclization of the enaminone intermediate and aromatization.
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 ...
Facile synthesis of iodopyridines from N-propargylic beta-enaminones via iodine-mediated electrophilic cyclization
KARABIYIKOĞLU, Sedef; Kelgokmen, YILMAZ; Zora, Metin (2015-06-24)
A facile, efficient and general synthetic method for iodopyridines is described. When treated with molecular iodine in the presence of sodium bicarbonate, N-propargylic beta-enaminones have underwent electrophilic cyclization to afford iodo-substituted pyridines in good to high yields. Iodocyclization has been found to be general for a broad range of N-propargylic beta-enaminones and tolerated the presence of aliphatic, aromatic and heteroaromatic groups with electron-withdrawing and electron-donating subst...
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.