A facile one-pot synthesis of 2-(prop-2-yn-1-ylidene)-2,3-dihydro-1,4-thiazepines

An unprecedented method for the synthesis of 2-(prop-2-yn-1-ylidene)-2,3-dihydro-1,4-thiazepines from N-(2,4-pentadiynyl) beta-enaminones is reported. Upon treatment with Lawesson's reagent, N-(2,4-pentadiynyl) beta-enaminones were thionated to furnish N-(2,4-pentadiynyl) beta-enaminothiones, which immediately underwent 7-exo-dig cyclization to generate 2-(prop-2-yn-1-ylidene)-2,3-dihydro-1,4-thiazepines in one-pot. A general trend was observed for various N-(2,4-pentadiynyl) beta-enaminones and cyclization proceeded with broad functional group tolerance. This operationally easy method may provide quick access to a library of functionalized 1,4-thiazepines in the field of pharmaceutical chemistry.


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 ...
A facile synthesis of 6-chloro-2-methylene-2,3-dihydro-1,4-oxazepines from N-propargylic beta-enaminones
Ibis, Ozge; Zora, Metin (Elsevier BV, 2020-11-01)
A new and efficient method for the synthesis of 6-chloro-substituted 2-methylene-2,3-dihydro-1,4-oxazepines has been demonstrated. Upon treatment with N-chlorosuccinimide in acetonitrile, N-propargylic beta-enaminones underwent chlorination to afford alpha-chlorinated N-propargylic beta-enaminones, which was then subjected to electrophilic cyclization with zinc chloride in refluxing chloroform to yield 6-chloro-2-methylene-2,3-dihydro-1,4-oxazepines. It was shown for the first time that on N-propargylic bet...
A new strategy for the synthesis of pyridines from N-propargylic beta-enaminothiones
Kelgokmen, Yilmaz; Zora, Metin (Royal Society of Chemistry (RSC), 2019-03-07)
A new method for the synthesis of 2,4,5-trisubstituted pyridines from N-propargylic beta-enaminothiones is reported. beta-Enaminothiones were prepared by thionation of the corresponding beta-enaminones with Lawesson's reagent. When treated with diisopropylamine in DMF at room temperature, N-propargylic beta-enaminothiones yielded 2,4,5-trisubstituted pyridines in moderate to high yields, along with small amounts of 2-methylene-2,3-dihydro-1,4-thiazepines. The reaction was found to be general for a broad ran...
A novel one-pot synthesis of ferrocenyl-substituted 1,2,4-oxadiazoles
Zora, Metin; Kelgokmen, YILMAZ (Elsevier BV, 2014-06-01)
One-pot synthesis of 5-ferrocenyl-1,2,4-oxadiazoles via the reaction between 3-ferrocenylpropynal and amidoximes is described. 3-Ferrocenylpropynal reacts with a variety of amidoximes in the presence of KOH in refluxing dioxane to afford a broad range of 5-ferrocenyl-1,2,4-oxadiazole derivatives. The reaction first produces the corresponding conjugate addition product which, upon cyclization and rearrangement, yields the targeted 1,2,4-oxadiazole. The reaction appears to be general for a diversity of amidox...
A facile synthesis of (+/-)-mintlactone
Tanyeli, Cihangir; Demir, AS (Informa UK Limited, 1997-01-01)
(+/-)-Mintlactone has been synthesized by applying a novel effective synthetic sequence. 4-Methylcyclohexanone was subjected to acetoxylation with Pb(OAc)(4). Hydrolysis followed by reaction with 2-chloroprogionyl chloride,then treatment with triethyl phosphite and, finally, Horner-Emmons-type intramolecular cyclization afforded (+/-)-Mintlactone.
Citation Formats
E. S. Yılmaz and M. Zora, “A facile one-pot synthesis of 2-(prop-2-yn-1-ylidene)-2,3-dihydro-1,4-thiazepines,” SYNTHETIC COMMUNICATIONS, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/69318.