Synthesis of 1,4-Thiazepines

Kelgokmen, Yılmaz
Zora, Metin
An efficient, general, and unprecedented methodology for the synthesis of 2-methylene-2,3-dihydro-1,4-thiazepines from N-propargylic beta-enaminones is described. Initially, N-propargylic beta-enaminones were thionated with Lawesson's reagent in good to high yields, and then the resulting N-propargylic beta-enaminothiones were subjected to electrophilic cyclization. When treated with zinc chloride in refluxing chloroform, Npropargylic beta-enaminothiones underwent electrophilic cyclization to yield 2-methylene-2,3-dihydro-1,4-thiazepines in good to high yields. A general trend was observed for all N-propargylic beta-enaminothiones, and the cyclization proceeded with high efficiency and large functional group tolerance. This process is also applicable to the cyclization of internal alkyne-tethered N-propargylic beta-enaminothiones. This operationally simple and facile method may represent a very rapid entry to a library of functionalized 1,4-thiazepines in the area of pharmaceuticals.


Synthesis of 3-[(4-Nitrophenyl)thio]-Substituted 4-Methylene-1-pyrrolines from N-Propargylic beta-Enaminones
Korkmaz, Esra; Zora, Metin (American Chemical Society (ACS), 2020-04-03)
A facile and efficient method for the synthesis of 3-[(4-nitrophenyl)thio]-substituted 4-methylene-1-pyrrolines is described. When treated with 4-nitrobenzenesulfenyl chloride in refluxing acetonitrile, N-propargylic beta-enaminones produced alpha-sulfenylated N-propargylic beta-enaminones, which, in the presence of sodium hydride or cesium carbonate, underwent nucleophilic cyclization to afford 4-methylene-3-[(4-nitrophenyl)thio]-1-pyrrolines in good to high yields. It was shown for the first time that on ...
Synthesis and enzymatic resolution of various cyclopentenoid and cyclohexenoid type compounds
İyigün, Çiğdem; Tanyeli, Cihangir; Department of Chemistry (2005)
The aim of this thesis is to synthesize enantiomerically enriched cyclopentenoid and cyclohexenoid type of compounds with quaternary carbon stereocenters that are the simplest precursors of the complex natural products. The first part of the study involves the preparation of ?'-acetoxy ?'-substituted ?,β-unsaturated cyclic ketones. Methylation, ethylation, benzylation and allylation of cyclohexenone and cyclopentenone derivatives are performed. Then, these compounds are regioselectively oxidized at the ?'-p...
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 ...
Synthesis of 1,2,3,5- tetrasubstituted pyrrole derivatives via 5-exo-dig type cyclization and stereoselective functionalisation of ferrocene derivatives
Kayalar, Metin; Demir, Ayhan Sıtkı; Department of Chemistry (2005)
A convenient and new method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds through acid catalyzed cyclization reaction is described. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of triflouroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The investigations on the studies of developing a new meth...
Synthesis of chiral lactones via the baeyer villiger oxidation of cyclic aromatic acetoxy ketones novel annulation reactions of 2-propynyl-1,3-dicarbonyl compounds to form pyrroles addition of acyl phosphonates to diethyl cyanophosphonate (depc)
Aybey, Asuman; Demir, Ayhan Sıtkı; Department of Chemistry (2009)
Chiral Baeyer-Villiger (BV) oxidation of cyclic ketones allows rapid access to asymmetric lactones as valuable intermediates in organic chemistry and frequently encountered precursors in enantioselective synthesis. In the first part, BV oxidation of functionalized ketones, especially cyclic -hydroxy and acetoxy ketones is described which could be a straightforward route to the -hydroxy lactones and -hydroxyalkanoic acid derivatives. The -acetoxylation of indanone, tetralone and chromanone derivatives by usi...
Citation Formats
Y. Kelgokmen and M. Zora, “Synthesis of 1,4-Thiazepines,” JOURNAL OF ORGANIC CHEMISTRY, pp. 8376–8389, 2018, Accessed: 00, 2020. [Online]. Available: