Naslov
Zeolite-Catalyzed 1,2-Dibromination of Cinnamates Using 1,3-Dibromo-5,5-dimethylhydantoin as a Bromine Source

Autori
Jurin, Mladenka ; Roje, Marin ; Palčić, Ana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
9th Conference of the Federation of European Zeolite Associations (FEZA 2023), Abstract Book / - Portorož, 2023, 213-213

Skup
9th Conference of the Federation of European Zeolite Associations (FEZA 2023)

Mjesto i datum
Portorož, Slovenija, 02.07.2023. - 06.07.2023

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
cinnamates ; zeolites ; DBDMH ; 1, 2-dibromination

Sažetak
Organobromine compounds, also called organobromides, are found in a variety of marine natural products (e.g. aeroplysinin-1, tyrian purple, 14-debromoaraplysillin and 14- debromoprearaplysillin) [1]. They are essential synthetic intermediates in the manufacture of derivatives of many natural products, pharmaceuticals, agrochemicals and other fine chemicals [2]. Organobromides are also very useful building blocks for some fundamental chemical transformations such as Grignard reactions, cross- coupling, nucleophilic substitution, etc [3]. Zeolites, as a class of inorganic microporous crystalline aluminosilicate materials [4], are widely used in numerous large-scale applications as catalysts, ion exchange materials, and adsorbents for organic compoundsn[5]. In addition to these conventional uses, zeolites have also emerged as advanced functional materials applied in the fields of luminescence, electricity, magnetism, medicine and microelectronics, etc [6]. In the present research, various esters of trans- cinnamic acid were chosen for 1, 2- dibromination with 1, 3-dibromo-5, 5- dimethylhydantoin (DBDMH) over zeolites beta, Y and ZSM-5 to study the influence of zeolite pore architecture and the reactant size on the product selectivities and reaction mechanism. The 1, 2-dibromination of a various cinnamates was carried out using a stable, non-toxic, inexpensive bromine source, DBDMH, and a zeolite (beta, Y or ZSM-5) as a catalyst at room temperature. In the present research, methyl trans-cinnamate was chosen to study the molar ratio of DBDMH (1.0 or 1.5 equiv), solvents (aceton, acetonitrile, chloroform, dichloromethane, diethyl ether, diisopropyl ether, dimethyl sulfoxide, ethanol, tetrahydrofuran and toluen), the reaction period (2 h to 24 h) and the quantity of zeolite catalysts (20 and 40 wt%) have been varied. Blank reactions were also carried out in the absence of catalyst. The progress of the reaction was monitored by TLC and by RP-HPLC. Reaction conditions were optimized by use of diethyl ether as solvents with 1.5 molar equivalents of DBDMH and 40 wt% of the catalyst. With the optimal condition in hand, esters were explored as electron-withdrawing groups on the 1, 2- dibromination reaction. The obtained results showed that the cinnamate conversion over 90% was achieved for both zeolite beta and Y in diethyl ether at room temperature. ZSM-5 is not as effective catalyst as the other two. In the absence of a catalyst the reactions were significantly slower. According to the 1H NMR it was found that in all cases the 1, 2-dibromination proceeded with anti- stereoselectivity to give the 1, 2- dibromide compounds.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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