Synthesis of nitro and amino derivatives of benzothiacrown ethers

Abstract

The condensation reaction of 1,2 bis(2 haloethoxy) 4 nitrobenzenes with acyclic α,ω (oxa)alkanedithiols in the presence of alkali metal carbonates produced a series of nitrobenzodithiacrown ethers with macrocycles of different size. The structures of three ethers were established by X ray diffraction. A new method was developed for the synthesis of nitrobenzomonothia 15 crown 5 ether. Nitro derivatives of benzodithiacrown ethers were tested as reagents for extraction of palladium(II), platinum(IV), and rhodium(III) from hydro chloric acid solutions. Extraction of Pd II salts was found to be highly selective compared to that of Pt IV and Rh III salts. Benzodithia 15 crown 5 ether is the most efficient extractant for palladium(II). Reduction of nitrobenzothiacrown ethers with hydrazine hydrate in the pres ence of a platinum catalyst afforded their amino derivatives.Thiacrown ethers are among the most promis ing macrocyclic sulfides. 1,2 Sulfur containing macro heterocycles have attracted interest because these com pounds can form stable complexes with transition and heavy metal ions. 3,4 These compounds can be used as selective extractants, materials for ion selective electrodes, reagents for modifications of chromato graphic sorbents, etc. The development of procedures for the synthesis of important functionalized derivatives of thiacrown ethers is of great importance for the exten sion of the possibilities of the practical use of these com pounds.In the present study, we developed convenient proce dures for the synthesis of nitro and amino derivatives of benzothiacrown ethers with macrocycles of different size and different combinations of O and S atoms. The con densation reactions of 1,2 bis(2 haloethoxy) 4 nitroben zenes 1a,b with terminal (oxa)alkanedithiols 2a-d in the presence of alkali metal carbonates (M 2 CO 3 ) in aqueous ethanol produced nitrobenzodithiacrown ethers 3a-d in 48-89% yields (Scheme 1). To suppress side reactions, Scheme 1

Macrocyclic Complexes of Palladium(II) with Benzothiacrown Ethers: Synthesis, Characterization, and Structure ofcisandtransIsomers

“…This was manifested in the X-ray diffraction pattern of [Pd(3)Cl 2 ] as a disordered structure. 9 A relatively low-lying (E conf = 3.2 kcal 3 mol À1 ) trans isomer was found for the PdCl 2 complex with benzodithia-18-crown-6 ether; its structure and electronic energy are given in the SI. One cannot rule out the possibility that this isomer occurs in equilibrium mixture with cis isomers (although in trace amounts).…”

“…Earlier, we found examples of such macrocycle rearrangement for the crystalline complexes cis-[Pd(3)Cl 2 ] and trans-[Pd(8)Cl 2 ]. 9 The crystalline complex cis-[Pd(5)Cl 2 ] was also studied by X-ray diffraction. It is unlikely that a replacement of the peripheral nitro group by the formyl group has a considerable effect on the conformational characteristics of macroheterocycles; therefore, a comparison of the crystal structures of the complexes of these compounds is well-posed.…”

“…8 Previously, in a brief communication, we presented the synthesis and study of PdCl 2 complexes with bidentate ligands, namely, nitro-and formylbenzodithia-18(21)-crown-6(7)-ether derivatives. 9 This article presents the synthesis and comprehensive structure study for a series of palladium(II) complexes with nitro-and formylbenzothiacrown-ether derivatives 1À9 having different sizes and ligand denticities (Chart 1). The study was carried out by means of NMR, X-ray diffraction, and density functional theory.…”

Some Aspects of the Synthesis of Crown Ethers

“…To obtain benzthiocrown-ethers we have developed an effective synthesis method of ethers which differ by the size of heterocycle and combination of atoms O and S. The synthesis of such thiocrown-ethers is known from literature [16] and the structures of their complexes were studied by the methods of NMR and RSA [17]. We obtained benzthiocrownethers by the For the synthesis of polyvinyl crown-ethers we studied the reaction of allylamine with ethylene oxide with excess of the last:…”

15-Hydroxybenzomonothia-15-crown-5 with the sulfur atom linked with the benzene ring and the derived sulfoxide: synthesis, structure, and complexation with the metal cations

“…It appears that resinification occurs due to the high reactivity of polyphenols in the strongly basic me dium inducing side reactions. However, upon coupling in aqueous ethanol in the presence of Na 2 CO 3 (see Refs 19,23,24), product 4 was also obtained in a low yield (4%), probably, owing to the use of insufficiently strong (under these conditions) base. The use of the diiodo derivative of tetraethylene glycol and replacement of the solvent by dry acetone 28 allowed us to increase the yield of the target product 4 to 14%.…”