Synthesis, X‐ray Characterisation and Studies of the New Ionic Complex [Bis(pyridin‐2‐yl) disulfide] Triiodide, Obtained by Oxidation of 2‐Mercaptopyridine with I₂ − Implications in the Mechanism of Action of Antithyroid Drugs

Abstract

The reaction of 2‐mercaptopyridine (C5H5NS or PYSH) with diiodine in a molar ratio of 1:2 in dichloromethane led to the oxidation and dimerization of the ligand and formation of [(PYS−PYSH)+·I3−]. The compound was characterised by elemental analysis, DTA‐TG, FT‐Raman, FT‐IR, UV/Vis and 1H NMR spectroscopy. The crystal structure of the complex has been determined by X‐ray diffraction at 293(2) K. The compound [(C5H4NS−SNC5H5)I3] is monoclinic with the space group P21 and a = 8.230(2) Å, b = 35.708(7) Å, c = 11.369(2) Å, β = 91.86(3)° and Z = 8. The results are discussed in relation to the mechanism of action of antithyroid drugs. The easy oxidation of PYSH by I2 to form the monocationic disulfide complex [(PYS−PYSH)+·I3−] is similar to the case of the antithyroid drug methimazole (MMI) and may indicate that PYSH might also possess antithyroid properties similar to those of MMI. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Crystal structure of bis(pyridin-2-yl)disulfide hydrotriiodide, [C10H9N2S2][I3]

“…Inaddition, there are relativelyshort distances (centroid separation of 3.648(4) Å,interplanar spacing of 3.542(4) Å)between the pyridine-ring plane and the symmetry-related plane at ( 3 ¤ 2 -x, 3 ¤ 2 -y ,1-z )inanadjacent cation, implying weak p -p interactions in this structure. The structure of the title compound represents asecond modification to aknown phase crystallizing in P 2 1 [1], which was synthesized by oxidation/dimerization of pyridine-2-thiol with diiodine in dichloromethane. The reason for the two modifications is adifferent crystal packing caused by different intermolecular bonds.…”

Pressure‐Tuning Raman Spectra of Diiodine Thioamide Compounds: Models for Antithyroid Drug Activity

“…The diiodine-heterocyclic thioamides 1 – 5 were prepared according to the literature procedures [2, 5–8]. Complete details of the pressure-tuning FT-Raman measurements, including the ruby R 1 fluorescence-pressure calibration procedure, have been described elsewhere [4, 9].…”

“…A second important field in which iodine chemistry plays a pivotal role is in the activity of antithyroid drugs and there is now a major research effort focused on determining structure-activity relationships of thioamides with iodine [2, 3]. The antithyroid drugs that are most commonly used today are the thioamide derivatives, 6- n -propyl-thiouracil, N -methyl-imidazoline-2-thione (methimazole), and 3-methyl-2-thioxo-4-imidazoline-1-carboxylate (carbimazole).…”

Organoiodine complexes: Structural and functional variety

“…The formation of such a hydrogen bond between the central atom of the triiodide ion and the H(6) atom of the pyridine ring has been detected in the crystal structure of di(pyridin 2 yl) disulfide triiodide, a product of oxidation of 2 mercapto pyridine with molecular iodine. 106 Despite a wealth of data on the compositions and structures of polyhalides of organic cations 107-109 and molecular iodine complexes, 8 their crystallographic examination remains very intensive. For instance, the crystal and molecular structures of N cetylpyridinium interhalides, 54 N propylisoquinolinium diiodine bro mide, 85 N methyl(ethyl)quinolinium triiodides, 37,54 N,N diethylbenzimidazolium triiodide, 110 3 carboxy propyl(triphenyl)phosphonium diiodine bromide, 103 tetra phenylphosphonium diiodine bromide, 90 and p xylylene bis(tetrahydrothiophenium) triiodide 91 have been deter mined in recent years.…”