The reaction of sulphides with iodobenzene dichloride in aqueous pyridine. Synthesis of sulphoxides free from sulphone and 18O-labelled sulphoxides

Abstract

Sulphides react with the stoicheiometric quantity of iodobenzene dichloride in aqueous pyridine between -40 and 20" to give high yields of the corresponding sulphoxides. The reaction applies to aliphatic, aromatic, and heterocyclic sulphides. The influence of electronic and steric effects is small. In vinylic sulphides containing electronwithdrawing groups p to the sulphur atom, oxidation is followed by heterolytic cleavage of the S-C(ethy1enic) bond. An excess of reagent may lead to the formation of sulphones or chlorosulphoxides. Both reactions are much slower than mono-oxidation, so that, under the conditions indicated, oxidation of sulphides with one molar proportion of reagent leads exclusively to sulphoxides. Use of 180-enriched water readily gives f80-labelled sulphoxides. VERY few reactions allowing selective oxidation of sulphides to sulphoxides areWith most reagents the competitive second oxidation stage can in no way be avoided,10,16 and sulphoxides are usually contaminated with the corresponding sulphones. The t Other methods of specific oxidation are limited by electronic or steric effects,bs by the occurrence of secondary reaction^,^^ le or by the poor solubility of reagent~,~*'l or were not sufficiently investigated for preparative purposes.1as13 Appreciable quantities of sulphones were also formed with sulphoxides in microbiological oxidations of sulphides 1 4 and in oxidations with oxygen in the presence of chlorophyll.'6

Oxidant‐Dependent REDOX Responsiveness of Polysulfides

“…Comparatively little has been done to understand the chemistry of the oxidation process, and specifically whether the action of different oxidants may result not only in different oxidation kinetics but also in different reaction products. Few literature reports have focused on the oxidation behavior of organic polysulfides,33–38 showing that they can be oxidized in vitro to polysulfoxides,33, 37 although an earlier report from Marvel and Weil hinted to polysulfones too 39. It is conceivable that under mild oxidation conditions (e.g., H 2 O 2 as an oxidizing agent) the reaction could generate lesser oxidized species, that is, sulfoxides, while using harsher conditions (e.g., oxidation with organic peroxyacids) polymeric sulfones can be obtained 34, 36, 38, 40.…”

Photochemical rearrangements of substituted thiochromanone sulfoxides

“…We have coilfirnled that this is the case by repeating the irradiation, under otherwise identical conditions, on the 180-labelled sulfoxide, prepared by the procedure of Montanari and coworkers (12). The mass spectral fragmentatioil pattern (see Experimental) strongly supports the exclusive location of the180-label on the phenolic hydroxyl group.…”

Study of the electrospray ionization mass spectrometry of the proton pump inhibiting drug Omeprazole

“…[ 14 C] Ome and [ 34 S] Ome were synthesized at AstraZeneca R&D (Mölndal, Sweden) using 14 CS 2 or C 34 S 2 as previously published 2. [ 18 O] Ome was synthesized using H 2 18 O, the sulfide analog of Ome and [bis(chloro)‐iodo]benzene 4. The isotopic purity of each of the labeled Ome derivatives (including the 14 C) was greater than 95%.…”