TsCl-promoted thiolation of quinoline N-oxides with thiophenols

Abstract

A metal-free method for the regioselective synthesis of 2-thiolated quinolines from quinoline N-oxides in water at room tempera-ture is developed. The reaction is conducted by using benzenethiols as thiolation reagents...

Electrochemical Oxidation Involving Sulfonyl Hydrazine for the Synthesis of 2‐Sulfonyl Quinolines/Pyridines

“…Based on our experimental results and the existing literatures, [3,21,22,29] we proposed a possible electrochemical deoxidation reaction mechanism of C2 sulfonation in Scheme 5. First, p-toluenesulfonyl hydrazide (2 a) was converted to the corresponding sulfonyl group B via three single electron transfer (SET) oxidation and deprotonation at the anode and further release of molecular nitrogen in the presence of a base, which can then be linked to quinoline via B The radical addition process of the N-oxide (1 a) forms intermediates C or D. The intermediate E was obtained by radical/radical cross coupling of oxygen oxygen-centered D and p-toluenesulfonyl radical B.…”

“…[1,2] In particular, the regioselective construction of CÀ S bonds of quinoline derivatives [3] is an important system for the functionalization of azaheteroaryl sulfones, [4] and is ubiquitous in natural products and drug molecules, such as antimalarial and antibacterial active drug molecules. [5] Most of the previous reports on the construction of CÀ S bonds of quinoline derivatives are the nucleophilic substitution reaction between halides and thiols, [3,6] which will cause irreversible damage to the environment and some halogenated quinolines are not available in the market. Therefore, it is very important to develop starting materials for the facile synthesis of functionalized quinoline derivatives.…”

Recent Progress in Functionalization of the Pyridine Ring through C−S Bond Formation under Transition Metal Catalyst Free Conditions

“…[40] Another activating agent that provides access to 2thioquinolines is p-toluenesulfonyl chloride (TsCl). [41] This mild protocol is implemented using thiols as nucleophilic agents and water as a solvent (preparation of 61 from 46 a, Scheme 20). Another green solvent, anisole, can be used for the thiolation of quinoline Noxide 46 b, with dialkyl disulfide 62 and t-BuOK as a base (Scheme 20).…”

“…[42] A more significant increase in the yield of S-arylated products 63 was observed using arylthiols 9 b in water (Scheme 21). [41] The reaction of arylthiols with elec-Scheme 18. S-Alkylation with cyclic thioethers.…”

TsCl promoted deoxygenative phosphorothiolation of quinoline N-oxides towards S-quinolyl phosphorothioates

“…On the other hand, quinolines are some of the most important nitrogen-containing heterocycles, and exist in many natural products, pharmaceuticals and functional materials. 18 In the past few decades, great efforts have been devoted to the synthesis of 2-substituted quinoline derivatives via C–H functionalization of quinoline N -oxides, 19 mainly including alkylation, 20 arylation, 21 alkenylation, 22 amination, 23 alkxoylation, 24 sulfenylation, 25 sulfonylation, 26 phosphorylation, 27 cyanation 28 and halogenation. 29 However, to the best of our knowledge, no relevant reports on the phosphorothiolation of quinoline N -oxides toward S -quinolyl phosphorothioates have been presented to date.…”