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• 2402-77-9 2,3-dichloro-pyridine 
• 5188-07-8 sodium thiomethoxide 
• 626-60-8 3-Chloropyridine 
• 624-92-0 Dimethyldisulphide 
• 96424-68-9 2-bromo-3-chloropyridine 
• 623-54-1 O-ethyl S-methyl dithiocarbonate 

Relevant academic research and scientific papers

Xanthates as Thiol Surrogates for Nucleophilic Substitution with Aryl Halides

We herein report an unprecedented xanthate-based protocol for the preparation of aryl-alkyl thioethers. Heating xanthates with aryl halides and namely cesium carbonate in methanol provides the target thioethers in generally good yields within short reaction times. This method allows one to avoid contact with odorous thiols and also to introduce substituents of which the corresponding thiols are virtually unavailable or inconvenient in use.

Regiocontrolled SNAr reaction on 2,3-dihalopyridines with NaSMe to obtain bromo(methylthio)pyridines as key precursors of 3-halo-2-(hetero) arylthieno[2,3- b ]pyridines and thieno[3,2- b ]pyridines

The synthesis of 3-halo-2-(hetero)arylthieno[2,3-b]pyridines and 3-halo-2-(hetero)arylthieno[3,2-b]pyridines has been performed through a three-step methodology from 3-bromo-2-chloropyridine or 2-bromo-3- fluoropyridine, respectively. The key step of this methodology is the formation of the required bromo(methylthio)pyridines by a regiocontrolled nucleophilic aromatic substitution (SNAr) with sodium methanethiolate (NaSMe). Then, the Sonogashira coupling with (hetero)arylalkynes followed by a halocyclization with bromine or iodine, afforded the expected 3-halo-2-(hetero)arylthienopyridines.

TMSCH2Li-LiDMAE: a new nonnucleophilic reagent for C-2 lithiation of halopyridines

A new superbasic reagent has been discovered by combining TMSCH2Li and LiDMAE in hexane. This reagent was found highly efficient for the C-2 lithiation of sensitive chloro- and fluoropyridines. The metallation occurred chemo- and regioselectively at 0 °C avoiding the nucleophilic addition or substrate degradation commonly obtained with other alkyllithiums even at lower temperatures.

First regioselective c-2 lithiation of 3- and 4-chloropyridines

We have shown that the BuLi/LiDMAE reagent promotes the clean and regioselective C2 lithiation of 3- and 4-chloropyridines, while other reagents such as LDA or BuLi/TMEDA lead to classical ortho lithiation products or mixtures of regioisomers. The method was successfully applied to the preparation of various reactive 2,3- and 2,4-disubstituted pyridines.

The Reaction of Some Halogenated Pyridine Thioethers and Sulphones with Carbon Disulphide

Dithiocarboxylation of some halogenated pyridine sulphones with carbon disulphide and sodium hydride leads to the formation of thiomethyl derivatives via Smiles rearrangement of the initially produced dianion, fragmentation and subsequent methylation.In one instance the pyridino-1,4-dithiine 7 was obtained.The thioether 2d was also converted into a thiomethyl derivative when subjected to the same reaction sequence.

NEW REACTIONS OF PYRIDINES AND TOTAL SYNTHESIS OF THE FUNGAL TOXIN ORELLANINE

Dihalogenated pyridines react easily with sulphur nucleophiles, in dipolar aprotic solvents (DMF), to afford the products of mono- or of bis-substitution depending on the experimental conditions.On the contrary, with oxygen nucleophiles the bis-substituted products can be obtained only with some particular substrates.A new and efficient procedure to effect the homo-coupling of halogenoarenes will be presented.This reaction, wich occurs under the influence of low-valent nickel complexes, allowed us to effect the total synthesis of Orellanine, the lethal toxin of Cortinarius orellanus mushroom, as well as the syntheses of its decompositionproducts Orellinine and Orelline.The chemical properties of these three products and their behaviour towards UV irradiation will be presented and discussed.

THE REACTIONS OF SOME HALOGENATED PYRIDINES WITH METHOXYDE AND METHANETHIOLATE IONS IN DIMETHYLFORMAMIDE

The reactions of 2,6- and 2,5-dibromopyridines and of 2,3- and 3,5-dichloropyridines with sodium isopropanethiolate and methanethiolate afforded the products of mono- or of bis-substitution depending on the experimental conditions.The same pyridines reacted with sodium methoxide to give good yields of the mono-substituted products; bis-substitution occurred easily only in the case of the 2,6-dibromo- and of the 3,5-dichloropyridine.The syntheses of some methoxy thiomethoxypyridine, starting from the halogeno methoxypyridines or from the halogeno thiomethoxypyridines are also described.The bis-(alkylthio)pyridines can be fragmented by sodium in HMPA to give the bis(mercapto)pyridines.