Transition metal-free, chemoselective arylation of thioamides yielding aryl thioimidates orN-aryl thioamides (original) (raw)
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Advanced Synthesis & Catalysis, 2010
In this article, we have developed a new protocol for the thioarylation of structurally diverse alkyl bromides such as benzyl, cinnamyl, n-octyl, cyclohexyl, cyclopentyl, and tert-butyl bromides with aryl iodides, bromides and an activated chloride using thiourea catalyzed by copper(I) iodide in wet polyethylene glycol (PEG 200) as an eco-friendly medium in the presence of potassium carbonate at 80 and 100 8C under an inert atmosphere. The process is free from foul-smelling thiols which makes this method more practical for the thioetherification of aryl halides. Another important feature of this method is the variety of alkyl bromides which are commercially available for the in situ generation of thiolate ions with respect to the existing protocols in which the less commercially available thiols are directly used for the preparation of arylthio ethers.
Org. Chem. Front. 2018, 5(16), 2447-2452., 2018
Thioesters were synthesized via palladium-catalyzed carbonylation of thioacetates and aryl iodides. S-Aryl thioacetates coupled with carbon monoxide and aryl iodides to afford the desired S-aryl thioesters in good yields. The reaction showed good functional group tolerance toward fluoro, chloro, ketone, ester, aldehyde, cyano, and nitro groups. The tandem reaction of the direct S-arylation of aryl iodides from potassium thioacetate (KSAc) and subsequent carbonylation of the intermediates S-aryl thioacetates provided S-aryl thioesters in moderate-to-good yields.
Convenient synthesis ofn-methylpyrrolidine-2-thione and some thioamides
Korean Journal of Chemical Engineering, 2003
The synthesis of thioamides and thiolactams, which are used as important organic intermediates, has attracted great attention. However, expensive reagents, severe reaction conditions and low yields of the target products made conventional methods inconvenient and economically infeasible. To overcome these disadvantages, we investigated a new process for synthesizing thioamides and thiolactams. We examined thermal reactions of CS 2 with Nmethyl-2-pyrrolidinone, formylamide, acetamide and N,N-dimethylformylamide, respectively. The results show that under optimum conditions N-methylpyrrolidine-2-thione and the corresponding thioamides can be obtained in good to excellent yields by the above thionation reactions.
ChemistrySelect, 2016
An efficient protocol was developed for the Friedel Crafts type thioarylation for the synthesis of aromatic/heteroaromaticthioamide derivatives from aryl isothiocyanates and electron rich aromatic/heteroaromatic molecules by employing the Lewis acid AlCl 3 and the less hazardous solvent cyclohex-ane at 708C. The developed protocol offers advantages over the previous methods such as use of stoichiometric amount of reactants/reagent, less toxic solvent, shorter reaction time and higher yields.
Kim, Y.; Song, K. H.; Lee, S. Org. Chem. Front. 2020, 7(19), 2938-2943., 2020
Aryl iodides and aryl sulfonyl hydrazides were reacted with carbon monoxide in the presence of DBU and a palladium catalyst to provide optimal yields of S-aryl thioesters. Aryl sulfonyl hydrazides served as aryl thiol surrogates. Optimal results were obtained when the reaction was carried out with Pd(dba) 2 /dppb in toluene at 80°C for 12 h. The methodology exhibits superior functional group tolerance, being compatible with moieties like fluoride, chloride, bromide, ester, ketone, cyanide and nitro. Scheme 1 Synthesis of thioester. † Electronic supplementary information (ESI) available. See
A novel method for heterocyclic amide-thioamide transformations
Beilstein journal of organic chemistry, 2017
In this paper, we introduce a novel and convenient method for the transformation of heterocyclic amides into heteocyclic thioamides. A two-step approach was applied for this transformation: Firstly, we applied a chlorination of the heterocyclic amides to afford the corresponding chloroheterocycles. Secondly, the chloroherocycles and N-cyclohexyl dithiocarbamate cyclohexylammonium salt were heated in chloroform for 12 h at 61 °C to afford heteocyclic thioamides in excellent yields.