A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• ; heterocyclic thioamides; N-cyclohexyl dithiocarbamate cyclohexylammonium salt; novel thiating agent; thiation; Introduction Transforming heterocyclic amides into thioamides is an important task in organic synthesis. Earlier reports for this type of O/S conversions were achieved by several thiating reagents

• ; for instance, Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide) [1][2][3], Berzelius reagent [4][5][6] (P4S10), and phosphorus pentasulfide [7] in dry toluene, xylene or pyridine under reflux conditions. A two-step approach for the purpose of thiation of

• heterocyclic amides attracted our attention: as a first step, we applied a chlorination of heterocyclic amides, followed by thiation via reaction with thiourea on the basis of reagent-promoted desulfurylation of isothiourea under strong basic conditions [8][9]. Aiming to continue our reseach work on the

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• unequivocally by X-ray crystallography analysis, thus supporting the data of 1H and 13C NMR spectroscopy (Figure 2). The Lawesson’s reagent appears to act firstly as a source of hydrogen sulfide to reduce the C=C double bond in compound 10a, and secondly, as the thiation agent to form thieno[2,3-b]indole 12a by