Pyridine-2-thiones synthesis

Imidazo[4,5-c]pyridine-2(3f7)-thione, 1-methyl-reactions with acrylonitrile, 5, 620 Imidazo[l,2-a]pyridine-2(3H)-thiones synthesis, 5, 632... 

Besides being useful precursors to pyrroles pyridine-2-ones -4-ones, -4-thiones. and -4-imines 4-alkylidene-dihydropyridines thiophenes 1,2,4-triazoles thiapyrane-2-thiones, isoquinoline-3-ones isoben-zothiophenes and 4-mercaptoimidazolium hydroxide inner salts, mesoionic thiazoles are potentially useful in the construction of molecules with herbicidic (39). central nerve stimulating, and antiinflammatory properties (40,41). Application in dye synthesis has likewise been reported (42). 

Pyridinethiones acylation, 2, 357 alkylation, 2, 357 aromaticity, 2, 148 protonation, 2, 357 tautomerism, 2, 356 Pyridine-2-thiones aromaticity, 2, 156 basicity, 2, 157 oxidation, 2, 357 N-oxide, sodium salt biocide, 1, 399 synthesis, 2, 360... 

Thieno[3,2-c]pyridine-4(5H)-thione, 6,7-dihydro-synthesis, 4, 762 Thieno[2,3-c]pyridin-4-ones synthesis, 4, 1007, 1008 Thieno[2,3-c]pyridin-7-ones synthesis, 4, 1007 Thieno[3,2-c]pyridin-7-ones synthesis, 4, 1007... 

Numerous examples of the synthesis of tricyclic systems based on indolizine derivative 232 have been reported <2000M959>. The product obtained from the reaction of 232 with carbon disulfide depends on the reaction medium. Thus, in aqueous potassium hydroxide the pyrimidine-dithione 233 is formed, whereas in pyridine the iminothiazine-thione 234 is obtained. In aqueous potassium hydroxide, compound 234 rearranges to 233 (Scheme 12) <2000M959>. 

Recently, a method has been developed for the synthesis of thieno[2,3-Z>] indeno[2,l-< ]pyridine derivatives 23 by the Thorpe reaction starting from thiones 24 (2000SC3883). It should be noted that compounds 23 were synthesized according to the same procedure three years earlier (1997MI1). However, the latter study is... 

Examples of the synthesis of thieno[2,3-Z>]pyridines according to method C are scarce. In this case, the synthesis of the starting 3-cyanopyridine-2(l //)-thione, its -alkylation, and cyclization of an intermediate occur as a multicomponent one-pot process. For example, the reaction of thioamides 28 with l-(4-morpho-lino)cyclohexene (29) in anhydrous ethanol followed by treatment with a twofold excess of KOH and then with a-bromo ketones produced thienoquinolines 30 (1997KGS1384). 

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