Synthesis of 6-alkylthioimidazo[1,2-a]pyridines

A number of 6-alkylthio(and sulfonyl)-substituted imidazo1,2-a]pyridines were synthesized by the reaction of 5-alkylthio- and 5-alkylsulfonyl-2-aminopyridines with -bromoacetophenone and -chlorocyclohexanone in order to search for new compounds that have fungicidal activity. 5-Alkylthio-2-aminopyridines were obtained from the double salt of 5-mercapto-2-aminopyridine with SnCl₂ and HCl by reaction with alkyl halides or tert-C₄H₉OH and 75% H₂SO₄. 5-tert-Butylthio-2-aminopyridine was oxidized by means of KMnO₄ to 5-tert-butylsulfonyl-2-aminopyridine. A double salt was synthesized from 2-aminopyridine-5-sulfonic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–638, May, 1979.