Reactions of polyfluorinated chalcones with o-aminobenzenethiol and its zinc salt

Abstract

The reactions of polyfluorochalcones with o aminothiophenol in methanol in the presence of HCl afford polyfluorine substituted 2,3 dihydrobenzo[b] [1,5]thiazepines. In some cases, the cyclization is accompanied by fluorine substitution in the perfluorophenyl ring. Probably, the formation of thiazepines proceeds through the Michael thia adduct. The Zn salt of o amino thiophenol reacts with chalcones in DMF exclusively via fluorine substitution.

Benzo[1,5]thiazepine: Synthesis, Reactions, Spectroscopy, and Applications

“…According to the IUPAC nomenclature, the benzo [1,5]thiazepine structures IA or IB may be named as ( )-2,3-dihydrobenzo[ ] [1,4]thiazepine or ( )-2,3-dihydro-substituted-benzo[ ] [1,4]thiazepine. Also, the substituted-benzo [1,5]thiazepines structure IIA or IIB may have the name: 2,3,4,5-tetrahydrobenzo[ ] [1,4]thiazepine or 2,3,4,5-tetrahydro-substituted-benzo[ ] [1,4]thiazepine (see Figure 1). …”

“…Reaction of 10b with o-aminothiophenol (2-moles) afforded 1,5-benzothiazepine 11b in 88% yield. When a threefold excess of the reactant was used in the reaction of 10c with o-aminothiophenol the benzo[ ] [1,5]thiazepine 11c was afforded (80% yield). To reveal the sequence step of formation of benzothiazepines, the thia-adducts 12a-c were synthesized by the reaction of chalcones 10a-c with o-aminothiophenol in MeOH at 20 ∘ C for 3-6 h. The thia-adduct 12a under reflux in MeOH in presence of HCl underwent partial ring closure to form benzothiazepine 11a and partially 12a transformed into chalcone 10a; however, the most part of 12a remains unchanged.…”

“…To reveal the sequence step of formation of benzothiazepines, the thia-adducts 12a-c were synthesized by the reaction of chalcones 10a-c with o-aminothiophenol in MeOH at 20 ∘ C for 3-6 h. The thia-adduct 12a under reflux in MeOH in presence of HCl underwent partial ring closure to form benzothiazepine 11a and partially 12a transformed into chalcone 10a; however, the most part of 12a remains unchanged. The adduct 12b under the same reaction conditions was completely consumed and the reaction mixture contained chalcone 10b, 1-(4-(2-aminophenylthio)-2,3,5,6-tetrafluorophenyl)-3-phenylprop-2-en-1-one 13 together with thebenzo [1,5]thiazepines 11b,d. Also, the same reaction of the adduct 12c under reflux formed a complicated mixture of products containing chalcone 10c, thia-adducts 12c,d, and benzothiazepines 11c,e [5] (Scheme 2).…”

“…The adduct 12b under the same reaction conditions was completely consumed and the reaction mixture contained chalcone 10b, 1-(4-(2-aminophenylthio)-2,3,5,6-tetrafluorophenyl)-3-phenylprop-2-en-1-one 13 together with thebenzo [1,5]thiazepines 11b,d. Also, the same reaction of the adduct 12c under reflux formed a complicated mixture of products containing chalcone 10c, thia-adducts 12c,d, and benzothiazepines 11c,e [5] (Scheme 2).…”

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This review article deals with synthesis and reactions of benzo [1,5]thiazepines and the related derivatives and their applications, biological activity as well as spectroscopic data. Most of the reported data on the methods of synthesis, chemical reactions, and biological activity of these heterocycles published over the last ten years are reviewed in this paper.

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