Some Reactions of 2-Cyanomethyl-1,3-benzothiazole with Expected Biological Activity

Abstract

New pyrido[2,1-b]benzothiazoles 2a,b, 3, 2-aminoquinoline 4, coumarin 5, cyclohexane 6a,b, and 2-(1,3-benzothiazol-2-yl) methylidene 7 derivatives have been prepared via the reaction of 2-cyanomethyl-1,3-benzothiazole 1 with α,β-unsaturated nitriles, α-chloro ethyl acetoacetate, 2-amino benzaldehyde, 5-chlorosalicylaldehyde, α,β-unsaturated ketone, and 2-aminobenzothiol hydrochloride. 2-Thiazole derivatives 9a,b were prepared from compound 1, which was converted to thioamide derivative 8 by reaction with HCl and thioacetamide, and cyclization of this thioamide with α-halogenated ketone gave 9a,b. Reaction of compound 1 and ethylacetate to afford ketonitrile 10. Treatment of 10 with hydrazine hydrate afforded aminopyrazole derivative 11. Substituted 4-aminothiophene 13 has been synthesized by reaction of compound 1 with p-chlorophenyl isothiocyanate. The resulting product 12 was then alkylated with phenacylbromide. Phenyl-2-yl-carbonylhydroximoyl-chloride 15 was prepared by treatment of the corresponding sulfonium bromide with sodium nitrite and hydrochloric acid in dioxane. Compound 15 reacted with α-(1,3-benzothiazol-2-yl) cinnamonitrile 14 afforded the isoxazole derivatives 16. Reaction of coumarin derivative 5 with anthranilamide, pyrimidine diamine, thiosemicarbazide, acetylacetone, and hydrazine hydrate yielded quinazoline-2-one 17, purine 18, triazole 19, 2-acetyl naphthalene-2-one 20, and N-aminoquinoline-2-one 21 derivatives.

Keywords:

• Cinamonitrile
• coumarin
• 2-cyanomethyl-1,3-benzothiazole and its derivatives
• cyanothioacetamide
• ketonitrile
• thioamide

Notes

∗Cl:Calcd = 9.79, Found = 9.80.

∗∗Cl:calcd = 12.93, Found = 13.00.

∗∗∗Cl:Calcd = 11.32, Found = 11.50.

∗¹H and ¹³C NMR for compound 6a,b in (CDCl₃).