Synthesis and Antifungal Activity of a Series of Trifluoromethyl Substituted Indole and Spiro Indole Derivatives

Abstract

Various fluorinated 3-indolylimines on cyclocondensation at

refluxing temperature with mercaptoacetic acid/mercaptopropionic

acid afforded 3´-phenyl spiro[indole-3,2´-thiazolidine]-2,4´ (1H)-diones

(V) while on stirring at room temperature gave [[2,3-

dihydro-3-phenyl amino-2-oxo-1H-indol-3-yl]thio] ethanoic acid

(IV). The reaction of (V) with acidic H₂O₂ resulted in corresponding

3´-phenyl spiro[3H-indol-3,2´-thiazolidine]-2,4´ (1H)-dione-1´,1´dioxide

(VI), while reaction with P₂S₅ in anhydrous pyridine

yielded 3´-phenyl spiro [3H-indole-3,2´-thiazolidine]-2,4´(1H)dithione

(VII). The compounds have been characterized on the basis

of elemental and spectral studies. The synthesized 34 compounds

have been screened in vitro for antifungal activity against Rhizoctonia

solani, Fusarium oxysporum and Colletotrichum capsici. IIIb

(X = 5-Cl; R² = 2-CF₃), IIIe (X = 7-NO₂; R² = 2-CF₃), Vc (X =

5-Cl; R = CH₃; R² = 2-CF₃), VIC (X = 5-Cl; R = CH₃;

R² = 3-CF₃; R² = 2-CF₃) Vllb (X = H; R = CH₃) and VIIC (X = H;

R = CH₃; R² = 3-CF₃) have shown remarkable activity against these

pathogens.