Synthesis and antifungal activity of some s-mercaptotriazolobenzothiazolyl amino acid derivatives

A series of s-triazolobenzothiazolylthioacetyl/propionyl amino acid derivatives were synthesized with the aim of evaluating their antifungal activity. Their chemical structures were confirmed by 1H, 13C NMR, IR, mass spectrometry and elemental analyses. The synthesized derivatives were screened for their antifungal activity against Aspergillus flavus and Candida albicans. Five compounds (3, 5, 7c, 8 and 17) were found to possess high activity comparable to fluconazole at 100 μg/mL against C. albicans. [Display omitted] Some s-triazolo[3,4-b]benzothiazolylthioacetyl/propionyl amino acid derivatives were synthesized from s-mercaptotriazolo[3,4-b]benzothiazole 3 by azide and DCC-coupling methods. Also the dicyclohexylurea derivatives were prepared for comparison. ► s-Triazolobenzothiazolyl amino acid derivatives were prepared easily by the azide method. ► HOBt was used in coupling by DCCI-method to suppress the formation of the by-product. ► The tested compounds were found to be more active against Candida albicans than Aspergillus flavus. ► The tyrosine derivative 7c showed the highest activity among other amino acids derivatives. ► The dicyclohexylurea derivatives 8, 11, and 17 showed potent antifungal activity.