Synthesis of 1-benzyl and 1-benzoyl -3-indole derivatives with expected antimicrobial activity

Schiff's bases 2[a,b] were prepared via the reaction of 1-substituted indole-3-carboxaldehydes 1[a,b] with p-methoxyaniline in glacial acetic acid. Electrophilic addition of hydrogen bromide to compounds 2 [a,b] gave 3[a,b], which were reacted with hydrazine hydrate to yield the hydrazino derivatives 4[a,b]. Cyclization of the latter compounds using carbon disulphide and 1,2-dibromoethane gave triazolidine and triazine derivatives 5[a,b] and 6[a,b], respectively. Also, reaction of compounds 2[a,b] with thiosalicylic acid and thioglycolic acid led to the formation of benzothiazinone and thiazolidinone derivatives 7[a,b] and 8[a,b], respectively. Condensation of 8[a,b] with various arylaldehydes gave 9[a,b]-11[a,b] which condensed with hydrazine hydrate and cyclized to afford the fused pyrazolo [3,4-d] thiazole derivatives 12[a,b]-14[a,b]. Moreover, reaction of 8[a,b] with paraformal-dehyde and secondary amines, namely morpholine and N-methyl piperazine gave the corresponding Mannich's products 15[a,b] and 16[a,b], respectively. The newly synthesized compounds were investigated for their antimicrobial activity against Gram-negative and Gram-positive bacteria and Fungi using Naldixic acid, Itraconazole and Nystatin as reference drugs. Some of the synthesized compounds showed high and moderate activity against various tested bacterial and fungal strains. MIC of the highly biological active compounds was also investigated

Synthesis and antifungal activity of 3-[2-substituted-5-oxo-3.5-dihydro-6.8-dicarbonitriles-1,2,4-triazolo [1,5-a] pyridin-7-y1] indole derivatives

Base catalyzed reaction of 1-substituted indole-3-carboxaldehydes 2a-d with malononitrile gave the corresponding 3-indolylidene malononitriles 3a-d. Heterocyclization of the latter compounds with 2-cyano-acetohydrazide, 2- acetyl-2-cyanoacetohydrazide and alpha-cyano acetyl arylaldehyde hydrazone derivatives gave the corresponding 1,6-diamino pyridine derivatives 4a-d, 3-[2-methyl-5-oxo-3,5-dihydro-6,8- dicarbonitriles-1,2,4-triazolo[1,5-a] pyridine-7-y1] indoles 5a-d and 3-[2-ary1-5-oxo-3,5-dihydro-6,8-dicarbonitriles-1,2,4-triazolo[1,5-a] pyridin-7-y1] indoles 6a-t, respectively. The target compounds 4a-d, 5a-d and 6a-t were evaluated in vitro against two strains of fungi, Candida albicans [AUCC-1720] and Aspergillus fumigatus [AUMC-1924], Fluconazole and Itraconazole were used as references. All compounds which contain the nitro group were found inefficient [MIC > 100 microg/mL], while the rest of the tested compounds exerted a slight activity [MIC 60-80 microg/mL] against each of C. albicans and A. fumigatus compared with the control