B. Shivarama Holla

Synthesis characterization and anticancer activity studies on some Mannich bases derived from 1,2,4-triazoles

A series of 3-substituted 4-[5-(4-methoxy-2-nitrophenyl)-2-furfurylidene] amino-5-mercapto-1,2,4-triazoles (3) were synthesized. Aminomethylation of compounds 3 with formaldehyde and various secondary amines furnished Mannich bases 4 and 5. These compounds were characterized on the basis of IR, 1H-NMR, mass spectral data and elemental analysis. The newly synthesized compounds were screened for their anticancer activity against a panel of 60 cell lines derived from seven cancer types namely, lung, colon, melanoma, renal, ovarian, CNS and leukemia. Some of the compounds were slightly more potent.

New bis-aminomercaptotriazoles and bis-triazolothiadiazoles as possible anticancer agents

A series of bis-phenoxyacetic acids 2 were prepared starting from corresponding unsubstituted/substituted 1,4-quinols 1. The fusion of bis-phenoxyacetic acids 2 with thiocarbohydrazide gave the corresponding bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl-methyleneoxy]phenylenes (3) in a one pot reaction. The reaction of bis-triazoles 3 with various reagents afforded N-bridged heterocycles 4-6 in good yields. The newly synthesised compounds were screened for their anticancer activity against a panel of 60 cell lines derived from seven cancer types namely, lung, colon, melanoma, renal, ovarian, CNS and leukemia. Some of the tested compounds showed promising anticancer properties.

Synthesis of some new 2,4-disubstituted thiazoles as possible antibacterial and anti-inflammatory agents

A series of arylthioureas (1), aromatic aldehyde thiosemicarbazones (2) and 5-aryl-2-furfuraldehyde thiosemicarbazones (3) were condensed with 2,4-dichloro-5-fluorophenacyl bromide to yield respective arylaminothiazoles, arylidene/5-aryl-2-furfurylidene hydrazinothiazoles (4). The newly synthesized compounds were characterized by IR, 1H-NMR and mass spectral studies. These compounds were also screened for their antibacterial and anti-inflammatory activities. Two of the newly synthesized compounds showed anti-inflammatory activity comparable with that of Ibuprofen.

Studies on arylfuran derivatives. Part X. Synthesis and antibacterial properties of arylfuryl-Δ2-pyrazolines

Arylfurylpropenones 3 were synthesized by Claisen-Schmidt condensation of arylfurfurals 1 with various substituted acetophenones 2. Cyclocondensation of these arylfurylpropenones 3 with hydrazine hydrate and phenylhydrazine furnished 1H-pyrazolines 4 and N-phenylpyrazolines 6, respectively. In order to study the structure-activity relationships, pyrazolines 4 were converted into their N-acetyl derivatives 5. The antibacterial properties of the new pyrazoline derivatives were studied.

Studies on some N-bridged heterocycles derived from bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes

A series of bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes have been synthesized and were converted into bis-[1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol-4-yl] alkanes. The newly synthesized compounds were characterized by analytical IR, NMR and mass spectral studies. Some of the newly synthesized compounds were screened for their antibacterial properties and exhibited activity with MIC in the range 3-12.5 micrograms/ml.

Synthesis and antitumor activity studies of some new fused 1,2,4-triazole derivatives carrying 2,4-dichloro-5-fluorophenyl moiety

A series of 3-(2,4-dichloro-5-fluorophenyl)-6-(substituted phenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (4) (Fig. 1) have been synthesized by the cyclization of 3-(2,4-dichloro-5-fluorophenyl)-1,2,4-triazol-5-thiol (3) with substituted phenacyl bromides. All the newly synthesized compounds were confirmed by IR, (1)H NMR and mass spectral studies. Among the compounds tested for their antitumor activity three compounds exhibited in vitro antitumor activity with moderate to excellent growth inhibition against a panel of sixty cancer cell lines of leukemia, non-small cell lung cancer, melanoma, ovarian cancer, prostate and breast cancer. The compound 4d showed promising antiproliferative activity with GI(50) values in the range of 1.06-25.4 microM.

Synthesis and antimicrobial activities of some new triazolothiadiazoles bearing 4-methylthiobenzyl moiety

A series of substituted triazolothiadiazoles have been synthesized by condensing 4-amino-3-[4-methylthiobenzyl]-4H-1,2,4-triazole-5-thiol (5) with substituted aryl furoic acids/aromatic acids in the presence of POCl3. The triazole (5) was obtained by the fusion of 4-methylthiophenyl acetic acid with thiocarbohydrazide. The structures of newly synthesized compounds are characterized by elemental analysis, IR, 1H NMR and mass spectroscopic studies and were screened for their antimicrobial activities. The preliminary results revealed that some of the compounds exhibited promising antimicrobial activities.

Studies on arylfuran derivatives. Part XI. Synthesis, characterisation and biological studies on some Mannich bases carrying 2,4-dichlorophenylfurfural moiety.

A series of 3-substituted-4-[5-(2,4-dichlorophenyl)-2-furfurylidine]amino-5-me rcapto-1, 2,4-triazoles (3) are synthesised. Aminomethylation of 3 with formaldehyde and a primary/secondary amine furnished Mannich bases 4 and 5. Both Schiff bases 3 and Mannich bases 4 and 5 are characterised on the basis of IR, 1H NMR, mass spectral data and elemental analysis. All the newly synthesised compounds are tested for their antibacterial activities. Some of the selected compounds are also tested for their fungicidal and herbicidal properties.

Synthesis of some new biologically active thiadiazolotriazinones—Part II☆

4-Amino-6-arylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones 1 are condensed with aromatic carboxylic acids, aryloxyacetic acids and anilinoacetic acids 2 to yield 7-substituted-3-arylmethyl-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-tr iazin-4-ones 3. Phosphorus oxychloride is used as cyclizing agent. Some of the newly synthesized compounds are screened for their antibacterial activities.

SYNTHESIS OF SOME NEW 1,2,4-TRIAZOLO[3,4-b]-THIADIAZOLE DERIVATIVES AS POSSIBLE ANTICANCER AGENTS

3-Substituted-4-amino-5-mercapto-1,2,4-triazoles are versatile synthons for constructing various biologically active heterocycles. Their cyclization with carboxylic acids gives fused five-membered derivatives, whereas with α-bromoketones gives a six-membered heterocycle. In this article we report the synthesis of a series of 1,2,4-triazolo[3,4-b]thiadiazoles 5 starting from 4-amino-3-substituted-5-mercapto-1,2,4-triazoles 3 and fluorobenzoic acids 4 using phosphorous oxychloride as cyclizing agent. Fourteen of the newly synthesized compounds were screened for anticancer properties. Four among them showed in vitro anticancer activity.