Constantin Draghici

Synthesis, characterization and antibacterial activity of some triazole Mannich bases carrying diphenylsulfone moieties.

A series of Mannich bases of 4-substituted 5-[4-(4-X-phenylsulfonyl)phenyl]-2,4-dihydro-3H-1,2,4-triazole-3-thiones, X=H, Cl, Br, 3 and 5 were synthesized and characterized on the basis of IR, NMR and elemental analyses. The potential antibacterial effects of the synthesized compounds were investigated using the Acinetobacter baumanii ATCC 19606; Citrobacter freundii ATCC 8090; Pseudomonas aeruginosa ATCC 9027; Enterococcus faecalis ATCC 19433; Staphylococcus aureus ATCC 12600; Staphylococcus epidermidis ATCC 14990; Bacillus subtilis ATCC 6633 strains. Some of them exhibited promising activities against A. baumanii and B. subtilis.

Synthesis, characterization and evaluation of antibacterial activity of some thiazolo[3,2-b][1,2,4]triazole incorporating diphenylsulfone moieties.

A series of thiazolo[3,2-b][1,2,4]triazole incorporating diphenylsulfone moieties were synthesized starting from 5-[4-(4-X-phenylsulfonyl)phenyl]-4H-1,2,4-triazole-3-thioles 3a-c, X=H, Cl, Br. Thus, alkylation of 1,2,4-triazoles 3 with phenacyl bromide or 4-bromophenacyl bromide afforded S-substituted 1,2,4-triazoles 4, 5. These new intermediates 4 and 5, in the presence of H(2)SO(4) (c), were cyclized to 2-[4-(4-X-phenylsulfonyl)phenyl]-6-(4-Y-phenyl)[1,3]thiazolo[3,2-b]-[1,2,4]-triazoles 6, 7 (I) and not to isomeric thiazolo[2,3-c][1,2,4]-triazoles 6, 7 (II). The newly synthesized compounds were characterized by IR, (1)H, (13)C NMR and elemental analysis. MS spectra confirmed the formation of thiazolo[3,2-b][1,2,4]triazole 6, 7 (forms I) in detriment of [2,3-c] isomeric compounds (forms II). The potential antibacterial effects of the synthesized compounds were investigated using standard bacterial strains: Acinetobacter baumannii ATCC 19606, Citrobacter freundii ATCC 8090, Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC 9027, Enterococcus faecalis ATCC 19433, Staphylococcus aureus ATCC 12600, Staphylococcus epidermidis ATCC 14990, Bacillus cereus ATCC 14579.

Synthesis of new pyrazole derivatives and their anticancer evaluation.

A series of functionally substituted pyrazole compounds have been synthesized and evaluated in vitro for their antiproliferative effects on a panel of 60 cellular lines, according to the National Cancer Institute screening protocol. Three of the 12 tested compounds showed moderate antitumor activity, one of them being chosen for the 5-dose assay and presented logGI(50) values up to -5.75.

New heterocyclic compounds from 1,2,4-triazole and 1,3,4-thiadiazole class bearing diphenylsulfone moieties. Synthesis, characterization and antimicrobial activity evaluation☆

Some new 5-(4-(4-X-phenylsulfonyl)phenyl)-4-(R)-2H-1,2,4-triazol-3(4H)-thiones 4a,b; 5a,b and 5-(4-(4-X-phenylsulfonyl)phenyl)-N-(R)-1,3,4-thiadiazol-2-amines 6a,b; 7a,b were obtained by cyclization of new N(1)-[4-(4-X-phenylsulfonyl)benzoyl]-N(4)-(R)-thiosemicarbazides 2a,b; 3a,b (X=H, Br). The 1,2,4-triazoles were synthesized by intramolecular cyclization of acylthiosemicarbazides, in basic media. On the other hand, 1,3,4-thiadiazoles were obtained from same acylthiosemicarbazides, in acidic media. These new intermediates from thiosemicarbazide class were afforded by the reaction of 4-(4-X-phenylsulfonyl)benzoic acids hydrazides (X=H, Br) 1a,b with 4-trifluoromethoxyphenyl or 3,4,5-trimethoxyphenyl isothiocyanate. The newly synthesized compounds were characterized by IR, (1)H NMR, (13)C NMR, MS and elemental analysis. All the new compounds were screened for their antimicrobial activity against some bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 13061, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 49141, Acinetobacter baumannii ATCC 19606 and Pseudomonas aeruginosa ATCC 27853) and yeasts (Candida albicans ATCC 90028 and Candida parapsilosis ATCC 22019).

Synthesis and antimicrobial evaluation of some fused heterocyclic [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives

A series of fused 1,2,4-triazoles with diphenylsulfone moiety are prepared utilizing 4-amino-5-[4-(4-X-phenylsulfonyl)phenyl]-4H-1,2,4-triazole-3-thiol 1 (X=H, Br). The latter on reaction with aromatic isothiocyanate in DMF, aromatic acid in POCl3 and CDI in dioxane gives five membered fused triazole derivatives 2a-c, 3a-c, 4a-g, 5a-g and 6a,b. The structures of newly synthesized compounds were confirmed on the basis of their elemental analysis and spectral data results (IR, 1H-and 13C NMR). New synthesized compounds were screened for their antimicrobial activities. The preliminary results revealed that some of the compounds exhibited promising antimicrobial activities.

New substituted 2-(pyrazol-1-yl)-dialkylacetanilides with potential local anesthetic and antiarrhythmic action. Part II.

Nine substituted 2-(pyrazol-1-yl)-dialkylacetanilides were synthesized by N-alkylation of pyrazole and its derivatives with several 2-iodoacetanilides. The new compounds exhibited local anesthetic and antiarrhythmic actions. They have been characterized by elemental chemical analysis, UV-Vis, IR, 1H NMR, 13C NMR, SM spectra and pharmacology research.

Synthesis and Antioxidant Activity Evaluation of New Compounds from Hydrazinecarbothioamide and 1,2,4-Triazole Class Containing Diarylsulfone and 2,4-Difluorophenyl Moieties

In the present investigation, new hydrazinecarbothioamides 4–6 were synthesized by reaction of 4-(4-X-phenylsulfonyl)benzoic acids hydrazides (X= H, Cl, Br) 1–3 with 2,4-difluorophenyl isothiocyanate and further these were treated with sodium hydroxide to obtain 1,2,4-triazole-3-thione derivatives 7–9. The reaction of 7–9 with α-halogenated ketones, in basic media, afforded new S-alkylated derivatives 10–15. The structures of the synthesized compounds have been established on the basis of 1H-NMR, 13C-NMR, IR, mass spectral studies and elemental analysis. The antioxidant activity of all compounds has been screened. Hydrazinecarbothioamides 4–6 showed excellent antioxidant activity and 1,2,4-triazole-3-thiones 7–9 showed good antioxidant activity using the DPPH method.

New Potential Antitumor Pyrazole Derivatives: Synthesis and Cytotoxic Evaluation

New pyrazole derivatives were designed and synthesized as potential protein kinase inhibitors in the view to develop specific antitumor therapies. The structures of the compounds were elucidated using spectral and elemental analyses. The antitumor potential was estimated using wheat seeds and the general toxicity was evaluated by alternative methods, using invertebrate animals. One 3-aminopyrazole derivative emerged as a potential candidate for the development of future cytotoxic compounds.

New 6-amino-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines and [1,2,4]triazolo[3,4-b] [1,3,4]thiadiazin-6-ones: Synthesis, characterization and antibacterial activity evaluation

(4-X-Phenylsulfonyl)phenyl] containing 6-amino-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines and [1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ones were synthesized by intermolecular condensation of 2-chloro-N-phenylacetamide, 2-chloroacetic acid, oxalylchloride and bromo-diethylmalonate with 4-amino-5-[4-(4-X-phenylsulfonyl)phenyl]-4H-1,2,4-triazole-3-thiols (X = H, Cl, Br). The structures of newly synthesized compounds were confirmed by elemental analysis and IR, NMR spectral data. All the compounds were screened for their antibacterial activities. Some of them exhibited good activities against Staphylococcus epidermidis ATCC 14990, Pseudomonas aeruginosa ATCC 9027, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922.

Synthesis and antimicrobial screening of N-(1-methyl-1H-pyrazole-4-carbonyl)-thiourea derivatives

In the search of bioactive molecules in the class of functionally 4-substituted pyrazolic compounds, a series of N-(1-methyl-1H-pyrazole-4-carbonyl)-thiourea derivatives were prepared by addition of various substituted anilines to 1-methyl-1H-pyrazole-4-carbonyl isothiocyanate. The new thioureides and the intermediary compounds were characterized by spectroscopic data and elemental analyses and were evaluated for antibacterial and antifungal activities.