Novel triazole derivatives as ecological corrosion inhibitors for mild steel in 1.0 M HCl: experimental & theoretical approach.

The present paper illustrates the investigation of two novel ecological triazole derivative corrosion inhibitors, namely ethyl 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate [Tria-CO2Et], and 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetohydrazide [Tria-CONHNH2]. The studied inhibitors were investigated against the corrosion of mild steel in 1.0 M HCl solution using different electrochemical techniques. Potentiodynamic polarization experiments indicated that the [Tria-CO2Et], and the [Tria-CONHNH2] acted as mixed type inhibitors. Electrochemical impedance spectroscopy measurements revealed that both inhibitors presented a high inhibition performance, achieving an inhibition efficiency of 95.3% for [Tria-CO2Et] and 95.0% for [Tria-CONHNH2] at a concentration of 1.0 × 10-3 M. Based on the Langmuir isotherm model and the activation parameters, these triazole derivatives were adsorbed onto a steel surface by physical and chemical bonds. Density functional theory based on B3LYp6-311G(d,p) was also carried out to correlate the inhibition efficiencies obtained experimentally with the theoretical descriptors of the studied molecular structures.

Synthesis and Antimicrobial Screening of Novel Thioglycosides and Acyclonucleoside Analogs Carrying 1,2,3-Triazole and 1,3,4-Oxadiazole Moieties.

The solvent-free 1,3-dipolar cycloaddition reaction of dimethylacetylene dicarboxylate (1) with 2-chlorophenyl azide (2) afforded 1,2,3-triazole diester 3 that upon hydrazinolysis, furnished the corresponding bis-acid hydrazide 4. The treatment of compound 4 with carbon disulfide in a refluxing potassium hydroxide solution furnished the desired bis-1,3,4-oxadiazole-2-thione 5 tethered to a 1,2,3-triazole moiety. The respective SOx-glycosides 9-11 were obtained by glycosylation of bis-oxadiazole 5 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide (6), 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide (7), and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-d-glucopyranosyl chloride (8) in dry acetone in the presence of Et3N, which acted as a base. However, alkylation of 5 with halogeno-alkanol 12 or 13, chloroglycerol 14, bromoethers 20 or 21, and epichlohydrin 22 in the presence of K2CO3 in DMF yielded the corresponding acyclonucleoside analogs 16-18 and 23-25. The isopropylidenes 19 and acetyl derivatives 26-28 of the products were also prepared. The newly synthesized compounds were characterized by (1)H NMR, (13)C NMR, 2D NMR, and mass spectra. The compounds were screened for their antibacterial and antifungal activities. A number of the tested compounds exhibited significant antimicrobial activity compared to the reference drugs.

Novel regioselective formation of S- and N-hydroxyl-alkyls of 5-(3-chlorobenzo[b]thien-2-yl)-3-mercapto-4H-1,2,4-triazole and a facile synthesis of triazolo-thiazoles and thiazolo-triazoles. Role of catalyst and microwave.

Regioselective alkylation of 5-(3-chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole (1) with hydroxy alkylating agents 2, 3, 13, and the 2,3-O-isopropylidene-1-O-(p-tolylsulfonyl)-glycerol (10) afforded the corresponding S-alkylated derivatives 6, 7, 11, and 14 under both conventional and microwave irradiation conditions; bentonite as a solid support gave better results, with no change in regioselectivity. A facile intramolecular dehydrative ring closure of 6, 7, 11, and 14 using K(2)CO(3) in DMF afforded the corresponding fused triazolo-thiazines and thiazolo-triazole 17-19. The isopropylidenes and acetyl derivatives of the products were prepared.