Abstract:A new series of N-(6-arylbenzo [d]thiazol-2-yl)acetamides were synthesized by C-C coupling methodology in the presence of Pd(0) using various aryl boronic pinacol ester/acids. The newly synthesized compounds were evaluated for various biological activities like antioxidant, haemolytic, antibacterial and urease inhibition. In bioassays these compounds were found to have moderate to good activities. Among the tested biological activities screened these compounds displayed the most significant activity for urease inhibition. In urease inhibition, all compounds were found more active than the standard used. The compound N-(6-(p-tolyl)benzo[d]thiazol-2-yl)acetamide was found to be the most active. To understand this urease inhibition, molecular docking studies were performed. The in silico studies showed that these acetamide derivatives bind to the non-metallic active site of the urease enzyme. Structure-activity studies revealed that H-bonding of compounds with the enzyme is important for its inhibition.

Abstract:In general, benzothiazole derivatives have attracted great interest due to their pharmaceutical and biological importance. New 2-amino-6-arylbenzothiazoles were synthesized in moderate to excellent yields via Suzuki cross coupling reactions using various aryl boronic acids and aryl boronic acid pinacol esters and the antiurease and nitric oxide (NO) scavenging activity of the products were also examined. The most active compound concerning urease enzyme inhibition was 6-phenylbenzo[d]thiazole-2-amine 3e, with an IC 50 value of 26.35 µg/mL. Compound 3c, 6-(4-methoxyphenyl) benzo[d]thiazole-2-amine, exhibited the highest nitric oxide percentage scavenging at 100 µg/mL.

A variety of novel 5-aryl thiophenes 4a-g containing sulphonylacetamide (sulfacetamide) groups were synthesized in appreciable yields via Pd[0] Suzuki cross coupling reactions. The structures of these newly synthesized compounds were determined using spectral data and elemental analysis. Density functional theory (DFT) studies were performed using the B3LYP/6-31G (d, p) basis set to gain insight into their structural properties. Frontier molecular orbital (FMOs) analysis of all compounds 4a-g was computed at the same level of theory to get an idea about their kinetic stability. The molecular electrostatic potential (MEP) mapping over the entire stabilized geometries of the molecules indicated the reactive sites. First hyperpolarizability analysis (nonlinear optical response) were simulated at the B3LYP/6-31G (d, p) level of theory as well. The compounds were further evaluated for their promising antibacterial and anti-urease activities. In this case, the antibacterial activities were estimated by the agar well diffusion method, whereas the anti-urease activities of these compounds were determined using the indophenol method by quantifying the evolved ammonia produced. The results revealed that all the sulfacetamide derivatives displayed antibacterial activity against Bacillus subtiles, Escherichia coli, Staphylococcus aureus, Shigella dysenteriae, Salmonella typhae, Pseudomonas aeruginosa at various concentrations. Furthermore, the compound 4g N-((5-(4-chlorophenyl)thiophen-2-yl)sulfonyl) acetamide showed excellent urease inhibition with percentage inhibition activity~46.23˘0.11 at 15 µg/mL with IC 50 17.1 µg/mL. Moreover, some other compounds 4a-f also exhibited very good inhibition against urease enzyme.

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A highly convenient method has been developed for the synthesis of (prop-2-ynyloxy) benzene and its derivatives. Differently substituted phenol and aniline derivatives were allowed to react with propargyl bromide in the presence of K2CO3 base and acetone as solvent. The compounds were synthesized in good yields (53–85%). Low cost, high yields and easy availability of compounds helped in the synthesis. Electron withdrawing groups favor the formation of stable phenoxide ion thus in turn favors the formation of product while electron donating groups do not favor the reaction. Phenol derivatives gave good yields as compared to that of aniline. As aprotic polar solvents favor SN2 type reactions so acetone provided best solvation for the reactions. K2CO3 was proved to be good for the synthesis. Antibacterial, Antiurease and NO scavenging activity of synthesized compounds were also examined. 4-bromo-2-chloro-1-(prop-2-ynyloxy)benzene 2a was found most active compound against urease enzyme with a percentage inhibition of 82.00±0.09 at 100 µg/mL with IC50 value of 60.2. 2-bromo-4-methyl-1-(prop-2-ynyloxy)benzene 2d was found potent antibacterial against Bacillus subtillus showing excellent inhibitory action with percentage inhibition of 55.67±0.26 at 100 µg/ml wih IC50 value of 79.9. Based on results, it can be concluded that some of the synthesized compounds may have potential antiurease and antibacterial effects against several harmful substances.

In this work, we evaluated the antimicrobial, cytotoxicity properties of the snapdragon (Antirrhinum majus) extract and fractions. The cytotoxicity, studied by haemolytic activity against human blood erythrocytes assays, indicated a low cytotoxic effect on the absolute methanol extract and its fractions from plant. Chemical analysis of whole plant was also carried out. For chemical analysis HP-LC analysis was carried out to determine the presence of phenolics. The GC-MS analysis was also carried out to determine the presence of some phytoconstituents in n-hexane extract (extracted by soxhlet). The results of present study revealed that snapdragon plant might be considered as a good source of natural antimicrobial.

A series of novel 2-aryl 1 -4-bromothiophenes (2a-f), biarylthiophenes with non-identical aryl groups (3a-e) and biarylthiophenes with identical aryl groups (4a-f) were synthesized in moderate to excellent yields by using different arylboronic acids in a Suzuki-Miyaura cross-coupling reaction. The experimental results showed that the use of K 2 CO 3 as base resulted in moderate yields compared with that of good yields obtained upon using K 3 PO 4 . The highest yield obtained using K 3 PO 4 was 82% for 2, 4-bis (4-chlorophenyl) thiophene (4d). The synthesized compounds in the present study were examined for their biofilm inhibition and hemolysis assay. Among all compounds 2, 4-bis (4-methoxyphenyl) thiophene (4b) was found to strongly inhibit the formation of bacterial biofilm against E. coli. The compound 4b exhibited higher inhibition (80.92%) compared with the standard Rifampicin with 97.43% inhibition. The compound 2, 4-bis (4-chlorophenyl) thiophene (4d) displayed strong anti-biofilm activity with its ability to prevent the formation of Pasteurell amultocida biofilm at the percent inhibition of 74.53%. In addition, 2f showed the highest percentage hemolysis 16.0% compared with that of the standard Triton-X-100. 3

A mild, practical protocol has been developed for the Suzuki cross-coupling of unprotected thienylsulfonamides from air- and bench-stable organotrifluoroborates in the absence of a protecting group on the sulfonamide nitrogen. The developed synthetic method can be applied to the preparation of various arylated and heteroarylated thienylsulfonamides under conditions that are tolerant of a broad range of functional groups.