Novel Structural Hybrids of Pyrrole and Thiazole Moieties: Synthesis and Evaluation of Antibacterial and Antifungal Activities

One of the best ways to design new biocidal agents is synthesizing hybrid molecules by combining two or more bioactive moieties in a single molecular scaffold. So, new series of pyrroles bearing a thiazole moiety were synthesized using 1-methyl-1H-pyrrole-2-carbaldehyde thiosemicarbazones 1a–c. Cyclization of thiosemicarbazone derivatives 1a–c with ethyl chloroacetate, ethyl 2-chloropropanoate, chloroacetone and phenacyl bromide afforded the corresponding thiazolidin-4-ones 2a–c, 5-methylthiazolidin-4-ones 3a–c, 4-methyl-2,3-dihydrothiazoles 4a–c, and 4-phenyl-2,3-dihydrothiazoles 5a–c, respectively. The antimicrobial activity of the new thiazole derivatives was evaluated.

Synthesis, Characterization of Novel Schiff’s Bases of 2-(1H-tetrazol-5-yl) Pyridine and Evaluation of their Antitubercular Activity

This study aimed to prepare some new 2-(1H-tetrazol-5-yl) pyridine derivatives from Pyridine Nitrile as a starting materials and to evaluate the antitubercular activity against Mycobacterium Tuberculosis. The first step involves the reaction of 2-(1H-tetrazol-5-yl) pyridine with ethyl chloroacetate to form ethyl [5-(pyridin-2-yl)-1H-tetrazol-1-yl] acetate (A). In step II it was further treated with hydrazine hydrate to form 2-[5-(pyridin-2-yl)-1H-tetrazol-1-yl] acetohydrazide (B). The compound B was treated with different aromatic aldehyde to form N'-[(E)-substituted phenylmethylidene]-2-[5-(pyridin-2-yl)-1H-tetrazol-1-yl] acetohydrazide (Schiff Bases) (C1–C10). The compounds obtained were identified by spectral data. The antitubercular activity of synthesized compounds were evaluated against Mycobacterium Tuberculosis. The compound C4 and C10 was found to possess potent activity while compounds C2 and C3 shows moderate activity.

Synthesis and Characterization of Some Heterocyclic Compounds and Evaluation of Antibacterial Activity

In this study, heterocyclic compounds with two nitrogen atoms are prepared by reaction of 2-aminobenzimidazole with formic acid to get amide derivatives (A), reacts with phenylhydrazine to get phenyl hydrazone derivatives (B), reacts with ethyl chloroacetate to obtain ethyl acetate derivatives (C). The derivative (D) obtains on heating in a basic medium. The (B) reacts with 2-chloroacetyl chloride to give derivatives (E). A number of Schiff bases are prepared (F, I) from reacting 2-aminobenzimidazole with benzaldehyde derivatives. The(F) reacts with propargyl bromide to give propargyl bromide derivatives (G). The cyclization with 4-nitrophenyl azide leads to obtain triazole compound (H). The compound (I) reacts with ethyl chloroacetate to give ethyl acetate derivatives (J), reacts with hydrazine to give N-amide hydrazine derivatives (K). The cyclization give rises to 1,3,4-oxadiazole derivatives (L). The compound (I) reacts with sodium azide to obtain tetrazole derivatives (M). Synthesizing of Triazine, Oxadiazole, Triazole, Tetrazole via cyclization of the Schiff base derivatives with ethyl chloroacetate and chloro acetyl chloride, benzoic acid, 4-nitrophenyl azide, sodium azide and phenyl azide are possible respectively. The FT-IR, 13C-NMR and 1H-NMR spectral data give good evidence for the formation of the compounds. Some prepared compounds exhibit antibacterial properties.

Synthesis and structure of ethyl 2-[(4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl)sulfanyl]acetate

The title compound, C18H16N2O3S, was synthesized by reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one with ethyl chloroacetate. The quinazoline ring forms a dihedral angle of 86.83 (5)° with the phenyl ring. The terminal methyl group is disordered by a rotation of about 60° in a 0.531 (13): 0.469 (13) ratio. In the crystal, C—H...O hydrogen-bonding interactions result in the formation of columns running in the [010] direction. Two parallel columns further interact by C—H...O hydrogen bonds. The most important contributions to the surface contacts are from H...H (48.4%), C...H/H...C (21.5%) and O...H/H...O (18.7%) interactions, as concluded from a Hirshfeld analysis.

SYNTHESIS AND BIOLOGICAL EVALUATION OF BENZIMIDAZOLE DERIVATIVES AS ANTIMICROBIAL AGENTS

Objective: The present study aims to synthesize and biological evaluation of benzimidazole derivatives as antimicrobial agents. Methods: 2-Methylbenzimidazole react with ethyl-chloroacetate gives N1-Ethylacetate-2-methyl-benzimidazole (1), which on reaction with thiosemicarbazide gives N1-acetylthiosemicarbazide-2-methyl-benzimidazole (2). The compound (2) on dehydrative annulation by mineral acid gives N1-(2’-amino-5’-methylene)-1’,3’,4’-thiadiazole-2-methyl-benzimidazole(3), which on condensation with various aromatic and hetero aromatic aldehydes gives N1-(2-substituted-Benzylidene-imino-5’-methylene)-1’, 3’, 4’-Thiadiazole]-2-methyl-benzimidazole(4a-4l). Results: The reaction sequence involves microwave-induced preparation of N1-Ethylacetate-2-methyl-benzimidazole (1) from reaction of 2-methylbenzimidazole with ethyl-chloroacetate. Further reaction with thiosemicarbazide gives N1-acetylthiosemicarbazide-2-methyl-benzimidazole (2). The compound (2) on dehydrative annulation by sulfuric acid gives N1-(2’-amino-5’-methylene)-1’,3’,4’-thiadiazole-2-methyl-benzimidazole(3), which on condensation with various aromatic and hetero aromatic aldehydes gives N1-(2-substituted-Benzylidene-imino-5’-methylene)-1’, 3’, 4’-Thiadiazole]-2-methyl-benzimidazole(4a-4l). Which were characterized by IR and 1H NMR spectral data. Conclusion: All the synthesized compounds were screened for antimicrobial activity by cup plate method. Most of the derivatives showed good antimicrobial activity against Gram-Positive and Gram-negative bacteria.

S-Alkylated 1,2,4-Triazoles Derivatives Synthesis, spectral analysis and cytotoxicity evaluation

This paper presents synthesis, characterization and cytotoxicity assessment of six S-alkylated 1,2,4-triazoles derivatives that were obtained by treatment of some 1,2,4-triazole-3-thiones containing in the molecule phenylsulfonylphenyl and propyl or 4-bromophenylsulfonylphenyl and 4-methoxyphenyl fragments with different alkylation agents (ethyl bromide, ethyl chloroacetate or phenacyl bromide) in basic media. The synthesized compounds were physico-chemically characterized and the IR, 1H-NMR, 13C-NMR spectra were consistent with the assigned structures. The cytotoxicity of S-alkylated derivatives was evaluated on Daphnia magna crustacean.

Synthesis and Biological evaluation of some new 2-thioxoimidazolidin-4-one derivatives (part II)

In the present work adifferent of new heterocyclic compounds were synthesized by reaction of thiosemicarbazide with tow aldehydes (4-bromo benzaldehyde,2-chloro benzaldehyde). the reacting `of compounds(1,2) with ethyl chloroacetate to give 3-[(arylidene)amino]-2-sulfanyl-3,5-dihydro-4H-imidazol-4-one (3,4) which treating with defferent aldehydes togive chalcones . the compound (3) reacted with ethyl aceto acetate to give ethyl 4-aryl-1-[(4-bromo benzylidene)amino]-6-oxo-2-sulfanyl-3a,4,5,6,7,7a-hexahydro-1H-benzimidazole-5-carboxylate,and in series of reaction converted into a variety of derivatives. The prepared compounds were characterized by 1H NMR and FTIR spectroscopy.further more antibacterial activity of some the prepared new cyclic compounds were evaluated against three types of bacteria