Synthesis, Molecular Structure Optimization, and Cytotoxicity Assay of a Novel 2-Acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene.

A novel thiophene-containing compound, 2-acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene (4) was synthesized by reaction of malononitrile with CS2 in the presence of K2CO3 under reflux in DMF and the subsequent reaction with chloroacetone followed by cyclization. This compound has been characterized by means of FT-IR, ¹H-NMR, (13)C-NMR, and mass spectrometry as well as elemental analysis. In addition, the molecular structures of compound 4 was determined by X-ray crystallography. The geometry of the molecule is stabilized by an intramolecular interaction between N1-H1···O1 to form S6 graf set ring motif. In the crystal, molecules are linked via N1-H2···O1 and C7-H7A···N2 interactions to form a three-dimensional network. Molecular structure and other spectroscopic properties of compound 4 were calculated using DFT B3LYP/6-31G (d,p) method. Results revealed a good agreement between the optimized geometric parameters and the observed X-ray structure. Furthermore, and by employing the natural bond orbital (NBO) method, the intramolecular charge transfer (ICT) interactions along with natural atomic charges at different sites, were calculated; results indicated strong n→π* ICT from LP(1)N5→BD*(2)C15-C16 (63.23 kcal/mol). In addition, the stabilization energy E(2) of the LP(2)O3→ BD*(1)N5-H6 ICT (6.63 kcal/mol) indicated the presence of intramolecular N-H···OH bonding. Similarly, calculations of the electronic spectra of compound 4 using, TD-DFT revealed a good agreement with the experimental data. Finally, compound 4 was evaluated for its in vitro cytotoxic effect against PC-3 and HeLa cell lines, as an anticancer agent, and found to be nontoxic.

Novel enaminone derived from thieno [2,3-b] thiene: Synthesis, x-ray crystal structure, HOMO, LUMO, NBO analyses and biological activity.

BACKGROUND: Due to their structural and therapeutic diversity, thienothiophene derivatives have attracted much synthetic interest because of their reactivity and biological activity. The thieno [2,3-b] thiophene moiety has been used in the design of a novel pharmaceutical therapies. Additionally, its enaminones derivatives are versatile synthons and have a lot of synthetic applications such as N-heterocycles, wide variety of naturally occurring alkaloids and pharmaceutical drugs. RESULTS: Synthesis of (2E,2'E)-1,1'-(3,4-diphenylthieno [2,3-b] thiophene-2,5-diyl) bis (3-(dimethylamino) prop-2-en-1-one) 5 was reported. The structure of compound 5 was deduced by spectroscopic techniques. The compound was crystallizes in the monoclinic system with space group P-1 with cell coordinates a=9.9685 (8) Å, b=10.1382 (8) Å, c=13.3220 (11) Å, α=101.018 (2) °, ß=94.480 (2) °, γ=107.207 (1) °, V=1249.3 (1) Å3, and Z=2. In the crystal molecules are packed in chains formed via weak intermolecular C21-H21A… O1, C22-H22A…O2 and C27-H27A…O2 hydrogen bondings. Theoretical quantum chemical calculations have been performed on the studied compound using the DFT B3LYP/6-311G (d, p) method. The geometric parameters of the optimized structure are in good agreement with the experimental data obtained from our reported X-ray structure. The two benzene rings and the two side chains are not coplanar with the fused thiophene rings. The electronic spectra of the studied compound have been calculated using the TD-DFT method at the same level of theory. The transition bands at 352.9 nm (f=0.5549) and 332.1 nm (f=0.2190) are due to the H-1 → L (72%) and H → L + 1 (82%) excitations respectively. The NBO calculations were performed to predict the natural atomic charges at the different atomic sites and to study the different intramolecular charge transfer (ICT) interactions occurring in the studied system. It is found that the O and N-atoms have the highest negative charge densities while the S-atoms are the most electropositive. These results give idea about how our molecule could react with the receptor active sites. Compound 5 was evaluated against ant-microbial activity. CONCLUSIONS: Synthesis, molecular structure and spectroscopic invesitgation of (2E,2'E)-1,1'-(3,4-diphenylthieno [2,3-b] thiophene-2,5-diyl) bis (3- (dimethylamino) prop-2-en-1-one) 5 was studied. Graphical AbstractMolecular structure investigation of novel enaminone derived from thieno [2,3-b] thiene.

Synthesis, bioactivity, molecular docking and POM analyses of novel substituted thieno[2,3-b]thiophenes and related congeners.

Several series of novel substituted thienothiophene derivatives were synthesized by reacting the synthone 1 with different reagents. The newly synthesized compounds were characterized by means of different spectroscopic methods such as IR, NMR, mass spectrometry and by elemental analyses. The new compounds displayed significant activity against both Gram-positive and Gram negative bacteria, in addition to fungi. Molecular docking and POM analyses show the crucial role and impact of substituents on bioactivity and indicate the unfavorable structural parameters in actual drug design: more substitution doesn't guaranty more efficiency in bioactivity.

Synthesis, anti-microbial and molecular docking studies of quinazolin-4(3H)-one derivatives.

In this work, synthesis, antimicrobial activities and molecular docking studies of some new series of substituted quinazolinone 2a-h and 3a-d were described. Starting form 2-aminobenzamide derivatives 1, a new series of quinazolinone derivatives has been synthesized, in high yields, assisted by microwave and classical methods. Some of these substituted quinazolinones were tested for their antimicrobial activity against Gram-negative bacteria (Pseudomonas aeruginosa and Esherichia coli) and Gram-positive bacteria (Staphylococcus aureus, and Bacillus subtilis), and anti-fungal activity against (Aspergillus fumigatus, Saccharomyces cervevisiae, and Candida albicans) using agar well diffusion method. Among the prepared products, 3-benzyl-2-(4-chlorophenyl)quinazolin-4(3H)-one (3a) was found to exhibits the most potent in vitro anti-microbial activity with MICs of 25.6±0.5, 24.3±0.4, 30.1±0.6, and 25.1±0.5 µg/mL against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Esherichia coli, respectively. Compound 3a was found to exhibits the most potent in vitro anti-fungal activity with MICs of 18.3±0.6, 23.1±0.4, and 26.1±0.5 µg/mL against Aspergillus fumigatus, Saccharomyces cervevisiae, and Candidaal bicans, respectively.