Hasnain Hussain

Bis-Thiourea Bearing Aryl and Amino Acids Side Chains and Their Antibacterial Activities

Abstract A series of symmetrical 1,3-bis thiourea 1a–e and 1,4-bis thiourea derivatives 2a–e have been successfully synthesized from the reactions of amines with 3-acetylbenzoyl isothiocyanate and 4-acetylbenzoyl isothiocyanate, respectively. All the synthesized compounds were characterized by FT-IR spectroscopy and 1H and 13C NMR spectroscopy. The compounds were screened for their antibacterial activity by turbidimetric method using gram-negative bacteria (E. coli ATCC 8739) using turbidimetric method. The newly synthesized bis-thiourea derivatives bearing aryl side chains showed good antibacterial activity against E. coli. The effect of the molecular structure of the synthesized compounds on the antibacterial activity is discussed. GRAPHICAL ABSTRACT

Synthesis and Antibacterial Activity of Acetoxybenzoyl Thioureas with Aryl and Amino Acid Side Chains

Abstract A series of acetoxybenzoylthioureas derivatives with aryl and amino acid ester side chains were prepared by reaction of acetoxybenzoyl isothiocyanate, an acyloxy benzyl ester-based derivative of aspirin, with aryl amines or amino-functionalized amino acids with overall yields of 46–73%. The products that display a thiourea segment as a linker showed improved antibacterial properties in comparison with aspirin. The structures of the synthesized compounds were characterized by infra red spectroscopy, 13C nuclear magnetic resonance (NMR), and 1H NMR spectroscopy. The compounds were screened for their antibacterial activity by using gram-negative bacteria (E. coli ATCC 8739). [2-(phenylcarbamothioylcarbamoyl)phenyl] acetate showed the highest antibacterial activity against E. coli compared with other synthesized compounds. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Synthesis and antimicrobial studies of hydroxylated chalcone derivatives with variable chain length

A series of (E)-1-(4-alkyloxyphenyl)-3-(hydroxyphenyl)-prop-2-en-1-one have been successfully synthesised via Claisen–Schmidt condensation. The synthesised chalcone derivatives consisted of hydroxyl groups at either ortho, meta or para position and differed in the length of the alkyl groups, C n H2 n +1, where n = 6, 10, 12 and 14. The structures of all compounds were defined by elemental analysis, IR, 1H- and 13C-NMR. The antimicrobial studies were carried out against wild-type Escherichia coli American Type Culture Collection 8739 to evaluate the effect of the hydroxyl and the alkyl groups of the synthesised chalcones. All the synthesised compounds have shown significant antimicrobial activities. The optimum inhibition was dependent on the position of the hydroxyl group as well as the length of the alkyl chains.

(E)-3-[4-(Hexyloxy)phenyl]-1-(4-hydroxyphenyl)prop-2-en-1-one

In the title compound, C21H24O3, the enone group adopts an s–cis conformation. The planes of the aromatic rings are inclined at an angle of 6.1 (1)°. The alkoxy tail is not linear, with the maximum deviation from the least-squares plane being 0.375 (2) Å. Molecules are connected into extended chains along the a axis through O—H⋯Ocarbonyl hydrogen bonds and are interlinked via C—H⋯O interactions to form a two-dimensional array parallel to the ab plane.

Application of Response Surface Methodology for Optimizing Process Parameters in the Production of Amylase by Aspergillus flavusNSH9 under Solid State Fermentation

Amylase is recognized as one of the important commercial enzymes. This group of enzymes has the ability in hydrolyzing starch into smaller oligosacharides. The present work aimed to determine the optimum fermentation conditions for maximum production of crude amylase enzyme by Aspergillus flavus NSH9 employing response surface methodology (RSM).Central composite design (CCD) was applied to determine the optimal fermentation condition with respect to the four main process parameters such as temperature, initial moisture content, pH and the incubation period. Solid state fermentation (SSF) was performed using 5.0 g of sago hampas inoculated with 1x107sporesmL-1following the experimental design obtained using CCD and further optimized by RSM. The initial moisture, pH and temperature showed significant effect on the amylase production (p<0.05). The maximum amylase activity produced was achieved and recorded as 1.055 ± 0.03U mL-1after four days of fermentation period with 100% (v/v) moisture holding capacity, pH 6.5 and temperature at 28°C. The optimum fermentation conditions for amylase production was determined with A. flavusNSH9 on sago hampas.

(E)-1-(4-Decyl­oxyphen­yl)-3-(4-hydroxy­phen­yl)prop-2-en-1-one

In the title compound, C25H32O3, the asymmetric unit contains two crystallographically independent molecules: both enone groups adopt an s-cis configuration. In the crystal, O—H⋯O and C—H⋯O intermolecular interactions form bifurcated hydrogen bonds, which generate R 1 2(6) ring motifs. These intermolecular interactions link the molecules into one-dimensional chains along the [10] direction. The crystal structure is further stabilized by C—H⋯π interactions.

(E)-3-(4-Hexyl­oxyphen­yl)-1-(3-hydroxy­phen­yl)prop-2-en-one

In the title compound, C21H24O3, the enone unit is in the s–cis configuration. The dihedral angle between the benzene rings is 2.18 (4)°. In the crystal, molecules are linked by pairs of O—H⋯O intermolecular hydrogen bonds, forming inversion dimers. The crystal structure is also consolidated by C—H⋯π interactions.

Novel Synthetic Monothiourea Aspirin Derivatives Bearing Alkylated Amines as Potential Antimicrobial Agents

A new series of aspirin bearing alkylated amines moieties 1–12 were synthesised by reacting isothiocyanate with a series of aniline derivatives in overall yield of 16–56%. The proposed structures of all the synthesised compounds were confirmed using elemental analysis, FTIR, and 1H and  13C NMR spectroscopy. All compounds were evaluated for antibacterial activities against E. coli and S. aureus via turbidimetric kinetic and Kirby Bauer disc diffusion method. Compound 5 bearing meta -CH3 substituent showed the highest relative inhibition zone diameter against tested bacteria compared to ortho and para substituent. Furthermore, aspirin derivatives bearing shorter chains exhibited better bacterial inhibition than longer alkyl chains.

Combined Overlap Extension PCR Method for Improved Site Directed Mutagenesis

The combined overlap extension PCR (COE-PCR) method developed in this work combines the strengths of the overlap extension PCR (OE-PCR) method with the speed and ease of the asymmetrical overlap extension (AOE-PCR) method. This combined method allows up to 6 base pairs to be mutated at a time and requires a total of 40–45 PCR cycles. A total of eight mutagenesis experiments were successfully carried out, with each experiment mutating between two to six base pairs. Up to four adjacent codons were changed in a single experiment. This method is especially useful for codon optimization, where doublet or triplet rare codons can be changed using a single mutagenic primer set, in a single experiment.

(E)-1-[4-(Hex-yloxy)phen-yl]-3-(3-hy-droxy-phen-yl)prop-2-en-1-one.

There are two molecules in the asymmetric unit of the title compound, C21H24O3, in which the dihedral angles between the aromatic rings are 6.4 (1) and 7.0 (1)°. The enone moiety of both molecules adopts an s–cis configuration. In the crystal, intermolecular O—H⋯O and C—H⋯O interactions to the same acceptor O atom generate R 2 1(6) ring motifs and further C—H⋯O interactions generate R 2 2(8) ring motifs. Topologically, the R 2 1(6) and R 2 2(8) ring motifs are arranged alternately, forming [001] chains of molecules. The crystal structure is further stabilized by C—H⋯π interactions.