Zurina Shaameri

Molecular Complexes between 2,2′-Biphenyl Dicarboxylic Acid and Phenazine: Anhydrous and Hydrated Forms

Abstract The formation of co-crystals of 2,2′-biphenyl dicarboxylic acid and phenazine is reported. By utilizing different solvents during the crystal preparation, two types of co-crystals, i.e. anhydrous and hydrated, were observed to form. The conformation of the component molecules and the packing arrangement within each co-crystal are described and discussed. In both co-crystals, the generation of a cyclic motif involving one weak (C-H…O) and one strong (O-H…N) hydrogen bonds are observed. Hydrogen bond geometries of the two types of interactions in the cyclic motif for both complexes are reported and discussed.

In Vitro Inhibitory and Cytotoxic Activity of MFM 501, a Novel Codonopsinine Derivative, against Methicillin-Resistant Staphylococcus aureus Clinical Isolates

28 new pyrrolidine types of compounds as analogues for natural polyhydroxy alkaloids of codonopsinine were evaluated for their anti-MRSA activity using MIC and MBC value determination assay against a panel of S. aureus isolates. One pyrrolidine compound, MFM 501, exhibited good inhibitory activity with MIC value of 15.6 to 31.3 μg/mL against 55 S. aureus isolates (43 MRSA and 12 MSSA isolates). The active compound also displayed MBC values between 250 and 500 μg/mL against 58 S. aureus isolates (45 MRSA and 13 MSSA isolates) implying that MFM 501 has a bacteriostatic rather than bactericidal effect against both MRSA and MSSA isolates. In addition, MFM 501 showed no apparent cytotoxicity activity towards three normal cell lines (WRL-68, Vero, and 3T3) with IC50 values of >625 µg/mL. Selectivity index (SI) of MFM 501 gave a value of >10 suggesting that MFM 501 is significant and suitable for further in vivo investigations. These results suggested that synthetically derived intermediate compounds based on natural products may play an important role in the discovery of new anti-infective agents against MRSA.

Antinociceptive activity of a synthetic oxopyrrolidine-based compound, ASH21374, and determination of its possible mechanisms

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg β-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

Tindak balas penurunan stereoselektif 1-benzil-3,3-dimetil-5-metilenapirolidina-2,4-dion menggunakan natrium borohidrat dengan logam klorida terpilih

1-benzyl-3,3-dimethyl-5-methylenepyrrolidine-2,4-dione is an intermediate product produced in the synthesis towards the natural bioactive compound, zopfiellamide A. This compound was synthesized via four main steps including dimethylations, addition with CuBr2, cyclization with benzylamine and reaction with formaldehyde. The corresponding intermediate was an α,s-unsaturated ketone having exo-alkene group, and it was subjected to reduction using sodium borohydride and selected metal chlorides. In this study, the effect and the hydride transfer mechanism of sodium borohydride-metal chlorides system in the reduction of 1-benzyl-3,3-dimethyl-5-methylenepyrrolidine-2,4-dione was investigated based on the stereochemical outcome of the product. Keywords: stereoselective, reduction, metal borohydride, exo-alkene

The electrical conductivities of polyimide and polyimide/Li triflate composites: An a.c. impedance study

Polymer electrolytes have been an essential area of research for many decades. One of the reasons was the need to find new electrolyte materials suitable for device applications like solid-state batteries, supercapacitors, fuel cells, etc. with enhanced characteristics. For more than 40 years, polyimide has been known as a super-engineering plastic due to its excellent thermal stability (Tg > 250 °C) and mechanical properties. Therefore, in an effort to develop new polymer electrolytes, polyimide as a polymer matrix was chosen. Composite films of the polymer doped with lithium salt, LiCF3SO3 was prepared. These PI based polymer electrolyte films were investigated by the alternating current (a.c.) impedance spectroscopy method in the temperature range from 300 K to 373 K. It was observed that conductivity increased with the increase of temperature and amount of doping salt. Alternatively, the activation energy (Ea) of the composite films decreased with the increase of the doping salt, LiCF3SO3.Polymer electrolytes have been an essential area of research for many decades. One of the reasons was the need to find new electrolyte materials suitable for device applications like solid-state batteries, supercapacitors, fuel cells, etc. with enhanced characteristics. For more than 40 years, polyimide has been known as a super-engineering plastic due to its excellent thermal stability (Tg > 250 °C) and mechanical properties. Therefore, in an effort to develop new polymer electrolytes, polyimide as a polymer matrix was chosen. Composite films of the polymer doped with lithium salt, LiCF3SO3 was prepared. These PI based polymer electrolyte films were investigated by the alternating current (a.c.) impedance spectroscopy method in the temperature range from 300 K to 373 K. It was observed that conductivity increased with the increase of temperature and amount of doping salt. Alternatively, the activation energy (Ea) of the composite films decreased with the increase of the doping salt, LiCF3SO3.

Ethyl 4-hy-droxy-1-methyl-5-oxo-2-phenyl-pyrrolidine-3-carboxyl-ate 1.25-hydrate.

The asymmetric unit of the title compound, C14H17NO4·1.25H2O, consists of four substituted pyrrolidone molecules (two pairs of enantiomers) and five water molecules. The five-membered rings each have an envelope conformation, with the C atom bonded to the ester group as the flap. The mean planes of the five-membered rings of the four pyrrolidone molecules make dihedral angles of 60.87 (5), 64.45 (5), 62.03 (5) and 65.79 (5)° with respect to the phenyl rings. In the crystal, the pyrrolidone and water molecules are connected through O—H⋯O hydrogen bonds, forming a layer parallel to the ab plane. The two-dimensional network is further stabilized by intermolecular C—H⋯O hydrogen bonds.