News Update on Phenyl: September 2021


Selective nigral toxicity after systemic administration of 1-methyl-4-phenyl-1,2,5,6-tetrahydropyrine (MPTP) in the squirrel monkey

1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) was administered via the intraperitoneal route to squirrel monkeys. Akinesia, rigidity and hypophonia were seen after repeated doses of 2 mg/kg. Postural tremor was present in one animal. Neuropathologic examination revealed cell loss restricted to the zona compacta of the substantia nigra. MPTP appears effective in producing an animal model for Parkinson’s disease in the squirell monkey, and may be one of themore selective neurotoxins described to date. [1]

Synthesis and use of bisoxazolinyl-phenyl pincers

The bisoxazolinyl-phenyl (Phebox) ligand is an example of an N,C,N tridentate (pincer type) ligand, which has a central carbon–metal covalent bond and two oxazolines. In this tutorial review, synthetic methods to prepare bisoxazolinyl-phenyl derivatives and their transition-metal complexes including rhodium, iridium, platinum, palladium, nickel and copper, are summarized. In addition, several applications to homogeneous and asymmetric catalysis with chiral bisoxazolinyl-phenyl metal complexes have been reviewed. [2]

Somatic mutation and the maturation of immune response to 2-phenyl oxazolone

Studies on the development of the immune response suggest that the repertoire of expressed antibody specificities is strongly influenced by antigen (reviewed in ref. 1). One way in which this influence is manifested is by a progressive increase in the affinity of antibody for antigen with time after immunization. This phenomenon, termed the ‘maturation’ of the immune response, must be due to a change in the structure of the antibody being synthesized. However, the precise nature of the changes involved and the genetic mechanisms used to produce them have not been clearly defined. We have now investigated the maturation of the immune response to the hapten 2-phenyloxazolone by mRNA sequencing of specific hybridomas. We conclude that somatic mutation of germ-line encoded genes plays a major role in the generation of antibodies with increased affinity for oxazolone with time after immunization. [3]

Analysis of Amantadine Hydrochloride-Phenyl Isothiocyanate Complex in Bulk and Pharmaceutical Dosage Forms by RP HPLC-PDA Method

Aim: The aim of the present investigation was to perform the precolumn derivatization of Amantadine Hydrochloride (AMT) with phenylisothiocyanate and to develop a RP-HPLC-PDA method for the quantification of Amantadine Hydrochloride-phenylisothiocyanate (AMT-PITC) complex in bulk and dosage forms which is rapid, sensitive and economical.
Study Design: Method development and Validation study.
Methodology: A Phenomenex C18 RP column of 250 x 4.6mm dimensions and 5µm particle size with mobile phase containing water and acetonitrile (40:60% v/v) was used at isocratic mode binary pump and eluent was monitored at 273nm.
Results & Discussion: The retention time of AMT-PITC complex was 6.3 min. The developed method showed a good linearity in the concentration range of 10-50µg/mL with a correlation coefficient >0.998. The recoveries ranged between 95-105% with a Relative Standard Deviation of (RSD) < 2%.
Conclusion: The developed method was validated as per ICH guidelines and successfully used for quantification of AMT by derivatization with PITC. The method was found to be rapid, specific and accurate. [4]

Comparative Study of Benzyl and Phenyl Compounds Chemical Structure Effects on the Inhibition of Methane Production by Digested Pig Manure Methanogens
Aims: The present paper aims to study the effect of aromatic structure on the inhibition of biogas production and more specifically the comparative study of benzyl and phenyl compounds chemical structure effects on the inhibition of methane production by digested pig manure methanogens. The objective of this study was also to examine the structure-toxicity relationships of aromatic compounds to acetoclastic methanogens.
Study Design: Anaerobic digestion of pig manure, anaerobic toxicity essay, comparison of benzyl and phenyl compounds structure effects on the inhibition of methane gas biosynthesis.

Place and Duration of Study: Department of Chemistry, University of Kinshasa (DR Congo), between September 2011 and May 2012.
Methodology: The toxicity to acetoclastic methanogenic bacteria was performed with the standard method of serum bottles; digested pig manure was utilized as inoculums and acetate as substrate. The methane gas volume produced was measured by serum bottles liquid displacement systems (Mariotte flask system).
Results: The obtained results indicate exist between the chemical structure of benzyl and phenyl compounds and their inhibitory effects on biosynthesis of methane by methanogenic bacteria. According to these results, α-chlorotoluene and bromobenzene with 0.61 and 2.90 mg/l IC50 values, respectively, are the most toxic compounds, while phenol and benzyl alcohol with IC50 values of 1248.90 and 2391.37 are less toxic.
Comparing the phenyl and benzyl compounds with the same substituents (Cl, Br, H, OH), their behavior was diverse. The benzyl chloride is more toxic than phenyl chloride and benzyl bromide is less toxic than phenyl bromide. Otherwise, benzyl alcohol is less toxic than phenol. A significant correlation between the toxicity of phenyl compounds and their hydrophobicity (R2 = 0.911). But any correlation was not found for benzyl compounds.
Conclusion: The obtained results indicate that relationships exist between the chemical structure of benzyl and phenyl compounds and their inhibitory effects on the production of methane by methanogenic archaea. The behavior of phenyl and benzyl are different in inhibition of methane production by the methanogens because their chemical structures are not identic. [5]

[1] Langston, J.W., Forno, L.S., Rebert, C.S. and Irwin, I., 1984. Selective nigral toxicity after systemic administration of 1-methyl-4-phenyl-1, 2, 5, 6-tetrahydropyrine (MPTP) in the squirrel monkey. Brain research, 292(2), pp.390-394.

[2] Nishiyama, H., 2007. Synthesis and use of bisoxazolinyl-phenyl pincers. Chemical Society Reviews, 36(7), pp.1133-1141.

[3] Griffiths, G.M., Berek, C., Kaartinen, M. and Milstein, C., 1984. Somatic mutation and the maturation of immune response to 2-phenyl oxazolone. Nature, 312(5991), pp.271-275.

[4] Vemuri, S.K., Krishna, N.R., Mohammad, M.J. and Nalluri, B.N., 2014. Analysis of amantadine hydrochloride-phenyl isothiocyanate complex in bulk and pharmaceutical dosage forms by RP HPLC-PDA method. Journal of Pharmaceutical Research International, pp.278-288.

[5] Kayembe, K., Basosila, L., Mpiana, P.T., Sikulisimwa, P.C. and Mbuyu, K., 2013. Comparative study of benzyl and phenyl compounds chemical structure effects on the inhibition of methane production by digested pig manure methanogens. International Research Journal of Pure and Applied Chemistry, pp.48-58.

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