SciELO - Scientific Electronic Library Online

 
vol.61Synthesis of some benzimidazole-substituted benzotriazolesDissolution kinetics of Icel-Aydincik dolomite in hydrochloric acid author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Article

Indicators

Related links

  • On index processCited by Google
  • On index processSimilars in Google

Share


South African Journal of Chemistry

On-line version ISSN 1996-840X
Print version ISSN 0379-4350

S.Afr.j.chem. (Online) vol.61  Durban  2008

 

RESEARCH ARTICLE

 

A coloured spin trap which works as a pH sensor

 

 

Petre Ionita*

Institute of Physical Chemistry, 202 Spl. Independentei, Bucharest 060021, Romania

 

 


ABSTRACT

Nitration of 4-hydroxybenzaldehyde afforded 2,6-dinitro-4-hydroxybenzaldehyde 2, which in the presence of thionyl chloride is converted to 4-chloro-2,6-dinitrobenzaldehyde 3. This compound is very reactive towards nucleophiles, and reacts easily with methoxyamine, affording the intermediate 4-aminomethoxy-2,6-dinitrobenzaldehyde 4. Reaction of 4 with N-t-butyl-hydroxylamine led to a new spin trap of the nitrone type, namely 4-aminomethoxy-3,5-dinitrophenyl-1-f-butylnitrone 6. The spin-trapping capabilities of the new compound have been tested in a classical system, in which short-lived radicals were generated by irradiation. The new compound 6 contains an acidic proton with a pKa value of 7.8, and removal of this by a base induces a colour change, from yellow to green-blue. In a similar way, a new stable nitronyl-nitroxide radical 8 has been obtained from the intermediate 4.

Keywords: Synthesis; free radical; spin-trapping; pH sensor; nitrone


 

 

Full text available only in pdf format.

 

Acknowledgement

Financial support from GAR 45/2008 is acknowledged.

 

References

1 F.A. Villamena and J.L. Zweier, Antiox. Redox Sign., 2004, 6, 619-629.         [ Links ]

2 S.M. Chemaly, S. Afr. J. Chem., 1994, 47, 37-47.         [ Links ]

3 R. Ruggiero, A.E.H. Machado, W. Hoareau, C. Gardrat, A. Nourmamode, S. Grelier and A. Castellan, J. Braz. Chem. Soc., 2006, 17, 763-770.         [ Links ]

4 VE. Sahini, G. Ionita and P. Ionita, Acta Chim. Slovenica, 2000, 47, 111-119.         [ Links ]

5 P.J. Thornalley, Life Chem. Reports, 1986, 4, 57-112.         [ Links ]

6 E.G. Janzen and D.L. Haire, Advan. Free Rad. Chem., 1990, 1, 253-295.         [ Links ]

7 K. Stolze, N. Udilova, T. Rosenau, A. Hofinger and H. Nohl, Biochem. Pharm., 2003, 66, 1717-1726.         [ Links ]

8 A. Allouch, V Roubaud, R. Lauricella, J.C. Bouteiller and B. Tuccio, Org. Biomolec. Chem., 2003, 1, 593-598.         [ Links ]

9 R.A. Floyd, Ageing Cell, 2006, 5, 51-57.         [ Links ]

10 K. Hensley and R.A. Floyd, Arch. Biochem. Biophys., 2002, 397, 377-383.         [ Links ]

11 P. Ionita, Free Radie Res., 2006, 40, 59-65.         [ Links ]

12 P. Ionita, Lett. Org. Chem, 2008, 5, 42-46.         [ Links ]

13 T. Constantinescu, G. Ionita, I. Chiorascu and P. Ionita, Central Eur. J. Chem., 2003, 1, 465-476.         [ Links ]

14 I. Covaci, T. Constantinescu, M.T. Caproiu, F. Dumitrascu, C. Luca and A. T. Balaban, Rev. Roum. Chim., 1999, 44, 531-537.         [ Links ]

15 P. Ionita, M.T. Caproiu, A. Meghea, O. Maior, M. Rovinaru and G. Ionita, Polish J. Chem., 1999, 73, 1177-1183.         [ Links ]

16 C. Luca, P. Ionita, M.T. Caproiu, H. Caldararu and T. Constantinescu, Rev. Roum. Chim., 1998, 43, 221-224.         [ Links ]

17 http://epr.niehs.nih.gov/pest.html (accessed September 2007).         [ Links ]

 

 

Received 9 January 2008
Revised 21 July 2008
Accepted 10 October 2008

 

 

* E-mail: pionita@icf.ro

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License