1. Institute of Chemistry, University of Białystok, Piłsudskiego 11/4,
15-443 Białystok, Poland
2. Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224
Warsaw, Poland
3. Departamento
de Química, CINVESTAV-IPN, Apdo.
Postal 14-740, 07000 México,
D.F., Mexico