Biomedical Engineering – From Theory to Applications

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Biomedical Engineering – From Theory to Applications
a. they are easy to prepare either via the Adler route (Adler et al., 1976) or by microvawe
(MW) irradiation
b. the phenolic hydroxy group is a suitable site on which to build a different substituent
(Milgrom LR, 1983)
c. the 4-methoxycarbonyl side-chains of the other meso-substituents may be de-esterified
to convert a hydrophobic porphyrin into a hydrophilic one.
3.4.2 Synthesis by microwave irradiation
Microwave-assisted procedure is now a valid method to synthesize various type of
compounds, including porphyrins and related structures, with significant advantages, from
eco-friendliness to fastness and selectivity (Loupi et al., 2001). Since the first successful
attempt for the meso-5,10,15,20 tetraphenylporphyrin (Petit et al., 1992), a wide range of
compounds were obtained using either professional or domestic microwave ovens. The
metalloporphyrins can also be obtained via MW methods (Mark et al., 2005).
Microwave-assisted procedures have become increasingly important in chemical synthesis
in the last two decades due to several already proved important advantages over
conventional heating pathways (table 4).
The position of the microwave irradiation stage in preliminary evaluation- synthetic processpurification-
analysis chain is just by replacing classical Rothemund method with no
additional operations (Fig. 9.)
Fig. 9. Synthesis strategy for obtaining porphyrinic compounds including both classical and
MW irradiation methods