CONCLUSIONS

1) The new synthetic procedure devised for (1) shows the following features:

• the two products (5) and (9) used in the macrocyclization step are easily prepared in a multigram scale, starting from cheap materials;

• the preparation of (9) from (5) occurs through four steps in almost quantitative overall yield;

• the final cyclization occurs under classical template conditions and (1) could be isolated in 45% yield.

2) The possibility of selective deprotection of (1) affords the bis-tosylamido (10) and the bis-benzyl (3) derivatives, which are versatiles building block for the preparation of macropolycyclic receptors, an example of which is (4).

3) Results of the extent of complexation show the great capability of these new receptors in dissolving solid ammonium salts and hydrochlorides of aminoacids methyl esters in organic low polar solvents. Under the same conditions, but using diaza-18-crown-6 (15) as ligand, values of the extent of complexation are, in any case, very low. Indeed it must be stressed that, in all these experiments, was used a solid salt/ligand ratio = 1.

REFERENCES

1) Anelli P. L., Montanari F., Quici S., Ciani G., Sironi A., J. Org. Chem., 53, 5292 (1988).

2) Bradshaw J. S., Krakowiak K. E., Izatt R. M. in "Aza-crown Macrocycles" Heterocyclic Compounds, Interscience Publ., J. Wiley, New-York, Vol. 51 (1993).

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