5. Conclusion
A series of 21 products from the coupling of three piperazine derivatives with seven 3-(thiophen-2-yl) acry-lamide amino acids was designed based on the concept of Nishikawa et al. [Figure 1, structure A]. Our novel de-sign depends on the replacement of the aliphatic chain
with the known biologically active amino acid segments. The obtained pharmacological screening results, showed that the presence of the amino acid residues in the prod-ucts as linkers between 2-thiopheneacrylic acid and pi-perazine derivatives [Figure 1, structure B], enhance their anti-allergy activity and has no effect on increasing their anti-inflammatory one. All tested products manifested highly LD50 values, so they are considered to be of high safety margins.