Aims & Objective:
In this work ZnO-nanorod (ZnO-NR) as reusable catalyst
promoted Strecker-type reaction of 2,4-dihydroxyacetophenone, isopropenylacetylene,
trimethylsilyl cyanide (TMSCN), primary amines and isocyanides at ambient temperature under
solvent-free conditions and produced α-amino nitriles benzofuran derivatives in high yields. These
synthesized compounds may have antioxidant ability.
Materials and Methods:
ZnO-NRs in these reactions were prepared according to reported article.
2,4-dihydroxyacetophenone 1 (2 mmol) and isopropenylacetylene 2 (2 mmol) were mixed and
stirred for 30 min in the presence of ZnO-NR (10 mol%) under solvent-free conditions at room
temperature. After 30 min, primary amine 3 (2 mmol) was added to the mixture gently and the
mixture was stirred for 15 min. After this time TMSCN 4 (2 mmol) was added to the mixture and
stirred for 15 min. After completion of the reaction, as indicated by TLC, isocyanides 5 was added
to mixture in the presence of catalyst.
Results:
In the first step of this research, the reaction of 2,4-dihydroxyacetophenone 1,
isopropenylacetylene 2, methyl amine 3a, trimethylsilyle cyanide 4 and tert-butyl isocyanides 5a
was used as a sample reaction to attain the best reaction conditions. The results showed this
reaction performed with catalyst and did not have any product without catalyst after 12 h.
Conclusion:
In conclusion, we investigate multicomponent reaction of 2,4-dihydroxyacetophenone
1, isopropenylacetylene 2, primary amines 3, trimethylsilyl cyanide 4 and isocyanides along with
ZnO-NRs as reusable catalyst at room temperature under solvent-free conditions which generates
α-amino nitrile benzofuran derivatives in high yields. The advantages of our method are high atom
economy, green reaction conditions, higher yield, shorter reaction times, and easy work-up, which
are in good agreement with some principles of green chemistry. The compounds 8c exhibit
excellent DPPH radical scavenging activity and FRAP compared to synthetic antioxidants BHT
and TBHQ.
Hydrotalcite as an Efficient and Reusable Catalyst for Acylation of Phenols, Amines and Thiols Under Solvent-free Conditions