| Abstrakt: |
The 4H-pyranopyrazoles are an important class of heterocyclic compounds due to their pharmacological and biological properties.[1] Compounds bearing the pyranopyrazole system have been found to have various biological activities, for instance antimicrobial,[2] anti-cancer[3] and anti-inflammatory properties,[4] analgesic activity,[5] activity as hypoglycemic,[3] hypotensive,[6] and vasodilatory agents,[7] inhibitory activity toward human Chk1 kinase,[8] molluscicidal activity[9] and antifungal properties.[10] In addition, such heterocycles bearing 4H-pyran units are important precursors in the synthesis of a large family of medicinally useful compounds.[11] The use of natural catalysts in organic synthesis offers many advantages in sustainable chemistry because the catalysts are inexpensive, readily available, non-toxic and show high selectivity. In summary, a catalyst derived from snail shells proved to be extremely effective in the four-component synthesis of pyranopyrazole derivatives I via i the one-pot reaction of aromatic aldehydes, ethyl acetoacetate, hydrazine, and malononitrile. Maleki, H. Eshghi, M. Barghamadi, N. Nasiri, A. Khojastehnezhad, S. S. Ashrafi and O. Pourshiani, Res. Chem. Intermed., 42, 3071 (2016). [Extracted from the article] |
