The vilsmeier-haack reaction - III Cyclization of hydrazones to pyrazoles

Synthesis of Some New 2-(3-Aryl-1-phenyl-4-pyrazolyl)-benzoxazoles Using Hypervalent Iodine Mediated Oxidative Cyclization of Schiff’s Bases

“…In order to study the scope of this approach, other Schiff's bases 3aa-3be, available by the condensation of 1a or 1b with different formylpyrazoles 2a-e, were subjected to oxidative cyclization using 1.1 equivalents of IBD in methanol. The reaction, indeed, afforded the desired benzoxazole derivatives 4aa-4be in yields ranging from 55% to 88% (Scheme 2, The formylpyrazoles 2a-e needed in this study were prepared by Vilsmeier-Haack reaction of acetophenone phenylhydrazones (Scheme 3) [6]. The formylpyrazoles 2a and 2e are known compounds [6] and were identified by comparison of their melting points with those reported in the literature.…”

“…The reaction, indeed, afforded the desired benzoxazole derivatives 4aa-4be in yields ranging from 55% to 88% (Scheme 2, The formylpyrazoles 2a-e needed in this study were prepared by Vilsmeier-Haack reaction of acetophenone phenylhydrazones (Scheme 3) [6]. The formylpyrazoles 2a and 2e are known compounds [6] and were identified by comparison of their melting points with those reported in the literature. The products 2b-2d are new compounds and were characterized by their spectral data.…”

Synthesis, Characterization and Docking Studies of Some Novel Dihydropyridine Derivatives

“…[29] General procedure for synthesis of 9-(3- C(73.06%), H(6.13%), Br(6.74%) N (7.99%), O (6.08%). ºC for 24 h. The MIC was the lowest concentration of the tested compound that yields no visible growth (turbidity) on the plate.…”

Synthesis and antimicrobial activity of some new 1,2-bis-[1,3-thiazolidin-3-yl]ethane derivatives

“…The antimicrobial activity was performed at the Regional Center for Mycology and Biotechnology (Al-Azhar University, Cairo, Egypt). α-Bromo ketones 11a,b [32], and 11c [33] and pyrazole-4-carboxaldehyde 6 [34] were prepared according to procedures reported in the literature.…”