A rational approach for the design and synthesis of 1-acetyl-3,5-diaryl-4,5-dihydro(1H)pyrazoles as a new class of potential non-purine xanthine oxidase inhibitors

Montmorillonite Clay-Promoted, Solvent-Free Cross-Aldol Condensations under Focused Microwave Irradiation

“…The reaction was not sensitive to steric hindrance in the aldehyde, since it tolerates well the presence of ortho substituents (compare the yields in entries 4-5, 7-9 and 15-16). Generally speaking, the substituents at the aromatic ring of the aldehyde component did not have a significant influence in the yield, but it is remarkable that some of the best results corresponded to reactions with methoxybenzaldehyde derivatives (entries 2,11,15,20), in spite of the fact that the electron-releasing nature of the methoxy substituent should lead to a lower reactivity as electrophiles. Since the catalytic affect of the clay can be attributed to the Lewis acid activity of its metallic centers (Scheme 2a), the good reactivity of the methoxy derivatives can be explained by accepting that coordination of the oxygen atom in the OMe group with cationic centers in the clay attenuates its electron-releasing effect (Scheme 2b) [40].…”

“…These properties include antineoplastic [5][6][7], antimalarial [8], antiviral (HIV) [9,10], antibacterial [4,11,12], antioxidant [12] and anti-inflammatory [4,13] activities, among others. These compounds are also flexible scaffolds for the construction of five-and six-membered rings or their subsequent elaboration into polycyclic systems [14,15]. Chalcones are traditionally accessed by cross-aldol condensations of aryl methyl ketones and aromatic aldehydes in the presence of alkali [16][17][18], a reaction that requires the use of an organic solvent and a highly polluting alkaline base and in most cases needs to be followed by purification by column chromatography, leading OPEN ACCESS again to waste generation in the form of volatile organic solvents and discarded chromatographic stationary phases.…”

Synthesis of novel Naphthalene COX inhibitors for anti-inflammatory activity

“…Naphthalene is important aryl ring in many active compounds such as anti-inflammatory , anti-bacterial , anti-microbial and anti-cancer . In recent trends , heterocycles plays a major role in drug synthesis (Joan.F et al, 2001, Kunal et al, 2011, Lake et al, 2011and Sharma et al, 2011 . Pyrazole derivatives have been the subject of substantial attention by synthetic and medicinal chemists because of the role of this heteroaromatic ring in many biological activities such as anticancer , antiviral , antiinflammatory , antifungal , antimicrobial , antihistaminic, antiplatelet and analgesic activities (Chauhan et al, 2011) In particular some of naphthalene derivatives were in depth investigated as nonsteroidal anti inflammatory drugs (NSAIDs) .…”

4,5-Dihydro-1H-pyrazole: an indispensable scaffold

“…With an incentive to improve the existing activities several modifications are being done on this scaffold and many of which are proved to be successful. The most extensive modification in 2-pyrazoline was the substitution of diaryl/hetroaryl groups mainly at -3, 5 position 40 since it was observed that heterocycles with functional groups greatly increased solubility in water 41,42 . The aryl substituted pyrazolines were detected to combine the activity of pyrazoline moiety with activity of heteroarene thus proving their usefulness 43 .…”