Syntheses and Reactions of 4′-[(ω-Bromoalkyl)oxy]-and 4′,4′′′-(Polymethylenedoxy)-bis Substituted Chalcones
Base catalyzed condensation of 4-hydroxyacetophenone (1) with several aldehydes resulted 4′-hydroxychalcones (2a-c). Reaction of α,ω -dibromoalkanes (3, n=2, 4 & 6) with (2a-c) in equimolar ratio resulted a mixture of 4′-[(ω-bromoalkyl)oxy]- substituted chalcones (4a-i) and 4′,4′′′-(polymethylenedioxy)-bis substituted chalcones (5a-i) separated by ethanol as soluble (4a-i) and insoluble (5a-i) products. Compounds (5a-i) were also synthesized by another route. Compound 1 on treatment with 3 in molar ratio 2:1 resulted 4′,4′′′-(polymethylenedioxy)-diacetophenone (4#a-c) which on base catalyzed condensation gave compounds (5a-i). Reaction of 4d with substituted phenols and thiophenols gave corresponding phenoxy and thiophenoxy substituted chalcones (6a-f) where as compounds 5a, 5b, 5d, 5h and 5e on treatment with hydrazine hydrate furnished corresponding bis-2-pyrazolines (7a-e). The structures of all synthesized compounds were confirmed on the basis of analytical and spectral data.