ISBN-13: 9783659787201 / Angielski / Miękka / 2015 / 284 str.
A new synthesis of 4-methyl-3-phenyl and 3-phenyl-4-styryl coumarins developed by condensing substituted o-hydroxyacetophenones and 2'-hydroxychalcones with phenyl acetic acid or its 4-methoxy derivative in the presence of DCC-DMSO 2'-Hydroxy- -cinnamylidene acetophenones undergo facile oxidative cyclisation to the corresponding 2-styryl chromone on treatment with potassium iodate-DMSO A new convenient method for the benzylation of chelated phenolic groups in various substrates developed by using benzyl chloride-acetone-anhydrous potassium carbonate with tetra-n-butylammonium iodide catalyst (quantitative yields) 2'-Benzyloxy- -cinnamylidene acetophenones were converted to their epoxides, which on treatment with BF3-etherate afforded the corresponding 3-styryl chromones 2'-Hydroxy- -cinnamylidene acetophenones gave the corresponding 3-hydroxy-2-styryl chromones on treatment with hydrogen peroxide- diethylamine in DMSO-dioxan In the 13C-NMR spectral studies of 2'-hydroxy- -cinnamylidene acetophenones the four olefinic carbons were assigned diagnostic and definite values."
• A new synthesis of 4-methyl-3-phenyl and 3-phenyl-4-styryl coumarins developed by condensing substituted o-hydroxyacetophenones and 2-hydroxychalcones with phenyl acetic acid or its 4-methoxy derivative in the presence of DCC-DMSO • 2-Hydroxy-ω-cinnamylidene acetophenones undergo facile oxidative cyclisation to the corresponding 2-styryl chromone on treatment with potassium iodate-DMSO • A new convenient method for the benzylation of chelated phenolic groups in various substrates developed by using benzyl chloride-acetone-anhydrous potassium carbonate with tetra-n-butylammonium iodide catalyst (quantitative yields) • 2-Benzyloxy-ω-cinnamylidene acetophenones were converted to their epoxides,which on treatment with BF3-etherate afforded the corresponding 3-styryl chromones • 2-Hydroxy-ω-cinnamylidene acetophenones gave the corresponding 3-hydroxy-2-styryl chromones on treatment with hydrogen peroxide- diethylamine in DMSO-dioxan • In the 13C-NMR spectral studies of 2-hydroxy-ω-cinnamylidene acetophenones the four olefinic carbons were assigned diagnostic and definite δ values.