Novel Short-Step Synthesis of Functionalized γ-Phenyl-β-hydroxybutenoates and their Cyclization to 4-Hydroxycoumarins via the N-Hydroxybenzotriazole Methodology

A novel method for the synthesis of functionalized 3-substituted 4-hydroxycoumarins is reported. C-Acylation compounds were derived from the reaction of the N-hydroxybenzotriazole ester of the functionalized acetyl salicylic acids and a variety of active methylene compounds and cyclized to the title compounds. The synthesis is simple and the compounds are produced in yields varying from 39 to 80%. The structure of the newly prepared C-acylation compounds was thoroughly studied through NMR spectroscopy for the first time in the literature