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Paper | Regular issue | Vol 45, No. 1, 1997, pp.71-75
Published online, 1st January, 1970
DOI: 10.3987/COM-96-7611
Synthesis of Hydroxyflavanones from Substituted Acetophenones and Benzaldehydes in the Presence of Silica Gel, Boric Acid and Piperidine

Wei Han Zhang, Wing Lai Chan,* Yuan Hua Lin, Yau Shan Szeto, Yong Cheng Lin, and Chi Hung Yeung

*Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom Kowloon, China


Direct synthesis of hydroxyflavanones from appropriately substituted acetophenones and benzaldehydes was achieved in the presence of boric acid, silica gel and piperidine. The formation of flavanones presumably involved the reaction between the acetophenone-boric acid complex (1) and the piperidinoaldehyde adduct (2) to yield the piperidino ketone (3). Elimination of piperidine from 3 gave the chalcone (4), which cyclized to flavanone (5).