98498-11-4Relevant articles and documents
Aromatic Benzhydrylation: Part I - Synthesis of Triarylmethane Group of Isoflavonoids through Benzhydrylation of 2,4-Dihydroxydesoxybenzoin and 5,7-Dihydroxy-2-methylisoflavone
Jain, A. C.,Arya, P.,Gupta, S. M.
, p. 383 - 388 (2007/10/02)
Malanervin (1) analogues in 2-methylisoflavones have been synthesized in two ways.The first route involves benzhydrylation of 2,4-dihydroxydesoxybenzoin (2) with diphenylcarbinol (3) in the presence of BF3-Et2O and dioxan yielding a mixture of three C-benzhydrylated products (4a, 5a, 6a) among which 5-C-derivative (6a) is the major product (27 percent) followed by 3-C-derivative (5a; 20 percent) and 3,5-di-C-derivative (4a; 10 percent).These products are converted into 2-methylisoflavone derivatives (7a, 7b and 7c respectively) by Perkin reaction with Ac2O-NaOAc.Location of benzhydryl group in desoxybenzoins has been made on the basis of PMR spectra of the hydroxy compounds and their methyl ethers (partial/complete). 5-C-Benzhydrylated desoxybenzoin (6a) is also converted into the corresponding 3-phenyl-4-hydroxycoumarin derivative (9).In the second route, the synthesis of 5,7-dihydroxy-2-methylisoflavone derivatives has been carried out by benzhydrylation at the isoflavone stage.Thus the reaction of 5,7-dihydroxy-2-methylisoflavone (10) with diphenylcarbinol has been carried out in the same way as in the case of 2, affording 6-C-(13), 8-C-(12) and 6,8-di-C-(11) benzhydrylated derivatives in decreasing amounts.Location of benzhydryl units in 6- and 8-positions has been made by studying the effect of acetylation on their aromatic protons.
