Reaction of 3-bromobenzyl and 3-bromoacetyl coumarin with phosphites. Synthesis of some new phosphonates and phosphates in the coumarin series

Article abstract of DOI:10.1016/S0040-4020(98)00892-8

The reaction of 3-(1-bromobenzyl)coumarin 3 with trialkyl phosphites afforded in good yields the corresponding dialkyl phosphonates 5, the Arbuzov reaction products. The interaction of trialkyl phosphites with 3-(ω- bromoacetyl)coumarin 4 gave the corresponding dialkyl vinylphosphates 8 as the only isolated products, whereas dialkyl phosphites reacted with 4 under phase transfer catalysis and gave vinylphosphates 8 or dialkyl 1,2-epoxy- ethylphosphonates 9. The β-oxo-phosphonates 7 were obtained from the reaction of hydrazone-derivative 10 with trialkyl phosphites and the subsequent hydrolysis of the dialkyl β-hydrazono-phosphonates 11 thus formed.